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Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. PLANTATION ESTABLISHMENT FOLLOWING CHE:MICAL SITE PREPARATION Wlffi TRICLOPYR AND PLANTATION RELEASE WITH TRICLOPYR-GLY PHOSATE HERBICIDE l\:IIXTURES by Joseph L Ladouceur @ A Thesis Submitted in Partial Fulfilment of the Requirements for the Degree of Master of Science in Forestry Faculty of Forestry Lakehead University Apri11996 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1+1 National Ubrary Bibliotheque nationale of Canada du Canada Acquisitions and Acquisitions et Bibliographic Services services bibliographiques 395 Wellington Street 395, rue Wellington Ottawa ON K1 A ON4 Ottawa ON K1 A ON4 Canada Canada Your 11/e Votnr refrlnlnctl Our 11/e Notre refrinlnt:tl The author has granted a non- L' auteur a accorde une licence non exclusive licence allowing the exclusive permettant aI a National Library of Canada to Bibliotheque nationale du Canada de reproduce, loan, distnbute or sell reproduire, preter, d.istribuer ou copies of this thesis in microform, vendre des copies de cette these sous paper or electronic formats. Ia forme de microfiche/film, de reproduction sur papier ou sur format electronique. The author retains ownership of the L' auteur conserve Ia propriete du copyright in this thesis. Neither the droit d'auteur qui protege cette these. thesis nor substantial extracts from it Ni Ia these ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent etre imprimes reproduced without the author's ou autrement reproduits sans son permission. autorisation. 0-612-33403-1 Canada Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Thesis Title: Plantation establishment following chemical site preparation with triclopyr and plantation release with triclopyr-glyphosate herbicide mixtures. Name of Candidate: Joseph L. Ladouceur Degree: Master of Science in Forestry Date: 1996 This thesis has been prepared under my supervision and the candidate has complied with the regulations for the degree: Supennsor Dare Crunnn~ Dare Graduare Studies In presenting this thesis in partial fulfilment of the requirements for the Masrer of Science in Forestry Degree at Lakehead University, Thunder Bay, I agree that the university shall make it available for inspection. This thesis is made available by my authority solely for the purpose of privare study and research and may not be copied or reproduced in whole or in part (except as permitted by Copyright laws) without my writren authority. Joseph L. Ladouceur Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. iii ABSTRACT Ladouceur, Joseph L. 1996. Plantation establishment following chemical site preparation with triclopyr and plantation release with triclopyr-glyphosate herbicide mixtures. 97 pp. + appendices. Key Words: Boreal, jack pine, chemical site r r ~ crop tree release, non-crop ~ ~ vegetation index, herbicide, herbicide mixtures, triclopyr ester, glyphosate. Two field studies were conducted to evaluate the use of Release™ (triclopyr ester) for chemical site preparation and its use in mixture with glyphosate for jack pine (Pinus banksiana Lamb.) plantation release. The objective oft he first field study was to determine the minimum time interval between chemical site preparation with 3.84 kg aelha of triclopyr ester and planting containerized jack pine seedHngs. In July 1992, a randomized complete block design was established on a well- drained, coarse sandy outwash, west ofThunder Bay, Ontario. The herbicide was applied on July 20 ~ 1992, and seedlings were planted into treated and untreated plotS 1, 7, 28, 56 and 84 days after application. Seedling responses were assessed one year later. Seedlings planted 1, 7 and 28 days after the herbicide application had consistently poorer survival, physical condition and volume growth than the controls. Needle length of seedlings planted 1 day after treatment were shorter in the treated plots than in the control plots. A minimum time interval of at least one month between the application of3.84 kg aelha oftriclopyr ester and the planting ofj ack pine is recommended. The objectives of the second field study were to: 1) test the efficacy of a variety tank mixtures ofReleaseTM, Touchdown 480™ (glyphosate) and VisionTM (glyphosate) herbicides in controlling common boreal forest weed species; and 2) document the growth response, if any, of planted containerized jack pine seerllings. In August 1992, a randomized complete block design was established on an upland mixedwood clearcut west of Thunder Bay, Ontario. Twenty-one herbicide treatments, one manually weeded control and one untreated control were compared. One year after treatment ~ non-crop vegetation andj ack pine seedling survival, physical n ~ needle length and volume growth were greatly affected by the composition oft he herbicides when applied alone and in mixtures. In general, herbicide mixtures offered no advantage over herbicides applied alone for jack pine plantation release because of the detrimental effects induced on the crop. VisionT M applied alone at 2:14 kg aelha resulted in the best control of non-crop vegetation and in the least damage to the crop trees. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. iv CONTENTS Page ABSTRACf Ul TABLES vi FIGURES vii ACKNOWLEDGEMENT Vlll INTRODUCTION RESEARCH OBJECTIVES 4 LITERATIJRE REVIEW ECOLOGICAL DISTIJRBANCE AND SILV ICULTIJRE 6 CONCEPTS OF 'COMPEL II ION' 'Competition' Defined 6 Interference and Interaction 7 Positive Interference 8 Negative Interference 8 Intraspecific and Interspecific Competition 10 RESPONSE OF CONIFERS TO COMPETING VEGETATION 11 Competition Below Ground for Available Water and Nutrients 11 Competition Above Grotmd for Available Light 14 The Capture and Occupation of Growing Space 16 Competition Thresholds 19 RESPONSE OF CONIFERS TO RELEASE FROM COMPETING VEGETATION 20 JACK PINE AND COMPETING VEGETATION Jack Pine Response to Interspecific Competition 23 Jack Pine Response to Release from Interspecific Competition 24 TRICLOPYR AND GLY PHOSATE.HERBICIDES A Profile ofReleaseTN Herbicide 25 A Profile of VisionT N Herbicide 26 A Profile of Touchdown 48QTN Herbicide 27 SUSCEPTIBILITY OF NON-CROP VEGETATION TO TRICLOPYR ESTER AND GLY PHOSATE 28 Efficacy ofTriclopyr Ester 29 Efficacy ofGlyphosate 29 SUSCEPTIBILITY OF CONIFER CROP TREES TO TRICLOPYR ESTER AND GLY PHOSATE 30 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. v Contents contiDued. Page MINIMUM TIME INTER.VA LS BETWEEN CHEMICAL SITE PREPARATION WITH TRICLOPYR ESTER AND PLANTATION ESTABliSHMENT 33 TilE USE OF HERBICIDE MIX1URES 34 Triclopyr Ester and Glyphosate Mixtures 35 Field Study ##1: MiDimum TUDe IDterval Betweea Chemical Site Preparation with Tridopyr Ester aDd Planting Jack Pine Container Stock MEIHODOLOGY 36 RESULTS 41 DISCUSSION 47 CONCLUSIONS AND RECOMMENDATIONS 51 Field Study ##2: Efficacy ofTridopyr-Giypbosate Herbicide Tank MixtuRs for Jack Pine Release MEIHODOLOGY 53 RESULTS 61 DISCUSSION 79 CONCLUSIONS AND RECOMMENDATIONS 83 I.II'ERATURE CITED 85 APPENDIX A Detailed Information with Respect to the Use ofReleaseTM (friclopyr Ester) 98 B Detailed Information with Respect to the Use of VisionT M (Glyphosate) 104 c Detailed Reference Information with Respect to Experimental Touchdown 480TM (Glyphosate). 108 D Location ofField Study #1 112 E Field Study #1: Results of the Analysis ofVariance 115 F Location ofField Study #2 117 G Field Study #2: Results of the Analysis ofVa riance for the Vegetation Indices 121 H Field Study #2: Mean Vegetation Indices for Each of the Vegetation Types, Important Individual Species and the Conesponding Results ofMultiple Range Testing 123 I Field Study #2: Mean Vegetation Indices Grouped Into Herbicide Rate Concentration Gradient 137 J Field Study #2: Results oft he Analysis of Variance for the Jack Pine Crop Tree Responses 140 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. vi Contents continued. Page K Field Study #2: Jack Pine Seedling Responses One Year After Each oft he Twenty-Three 142 L Field Study #2: Mean Jack Pine Seedling Responses Grouped Into Herbicide Rate Concentration 147 Gradient TABLES Table Page 1 A S1lllliiWY of possible interactions between plants and the interference classification associated 7 with each. 2 References, by conifer species. documenting survival and/or growth benefits resulting from the control of non-crop vegetation. 22 3 A comparison of the suscept1bili1y of selected boreal forest vegetative species to Releasetw and VisionTN. 31 4 Observed minimum time intervals between chemical site preparation with triclopyr ester and the planting of conifer seedlings. 34 5 The expected means squares (EMS) and associated degrees off reedom for the linear model; including the test statistics and reference distnbutions for the null hypothesis (Field study #1). 39 6 Codes used to describe the physical condition of the jack pine seedlings based on visual assessment. 40 7 The twenty-three release treatments (controls and mixtures). 55 8 The expected means squares (EMS) and associated degrees off reedom for the linear model; including the test statistics and reference distnbutioos for the null hypothesis (Field study #2). 51 9 A listing of all shrub species tallied on the site. 62 10 A listing of all herb species tallied on the site. 62 11 The twenty-three treatments ranked according to mean total vegetation index (in increasing order) and the corresponding mean vegetation indices of the remaining vegetation types; one year after each treatment 63 12 The twenty-three treatments ranked according to mean percent survival (m decreasing order) and the coue5p1 mcfing mean physical condition code. mean needle leogth and mean volume increm.entlba; one year after each treatment. 71 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. vll FIGURES 1 The decision making process for detenniniog an appropriate herbicide for application. 3 2 A schematic of the occupation of space by vegetation on an even-aged boreal forest conifer site fullowiog disturbance.. 18 3 Three possible volume growth responses of radiata pine to removal ofn on-crop vegetation. 21 4 The randomized complete block design established in the boreal forest for field study #1, approximately 60 kilometres west ofThunder Bay, Ontario. 37 5 The mean percent survival rates of the jack pine n~ for each herbicide and planting time treatment after one growing season. 42 6 The mean physical condition codes of the jack pine n~ for each herbicide and planting time treatment after one growing season. 44 7 The mean needle lengths (m mm) of the jack pine n~ for each herbicide and planting time treatment after one growing season. 45 8 The mean volume incrementslba + 400 cmJ of the jack pine n~ for each herbicide and planting time treatment after one growing season. 46 9 The randomized complete block design established in the boreal forest for field study #2. approximately 50 kilometres west ofThunder Bay, Ontario. 54 10 Conversion ofherbicide rates from 1/ha to kg aelba. 56 11 The mean total vegetation indices grouped by herbicide rate (0, 1-3 and 4-6 1/ha). 65 12 The mean shrub vegetation indices grouped by herbicide rate (0, 1-3 and 4-61/ha). 66 13 The mean herb vegetation indices grouped by herbicide rate (0, 1-3 and 4-61/ha). 67 14 The mean graminoid vegetation indices grouped by herbicide rate (0, 1-3 and 4-61/ha). 68 15 The mean bracken fern vegetation indices grouped by herbicide rate (0, 1-3 and 4-6 1/ha). 69 16 The mean percent seedling survival grouped by herbicide rate (0, 1-3 and 4-6 1/ha). 72 17 The mean seedling physical condition codes grouped by herbicide rate (0, 1-3 and 4-61/ha). 73 18 The mean seedling needle lengths (in mm) grouped by herbicide rate (0, 1-3 and 4-6 1/ha). 75 19 The mean seedling volume incrementslha (m cml) grouped by herbicide rate (0, 1-3 and 4-61/ha). 76 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. viii ACKNOWLEDGEMENT The author wishes to thank Tip Haagsma, Dan Tai and Brian Ure, ofDowElanco Canada Inc., for the initial funding for these field studies; and Roy Maki, of Monsanto Company, for the additional and much needed financial support. The author also wishes to thank Eli Partika, of Zeneca Agro Research and Development, for the technical information regarding Touchdown 480 TM herbicide. Special thanks to the supervising committee: Professor Robert J. Day, Mr. Laird Van Damme R.P. F. and Dr. Robert Farmer, ofLakehead University; and Dr. Dean Gjerstad of Auburn University. Without the constructive criticism and invaluable technical assistance from these professionals, this thesis could not have been completed. The author acknowledges the following people who facilitated both directly and indirectly with this thesis: Neil Stocker, Rachel Day, Gordon Whitmore, Arnold Rudy, Kevin Shaw, Vivian Piercey, Garth Thoroughgood and, last but not least, Karen Kirton. Finally, thanks are due to Mr. and Mrs. Ladouceur for their continued support of my endeavours. Joseph Ladouceur Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. INTRODUCTION Non-crop vegetation (brush and herbaceous plants) may compete with conifer crop species for growing space, light, soil moisture and nutrients. This can result in: 1) failures or delays in the regeneration and establishment ofc rop trees; 2) losses in future harvest volumes (Deloitte & Touche, 1992) and; 3) higher variability in the size of individual trees (Brand & Weetman, 1986). The major objective of vegetation control with herbicides in commercial forestry is to stimulate the establishment and growth of desirable timber species (Deloitte & Touche, 1992). Herbicides are among the most economical silvicultural tools used to control non-crop vegetation in North American forestry operations. They are rarely used to kill non-crop vegetation outright, but to suppress it for a short period of time to provide crop trees with favourable establishment and growing conditions (Malik & Vanden Born, 1986). Often, the control of one or more species will allow other new species to invade the etivironment of the crop tree [Day, (pers. comm., 1993)]. Vegetation control treatments more often result in a partial or temporary reduction in the overall vegetation biomass coupled with a shift in the dominant non-crop vegetative species (Morris eta/. 1993). In Ontario, the mandate of the Vegetation Management Alternatives Program (VMAP) is to develop approaches to managing non-crop forest vegetation that will reduce the dependence on herbicides. Unfortunately, adequate alternatives do not currently exist for most of Ontario's forest conditions (Wagner eta/. 1993). Buse eta/. (1994) present the results of a recent province wide swvey that illustrates the magnitude of herbicide use by the forest industry and the Ontario Ministiy of Natural Resources (OMNR) (over a three year period; 1990-1992). On average, 15% of site preparation and 90°/o of forest tending was accomplished with herbicides. Herbicides can be viewed as having specific "silvicultural niches". A silvicultural niche is defined by the vegetation management objective(s ), the type ofs ilvicultural activity (site preparation, release or cleaning, precommercial thinning) and the specific site conditions (time ofy ear, vegetation types, soil types, topography, etc.). For a herbicide 'to fif in a specific niche, it must be biologically, logistically and economically efficient to coincide with the criteria and conditions associated with the niche. In Canada, there are only a few herbicides registered that are available for use in vegetation management. Each of these herbicides have specific silvicultural niches, which are defined by a variety of product attnbutes, including: the types ofv egetation controlled; the method of herbicide Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2 application; the time of application; the herbicide mode of action; and the silvicultural activity for which the herbicide can be applied. The following are three common silvicultural activities, where the opportunity for vegetation control with herbicides exists. 1) Site preparation is the control of non-crop vegetation on recently harvested areas prior to seeding or planting, to provide a suitable environment for planting or seeding, and to ensme the crop seexDings sufficient time to become established before the regrowth ofu ndesirable species (Deloitte & Touche, 1992; Stewart, 1987). The herbicide chosen must, among other things, be able to control the undesirable vegetation effectively, must not have residual adverse effects on the future planted crop trees and could be applied concurrent with mechanical site preparation to reduce costs. 2) Release or cleaning is the control of non-crop vegetation that is overtopping, surrounding or threatening crop trees, to permit a 'free-growing' condition that increases survival, vigour and growth of desired tree species (Deloitte & Touche, 1992; Stewart, 1987). The herbicide chosen must, among other things, not have adverse effects on planted crop trees and must be easily applied at the appropriate time for effective vegetation control. 3) Precommercial thinning is the removal of poorly formed, slow growing, diseased or excess unmerchantable trees of desirable species, between 5 and 15 years after establishment to control spacing (Deloitte & Touche, 1992). The herbicide chosen must, among other things, be economically applied (e.g. inexpensive use ofEZJECTw relative to hack and squirt or girdling techniques) and must not translocate through grafted root systems or indirectly cause damage to crop trees (e.g. the introduction of pathogens through dead stems). An additional, relatively uncommon silviculture activity for which herbicides are being tested is herbicide application concurrent with timber harvest with a feller-buncher-sprayer (Vidrine, 1993 ). Figure 1 summarizes the general decision making process of determining an appropriate herbicide for a specific silvicultural niche in accordance with the objective(s) , silvicultural activity and specific site conditions. Glyphosate and lriclopyr ester are two of only five commonly used herbicides registered for vegetation control in Canadian forest management (the other three being hexazinone, 2,4-D and simazine) (Campbell, 1991). Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 3 Glyphosate is a broad spectrum non-selective herbicide that is effective in the control of many Wldesirable woody and herbaceous plants and grasses in the boreal forest (Canadian Pulp & Paper Association (CPPA), 1994). However, it does not consistently control maple (Acer L. spp.) (Pitt eta/. 1992). Glyphosate has been registered for ground and aerial use in Canadian forest vegetation management since 1984. SILVICULT URAL NICHE I VEGETATION MANAGEMENT OBJECTIVE(S) I I I ·CHEMICAL SITE PREPARATION SILVICULTURALACTIVITY • RELEASE OR CLEANING • PRECOiiiiERCIAL THINNING I.S ITE SPECIFIC CONDITIONS !• •· V EGETATION TYPES AND ABUNDANCE TillE OF YEAR ·SOIL TYPES ·ETC. I. ~ C EFFICIENCY !• MUST BE BIOLOGICALLY. LOGISTICALLY AND ECONOIIICALLY EFFICIENT TO COINCIDE WITH THE SILVICULTURAL NICHE CHOICE OF HERBICIDE APPUED I Figure 1. The decision making process for determining an appropriate herbicide for application. As triclopyr ester has only recently been registered (in 1991) for Canadian forest vegetation management, its feasibility as a silvicultural herbicide has yet to be fully evaluated. Triclopyr is a broad spectrum, auxin type, selective herbicide used for the control ofbroadleaf herbaceous weeds and woody plants (DowElanco, nd) . However, triclopyr is ineffective in the control of grasses and bracken fern (Pteridium aquilinum (L.) Kuhn.) (Buse, 1992). The resistance of Carex (Dill.) L. spp. to the application of triclopyr is not documented (Buse & Bell, 1992). This herbicide is equivalent to glyphosate in the control of many hardwood species (Deloitte & Touche, 1992). Information about the effectiveness and efficiency of this herbicide is not as abundant as compared to glyphosate. Additional baseline data are required to refine the use oft riclopyr ester and determine its potential as a tool for vegetation management. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 4 RESEARCH OBJECTIVES Two field studies were conducted to assist DowElanco Canada Inc. with further evaluation ofReleaseTM Silvicultural Herbicide (triclopyr ester). Based on DowElanco's experimental design criteria, both the studies were initiated in the summer of 1992, west of Thunder Bay, Ontario. The objective of Field Study #1 was: To determine the minimum safe time interval between chemical site preparation with triclopyr ester and planting containerized jack pine (Pinus banlcsiana Lamb.) seedlings. The incentive for this study lies in the fact that ·some herbicides used for chemical site preparation persist on a site for a period of time while their degradation takes place. It is important to know what effect such a persistence may have on conifer seedlings. The Release TMproduct label indicates that conifer planting should be delayed for at least one year after chemical site preparation (DowElanco, 1995). Shortening the time interval between chemical site preparation and planting will prolong the period which planted seeAlings are able to grow in the absence oft he effects of non- crop vegetation. With good initial preparation and the rapid initial growth of the crop trees, subsequent release treatments may be minimi?P.d or eliminated (Becker eta/. 1990). It is essential to know both the negative effects of triclopyr herbicide on the jack pine crop and the time period during which such effects occur1• If it is not necessary to delay planting for one year following application, this herbicide's silvicultural niche could potentially be expanded for use on forest sites which require chemical site preparation and immediate (same year) regeneration. The objectives of Field Study #2 were: a) To test the efficacy of tank mixtures ofReleaseTM (triclopyr ester) and Touchdown 480 TM (glyphosate) or VisionT M (glyphosate) herbicides in controlling common boreal forest weed species; and b) To document the growth response, if any, of planted containerized jack pine seedlings one growing season after the application of triclopyr-glyphosate herbicide mixtures. 1 This field study also included containerized black spruce (Picea mariana (Mill.) B.S.P) seeAHngs. However this report focuses strictly on jack pine. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 5 The incentive for this trial lies in the fact that many herbicides are limited in their ability to successfully control all species of non-crop vegetation on a forest site (Walstad eta/. 1987). It is favourable to use a single herbicide or a herbicide mixture which will control/reduce either the most abundant species and/or those which are most threatening to the well-being of the crop trees. It is not economically desirable to have more than one herbicide application, per rotation, to release crop trees from the influence of non-crop vegetation. However, chemical site preparation followed by a post-plant chemical release from non-crop vegetation is commonly practiced worldwide. Herbicide mixtures can be used to: a) widen the spectrum ofv egetation control greater than that achieved from a single herbicide and; b) to control several different species with a single herbicide application (Bohmont, 1983; Hydrick & Shaw, 1994; Walstad eta/. 1987). Therefore by applying a herbicide mixture, the silviculture niche in which both glyphosate and triclopyr ester may be used, may be broadened. It bas recognizexf that there is an imminent need for a herbicide product that will control a broad spectrum of forest vegetation with a single application. Literature Review A comprehensive literature review was undertaken which addresses the following: • Ecological disturbance and silviculture; • Concepts of'competition'; • Response of conifers to competing vegetation; • Response of conifers to release from competing vegetation; • Jack pine and competing vegetation; • Triclopyr ester and glyphosate herbicides; • Susceptibility of non-crop vegetation to triclopyr ester and glyphosate; • Susceptibility of conifer crop trees to triclopyr ester and glyphosate; • Minimum time inteivals between chemical site preparation with triclopyr ester and plantation establishment; and, • The use of herbicide mixtures. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 6 LITERATURE REVIEW ECOLOGICAL DISTURBANCE AND SILVICULTURE Succession refers to the process ofc hange by which biotic communities replace each other and by which the physical environment becomes altered over a period oft ime (Kimmins, 1987). An ecological disturbance refers to the total or partial destruction ofp lant biomass. Such disturbances can alter plant succession in terms of species composition, rate of change, spatial distribution and growth patterns (Wagner & Zasada, 1991). One objective of silviculture, from both the biological and economic standpoints, is to restrict the ~ n and structure of forest stands to those vegetative species that can maximize their growth on a particular site (Smith, 1986). This is achieved, essentially, through a controlled series ~ ecological disturbances. Nearly all silvicultural activities are disturbances to the forest ecosystem (Wagner & Zasada, 1991). Understanding the patterns and mechanisms of plant succession following disturbance is important ifs uccessful control ofn on-crop vegetation is to occur. Wagner & Zasada (1991) indicate that the presence of non-crop vegetation on a forest site is determined by: 1) species composition of plants that are presently on the site, were on the site in the past and are capable of invading in the future, and 2) the type, intensity, timing and frequency of the disturbance. Plant succession is determined largely by how the ecological characteristics ofp lant species interact with each other and with the disturbance (silvicultural activity). Ecological distln"bance and the mechanisms ofp lant and forest succession are well addressed byOdum (1993), Kimmins (1987) and Walstad & Kuch (1987). However, in the context of this study, it is necessary to summarize some of the basic ecological concepts about the manipulation of vegetation in silviculture. Although, not always correct, plant species interactions with crop trees are often viewed by the silviculturist as competition. CONCEPTS OF 'COMPETITION' 'Competition' Defined The usage of the term 'competition' by forest managers generally makes reference to an abundance of non-crop vegetation associated with establishing crop trees. Competing vegetation is defined as unwanted or undesirable vegetation which suppresses or inhibits the growth and survival of conifer crop trees (Coates & Haeussler, 1986). This definition of competition is somewhat Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 7 simplistic and misleading, because there are other types of plant-plant interactions which may influence crop tree growth. Interference and Interaction The term interforence has been used to descnbe interactions caused by the presence of a plant population in the environment of one or more neighbouring plant populations. Interference is classified as neutral (no effect), positive (stimulation) or negative (depression or inhibition). The actual causes of interference may include: the production or consumption of resources, the production of growth stimulants or toxins, parasitism, predation, or protection (Radosevich & Osteryoung, 1987). An interaction is defined as the effect that two or more plants or plant populations have on each other. Odwn (1993) descnbes the possible interactions that may occur among plants growing together and they are defined by the type of interference that occurs. These include: neutralism, mutualism, protocooperation, commensalism, competition, amensalism, parasitism and predation. Table 1, adapted from Radosevich and Osteryoung (1987), summarizes possible interactions between plants and the types of interference associated with each (positive, neutral or negative). Table 1. A summary of possible interactions between plants and the interference classification associated with each('+'= positive; '0' =neutral;'-'= negative) (adapted from Radosevich & Osteryoung, 1987). INTERACTION INTERFERENCE INTERFERENCE ON SPECIES A ONSPECIESB Neutralism 0 0 Mutualism + + Protocooperation + + Commensalism + 0 Competition - - Amensalism 0 - Parasitism, predation + - This review focuses on three specific interactions which are particularly relevant in vegetation control strategies; commensalism, amensalism and competition. Commensalism is a positive interference; while both amensalism and competition are negative interferences. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 8 Positive Interference Commensalism is an interaction involved in positive interference, whereby one plant population is benefited, but the other is not (Odum, 1971; Begon & Mortimer, 1986; Odum, 1993). Non-crop vegetation may positively interact with conifer crop trees in several ways by: • maintaining site productivity by reducing nutrient losses due to soil leaching (Comeau et a/. 1993) or by fixing nitrogen (LePage & Coates, 1993; Richardson, 1993); • retarding soil erosion through stabilization of soil by their root systems (Comeau et a/. 1993); • adding organic matter to the soil through leaf fall and root slo1Jgbing, thereby improving soil moisture and the cation exchange capacity of the soil; • protecting the upper soil layers from temperature extremes (Radosevich & Osteryoung, 1987; Bell, 1991); • shading c;eerllings in some circumstances, thereby moderating extremes of environmental factors such as temperature, moisture and light (Radosevich & Osteryoung, 1987; Bell, 1991); • improving seedling growth and development by reducing moisture stress and respiration rates; • reducing the potential for the development of additional non-crop vegetation; and by, • reducing some types of pest damage (Comeau eta/. 1993). Initial conifer survival tends to be enhanced by the association with non-crop vegetation. It appears, however, that once the geedlings become established (approximately one year), the benefits of non-crop vegetation decrease as the crop tree's requirements for resources increase (Radosevich & Osteryoung, 1987). Negative Interference Amensalism and competition are two key interactions involved in negative interference. Amensalism. is the interaction in which only one oft he plant populations is depressed or inhibited, whereas the other is not. Competition is the interaction in which two or more plant populations, utilizing the same limited resource, depress or inhibit each other (Odum, 1971; Silvertown, 1982; Began & Mortimer, 1986; Radosevich & Osteryoung, 1987). Radosevich & Osteryoung (1987) state that amensalism and competition are often considered Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 9 together and termed 'competition' because, in both the forms of interaction, one species usually is depressed or inhibited more than the other. Artificial regeneration by planting generally results in a fixed number oft rees and an invasion ofn umerous other plant species. It is unlikely that newly established crop trees suppress or inhibit invading vegetation. Hence, it may be more appropriate to use the term 'amensalism' (Begon & Mortimer, 1986). In such 'one-sided' cases ofc ompetition, it is impossible to discern any measurable detrimental effects on the stronger competitor (i.e. the crop trees' effect on non-crop vegetation) (Begon & Mortimer, 1986). In fact, many 'competition' experiments only measure the response of one species (the crop tree) to the interaction, which makes any differentiation between competition and amensalism impossible. Hence, the use of the term 'competition' may be incorrect, from an ecological standpoint, but it generally refers to the suppression of one plant species by another (Radosevich & Osteryoung, 1987). Many species of non-crop vegetation have inherent biological advantages over desired crop trees. Some of these advantages are as follows: • they often produce abundant seed crops at frequent intervals; • they are often capable of rapid juvenile growth from either seed or sprouts (Deloitte & Touche, 1992; Newton eta/. 1987); • they often have a variable range of shade tolerance; • they are often able to germinate in either softwood or hardwood litter; • they may be faster growing than conifers; • they often sprout prolifically from established roots, rhizomes and stolons (Deloitte & Touche, 1992; Walstad eta/. 1987); • they often have the ability to become established from seed banks (i.e. pin cheny (Prunus pensylvanica L.f.) and raspberry (Rubus L. spp.) (Bell, 1991; Newton eta/. 1987); and, • they are often able to smvive various and severe distUibances in a relatively intact form and, thereby, are in a position to rapidly capture space previously occupied by conifers (Walstad eta/. 1987). Because oft hese advantages, non-crop vegetation can negatively interact with crop trees in several ways by: • directly competing with ~ n for available light, moisture, nutrients and/or physical space (Comeau eta/. 1993; Ross & Walstad, 1986; Bell, 1991); Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 10 • causing physical injmy to seedlings (e.g. through abrasive action); • smothering seedHngs with fallen leaves or snow-pressed non- woody vegetation (Comeau et a/. 1993); • causing allelopathic effects; • increasing fire potential (Sutton, 1985; Bell, 1991); and by • providing a favourable habitat for biological pests or rodents which have the potential to damage or kill young senflings (Comeau et a/. 1993; Sutton, 1985; Ross & Walstad, 1986; Bell, 1991). The direct competition, between crop trees and other vegetation for essential resources, becomes the focus of attention because these resources are required for the proper physiological functioning of establishing seedlings, Without an adequate supply of moisture, nutrient, light and space, seedHngs may die or, at best, may grow well below their potential rate (Ross & Walstad, 1986; Bell, 1991 ). Crop trees are most susceptible to competition from other vegetation during the regeneration stage, but may still be susceptible up to the sapling and even the pole stages of growth (Stewart, 1987). When assessing the effects of positive and negative interference of vegetation on the crop, the net effect must be determined. The potential benefits of non-crop vegetation (e.g. favourable seerfling microenvironment) must be balanced against the potential liabilities caused by its presence (e.g. increased demand for resources) (Wagner & Zasada, 1991). The net effect of the concurrent presence of non-crop vegetation and conifer crop trees is usually negative (Greaves et a/. 1978). Intraspecific and Interspecific Competition Plant density and/or rate growth will be reduced or held in 'check' by competition. Both competition within species and between species are important in determining the number and species of plants found on a particular site (Odum, 1993) . Radosevich & Osteryoung (1987) define intraspecific competition as the negative interactions between plants oft he same species. It is very intense because closely related individuals must exist in similar, if not identical, niches. Conifer crop species often naturally regenerate at extremely high densities and this can be as disadvantageous as the establishment of non-crop vegetation (and more difficult to manage silviculturally) [Day, (pers. comm., 1993)]. Control of initial plantation spacing, the use ofn urse crops and/or precommercial thinning are often the only silvicultural solutions to limiting intraspecific competition. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 11 Interspecific competition involves negative interactions among plants of different species (Radosevich & Osteryotmg, 1987). It includes both the amensalistic and/or competitive interactions between crop trees and other non-crop vegetation. Prompt reforestation after harvest to obtain fully stocked stands and crown closure, and the application of intensive silvicultural practices will limit interspecific competition. Such practices include mechanical and chemical site preparation, the use of muse crop trees and/or crop tree release with herbicides (Kershaw, 1973; Stewart, 1987). RESPONSE OF CONIFERS TO COMPETING VEGETATION Although black spruce (Picea mariana (Mill.) B.S.P.) and jack pine comprise 75% of all planting stock in Ontario, little has been published regarding their response to non-crop vegetation (MacDonald & Weetman, 1993). However, there is abundant information pertaining to the responses ofo ther conifer species to competition with un~ vegetation for essential resolU'Ces. There are two types of competition which may be identified: below ground competition for water and nutrients, and above ground competition for light. Although reference here has been made almost entirely to interspecific competition, the concepts discussed are similar for intraspecific competition. No essential resource is more important than another; light, moisture and nutrients are all important. Moisture and nutrients are the probable primary factors contnbuting to the initial species composition of an establishing plant community, while light is the probable primary factor contributing to changes in species composition and structure of that community (Larsen, 1980; Kimmins, 1987). Competition Below Ground for Available Water and Nutrients Tourney eta/. (1947) explain that development oft rees, shrubs, grasses and mosses depends on the degree of soil desiccation caused by root competition. Root growth, size and geometry are the most important contnbutors to a plant's ability to compete successfully for a limited supply of water and nutrients (Nambiar & Sands, 1993). Differences in the amount ofp hotosynthate allocated to root growth will affect the relative competitive abilities of different species (Radosevich & Osteryoung, 1987). A plant species may have a competitive advantage over another for water and nutrients by: a) acquiring a greater proportion ofa vailable soil water and/or nutrients; b) using water and nutrients more efficiently in producing biomass and/or; c) allocating photosynthate in ways which maximize Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 12 survival and growth (Nambiar & n ~ 1993). Different species of non-crop vegetation exhibit different water usage patterns because oft heir growth ~ physiological characteristics and type and depth of root system (Richardson, 1993). Experimental evidence indicates that interspecific competition for available soil moisture poses great limitations on conifer survival and growth (Radosevich & Osteryoung, 1987; Morris et a/. 1993). Available soil moisture and soil temperatme will affect the soil nutrient supply because they regulate the rate of decomposition of dead vegetation (Greaves eta/. 1978). In addition, the amount ofa vailable moisture regulates the availability ofs oluble nutrients and their uptake by plants. It is not possible for a geerllingto experience ~ r stress (through competition) without some degree ofn utrient stress; but the opposite may not be true in some soil environments (Nambiar & Sands, 1993). Hence, competition for nutrients is ~ u to identify because of its association with available soil water (Richardson, 1993). Nambiar & Sands (1993) explain that water and nutrient deficits are caused by water and nutrients not being supplied to a plant at a rate required for maximum growth. 1bis is caused by primary deficiencies ofw ater and nutrients in the soil and/or by competition for these resources from other plants. Tourney & Kienholz (1931) found that trenched quadrats in white pine (Pinus strobus L) forests, initially without understory vegetation, soon became covered with invading vegetation. The roots of the white pines were severed at the time of trenching. In every case, irrespective of the density of the canopy, abundant vegetation appeared in the trenched quadrats, compared to untrenched quadrats, because the soil had been freed from the living roots of surrounding trees. It was also found that am01m.t ofa vailable moisture was greatly increased by the elimination of root competition. Similar results were obtained with loblolly pine (Pinus taeda L.) and shortleaf pine (Pinus echinata Mill.) by Tourney eta/. (1947). Stiell (1970) attempted to differentiate between the intraspecific competitive effects of crowns from those of roots in a 13-year-old red pine (Pinus resinosa Ait.) plantation. Crown competition was artificially increased by inserting the tops ofs evered red pines in an upright position armmd live trees. The artificial crown competition did not affect the red pine growth and it was concluded that adequate allowance for root competition must be made by providing greater space for each tree than above-ground appearances might suggest Excavated root systems were found to be very widely dispersed and to extend over many times the area occupied by the respective live crowns. Conard & Radosevich (1982) found similar results in young white fir (Abies concolor Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 13 (Gord. & Glend) Lindle. ex Hildebr.) plantations. The effect of root competition on the white fir was reduced when the roots of shrubs were killed while leaving the shrub canopy in place. Morris eta/. (1993) found convincing evidence that the use of surface soil water by neighbouring plants, and the resulting water stress in loblolly pine senllings during the first growing season, was the primary factor affecting pine growth. Nutrient deficiencies were associated with reduced water availability during this period However, it was found that non-crop vegetation had less influence on seedling water use and nutrition during the second growing season. 1bis concurs with observations on the growth ofr adiata pine (Pinus radiata D. Don); where competition for water is most pronounced in the first summer after planting and diminishes with each following summer as roots tap water from successively greater depths (Richardson, 1993; Nambiar & Sands, 1993). As trees establish deeper root systems, there is a critical shift from competition for water to competition for nutrients (Nambiar & Sands, 1993). The amount of available water and the need for water uptake is influenced by the rate of transpiration by vegetation. Towriey eta/. (1947) describe research which showed that a site covered with vegetation had a much lower soil moisture content over the growing season than did a similar site without any vegetation. The control of competing vegetation will subsequently reduce root competition yielcting more available moisture for crop trees. Numerous studies have shown that the reduction ofn on-crop vegetation reduced competition for moisture with: loblolly pine (Carter eta/. 1984; Lanini & Radosevich, 1986; Morris eta/. 1993); ponderosa pine (Pinus ponderosa Dougl. ex Laws) (Lanini & Radosevich, 1986); white pine (Sterrett & Adams, 1977); sugar pine (Pinus lambertiana Dougl.); white fir (Lanini & Radosevich, 1986); and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) (Cole & Newton, 1986; Wagner & Radosevich, 1991). Radosevich & Holt (1984) state that it is undebatable that non-crop vegetation in proximity to crop trees consumes nutrient resources. It has been observed that the reduction of non-crop vegetation reduces the competition for nutrients with: loblolly pine (Carteret al. 1984; Morris eta/. 1993); radiata pine (Smethurst & Nambiar, 1989); and Douglas-fir (Cole & Newton, 1986). The benefit of increased nutrient availability, through competition control, is determined by the ability of the crop tree to respond to and use the added resource, within the limits imposed by water or other resources. Richardson (1993) states that the retention of non-crop vegetation at establishment can conserve nutrients. Although there may be competition in the short term, the benefits may be apparent in the long term; especially on forest sites susceptible to nutrient loss through leaching. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 14 Competition Above Ground for AvaUable Light The magnitude oft he capture ofs olar energy is determined by the magnitude and efficiency ofp lant foliage. The ultimate determinant oft he economic productivity ofc rop trees is the presence ofa n adequate biomass off oliage, oft he desired species, which is adequately supplied with moisture and nutrients. Ifm ost oft he leafbiomass is that ofn on-crop vegetation, then growth and subsequent economic yields will be small (Kimmins, 1991). The actual levels of light reduction caused by non-crop vegetation and the effects it has on the performance of Ontario conifers is not well documented (Bell, 1991). However, Nambiar & Sands (1993) indicate that the production of wood is linearly related to the amount of intercepted , radiation and that this relationship is largely unaffected by water and nutrient stress. This is contradictory to Richardson (1993}, who states that radiata pine stem diameter growth is very sensitive to competitor-induced water stress. Competition for light occurs when one species, because of more rapid growth, taller stature or established presence, casts shade on and limits the growth of another (Radosevich & Osteryoung, 1987). Kramer & Kozlowski (1979) and Larcher (1980) explain how light intensity directly affects photosynthetic rates in plants. Light compensation is the point at which light intensity is high enough for a given plant to produce the same amount of photosynthate as it uses for respiration. As light intensity increases, photosynthetic rates will increase proportionally until light saturation occurs. The rate of photosynthesis then becomes more or less constant. These points of light compensation and saturation vary among species which are adapted to growing under different light intensities. In the context of competition for light, the main physiological differences between species are found in: a) the adaptability of photosynthesis to different light regimes, and b) the change in carbon allocation caused by a change in the availability of resources (Cannell & Grace, 1993). Shade tolerance is the term used to descn"be plants with the ability to survive and grow under low light intensities. A shade tolerant plant will reach its point of light compensation, its point oflight saturation and its maximum rate of photosynthesis sooner than a shade intolerant plant will. In addition, it will make more efficient use oflow intensity light for the production of photosynthate than a shade intolerant plant will (Radosevich & Osteryoung, 1987). Intolerants are less efficient at photosynthesis and require more light for growth (Greaves eta/. 1978). Therefore they must have the ability to: a) grow rapidly and overtop other vegetation, and b) produce high amounts of foliage (photosynthetic area) to keep growing rapidly. As the vegetative canopy closes (be it herbaceous, shrub or tree canopy), only the shade tolerant species will compete successfully under that canopy. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 15 The amount of photosynthate produced by a plant decreases as competition for light increases (Bell, 1991). Comeau eta/. (1993) observed that Engelmann spruce (Picea engelmannii Pany) seeAHng growth increased as needle biomass increased and non-crop vegetation abundance and shading decreased Comeau (1988) observed a negative relationship between photosynthate production and light competition with Douglas fir seffilings under a canopy of fireweed (Epilobium angustifolium L.) and thimblebeny (Rubus parviflorus Nutt. ). Ifa plant beneath a canopy is not shade tolerant, its photosynthetic rate will tall below its inherent light compensation point. It will, inevitably, not produce the required amount ofp hotosynthate to maintain and grow new tissues (e.g. roots) for the uptake of other essential resources (e.g. moisture, nutrients). Results obtained by Brand & Weetman (1986) concur with those of Comeau (1988), indicating that, at least with Douglas-fir, competition for light is generally the limiting factor for successful growth. However, this also demonstrates the importance ofr ecognizing the limiting factor( s) for successful crop tree growth and coordinating silvicultural activities so that they address the limiting factor( s ). Howard & Newton (1984) indicate that crop tree seedlings can be influenced by overtopping, encroaching and/or ground cover vegetation. It was ~ r with Douglas-fir, that the control of overtopping non-crop vegetation is more important than the control of encroaching shrubs and/or ground cover in the immediate environment of the crop tree. Encroaching and ground cover vegetation was defined as any vegetation in proximity to the crop tree within the distance of the seedling's longest lateral branch, but that was not overtopping the crop tree. Height, diameter and volwne growth of overtopped Douglas-fir was significantly less for the first seven years than that of seedlings influenced by encroaching vegetation. Bracken fern, bigleaf maple (Acer macrophyl/um Pmsh), red alder (Alnus rubra Bong.) and dogwood (Comus L. spp.) were the major overtopping species. After seven years, 75% ofa ll the seeAHngs planted that were still alive and undamaged were influenced only by encroaching and ground cover vegetation. The seedlings in the study sites were in a low to medium range of moisture stress, which permitted the conclusion that overtopping vegetation competed more for light than for below ground resources. Newton eta/. (1992b) observed that the percentage of overtopping hardwood cover was the single best indicator ofheight growth in balsam fir (Abies balsamea (L.) Mill.). Crop trees grew an average of4 0, 27.6 and 15 centimetres in height annually when 0%, 50% and 100% overtopped by non-crop vegetation, respectively. However, it must be remembered that a competitor species need not be in the immediate vicinity ofa crop tree to compete for below ground resources (e.g. bracken fern). It can often be practically impossible to determine and separate the effects of non-crop Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 16 vegetation use ~ moisture and nutrients as individual causal agents of poor crop tree growth. For this r ~ the concept of growing space has been developed. The Capture and Occupation of Growing Space The availability of essential resources (moisture, nutrients, light) to an individual plant growing in a plant community appears to be a function of the physical space that the individual occupies. A site has a specific carrying capacity for plant growth, tmtil an essential resomce becomes limiting. Growing space can be used to describe the combination or composite of all resources necessary for seedling growth (Begon & Mortimer, 1986; Radosevich & Osteryoung, 1987; Oliver & r ~ 1990). The more space available for use by the seed1ing, the less intra- and interspecific competition it experiences. Growing space availability changes over time and may be described both in terms of stand dynamics and in terms of succession. Stand dynamics is a change in allocation of space to species in a relatively stable community, over a short period of time; whereas succession is a change in the allocation ofs pace to species where there is a change or shift in plant community composition, over a longer period of time. Oliver & Larson (1990) explain that the amount of growing space that each plant occupies is defined by surrounding plants. Plants must expand in size to grow. A plant first allocates the products (energy) obtained through photosynthesis, using its available growing space, to the maintenance of its presently living cells. Any extra or additional products are used for growth. A plant occupying afJXed growing space increases in size at a progressively slower rate. This is so, because it obtains a fixed amount ofp roducts through photosynthesis, while it requires an increasing amount of products to maintain its increasingly larger self. Its size eventually reaches a maximum in that fixed growing space because all the products are used to maintain itself, and there are none available for additional growth. The plant can not grow larger unless its growing space is increased. Oliver & Larson (1990) also explain that once plants have filled all available growing space, they will compete with other plants to obtain additional space. If one plant has a competitive advantage, it will expand at the expense ofa nother. The n~ whose growing space is reduced, may only be able to survive ifi t can use some space which its competitor can not (e.g. two species with different light tolerance levels or rooting depths). Otherwise it will die ift here are no differences in space utilization. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 17 Following a disturbance that kills or inhibits vegetation (e.g. fire, windthrow, site prepaiation), space become available and, hence, resources become available. There are several successional models which explain to varying degrees how space is captured and occupied. Such models include the classic Clementsian model, the Individualistic Concept ofPiant Association, the three-pathway model and themultiplepathwaymodel (Kimmins, 1987; Robertson, 1993). Perhaps the most useful model is the three-pathway model of ecological succession proposed by Connell & Slatyer (1977). Each oft he three pathways descnbed below is distinguished by the way in which non-crop vegetation reinvades the available growing space. Therefore each pathway may have significant effects on establishing conifers. Although all occur in the boreal forest, the second and third are most common (Towill, 1992). The facilitation pathway assumes that only certain species are able to colonize a site in the conditions that immediately follow a disturbance (CQnnell & Slatyer, 1977). Early plant communities alter the chemical and/or the physical characteristics of the environment creating favomable conditions for the species in the next stage ofs uccession. These early successional stages are necessary for satisfactory growth. of the subsequent communities. This pathway may involve commensalistic interactions (Towill, 1992). The tolerance pathway occurs when pioneer communities are not mandatory for the growth ofs ubsequent communities, and many different species are capable ofo ccupying the available space. Early successional species which establish first may prevent or delay the establishment of mid- successional species, but have little effect on late successional species (Towill, 1992). The sequence ofs pecies in succession is determined solely by their autecological characteristics (Connell & Slatyer, 1977). The inhibition pathway differs from the tolerance pathway in that the pioneer species which invade and secure the available space and suppress or retard the invasions of all other later successional species, for prolonged periods of time (Connell & S1atyer, 1977; Towill, 1992). The pioneer species, which preempt/capture the space, will continue to exclude or inhibit later species, until the former die and release the space (resources). Only then can later colonists become established and eventually reach maturity (Radosevich & Holt, 1984; Radosevich & Osteryoung, 1987). Both the latter two pathways involve amensalistic and competitive interactions and seem to explain crop tree establishment problems in the boreal forest Figure 2 illustrates a schematic example of the occupation of space by vegetation following a disturbance (e.g. fire) of an even-aged, unmanaged boreal conifer species (e.g. jack pine), over Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 18 time. It is similar to that which that descnbed by Radosevich & Conard ( 1981) and it parallels the relationships between foliar area (or yield) and time described by Begon & Mortimer (1986), Kimmins (1987), Oliver & Larson (1990) and Odum (1993). The five phases described are not necessarily discrete and there is a degree ofc oexistence oft he associated species over time, especially in Phase I. IV V 1 ···. .. ... PHASES _.. . 90 SECONDARY w CONIFER c0 00 A. 0 u. 0 z !...!. f J 0 0 .0z.. . 11.1 0 ~ Ill A. ---- TIME--•._._. DISTURBANCE Figure 2. A schematic of the occupation of space by vegetation on an even aged Boreal forest conifer site following disturbance (refer to text). Phase Ia: Invasion of graminoid, herbaceous and low shrub vegetation such as fireweed, raspberry and sedges (Carex (Dill.) L. spp.). These species are very intolerant to shade and are generally inefficient users of space (resources). Phase Th: Invasion ofh igh shrub vegetation such as alder (Alnus B. Ehrh. spp. ), mountain maple (Acer spicatum Lam.) and beaked hazel (Cory/u s cornuta Marsh.). The species in Phase Ia may coexist with or be out-competed by the more tolerant and efficient users of the space. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 19 Phase Ic: Invasion oft ree species such as trembling aspen (Populus tremu/oides Michx.) and white birch (Betula papyrifera Marsh.). Again, these species may coexist with or out-compete the species in Phases Ia and lb. Phase ll: The colonizing non-conifer vegetation begins to die and/or becomes inhibited by the primary conifer as it approaches maturity and crown closure. Phase m The conifer achieves maturity and occupies the majority oft he space in the stand Other minor but 'efficient' users of space may exist in the understory (e.g. mosses). Shade tolerant conifers may establish at this time (e.g. balsam fir). They tend to 'sit' on the space but can not make use of it. Therefore they survive but remain suppressed Intraspecific competition is the predominant form of interaction in this phase. Phase IV: The primary conifer begins to decline. The loss of foliage and mortality of roots releases space. At this point, the space is prone to a new disturbance (especially fire) which would likely return it back to Phase l In the abseD:ce ofa distmbance, a secondary conifer (e.g. one which was suppressed in the understory in Phase lli) may occupy the space. Phase V: The primary conifer continues to decline and will eventually surrender all the space to either a) a secondary conifer, b) reinvading non-crop vegetation (Phase I species), or c) a combination both. Competition Thresholds It is necessary for silviculturists to understand that a threshold measme of the abundance of non-crop vegetation in or encroaching the same growing space of a crop tree will affect the tree's survival and growth. The point at which crop tree survival and/or growth becomes in jeopardy because of non-crop vegetation is referred to as the competition threshold. However, it is difficult to quantify the relationship between non-crop vegetation abtmdance and crop tree growth (Day, pers. comm., 1994). The competition threshold will vary depending on the critical silvics ofboth the crop tree and the non-crop vegetation. It will also depend on the type of unfavourable crop tree growth conditions which the non-crop vegetation may be creating (i.e. the degree ofc ompetition for essential resources). Wagner (1994) indicates that competition thresholds appear to be different for survival and height growth than for diameter growth. If survival is more important than diameter growth, then moderate levels of non-crop vegetation may be maintained in young forests. Similarly, height growth appears to be sustained under moderate levels of competition. However, if crop tree Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 20 diameter growth is to be maximized, much lower levels of competition are required. In Ontario, competition thresholds for conifer crop trees are currently being researched by Wagner (1994) and Bell (1994) . RESPONSE OF CONIFERS TO RELEASE FROM COMPETING VEGETATION A reduction of non-crop vegetation that is competing with crop trees will lead to increased growing space and a 'free-growing' condition that almost always increases survival, vigour and growth (Sutton, 1985; Deloitte & Touche, 1992). Any exceptions to this general trend are rare (Morris eta/. 1993). A conifer crop, which is released from the influence of other vegetation, has the potential to 'respond' and occupy the new growing space. Intolerant crop tree species such as pines (Pinus L. spp.) tend not to respond ift hey have been suppressed for several years and have experienced 'checked' growth (Day, pers. comm. 1994). Responses are most commonly observed in diameter/basal area growth and seerfljng swvival. Morris eta/. (1990) indicate the ~ consistent response variable for jack pine and black spruce is seedling dey weight. But as this is often an inappropriate measure (because ofd estructive sampling), seedling root collar diameter is the best substitute because it correlates well with dry weight. Responses may also be observed in one or more of the following tree and/or stand attributes: height growth, and individual tree or stand volume growth; crown length and width; bud size; needle nmnber, colour, length and retentivity; nutrient status, tree vigour and resistance to damaging agents (insects, disease) (Bell, 1991). Richardson (1993) describes three identified responses ofradiata pine volume growth in Australia and New Zealand, over time, to the removal of non-crop vegetation. Figure 3 illustrates each growth response relative to no treatment. Type I responses result from treatments that have little or no permanent effects on soil characteristics and lead to higher yet parallel volume growth trends in treated relative to untreated stands. This may result from the removal of non-crop vegetation such as grasses, herbs and low shrubs which likely have little long term impact on crop tree growth. Type II responses result in a change of site productivity or carrying capacity and a divergence of growth CUIVes of treated and untreated stands. This may result from the removal of non-crop vegetation that is more tolerant and has the ability to persist under a closed canopy and compete for water and nutrients. For example, Richardson (1993) indicates that in radiata pine Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 21 t ./ TYPEII VOW ME .· .. ··. . ··· .· TYPE I .. " " , " _. . ... -·'' ~ ~ UNTHEATED _,.·' _.,.,' . •' ,,·' .. ··"· ,. .. ,, . ~ ~ ~ ~ _.., ~~ AGE Figure 3. Three possible volume growth responses of radiata pine to removal of non-crop vegetation (refer to text) (adapted from Richardson, 1993). plantations in Australia and New Zealand, if native bracken fern (Pteridium escu/entum (Forst. f) Cockayne) is not removed, it can persist in the understory. This can cause "spindle", phosphorous deficient pine stands which are unable to close canopy, and becomes a very serious problem ift he plantations are initially established at low densities for sawlog production. A Type m response is soil dependent. Where some competitors occupy a low-nutrient site, such as on sand dunes or aeolian deposits, initial crop tree growth may be reduced relative to stands with vegetation control. However, the competitor species can conserve nutrients which would otherwise be lost from the site through leaching. Although there may be initial growth benefits to the removal ofn on-crop vegetation, the volume growth curve for such stands may fall below that of a stand in which there was no treatment (Figme 3) (Richardson, 1993). Table 2 presents numerous references, by conifer species, documenting improved crop tree survival and/or positive growth responses resulting from the reduction ofn on-crop vegetation. Perala (1982) concluded from a comprehensive literature review, that the release of conifers from undesirable vegetation, in the Upper Great Lakes Region resulted in, on average, 43% greater survival, 120% greater height growth and 84% greater biomass growth than unreleased conifers. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 22 Table 2. References, by conifer species, documenting survival and/or growth benefits resulting from the control of non-crop vegetation. CONIFER SPECIES REFERENCE(S) Jade piDe (PiltJls ballbia1la Lamb.) Aw:fdwheut a/. (1990) :Krisbka aud Towill (1989) SUUclliJid Weldon (1993) SUUcllcta/. (1991) Weetman ad ~ (1984) Loblolly piDe (Prmu fMda L.) Busby ct a/. (1993) CreishfDUtal. {1987) Edwards (1994) Haywood (1994) KDovle eta/. (1985) Lodgepole pine (Prmu COI'IIDrta Dougl. ex. Loud.) Blackmore aud Cams (1979) LePage aud Coates (1993) I.onsleaf piDe (PinJU pahatns MilL) ereigb1anetal. (1987) Nelsmuta/. (198S) Ponderosa pine (Prmu ]IOIItluos.a DougL ex. Loud.) Llmini IIDd Radosevich (1986) Red piDe (Puuu resUJOSa Ait.) Allmmd Weutwarth (1993) ADcoymous {1993) Aschbec:her •t a/. (1990) Buckman aDd Lundgren (1962) I...atalme (1989) Slash pine (Prmu •liottzi Enlem..) •tal. (1987) PinJU falrrMrtilma ~ LmiDi IIDd Radosevich (1986) White piDe (Puuu sti'ObJU L.) Buckman IIDd Lundgren ( 1962) Stem:tt IIDd Adams (1977) Black spruce (Picea manana (MilL) B.S.P.) ADoa.ymolls (1993) Richardson (1982) Wood IIDd V011Althen (1993) Wood eta/. (1990) . spruce (Picea ~ nn Parry) Comeau •t a/. (1993) NOl'W!IY spruce (Picea abzu (L.) Karst.) ; (1993) Red SPr1IICe (Picea rvbas SIQ.) ; (1993) Sitka spruce (Picea sitclwnsi.s (Boog) CarrJ Reyuold$ •t al. (1993) White spruce (Picea glcnu:a {MDeul:h) Voss) Azdrrmcta/. (1992) Blackmare Slid Cams (1979) Cain(1988) Wood aud Dominy (1988) Wood aud VOD.Althen (1993) Ymg(l991) Hybrid spruce (Picea glcnu:a XPicea ~ u LePage IIDd Coates {1993) Balsam fir ~ balsalrwa (L.) Mill) r ~ MlcLelln IIDd Morpn (1983) Newtmuta/. (1992b} White fir ~ COIICOlor(Gord. .!1: Gleud.) Lindle. ex Hildebr.) Collard aud Radolevich (1982) Llmini IIDd Radosevich (1986) Douglas-fir ~ lriiiiiZii!Sii (Mirb.) Frmu:o) Dunsworth aDd Deyoe (n.d) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 23 Buse & Bell (1992) state that increased volume growth from 40 to 100% or more, in the short term, is common. Long term studies(>1 5 years) suggest that tree growth response after release persists or increases with time, continuing at least until crown closure. However, long term responses would depend on the intensity oft reatment and target species of non-crop vegetation (Richardson, 1993). Bell (1991) states that there are two fundamental considerations when manipulating non- crop vegetation. Firstly, no matter how effective a treatment is, it will not be beneficial unless the crop trees have the vigour to respond to the resources made available. Secondly, ift he resources are released at rates in excess oft he ability oft he crop trees to use them, the crop trees will not benefit from the surplus. .JACK PINE AND COMPETING VEGETATION .Jack Pine Response to Interspecific Competition According to Sims et a/. (1990), jack pine is a shade-intolerant species requiring full light to smvive and achieve optimum growth. Certain herbs and shrubs can provide protection from heat and moisture stress by providing a shady, cool microenvironment. This may be beneficial to the initial survival and establishment oft he seedlings (Bell, 1991; Buse & Bell, 1992). The best initial survival of seedHngs occurs on microsites with less than four hours of direct sunlight daily (Sims et a/. 1990). However, the benefits of shade to the early survival are short-lived and it soon becomes detrimental (Bell, 1991 ). Once the seedlings have established, they should receive full light (Rudolph & Laidly, 1990; Benzie, 1977). Sims eta/. (1990) descnbe a detailed smvey performed by Bakusis & Hansen (1959) on jack pine forests in Minnesota. On a five-unit "requirement" scale (where 1 = least and 5 = greatest), jack pine ranked 5.0, 1.0 and 1.9 for light, moisture and nutrient requirements, respectively. Logan (1966) performed a five year study on the effects of four light intensities; 13%, 25%, 45% and 100%, on jack pine seedlings, Total seedling height, shoot dry weight, root dry weight and root collar diameters increased with increasing light intensity and all were maximized in 100% full light Mean needle lengths were maximized in 25% sunlight and decreased with increasing light intensity. Logan (1966) states that poor root growth observed in low light intensities may well be related to the translocation of photosynthate. It has been observed that shaded white pine seedlings translocate a smaller fraction ofp hotosynthate to the roots than those grown in full light In addition, decreases in stem growth in low light intensities may be due, in part, to hormone deficiencies. Kozlowski & Peterson (1962) indicate that hormone production may be reduced in the shade and this subsequently delays the initiation of cambial activity in the plant Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 24 Although jack pine is a very drought resistant species, it has been found that intense root competition results in a consequent decrease ofa vailable soil moisture, reducing diameter growth prior to the reduction ofheight growth. Ericaceous shrub species (e.g. bluebeny (Vaccinium spp. L.)) reduce survival and growth on coarse textured soils through competition for moisture while raspberry and grasses compete for moisture on silty and clayey sites (Buse & Bell, 1992). Early height growth in jack pine plantations varies inversely with the ground occupancy ofe ricaceous plants (Bell, 1991). Cayford eta/. (1967) found that competition from trembling aspen and hazel has been responsible for poor survival of jack pine planted on clay soils in Manitoba and Saskatchewan. . Jack pine has a relatively low nutrient requirement (previously indicated as 1.9 on Balrusis & Hansen's (1959) requirement scale from 1 to 5) and is usually found on sites oflow nutrient status (Sims et a/. 1990; Bell, 1991 ). No information was found with respect to the specific effects of competition for nutrients on jack pine. Examples ofo ther agents which negatively interact with jack pine are presented by Bell (1991). For example, both aster (Aster L. spp.) and goldenrod (Solidago L. spp.) serve as the alternate hosts for needle rust fungus (Coleosporium asterum (Diet) Syd.) (Hiratsuka, 1987). Buse eta/. (1994) concluded, from an intensive survey of the forest industry and of the Ontario Ministry ofNatural Resources, that the most important competitor species ofj ack pine were: Populus L. spp., beaked hazel, white birch, Alnus B.Ehrh. spp., red maple (Acer rub rum L. ), pin cherry, raspberry and grasses (not ranked in any order of importance). Jack Pine Response to Release from Interspecific Competition Generally, the response ofj ack pine parallels the positive survival and growth responses to vegetation control observed in other conifers. As previously reported, the requirements ofj ack pine for moisture and nutrients are relatively low compared to its light requirements. Jack pine should be released from overtopping non-crop vegetation within a year after planting (Bell, 1991). A 50% or greater reduction in the percent cover of overtopping vegetation is required to increase survival and growth of seedlings. Weetman and Fournier (1984) observed that the elimination ofc ompetition for water by ericaceous plants (may have) contnbuted to positive ! 1 jack pine growth responses. I Studies by Sutton et al. (1991) and Sutton & Weldon (1993) indicated that jack pine survival I I l Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 25 was not enhanced from chemical site preparation but positive growth responses were maintained through five growing seasons. Buse & Bell (1992) state that removal ofI lOD-a'Op vegetation through chemical site preparation has resulted in stem volume increases of 18% after three years of growth, but they note no difference in height growth, when compared to controls. In contrast, Richardson (1982) did find that jack pine height growth was enhanced, four years after crop tree release treatments, but it was also noted that growth was only improved when the overtopping vegetation was more than twice the height of the crop trees. TRICLOPYR ESTER AND GLY PHOSATE HERBICIDES A Profile of RELEASE™ Herbicide1 Triclopyr herbicide has both an amine formulation and an ester formulation. In 1991, the ester formulation received federal registration status in Canada, as ~ for groWld application (CPPA, 1992; Campbell, 1991). It received restricted registration for aerial application in 1995 (DowElanco, 1995). Release1 M, is an emulsifiable liquid form oftriclopyr. It has an acid equivalent of4 80 gil oftriclopyr, present as a low volatile butoxyethyl ester and is manufactured by DowElanco Canada Ltd. (DowElanco, 1995; Pitt eta!. 1993). Release1 M is recommended for the control of woody and herbaceous vegetation on forest sites. It is a selective herbicide which is readily absorbed by the foliage of the target plant ( CPPA , 1992). It is translocated throughout the shoot and root system, via both symplastic and apoplastic tissues (Pitt eta!. 1993; Dow Chemical, n.d), where it accumulates in the meristematic tissues (Weed Science Society ofA merica (WSSA), 1989). Symplastic tissues are defined by the total mass of living cells in the plant Apoplastic tissues include non-living cell walls, intercellular spaces and xylem elements surrounding the symplastic tissues (Stephenson, 1992). It behaves similar to phenoxy acid herbicides (e.g. 2,4-D) by inducing auxin-type responses in the target plants. This causes rapid, abnormal growth and cell division (Pitt eta!. 1993; WSSA, 1989), disrupting the food production mechanisms and severely injuring or kiUing the plant (DowElanco, n.d) . In addition, it can prevent root sprouting of perennial vegetation (WSSA, 1989). Triclopyr ester is not strongly absorbed in principal soil types but the degree of absorption is dependant on soil pH and organic matter content Some leaching may occur in soils under high 1 The information presented here is not meant to be used as a substitute to the manufacturer's label directives. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 26 rainfall conditions. Triclopyr is degraded by microbes, has a mean half life of 46 days in soil (depending on soil and climatic conditions) and a mean halflife in water of 10 hours at 25°C. It has a low order oft oxicity to wildlife (WSSA, 1989) but is highly toxic to fish and aquatic plants and invertebrates ifa pplied to water. It is not registered for application to water surfaces (DowElanco, 1995). ReleaseTM, although registered federally, only has provincial registration in British Columbia, Ontario, Quebec and the Atlantic provinces. The types of applications which are permitted are as follows: • Broadcast foliar am>lication from the air or ground sprayers for site preparation and conifer release; • Sin2le stem foliar am>lication for site preparation and conifer release; and, • Basal bark aPPlications, including one-sided low volume spraying, thinline spraying, streamline spraying, dormant stem spraying and cut stump spraying (DowElanco, 1995) (refer to product label). Basal bark applications are not recommended if snow or water cover the area to be treated (Pitt eta/. 1993; Buse & Bell, 1992). Buse & Bell (1992) state that triclopyr ester requires a minimum two hour rain-free period following application. As with any herbicide, proper timing of an application can significantly improve results. Herbicide induced injury to conifer crop trees most often occur when applications are made during periods ofa ctive growth, low water stress and high photosynthetic activity (Bell, 1991). The application oftriclopyr ester for site preparation should occur from early June through to July in Northwestern Ontario. The timing for plantation release should occur from late August to frost, while basal bark treatments may be made year round (Buse & Bell, 1992). Appendix A presents more detailed information with respect to the use of Release'™. A Profile of Vision™ Herbicide1 In 1984, glyphosate herbicide received federal registration status in Canada, as n~ for both aerial and ground applications (Reynolds eta/. 1993). Vision'™ is a liquid formulation of glyphosate. It has an acid equivalent of356 gil, present as the isopropylamine salt of glyphosate and is manufactured by Monsanto Company of Canada (CPPA, 1993). 1 The information presented here is not meant to be used as a substitute to the manufacturer's label .1 directives. .j Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 27 Visionm is recommended for the control ofw oody and herbaceous vegetation and grasses on forest sites. It is a non-selective herbicide which is readily absorbed by photosynthetically active portions oft he target plant. It is generally translocated throughout the target plant in both symplastic and apoplastic tissues (Pitt eta/. 1993). It inhibits the production of 5-enolpyruvyl shikimic acid-3- phosphate synthase, an essential enzyme in the shikimic acid pathway and in the synthesis of aromatic amino acids and secondaiy metabolites (Pitt eta/. 1993; CPPA , 1993; Zwiazek & Blake, 1990). Glyphosate will also prevent root sprouting of perennial vegetation (WSSA, 1989). Glyphosate is strongly absorbed in principal soil types and the occurrence of leaching is very low. Glyphosate is degraded by soil microbes and has a mean half life less than 60 days in soil (depending on soil conditions and microfloral population types) (WSSA, 1989) and a mean half life in water of 12 hours (CPPA , 1993). Glyphosate has a very low order oft oxicity to wildlife and fish (WSSA, 1989). Visionm is currently registered in all provinces except Alberta and Saskatchewan. The types of applications which are permitted ~ as follows: • Broadcast foliar agplication from the air or ground sprayers for site preparation and conifer release; • Single stem foliar ap_plication for site preparation and conifer release; and, • Individual stem injection (CPPA, 1993). Buse & Bell (1992) state that glyphosate requires a minimum six hour rain-free period following application. The application ofg lyphosate for site preparation should occur from late June through to July in Northwestern Ontario. Timing for plantation release should occur from mid- August to frost, and stem injection applications from April to mid-December. Appendix B presents more detailed information with respect to the use of Visionm _ A Profile of Touchdown 480TM Herbicide' An experimental glyphosate herbicide called Touchdown 480 mhas been tested for forestry use since 1989 (Campbell, 1990), but it has still not obtained federal approval in Canada This is a liquid formulation of glyphosate that has an acid equivalent of 330 g/1, present as the 1 The information presented here is not meant to be used as a substitute to the manufacturer's label directives. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 28 trimethylsulphonium salt ofg lyphosate (VisionT M contains the isopropylamine salt of glyphosate) (Zeneca Agro, 1989). This herbicide is manufactured by Imperial Chemical Industries and is distributed in Canada by CHIPMAN. The behaviour and mode of action of Touchdown 48o'rM essentially the same as VisionT M (Pitt eta/. 1993). Touchdown 480TM is recommended for the control of woody and herbaceous vegetation and grasses on forest sites. It is a non-selective herbicide which is readily absorbed by photosynthetically active portions of the target plant. There is no occurrence of leaching from soil and this herbicide is rapidly degraded within days or at most a few weeks in the soil. It has a very low order of toxicity to wildlife and fish. Touchdown 480TM requires a minimum six hour rain-free period following application (Zeneca Agro, 1989). The principal difference between the formulations ofVisionT M and Touchdown 480 no; other than the difference in glyphosate sa!ts, is that the latter has a built-in glucocide wetting agent. Touchdown 480TM may affect jack pine more adversely than VisionT M because of this adjuvant; not because it is the trimethylsulphonium salt of glyphosate [Partika (pers. comm., 1993)]. Appendix C presents detailed reference information with respect to Touchdown 480 TMexperimental herbicide. [Note: Unless otherwise indicated, any reference to glyphosate in the remainder of the literature review pertains to VisionT M (or its identical counterpart un u ~ not to Touchdown 480T M_ In addition, any reference to triclopyr in the remainder oft his report pertains to the ester formulation, not the amine formulation of triclopyr.] SUSCEPTIBILITY OF NON-CROP VEGETATION TO TRICLOPYR ESTER AND GLYPHOSATE Both triclopyr ester and glyphosate herbicides are used for the control of both woody and herbaceous vegetation Many environmental factors influence foliar applied herbicide absorption, translocation and efficacy. Temperature, photoperiod, relative humidity and plant water stress (Seiler eta/. 1993). Table 3 compares the susceptibility of selected boreal forest vegetative species to ReleaseTM and VisionT M. Except for grasses, sedges and bracken fern, most non-crop species tend to be more susceptible to triclopyr ester than to glyphosate. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 29 Efficacy of Triclopyr Ester In Canada, published material reporting positive results in vegetation control with triclopyr ester in Canada is minimal. This is because triclopyr has only recently received federal approval for forestry operations. Jotcham (1988b) reported successful control oft rembling aspen with triclopyr ester when applied with a backpack at a rate of0.87 kg aelha; and 100% red oak (Quercus rubra L) and red maple stem kill at 0.87 and 1.75 kg aelba. Ritty & Welker (1984) observed satisfactory control of maple, poplar, oak (Quercus L. spp.) and hazel (Cory!u s L. spp.) with applications of triclopyr at rates of 1.68 kg ae/ha and 2.25 kg aelha. It was found that the degree of control was directly related to age, size and intensity of the non-crop vegetation. MacKay eta/. (1988a) report 95% trembling aspen stem kill with aerially applied triclopyr at a rate of2.2 kg ae/ha. MacKay et al. (1988b) also observed at least 85% trembling aspen, white birch and pin cherry stem kill with aerially applied triclopyr at 2.5 kg aelha. Both these trials occmred near Thunder Bay, Ontario. Other trials with triclopyr in Northern Ontario resulted in: 800/o or greater stem kill oftremblingaspen, white birch and willow(Sa/i% L. spp.) after basal bark applications near Kapuskasing; good control oft rembling aspen and pin cheny two years after an aerial application, at a rate of1.45 kg aelha near Fort Frances, and; excellent control of trembling aspen, beaked hazel and mountain maple two years after a ground broadcast application from a Briicke herbicider, at a rate of2.9 and 3.87 kg ae/ha near Thunder Bay (Mercier & Leach 1991; Mercier eta/. 1992; Mercier & Mihajlovich 1992). Efficacy of Glyphosate Positive results in vegetation control using glyphosate is well documented. In British Colwnbia, Pollack eta/. (1990) observed satisfactory control ofw illow when glyphosate was applied with backpack sprayers at a rate of 2.1 kg aelha. In Manitoba, Ardron et a/. (1992) observed increased trembling aspen mortality with increasing rates of glyphosate (0.88 to 1.96 kg aelha) when releasing white spruce (Picea glauca (Moench) Voss) plantations. In Nova Scotia, Jotcham (1988a) observed 90% dieback of raspbeny with the backpack application of 2.24 kg aelha of glyphosate. Anonymous (1989) observed adequate control of raspberry with an application of glyphosate at 0.61 kg aelha and red maple at 0.82 kg aelha. Also in Nova Scotia, successful reductions of woody and herbaceous vegetation were observed five to eight years after the application of glyphosate at 1.65 kg aelha (Anonymous, 1993). Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 30 In New Brunswick, Pitt et al. (1992) observed >60% cover reduction of raspberry, pin cherry, elderbeny(Sambucus L. spp.) and trembling aspen at rates between 0.5 and 1.0 kg aelha of glyphosate. Crown cover reductions of 60% for red maple and white birch were achieved with the application of 1.0 kg aelha. Pitt eta/. (1993) observed that both VisionT M and Touchdown 480TM glyphosate herbicides were effective in controlling sugar maple (Acer saccharum Marsh.), mountain maple, and yellow birch (Betula Iutea Michx. f.) at rates above 0.5 kg aelha; but were not effective in controlling beaked hazel and striped maple (Acer pensylvanicum L.). Touchdown 480 TM was found to be slightly inferior to VisionT M in the control of mountain maple. In Maine, Newton eta/. (1992a) reported effective control of trembling aspen, red maple and raspberry with glyphosate applied at rateS of 1.65 and 3.3 kg aelha; two and seven years after herbicide application. In Northeastern Ontario, Wood & von Althen (1993) applied glyphosate at a rate of2.0 kg aeJba for site preparation and observed a 95% reduction of woody sprouts, shrubs and herbaceous vegetation. In North Central Ontario, Stasiak et al. (1991) observed that the growth and vigour ofp in cherry and trembling aspen was negatively affected two years after the application ofv ery low rates of glyphosate (0.04 .to 0.5 kg ae/ha). Herbicidal activity was measured in the field by monitoring shikimic acid levels in the target plants long before any visual effects could be detected (within two days after herbicide application). Campbell (1990) stated that glyphosate constituted 81% of all Canadian forest herbicide applications made in 1988, followed by 2,4-D, simazine and hexazinone. Triclopyr was not registered for use at that time. SUSCEPTIBILITY OF CONIFER CROP TREES TO TRICLOPYR ESTER AND GLY PHOSATE The effectiveness of herbicides is often limited by their ability to control undesirable vegetation selectively without injuring the conifer crop (Willis eta/. 1989). Coniferous species generally tolerate herbicides best ift hey are applied during periods without active apical growth; therefore applications are timed to coincide with conifer 'dormancy'. However, herbicide tolerance varies widely among conifer species (King & Radosevich, 1985). Radosevich eta/. (1980) observed that the highest level ofc onifer seedling injmy occurred when triclopyr and glyphosate were applied during periods of active growth, low water stress (Zwia.zek & Blake, 1990) and high photosynthetic activity. These observations were made on ponderosa pine, Jeffrey pine (Pinusjeffreyi Grev. & Balf.), sugar pine, Douglas-fir, white fir and red fir (Abies magnifica A. Murr.). Similar observations were made by King & Radosevich (1985) on these same species except ponderosa pine. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 31 Table 3. A comparison of the susceptibility of selected boreal forest vegetative species to ReleaseTM and Vision' I'M (where: 'R.' =resistant; 'I-R' =intermediate to resistant; T = intermediate; ·s-r =susceptible to intermediate; 'S' = susceptible; '-' = no information) {adapted from Buse & Bell, 1992). VEGETATIVE SPECIES RELEASE VISION (Triclopyr) (Glyphosate) Aster L. spp. R* R* Calamagrostis canadensis (Michx.) Beauv. R I Carex (Dill.) L. spp. - S-I Graminae (E.P., B.H.) spp. R S-I Epilobium angustifolium L. s I Pteridium aquilinum (L.) Kuhn. I-R S-I Acer spicatum Lam. s S-I Alnus B. Ehrh. spp. s S-I Amelanchier Medik. spp. s s Betula p_apyrifera Marsh. s S-I Comus stolonifera Michx. s I-R Corylus cornuta Marsh. S-I S-I Ledum groenlandicum Oeder I-R R Populus L. spp. s S-I Prunus L. spp. s s Ribes L. spp. s I Rosa acicularis Lindl. s S-I Rubus L. spp. s I Salix L. spp. s I-R Vaccinium L. spp. s S-I • Note: Aster spp. has only been controlled with triclopyr and glyphosate at rates higher than those approved for forestry use (Hollstedt, 1992). Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 32 Late fall applications ofg lyphosate ~u some injury to dormant Douglas-fir, white fir and red fir (Radosevich eta/. 1980). Damage in late fall was also observed by Lund-Hoie (1975) with Norway spruce (Picea abies (I..) Karst.) and Scots pine (Pinus sylvestris L.). In New Zealand, Saville (1989) noted that during periods of active growth, triclopyr applications greater than 0.6 kg aelha caused significant growth suppression and malformation of radiata pine seedlings. It was found that release lreatments for.dormant radiata pine transplants less than 1-year-old should not exceed 1.8 kg ae/ha. Balneaves & Davenhill (1990) observed that the application oftriclopyr at rates greater than 0.6 kg aelha for releasing radiata pine and Douglas-fir caused apical death, multi- leadering and reduced growth. Anjou & Pendl (1986) indicate that grand fir (Abies grandis (Dougl.) Lindl.) in British Columbia could tolerate rates oftriclopyr up to 2.9 kg aelha. Boyd eta/. (1985) indicate that ponderosa pine and lodgepole pine (Pinus contorta Dougl.) are very susceptible to foliar applications oftriclopyr ester. Warren (1982) observed that a long needled pine such as ponderosa pine was slightly more susceptible to triclopyr at rates of 1.1 to 1.6 kg ae/ha than a short needled pine, such as western white pine (Pinus monticola Dougl. ), during August/September applications. These observations concur with those of Cole & Newton ( 1988) and Cole eta/. (1987). Gnegy & Lichy (1984) observed adverse effects oftriclopyr at 1.1 to 1.68 kg aelha on loblolly pine growth, but normal growth resumed 2 years after application. Application was made in the third week of September in Virginia. This is contrary to observations made by Fitzerald & Griswold (1984), who observed safe release of dormant loblolly pine with triclopyr applied at rates from 0.56 to 1.68 kg aelha in Georgia. With the exception ofj ack pine, all major boreal forest conifer crop trees (balsam fir, black spruce, white spruce, red pine and white pine) are resistant to the herbicidal effects of triclopyr and glyphosate. Jack pine is considered intermediate to resistant to both herbicides. However, resistance is dependent on the proper timing and rates ofa pplication (Buse & Bell, 1992). Jack pine has the potential for larnmas or late season shoot growth. In addition, it has a very thin needle cuticle (Bell, 1991) and the needle stoma are not as well covered by waxy diaphrams, as compared to other conifers [Lehala eta/. 1972; Day (pers. comm. 1994)]. Willis eta/. (1989) found that foliar injury to jack pine was highest following field applications of glyphosate and triclopyr in July. Triclopyr injured jack pine more so than did glyphosate in both field and growth chamber studies. Increased wax deposition on the needles over the growing season increased jack pine tolerance to both herbicides. However, Willis et a/. (1989) observed that, regardless of application date, triclopyr always caused some injury to jack pine. This parallels observations made by Paley & Radosevich (1984) who fotm.d that ponderosa pine was damaged by triclopyr regardless Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 33 of application date. The ReleaseTM (triclopyr ester) product label cautions that the probability of injury to jack pine is greater when the herbicide application is made in the same year as planting. It is indicated that senflings planted for at least two years prior to application are less likely to show symptoms of injury. (DowEianco, 1995). Similarly, the Vision TM(glyphosate) product label indicates that conifers should be established for more than one year before crop tree release (Monsanto, 1992). MINIMUM TIME INTERVALS BETWEEN CHEMICAL SITE PREPARATION WITH TRICLOPYR ESTER AND PLANTATION ESTABLISHMENT Herbicides are rarely used to kill non-crop vegetation outright but to suppress it for a short period oft ime to provide crop trees with favomable establishment and growing conditions (Malik & Vanden Born, 1986). Control treatments more often result in a partial reduction in overall biomass coupled with a shift in the dominant plant species (Morris eta/. 1993). Consequently, there is a need to reestablish crop trees prior-to the reinvasion ofn n~ vegetation in order to maximize the competition-free period. A herbicide may persist on a site following chemical site preparation while it degrades. For example, 2,4-D has a half life of three to four weeks in warm moist soil (CPPA, 1994). Such a persistence may have a detrimental effect on conifer crops planted to soon after the application. In addition, herbicides applied concurrent with planting may result in detrimental nutrient immobilization, and decomposing plant residues may have also have a detrimental chemical effect on the planted trees. Such undesirable effects may only be eliminated by applying the herbicide well in advance ofp lanting (Bell, 1991 ). The knowledge oft he minimum time interval between herbicide application and outplanting conifer crop trees is crucial. The Release TM(triclopyr ester) product label indicates that the planting of conifers should be delayed until the year following chemical site preparation (DowElanco, 1995). Table 4 presents results of several studies regarding the minimal time interval between chemical site preparation with triclopyr ester and planting conifer seedlingsThe rates oftriclopyr applied in these studies varied from 2.24 to 3.85 kg ae/ba. Generally, research indicates that spruces (Picea A Dietr. spp.) require a minimum of7 days to one month between chemical site preparation and safe outplanting; while pines (Pinus L. spp.) require a minimum of22 days to a month between chemical site preparation with triclopyr and outplanting. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 34 Table 4. Observed minimum time intervals between chemical site preparation with triclopyr ester and the planting of conifer seedlings. CONIFER SPECIES TIME INTERVAL LOCATION REFERENCECS) Jack pine ooemooth Michigan Becker et al. (1990) (Pinus banltsiana Lamb.) >7days Nova Scotia Jotcbam (1992)b . 24days New Bnmswick ~ ~ N.E. Ontario "'· _-u. et al. (1988)e Red pine ooemooth Michigan Becker eta/. (1990) (Pinus resinosa Ail) 22days Nova Scotia ,..,_ _- u_ et al. (1988)c: European larch ooemooth Michigan Becker et al. (1990) (Lara decidua Mill.) Norway spruce 22days Nova Scotia ~ et al. (1988)c (Picea abies (I..) Karst.) White spruce (Picea 7days Nova Scotia Jotcham (l992)b glauca Voss) Black spruce 7days Nova Scotia Jotcbam (1992)b (Picea mariana (Mill.) B.S.P.) 22days Nova Scotia ~ et al. (1988)c 24 days New Bnmswick et al. (1988)d 33 daYs N.E. Ontario .. I . . TI. et al. (1988)e Balsam fir 7days Nova Scotia Jotcham (1992)b (Abies balsamea (I..) Mill) MacKay eta/. (1988e) chemically site prepared a site in Northeastern Ontario with triclopyr ester at two rates: 2.88 and 3.84 kg ae/ha. It was observed that both black spruce and jack pine seedlings planted 33 days after the applications exhibited little or no injury. However, only two planting times were evaluated: 1 how- after application and 33 days after application. There were no plantings during the interim period. THE USE OF HERBICIDE MIXTURES Most selective herbicides are limited in their ability to successfully control all undesirable vegetation that might be encountered on a given area (Walstad eta/. 1987). In addition, it is generally not economically desirable and/or logistically feasible to make multiple herbicide applications in the same rotation. Hence, there is interest in the development and registration of a product containing two or more herbicides to maximize non-crop vegetation control in a single application. Herbicide combinations or mixtures can: a) widen the spectrum of non-crop vegetation control greater than that obtained from a single herbicide, and b) control different species of Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 35 vegetation with a single application (Bohmont, 1983; Walstad eta/. 1987). There is currently no product registered in Canada for forestry use that contains a combination oft wo or more herbicides (CPPA , 1992). However, they are common in the United States. Herbicide mixtures which have been researched for silvicultural activities include: picloram • and triclopyr (Fitzgerald & Griswold, 1984; Shiver eta/. 1990; Balneaves & Davenhill, 1990); picloram and glyphosate (Yeiser, 1991); glyphosate and imazapyr (Yeiser, 1991; Maass, 1991); triclopyr and 2,4-D (Warren, 1982) and triclopyr and imazapyr (Maass, 1991). Triclopyr Ester and Glyphosate Mixtures McCormack et al. (1982) applied a mixtures oftriclopyr ester and glyphosate, both at 0.28 kg aelha and also at 0.56 kg aelha, over a variable range of.site conditions. The mixtures showed excellent potential for site preparation and release activities with small quantities ofherbicide. Yeiser (1991) observed after August applications of several herbicides alone and in mixture that triclopyr and glyphosate at 3.38 and 2.45 kg ae/ha respectively, provided optimum brownout ofbroadleaves and pines in Arkansas. In Nova Scotia, Jotcham (1988a) observed 100% control of raspberry with triclopyr and glyphosate in mixture at rates of0.87 kg aelha and 0.28 kg aelha, respectively. Jotcham (1988b) reported significant control of red oak and red maple of triclopyr and glyphosate mixtures (rates ranged from 0.44 to 1.82 kg aelha and 0.28 to 1.12 kg aelha, respectively) relative to glyphosate alone (at 1.12 kg aelha). Jotcham (1992a) also reported safe release ofblack spruce and red spruce (Picea rubens Sarg.) after budset (after the third week in July), with a triclopyr and glyphosate mixture of 1.20 kg ae/ha and 0.89 kg aelha, respectively. In Northwestern Ontario, MacKay eta/. (1988a) observed that late August aerial application oftriclopyr and glyphosate, both at rates of 1.1 kg aelha, provided 93%, 94% and 100% control of trembling aspen, speckled alder (Alnus rugosa (DuRoi) Spreng.) and willow, respectively, two years after treatment. However, it was noted in this study by Helewa (1988) that this mixture did induce some needle bum in the black spruce crop trees, while triclopyr ester, when applied alone, did not. 1 Picloram: 4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid 2 Imazapyr: (±) -2-[4 ,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-im.idazol-2-y1 ]-3- pyridinecarboxylic acid Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 36 FIELD STUDY #1 MINIMUM TIME INIERVAL BETWEEN CIIEMICAL SITE PREPARATION WITH TIUCLOPYRESTERAND PLANTING .JACK PINE CONTAINER STocK :METHODOLOGY Location The trial was conducted in a boreal forest setting approximately 60 kilometres (km) west of Thunder Bay, Ontario [Lat. 48° 24' N; Long. 90° 04' W]. The field plots were established in a cutover adjacent to the Ontario Ministry ofNatural Resources 'Mattawin Seed Orchard', east of the Mattawin River. Appendix D illustrates the location of the study area. Site Description The site was a recently harvested jack pine stand, on a flat, rapidly drained, coarse sandy outwash plain (Vegetation Type 29 according to the Forest Ecosystem Classification for Northwestern Ontario (Sims et al. nd)). In 1990, a root rake was used to remove all the slash and most oft he shallow humus to expose mineral soil on 60 to 70 percent(%) of the area. This site was considered to be ideal for the study as it was a typical site for jack pine growth and the majority of non-crop vegetation was removed with the site preparation treatment. "This allowed for observation of the herbicide effects on the seedlings without the influence of other competing vegetation. Seedling Stock Overwinter cold stored jack pine container stock, grown in Trimroot 165 Ventblocks ™was obtained from A&R Greenhouses of Thunder Bay, Ontario. The Trimroot 165 Ventblocks have cavities with a volume of only 49 millilitres (ml). Therefore the mean seedling was small, with a weight of approximately 1000 milligrams (mg). The seedlings were carefully heeled-in on the planting site approximately one week prior to the first time of planting. Heeling-in was done to ensure that all the stock would be in as uniform morphological and physiological condition as possible at each planting time. Ift he ~ n had been kept in cold storage until just prior to each planting, they would not likely have been in good physical condition; especially for the later planting times. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 37 Experimental Design A randomized complete block design (RCBD) composed oft hirty 6 x 10 metre (m) [60 m ~ plots was surveyed and staked in the field in early July, 1992 (Figure 4). Three rows off ive seffiling [15 senfling;;] were planted on the appropriate plots at 2 x 2m spacing at each time ofp lanting. The design also included the same number of plots for black spruce, which were randomly placed in amongst the jack pine plots (Figure 4). The treatments are explained below. LEGEND 6m SPRA YEO CONTROL j28 DAYS l =Planted 28 days after spraying Jack Pine Ill mE ld ( Black Spruce ~ D> NORTH Figure 4. The randomized complete block design established in the boreal forest for field study # 1, approximately 60 kilometres west of Thunder Bay, Ontario. Treatments There were two sets of treatments applied to the jack pine seedlings: the first was a set of herbicide treatments and the second was a set of planting time treatments. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 38 I} The Herbicide Treatments were as follows: a) Control (0.0 kg aelha oftriclopyr ester) b) Sprayed 3.84 kg ae/ha (81/ha) oftriclopyr ester (maximum recommended rate) 2) The n n~ Time Treatments (days after herbicide application/date) were as follows: a) 1 day/July 21st, 1992. b) 7 days/July 2'J'h, 1992. c) 28 days/August 18th, 1992. d) 56 days/September ~ 1992. e) 84 days/October 13th, 1992. Linear Model The linear model for this RCBD study was as follows: where: i = 1,2,3; j = 1; k = 1,2; 1 = 1,2,3,4,5 Y ijld = the measured seedling response resulting from the interaction of the k* herbicide treatment with the" 1 time treatment of the i* block; J.L = the overall mean; B i =the fixed effect of the i* block; 6 (i)j = the random effect of the r randomization of the time and herbicide treatments within the !' block. The 6 (i)j's are assumed to be liD (O,o2) [identically and independently distributed according to the normal probability density fimction with a zero mean and variance o 2 (Brown, 1992)]. H k =the fixed effect oft he k* herbicide treatment BH ik = the interaction effect of the i* block and the k* herbicide treatment. T 1 = the fixed effect of the P. time treatment. BT ik =the interaction effect of the i* block and the k* time treatment. BHr ikl =the interaction effect oft he i* block with the k* herbicide treatment and the 1.* time treatment. e(ijkl) =the random effect of the k* herbicide treatment and the r time treatment within the1 randomization within the i* block. The e(ijld)'s are assumed to be llD (O,o2) [identically and independently distributed according to the normal probability density fimction with a zero mean and variance o 2 (Brown. 1992)]. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 39 Expected Mean Squares (EMS) Table 5 presents the expected mean squares (EMS) and associated degrees of freedom for the linear model. The test statistics and reference distributions for the null hypothesis are also presented The EMS notation follows Anderson & MacLean (1974). Table 5. The expected mean squares (EMS) and associated degrees off reedom for the linear model; including the test statistics and reference distnbutions for the null hypothesis. VARIABLE EMS OF HYPOTHESIS TEST STATISTIC REF.DIST. R o 2 + 10o. . 2 + l()cf)(B) 2 cii{B)=O DO rest 6m; o 2 + 10oA2 0 OA2 =0 DO rest ~ 0 2 + 15cj){H) 1 cii{H) 0 F(l.2) BH. o 2 +5cii{BH) 2 cii{BH) 0 EMS F(2..8) L oz+6cj)(O 4 ~~ o -r.ra.;)\1 F(4,8} BT. 0 2 +2cii{BU 8 ci>(HI) 4 cii(Hf) 0 F(4,8) BHfid oz+ 8 .I..,.,_T ......... 0 DO rest E1ildl oz 0 Herbicide Application The herbicide was applied at walking speed by personnel carrying a Research and Development (R&D) pressurized backpack sprayer, fitted with a 1.42 m short boom held at waist height. The boom was fitted with four #8002 flat fan nozzles. The 3.8 kg aelba (8 IJha) of triclopyr was diluted in 150 litres (1) of water per hectare and applied at a pressure of 275 kPa (4 0 psi). The herbicide was applied on July 20th, 1992; a clear day without rainfall or significant wind There was 9.2 mmimetres (mm) ofr ainfall reported the day before application (July 19 ~ n 0.6 mm ofr ainfall the day after (July 2111) at Thunder Bay Airport (Environment Canada, 1992). It must be noted that the study area was located inland from Lake Superior and Thunder Bay. Hence, meteorological information, especially temperature, may not be accurate for the study area. Crop Tree Assessment & Data Analysis The following measurements were made on all seedlings at time of planting (i.e. on each planting date in 1992): 1) basal calliper (Be) in mm, and 2) total height (T-Ht) in centimetres (em) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 40 from ground to the base of the terminal bud BC was measured at ground level using machinist's callipers and T -Ht was measured with a retractable carpenter's measuring tape. In late September, 1993, the following measurements were made on all seedlings: 1) BC in mm, 2) T-Ht in em and 3) needle length in mm (i.e. ofa randomly selected needle of the youngest needles in the Jeadjng shoot). The BC measurements were taken using callipers with digital readout; the T-Ht measmements were taken using a carpenter's tape; and the needle lengths were measured using a machinist's steel ruler. The physical condition of each seedling was visually assessed, encoded and recorded; primarily on the basis of entire seedling needle condition. The physical condition codes used are presented in Table 6. The author suspects that a physical condition code > 2.5 probably would result in mortality or 'checked' growth. Table 6. Codes used to descnbe the physical condition of the jack pine seedlings based on visual assessment. [Note: SeMHngs with condition codes 1 - 3 were considered to be 'alive', and those with code 4 were considered to be 'dead'.] Code Number Physical Condition 1 Foliage healthy (green); <20% brown or defoliated 2 21 to 60% brown or defoliated 3 61 to 99% brown or defoliated 4 100% brown or defoliated; buds dead and inner bark dry Seedling performance from time of herbicide application in 1992 to the fall of 1993 was evaluated by computing the following means (per plot): 1) Percent survival of all planted seedlings; 2) Physical condition of all seedlings; 3) Needle length (mm) of the surviving seedlings; 4) Volume Incrementlha in cubic centimetres (cm3) of surviving seedlings (calculated using Formula 1) ; Vol. lnc./ha = C> a: ::l tl) w~ 0aw: Q. 1 ~ ~ ~ M DAYS FROM HERBICIDE APPLICATION ~C ~ Figme 5. The mean percent survival rates oft he jack pine seedling:; for each herbicide and planting time treatment after one growing season. The Tukey's - HSD multiple range test indicated that there were significant differences in sefflling survival between the planting times. The mean percent survival ofs eedling:; planted 7 days after treatment was significantly higher than those observed at 1 and 56 days. The survival of geeAJingc; planted at 28 and 84 days after spraying were also significantly different from that observed of seedlings planted 56 days after herbicide application. The paired t-tests indicate that there were no significant differences between control and sprayed plots at any of the planting times. However, the difference in seedling survival between the control and sprayed plots, planted 1 day after spraying, was significant at p = 0.07. Results in Figure 5 suggest a trend of decreasing differences in seedling survival between control and sprayed plots as post-application planting time increases. Although there were no statistically n ~ differences in mean percent seeAling survival between the control and sprayed Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 43 plots at I, 7 and 28 days, the differences that were observed could well be of significance to the silviculturist. Mean Physical Condition Figure presents the mean condition code of the jack pine seedlings for each herbicide and planting time treatment after one growing season. As the code increases from I.O to 4.0, seedHng physical condition decreases (refer to Table 6 in Methodology). The ANOVA indicated that the two-way interaction effect ofblock and herbicide treatment was significant. The herbicide treatment effects; the planting time treatment effects; the interaction effects of block and planting time, and those of herbicide and planting time treatments, were all highly significant at p = 0.05. The Tukey's - HSD multiple range test indicated that seedHngs planted 7 days after herbicide application were in significantly better physical condition than those planted I day after spraying. The paired t-tests indicated that there was no significant differences in mean seedling physical condition between the control and sprayed plots at each planting time. The largest difference in condition code between seedlings in the control and sprayed plots, which occurred at the first planting time, would have been significant at p = 0.06. With the exception of planting time at day 56, the seedling condition code approximated 2.5 in all the control plots and the seedlings were in better or equal physical condition than seedlings planted into sprayed plots (Figure 6). The mean seedling planted into sprayed plots I day after herbicide application was dead (code 4). Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. w Q 0 () z 0 t= Qz 0 () 1 7 28 58 84 DAYS FROM HERBICIDE APPLICATION ~C ~ Figure 6. The mean physical condition codes of the jack pine seedlings for each herbicide and planting time treatment after one growing season. Mean Needle Length Figure 7 presents the mean needle length (in mm) of the jack pine seedlings for each herbicide and planting time treatment after one growing season. The ANOVA indicated that only the planting time treatments had significant effects on mean needle length. Herbicide treatment effects and all the interaction effects were not significant at p = 0.05. The Tukey's- HSD multiple range test indicated that there were no significant differences in mean needle lengths of seedlings observed between the five planting times. This did not concur with the results oft he ANOVA , likely because of the inclusion ofblock effects in the range testing procedure when using SPSS/PC+. The paired t-tests indicated that there were no significant differences in mean needle lengths between the control and sprayed plots at each planting time. The largest difference in needle length was observed at the first planting time, where the needles of the control seedlings were Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 45 ~ ~ l: t- "zw ..J w ..J 0 ww z 1 _ 7 ~ ~ M DAYS FROM HERBICIDE APPLICATION ~C ~ Figure 7. The mean needle lengths (in mm) of the jack pine seedlings for each herbicide and planting time treatment after one growing season. approximately 22 mm longer than those of seedlings in the sprayed plots. The needle lengths observed in the control plots n r ~ and those observed in the sprayed plots increased, as planting time from herbicide treatment increased (Figure 7). Mean needle length did not appear to be in any way related to seedling survival (Figure 5). Volume Incrementlha Figure 8 presents the mean volume incrementlha in ~ of the jack pine seedlings for each herbicide and planting time treatment after one growing season. The addition of a constant of ( + 400) to each mean was necessary for graphical presentation because of negative volume incrementslha. Seedling volume was calculated as a function of height. As the leaders of many seedlings died, seeAJing heights were subsequently measured to the base of the terminal bud of the next tallest, secondary, live branch. r Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 46 (- 2500 I) < .- E 0 0 0. + -Cl: :I: z.... w w~ ~ 0z w :E ::) ..J >0 1 7 28 58 84 DAYS FROM HERBICIDE APPLICATION ~C ~ Figure 8. The mean volume incrementslha + 400 cm3 of the jack pine seedlings for each herbicide and planting time treatment after one growing season. The ANOVA indicated that the herbicide treatments had significant and the planting time treatments had highly significant effects on volume incrementlha. There was a significant interaction effect ofblock by planting time treatment on volume incrementlba at p = 0.05. The Tukey's - HSD multiple range test indicated that the mean volume incrementlha oft he seerllings planted 7 days after spray was significantly higher than those planted at 56 and 84 days after herbicide application. In ~ the mean incrementslha ofS C"'#dHngs planted at 1 and 28 days were also significantly higher than that of seedlings planted at 56 days. The paired t-tests indicate that there were no significant differences in mean volume incrementlha between the control and sprayed plots at each planting time. It was observed that at 1, 7 and 28 days, the mean volume incrementslha in the controls were more than twice those observed in their respective sprayed counterparts (Figure 8). The sprayed plots at 56 and 84 days had higher mean volume incrementslha than the respective control plots. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 47 DISCUSSION Label directives for Release m (1riclopyr ester) recommend an application rate of 3 to 8 l/ha (1.44 to 3.84 kg aelha) for broadcast foliar chemical site preparation. The label also recommends that the planting of conifer seedlings should be delayed for one year following the application (DowElanco, n.d) . In this study, 1riclopyr ester was applied at the maximum recommended rate of 8 1/ba (3.84 kg aelha). Under the soil and climatic conditions of this study, the results suggest that a period of one year between herbicide application and planting jack pine is not necessary. After one growing season, comparisons of mean jack pine percent survival, physical condition, needle length and volume increment!ha between control and sprayed plots showed no statistically significant differences at each planting time. However, this could be a function of the experimental design not having not having sufficient power 2.5 probably would result in mortality or 'checked' growth. Seedling performance from time of herbicide application in 1992 to the fall of 1993 was evaluated by computing the following means (per plot): 1) Percent survival of all planted seedlings; 2) Physical condition of all seedlings; 3) Needle length (mm) of the surviving seedlings; 4) Volume increment/ha in cubic centimetres {cm3) of surviving seedlings (calculated using Formula 4); Vol. Inc.lba = (03C + 2f x 1t) x {T- Ht inc.) x K ( 4) 3 where: BC =basal calliper increment (1992 to 1993) (em) T-Ht inc. =total height increment (1992 to 1993) (em) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 60 K =conversion factor= (10000 m2/ha)+ 40m2 x no. live trees/plot The crop tree data were analyzed using ANOVA Tukey's- HSD Multiple Range Test was used to determine the statistical differences between ranked treatment means at p = 0.05. ~ Percent smvival was transformed to angles using arcsin(proportion) 'h(Snedecor & C ~ 1967) for the statistical analysis because of the non-normality of percentage data.] The physical condition code data was an ordinal type of measurement. Generally, it is not advised to use multiple range tests for significance, such as Tukey's - HSD, for ordinal data unless it appears to have a normal distribution or unless it comes from large sample sizes (Freese, 1962; . Freese, 1967). Exploratory analysis and the Bartlett-Box F test for homogeneity of variance indicated that the data was normally distributed. Data was organized using a Quattro Pro 4.0TM spreadsheet and all statistical analyses were performed using SPSS/PC+TM. Mean seenling responses were calculated for herbicide treatments grouped along a treatment rate concentration gradient (0, 1-3 an4 4-6 llha), to determine ifa ny trends in yed]ing performance existed. To further synthesize the data, the mean of each seedling response variable between herbicide treatments which resulted in above 70% seedling survival and those which resulted in below 70% seedling survival was calculated. Seedling responses resulting from the two control treatments were not included in this calculation. To determine the optimum treatments which resulted in 'safe' and satisfactory control ofe ach oft he major vegetation types, it was fotmd necessary to set tolerance limits on seniling survival and physical condition code following each treatment. When conducting conifer release treatments with herbicides, the survival and health of the crop trees are of greatest concern. That is, if non-crop vegetation is not effectively controlled, there are still other alternatives available. However, ift he herbicide applied damages or destroys the crop, then the implications are much more serious. In this context, the choice herbicide or herbicide mixture must be based primarily on the effects on the planted crop, and secondly on the efficacy with which it controls tmdesirable vegetation. Hence, the author set the tolerance limits on seedling survival and physical condition code, and then recommended potential herbicide mixtures on the basis of observed and statistical evidence. An acceptable treatment should not cause more than 30% mortality and/or cause physical condition codes to exceed 2.5. These tolerance limits, although arbitrarily chosen, should be similar to the expectations and tolerance limits of the field forester. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 61 RESULTS ·Results of Non-Crop Vegetation Assessment & Data Analysis Tables 9 and 10 present a listing of all tree/shrub and herbaceous plant species observed, respectively, on the site one year after treatment application. Those listed in bold were the species (or groups ofs pecies) which were ofm ost interest to DowEianco Canada Inc. . Trembling aspen and white birch were the only two tree species encountered, but as the vegetation in each plot was cut to approximately 1 min height prior to treatment (see Methodology), these two species were tallied as shrubs. In addition, two cherry and two raspberry species, although tallied separately, were grouped as Prunus L. spp. and Rubus L. spp., respectfully, for statistical analysis and results : presentation. Canada blue-joint grass ( Calamagrostis canadensis (Michx.) Beauv. ), sedges (Care x · (Dill.) L. spp.) and bracken fern were also obsetved on the ~ Mosses, other ferns and fern allies : were not tallied. Herbicide rates in the results are expressed in 1/ha but they are expressed in both 1/ha and kg aelha in the discussion. See Table 7 or Figure 10 for equivalent application rates in 1/ha and kg aelha. The analysis ofv ariance (ANOVA) indicated that, one year after treatment application, there was a significant treatment effect on total vegetation index and a highly significant effect on shrub vegetation index. The remainder vegetation was not significantly affected by the herbicide treatments. Appendix G summarizes the results of the ANOVA. Table 11 lists the mean total vegetation indices, ranked in increasing order (Ranked Mean . Total Veg Index), that were observed one year after each of the twenty-three treatments. The corresponding mean shrub, herb, graminoid and bracken fern vegetation indices are also presented. For the ranked mean total vegetation index and the mean shrub vegetation index, letters are used to show the mean indices which were significantly different from each other, as identified by Tukey's - HSD multiple range test (at p = 0.05). Three statistical groups were identified; a, ab and b. Treatment #1 (unweeded control) and #2 (manually weeded control) are listed in italics and marked with an asterisk '*'. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 62 Table 9. A listing of all shrub species tallied on the site. Those listed in bold were the species (or species groups) of most interest to DowElanco Canada Inc. . SHRUB SPECIES Trembling aspen Populus tremuloides Michx. Mountain maple Acer spicatum Lam. Beaked hazel Corylus cornuta Marsh. Pni1111S L spp. Choke cherry P. virginiana L.fil. Pin cherry P. pensylvanica Lfil. Bush honeysuckle Diervi//a lonicera Mill. RMbus L spp. Wild raspbeny R. idaeus var strigosus (Michx.) Maxim. Dwarf raspbeny R. u ~ Raf. White birch Betula papyrifora Marsh. Ame/anchier Medik. spp. Mountain junebeny A. bartramiana (Tausch) Roem. Red-twigged servicebeny A. sanguinea (Pursh) DC. Prickly wild rose Rosa acicularis Lindl. Velvet leafbluebeny Vaccinium myrti//oides Michx. Green alder Alnus crispa (Ait.) Pursh Canada fly honeysuckle Lonicera canadensis Bartr. Table 10. A listing of all herb species tallied on the site. Those listed in bold were the species of most interest to DowElanco Canada Inc. . HERB SPECIES Aster L spp. A. macrophy//us L; A. ciliolatus Lindl. Fireweed Epilobium angustifolium L Rose twisted stalk Streptopus roseus Michx. Wild sarsaparilla Aralia nudicaulis L. Pale vetchling Lathyrus ochroleucus Hook Blue bead lily Clintonia borealis (Ait.) Raf. Spreading dogbane Apocynum androsaemifo/ium L. False buckwheat Polygonum scandens L. Wood anemone Anemone quinquefo/ia L. Bicknell's cranesbill Geranium biclaze//ii Britt. Appendix H presents graphically the mean vegetation indices for each vegetation type by individual treatment. The results for individual species or species groups which were ofm ost interest Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 63 to DowElanco Canada Inc. are also presented Results ofTukey's - HSD testing at p = 0.05 are given where significant differences between mean indices existed one year after treatment. Table 11. The twenty-three treatments ranked according to mean total vegetation index (in increasing order) and the corresponding mean vegetation indices for the remaining vegetation types; one year after each treatment. Treatment #I (no control) and #2 (manual control) are listed in italics and marked with an asterisk. Rel- T dn - VIS refers to: Release - Touchdown 480 - Vision. Letters denote significant differences identified by Tukey's - HSD multiple range tests. Treatmeat Herbicide RaDiu!d Mean Mean Mea Mea No. Mimlres Mean Shrub Herb Gnmiaoid Fena Rel-Tda-Vu Total Vegllldex Veg Veg Veg fm llba) Vegllldex liadex ~ liadex 5 0 3 0 1349a 409ab 870 77 0 20 3 6 0 1388 a 253ab 984 169 4 6 0 4 0 1450a 156a 1180 93 25 22 5.1 5.1 0 1458 a 641ab 704 83 54 4 0 0 6 1503 a 287ab 1085 56 81 17 3 1 0 1619 a 400ab 282 342 74 8 3 0 0 1740a 323 ab 919 433 75 3 0 0 4 1745 a 576ab 1098 40 38 14 2 0 2 1945 a 432ab 936 138 456 19 3 3 0 2010 a 457ab 1365 208 0 7 0 6 0 2030a 467ab 1330 117 125 18 3 2 0 2034a 896ab 981 110 67 • 2 0 0 0 2183a 317ab 1526 206 138 13 0.9 5.1 0 2354a 994ab 1158 56 160 15 3 0 1 2776a 742ab 1668 258 125 11 6 0 0 2800ab 688 ab 1281 469 315 10 50 0 2817ab 603ab 1717 392 118 12 0.9 0.9 0 2829ab 1168 ab 1440 235 0 9 4 0 0 2843 ab 1409 ab 1093 296 56 21 5.1 0.9 0 3284ab 825ab 2180 69 234 23 6 3 0 3490ab 1609 ab 1566 96 254 16 2 2 0 4205 ab 2293 ab 1767 146 17 • I 000 532/b 3203b 2140 227 54 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 64 Mean vegetation indices for each vegetation type were calculated for the herbicide treatments, and presented graphically, on the basis of a grouped herbicide rate concentration gradient: 0 ~ 1-3 1/ha and 4-6 1/ha. This was done to determine if any general trends in vegetation control existed It must be noted that when comparing treatments with Touchdown 480TM to those with Vision™ , similar concentrations in litreslha of do not represent the same acid equivalent concentrations in grams/litre (330 g ae/1 and 356 g ae/1, respectively). Appendix I presents the calculated means grouped along the herbicide concentration gradient in tabular form. Mean Total Vegetation Index The ANOVA indicated that there were significant differences between the mean total vegetation indices. The Tukey's- HSD Multiple Range Test indicated that the resultant mean index in Control A (no vegetation control) was significantly different from the majority of the herbicide treatments and from the manually weeded control (Control B) {Table 11 ). Relative to no vegetation control, treatment #5 (0-3-0) was the most effective in reducing the mean total vegetation index while treatment #16 (2-2-0) was the poorest. Figure 11 presents the mean total vegetation indices grouped by herbicide treatment rates (0, 1-3 and 4-61/ha). It shows that, with the exception of the application ofReleaseTM mixed with Touchdown 480TM, both at rates ~ 41/ha, no herbicide mixtures were as effective in reducing the mean total vegetation indices as were glyphosate treatments applied alone. However, all the herbicide treatments and manual weeding did substantially reduce the mean index relative to no vegetation control (Control A). Application rates of Release TM ~ 4 Ilha were not as effective as that at 31/ha. The application oftriclopyr ester appears to be associated with less control of vegetation. However, despite this organization of the treatments into a concentration gradient, few strong patterns emerge, posstbly a result oft he experimental problems in the methodology (i.e. the cutting oft he shrubs and the lack ofa pre-treatment vegetation assessment).(O, 1-3 and 4-6 1/ha). It shows a similar trend to that observed with mean total vegetation index (Figure 11 ). Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 65 UNWEEDED CONTROL --1-MIANUAI..LY WEEDED CONTROL 0 1-3 4-6 1-3 4-6 TOUCHDOWN (IJhe) VISION (1/he) Figure 11. The mean total vegetation indices grouped by herbicide rate (0, 1-3 and 4-61/ha) (adapted from Table 11). Mean Shrub Vegetation Index The ANO VA indicated that there were highly significant differences between the mean shrub vegetation indices. Tukey's- HSD Multiple Range Test indicated that the lowest mean shrub vegetation index resulted from treatment #6 (0-4-0) and was significantly different from Control A (no vegetation control) (Table 11 ). As with mean total vegetation index, herbicide treatment# 16 (2- 2-0) resulted in the poorest vegetation control. Figme 12 presents the mean shrub vegetation indices grouped by herbicide treatment rates Mixtures ofReleaseTM with either Touchdown 480TM or VisionT M did not reduce the mean shrub indices as much as did either glyphosate herbicide applied alone. However, all the herbicide treatments and the manual weeding did substantially reduce the mean shrub index relative to no vegetation control (Control A). Again, application rates oftriclopyr ester: Q 0z i< a: 0 z .<.... ::E 0 1-3 ~ 1-3 4-6 TOUCHDOWN (IJhe) VISION (llhe) Figure 14. The mean graminoid vegetation indices grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 11). It shows that, with the exception of mixtmes Release TMand Touchdown 480 TMboth applied at r ~ 41/ha, none of the herbicide mixtures nor those ofReleaseTM applied alone were as effective as either glyphosate herbicide applied alone. Vision TMtreatm.ents applied at rates ~ 4 1/ha were the most effective in reducing the mean graminoid vegetation index relative to no vegetation control (Figure 14). Mean Bracken Fern Vegetation Index There were no significant differences between the mean bracken fern vegetation indices resulting from the treatments. Three treatments resulted in I 00% control ofb racken fern while the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 69 poorest control resulted from treatment #14 (2-0-2) (Table 11). Figure 15 presents the mean bracken fern vegetation indices grouped by herbicide 1Ieatment rates (0, 1-3 and 4-6 llha). It shows that, with two exceptions, all treatments generally increased the mean index ofbracken fern relative to no vegetation control (Control A). The exceptions included the one treatment with Touchdown 480TM applied alone at a rate of3 llha and the mixtures of Release™ and Touchdown 480™ both applied at rates ~ 3 1/ha (Figure 15). UNWEEDED CONTROL M = 54) I I I MANUALLY WEEDED CONTROL )( 1.1.1 c ~ z 0 I= c( 1- 1.1.1 ~ >1.1.1 az: 1u.1..1. z ~ ~ =a: z c( 1.1.1 :::i 0 1-3 ~ 1-3 4-e TOUCHDOWN (f,e) VI Sl ON (l,e) Figure 15. The mean bracken fern vegetation indices grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 11). Results of Jack Pine Crop Tree Assessment & Data Analysis The analysis ofv ariance (ANOVA) indicated that, one year after treatment application, the herbicide treatments had a significant effect on survival and needle length. Physical condition and volume increment was not significantly affected by the herbicide treatments. Appendix J smnmarizes Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 70 the results of the ANO VA Table 12 lists the mean ~ n percent smviva1 rates, ranked in decreasing order (Ranked Mean% Survival), that were observed one year after each oft he twenty-three herbicide treatments. Statistical analysis was performed on the transformed survival data, however the raw data is presented The corresponding physical condition codes, needle lengths and volume increments are also presented An overall mean for each Sf'A'dling response variable is presented (in bold) for the treatments which were in the 'above 70% survival group' (A70G) and for those which were in the 'below 70% survival group' (B70G). The unweeded control (treatment #1) and the manually weeded control (treatment #2) are not included in the overall mean of the A70G and B70G. The two control treatments are listed in italics and marked with an asterisk '*'. Appendix K presents the results graphically for: ~ percent survival rates; mean physical condition codes, mean needle lengths and mean volume incrementslha, of the jack pine seedlings, one year after each treatment. Means for each Sf'A'dling response variable were calculated for the herbicide treatments, and presented graphically, on the basis of a grouped herbicide rate concentration gradient: 0 1/ha, 1-3 1/ha and 4-6 llha. This was done to determine if any general trends in seedling response existed. It must be noted that when comparing treatments with Touchdown 480™ to those with Vision™ , similar concentrations in litreslha of do not represent similar acid equivalent concentrations in grams/litre (330 g ae/1 and 356 g ae/1, respectively). Appendix L presents the calculated means grouped along the herbicide concentration gradient in tabular form. Mean Percent Survival The ANOVA indicated that there were significant differences between mean seedling survival. However, the Tukey's - HSD multiple range test did not distinguish which treatments means were significantly different. This may be due to the inclusion of block effects in the range testing procedure when using SPSS/PC+. As presented in Table 12, 100% seedling survival was observed, one year after treatment application, as a result of manual weeding (Control B) and of treatment #12 (0.9-0.9-0). Poorest survival was observed with treatments #20 (3-6-0) and #21 (5.1-0.9-0); 32% and 34%, respectively. The A70G survival mean was much higher than the B70G survival mean; 81% vs 51%, respectively. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 71 Table 12. The twenty-three treatments ranked according to mean percent survival (in decreasing order) and the corresponding mean physical condition code, mean needle length and mean volume incrementlha; one year after each treatment. Treament #1 (no control) and #2 (manual control) are listed in italics and marked with an asterisk. Rei- Tdn- Vts refers to: Release- ~ n ~ n Treatmeat Herbicide R.uked Meaa Mean MeaaVoL No. Mimlres Mean% Coaditioa Needle Iauemeat Rei-Tela-VIS Sarvival Code Lagth (mm) (c:mslha) (mlllla) • 2 000 100.00 1.00 79 753 12 0.9 0.9 0 100.00 133 74 355 14 2 0 2 9333 1.67 76 334 4 0 0 6 8633 1.67 64 193 17 3 1 0 7933 233 65 201 15 3 0 1 75.00 2.00 64 127 16 2 2 0 75.00 2.00 71 219 8 3 0 0 1333 2.00 75 339 5 0 3 0 73.00 2.00 52 88 10 5 0 0 71.00 233 62 71 MEAN 80.70 1.92 67 214 SURVIVAL CUfOFF OF 70 PERCENT *I 0 0 0 67.00 2.00 68 UJ 11 6 0 0 62.00 233 56 164 9 4 0 0 61.33 2.67 75 378 3 0 0 4 61.00 1.67 56 70 18 3 2 0 61.00 2.67 70 102 13 0.9 5.1 0 57.67 3.00 33 22 6 0 4 0 54.00 2.67 38 34 7 0 6 0 54.00 2.67 52 47 19 3 3 0 4933 2.67 53 85 22 5.1 5.1 0 42.00 3.00 57 24 23 6 3 0 4133 3.00 59 304 21 5.1 0.9 0 33.67 3.00 56 76 20 3 6 0 32.00 333 28 37 MEAN !50.80 2.70 S3 112 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 72 Figure 16 presents the mean cw:dling survival rates grouped by herbicide treatment rates (0, 1-3 and 4-6 Jlba). , 0 1-3 4-CI 1-3 4-6 TOUCHDOWN (IJhe) VISION (llhe) Figure 16. The mean seedling percent survival grouped by herbicide rate (0,1-3 and 4-6 Jlba) (adapted from Table 12). It shows that all mixtures ofReleaseN and Touchdown 480 Nan resulted in cw:dling survival rates below the 70% acceptable survival cut-off In addition, applying either Touchdown 480 TMor Release' I'M alone at rates ~ 41/ha was detrimental to seedling survival. No vegetation control (Control A) resulted in only 6?0/o survival as opposed to the 100% survival observed in the manually weeded control. Although not well represented, treatments with VisionT M both alone and in mixture with Release Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 73 Mean Physical Condition The ANOVA indicated that there were no statistically significant differences in seedling physical condition. As presented in Table 12, seedlings in the best physical condition one year after treatment application were those in the manually weeded control followed by those in treatment #12 (0.9-0.9-0). Seedlings in the poorest physical condition were those observed in treatments #20 (3-6- 0); #21 (5.1-0.9-0); #23 (6-3-0); #22 (5.1-5.1-0) and #13 (0.9-5.1-0) (all had ~ 3.00). As with seeiiHng survival, the A70G mean physical condition code was better than that of the B70G; 1.9 vs 2. 7, respectively. Figure 17 presents the mean physical condition codes grouped by herbicide treatment rates {0, 1-3 and 4-6 1/ha). MAHUALLY WEEDED CONTROL (CODE - 1) Q" 0" ' (.) z 0 i= Ez 0 (.) -I ~ 0 => Q. .~..., ::& 0 1-3 4-0 1-3 4-0 TOUCHDOWN (1Jhe) VI Sl ON (I /he) Figure 17. The mean SC¥d1ing physical condition codes grouped by herbicide rate {0, 1-3 and 4-6 1/ha) (adapted from Table 12). It shows that: mixtures ofReleaseTM and Touchdown 480 TM applied at rates ~ 4 1/ha (of each herbicide) and; the application ofTouchdown 480TM alone at r ~ 41/ha; all resulted in mean Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 74 physical condition codes greater than the acceptable 2.5 limit set by the author. VisionT M applied alone and in mixture with ReleaseT M resulted in better S"dling physical condition than did either no vegetation control, or ReleaseTM or Touchdown 480TM applied alone. Mean Needle Length As with mean percent survival, there were significant differences between mean needle lengths. However the Tukey's - HSD test may not have identified any perhaps because of the inclusion ofblock effects in the range testing procedure when using SPSSIPC+. As presented in Table 12, the greatest mean needle lengths were observed on seedlings in the manually weeded control (79 mm), followed by those in treatment #14 (2-0-2) (76 mm). The A70G mean needle length was 67 mm while that of the B70G was only 53 mm. Figme 18 presents the mean needle lengths (in mm) grouped by herbicide treatment rates (0, 1-3 and 4-6 1/ba). It shows that needles of Sf'A'dlings growing with no vegetation control treatment were 11 mm shorter than those in ~ manually weeded control. The general trend was that mean needle lengths decreased as herbicide application rates, both alone and in mixture, increased All but one oft he herbicide treatments with Touchdown 480 TM resulted in mean needle lengths less than those which resulted from treatments with VisionT M_ Mean Volume Incrementlba The ANOVA indicated that there were no statistically significant differences in mean volume incrementlha. However, seedling growth responses to vegetation control treatments are generally not evident after one growing season, and volume incrementlha was directly dependant on seedling survival. As presented in Table 12, the manually weeded control had the highest mean volume increment/ha; likely because the seedlings were able to achieve full growth potential and there was 100% survival. With the exception oft reatment #9 ( 4-0-0), the volume incrementlha of manually weeded seedHngs were twice that observed with the remaining herbicide treatments and more than 5 times that observed in the unweeded control. Poorest volume incrementJha OCCUITed in treatments which were observed to have either poor survival or physical condition codes ~ 3.0 (with the exception oft reatment #23 (6-3-0)). The A70G mean volume incrementlha was almost twice the B70G mean; 214 and 122 cm3/ha, respectively (Table 12). Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 75 0 1-3 4-0 1-3 4-6 TOUCHDOWN (IJhe) VISION {IJhe) Figure 18. The mean seedling needle lengths (in mm) grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 12). · Figure 19 presents the mean volume incrementslha (in cm3/ha) grouped by herbicide treatment rates (0, 1-3 and 4-6 1/ha). It shows that increasing rates ofh erbicide, alone and in mixtme generally resulted in decreasing volume increm.entslha. The application of Touchdown 480 1Ma lone and in mixture with Release1 M at rates ~ 4 1/ha was detrimental to seedling survival and this was, consequently, reflected in the low volume increments/ha. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 76 MANUALLY WEEDED CONmOL .. ~ < !... z . :..... .a.. :.. : (,) !5 ..... =_:IE, >0 .~.... ~ 0 1-3 4-C 1-3 4-e TOUCHDOWN (1/ha) VISION (1/ha) Figure 19. The mean seedling volume increments (in cm1/ha) grouped by herbicide rate (0, 1-3 and 4-6 IJha) (adapted from Table 12). DISCUSSION Non-Crop Vegetation Response Assessments ofn on-crop vegetation control with herbicides after one growing season are generally not reflective oft he full extent oflong-term control Long-term herbicidal effects on non- crop vegetation do not reach a maximum until about two years after treatment for glyphosate (Carruthers & Towill, 1988) and triclopyr ester (Deloitte & Touche, 1992}. Nevertheless, there were distinguishable short-term effects of the 23 treatments on non-crop vegetation observed one year after application. The majority of herbicide treatments significantly reduced the mean total vegetation index Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 77 relative to no control. Optimal control was achieved with the application of3 llha (0.99 kg aelha) ofTouchdown 4801M while the poorest control was observed with the application ofRelease'IM with Touchdown4801M, both at211ha(0.96 and0.66 kg aelha, respectively) (fable 11). The application of triclopyr at any rate with rates ofg lyphosate ~ 3 llha tended to be the least effective (Figure 11 ). All glyphosate treatments applied alone resulted in the best total vegetation control, as did the mixtw'e ofReleast?M with Touchdown 48rf1M, both at 5.1/lha (2.45 and 1.68 kgaelha, respectively) (Figure 11). The examination oft he vegetation indices oft he individual vegetation types provides a clearer picture of the treatment results. The application of 41/ha (1.32 kg aelha) ofTouchdown 4801M resulted in the most significant control ofa ll shrubs (fable 11 ). All the glyphosate trea1ments applied alone, the manual wefflingtreatment, and the application oftriclopyr alone at 3 llha (1.44 kg aelha), were the most effective (Figure 12). Beaked hazel was the most difficult shrub species to control (see Appendix H). Trea1ments with triclopyr alone did not reduce the mean beaked hazel index as effectively as did glyphosate alone, particularly those with n~ This concurs with results by Pitt et al. (1993), who fmmd in New-Brunswick, that crown cover reductions of beaked hazel and other major shrubs were more consistent with glyphosate than with triclopyr. One year after treatment, there were no distinguishable trends in control of trembling aspen, mountain maple, Prunus spp., bush honeysuckle and Rubus spp. (see Appendix H). All treatments except the application ofReJease'IM with Touchdown 4801 M, both at 2 1/ha (0.96 and 0.66 kg aelha, respectively) reduced the mean shrub index to halft hat observed in the unweeded control (fable 11 ). However, in general, herbicide tank mixtures offered no advantage over single herbicides for the control ofs hrubs one year after treatment. There were no significant differences between treatments in the control of herbs. Few trea1ments reduced the mean herb vegetation indices to less than half observed on the unweeded control. Greatest reductions were achieved with mixtures of Release1 M and Touchdown 480 TM at rates ~ 4llha (1.92 and 1.32 kg aelha, respectively) (Figure 13). Aster spp. and fireweed were the most dominant herb species on the site one year after trea1ment application. Hollstedt (1992) states that the control of large-leaved aster (Aster macrophy/lus L.) with glyphosate is not possible using application rates approved for forestry use in Ontario; and that triclopyr ester will not control Aster spp., except at extremely high rates. Freedman et al. ( 1993) explain that many individuals of some perennial species of ground vegetation survive herbicide treatment because of reduced exposure caused by the physical shielding by taller, overtopping Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 78 vegetation. These surviving plants would subsequently experience relatively free growth for several seasons, because of a temporary decrease in the intensity of overtopping shrub-sized plants. Both Aster spp. and fireweed are prolific seeders and regenerate easily on exposed mineral soil. They are also stimulated to vegetatively reproduce when their root systems are fragmented by mechanical site preparation (Buse & Bell, 1992). ~ n eta/. (1993) observed that these and other herbaceous species were often more abundant for several years after spraying herbicide than before. There were no significant differences between treatments in the control of graminoids. Vision1 M applied at rates ~ 41/ha (1.42 kg aelha) was the most effective in controlling Canada blue- joint grass and Carex spp. but glyphosate treatments in general reduced graminoid vegetation indices relative to the unweeded control (Figure 14). Triclopyr was ineffective in the control of graminoids. It is known that Canada blue-joint grass is resistant to triclopyr but it is not known about the effect oftriclopyr on Carex spp. (Buse & Bell, 1992). From the results oft his study it appears that Carex spp. is also resistant to triclopyr at rates as high as 61/ha (2.88 kg aelba). Mixtures oftriclopyr with Touchdown 4801M were less effective than mixtures oftriclopyr with VisionT M. The abundance of graminoids in many of the treatmentS may be a result of the mechanical site preparation, because both grass and sedges are stimulated by the fragmentation of roots and rhizomes (Buse & Bell, 1992). As with graminoids, there were no significant reductions of bracken fern with any of the treatments. It is known that bracken fern is resistant to triclopyr (Buse, 1992; Buse & Bell, 1992) therefore any reductions probably resulted from the application of glyphosate. The lowest bracken fern indices resulted from treatments with Touchdown 480 TMat 3 1/ha (0.99 kg aelha) alone and in mixture with ReleaseTM at rates ~ 3 1/ha (1.44 kg aelha) (Figure 15). The manual weeding treatment was effective in reducing the total mean vegetation indices to less than halft hat observed in the unweeded control. The greatest impact was on the shrubs, but it had little effect on herbs, graminoids and it promoted the growth of bracken fern. The manual weeding treatment involved the removal of both stems and roots of all non-crop vegetation and a mixing of the soil (as a result ofr oot removal). It is interesting to compare other treatment results to those of a manual wPi'ding treatment, but it has little bearing on the overall results. This method ofm anual weeding would not a feasible vegetation control alternative for releasing Northwestern Ontario conifer plantations and its effects are probably very short term (1-2 years). There were three circumstances that potentially influenced the observed vegetation responses in this study. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 79 Firstly, the site was an upland Boreal mixedwood prior to harvest in 1991 that was then mechanically site prepared with shark-fin barrels in the same year. The release treatments were applied only one year later in 1992. In 1993, it was observed that most of the non-crop vegetation on the site were species which were capable ofs ome form ofv egetative reproduction. All the major tree/shrub species were likely stimulated to vegetatively reproduce following the mechanical breakup ofr oots/rhizomes (with the exception pin cherry which reproduces prolifically by seed and buried seed) (Buse & Bell, 1992). The major herb species, namely Aster spp. and fireweed, will also reproduce in abundance following the breakup of rhizomes and the exposure ofm ineral soil; as will Canada blue-joint grass, Carex spp. and bracken fern (Buse & Bell, 1992). The full effects oft he mechanical site ptepcuation on the asexual reproduction capabilities oft he vegetation were probably still not realized at the time of herbicide treatment application. The chemical release treatments should have been applied at least two years after the mechanical site preparation to ensure more thorough vegetative reproduction control. Secondly, there was no pre-treatment assessment of the non-crop vegetation other than a general visual assessment of the invading species (a function of financial and administrative difficulties in August 1992). Hence, there was no record of the changes in vegetation abundance/type which may have occurred between 1992 and 1993. Subsequently, assessments and statistical analyses could only be made which reflected the conditions obseiVed in July 1993 relative to the controls; and not what vegetation changes that may actually have occurred on each treatment plot Pre-treatment assessments of non-crop vegetation would have allowed for covariate statistical analyses. This type of analyses would determine if, for example, a low vegetation index of a species was the result of the herbicide treatment or simply because the species had a low index prior to treatment Thirdly, all non-crop vegetation was reduced in height to I metre in order to facilitate the use ofa Research and Development (R&D) hand-held spray boom (at the request ofDowElanco Canada Inc.). This spray boom was one which would not normally be used to apply herbicide operationally for forestry purposes. It is speculated that by reducing the height of species such as trembling aspen, mountain maple, and beaked hazel may have had two key effects on the results. Firstly, there was a reduction of the foliar area of the major target tree and shrub species; subsequently reducing the potential for the herbicide treatments to be effectively absorbed by the target plants. Secondly, there would have been a stimulation of root suckering (in the case of trembling aspen) and root collar or stem sprouting (in the case of mountain maple and beaked hazel). The cutting oft he stems above one metre was a poor and unsubstantiated decision for this herbicide Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 80 trial, since the use of the special R&D spray boom was not the focus of the study. .Jack Pine Crop Tree Response The effects oft he treatments on seroljng SUIVival, physical condition and needle length were measures of health and vigour one year after application Volwne growth responses tend not to be observed after one year. In tact, growth responses can not usually be assessed until at least two years after the release treatment because the growth potential of a seedling in one year is determined by the its growth and budset in the previous year. Herbicides applied for conifer release are usually applied after budset Consequently, a reduction in non-crop vegetation would have little impact on seedling growth the year following application. SCC111ing survival was the highest (100%) with ~u weeding and with the application of ReleaseTM with Touchdown 480TM, both at 0.9 1/ha (0.43 and 0.30 kg aelha, respectively) (Table 12). In general, mixtures of ReleaseT M with Touchdown 480 TM at any rate resulted in survival rates less than 70%. 1bis was also observed with either the application of Release TM alone at rates ~ 4 1/ha (1.92 kg aelha) or Touchdown 480TMalone at rates ~ 41Jha (1.32 kg aelha) (Figure 16). Label directives for triclopyr ester cautions that the probability of injury to jack pine seedlings is greatest when application is made in the same year as planting (DowElanco, 1995). Partika (pers. comm., 1993) indicated that the glucocide wetting agent used in Touchdown 480 TM may be detrimental to jack pine seedlings. 1bis information appears to coincide with the survival results obtained in this study. Ofa ll the herbicide treatments, Vision TM applied alone or in mixture with Release TM resulted in the highest seedling survival rate. There were no significant differences in seedling physical condition one year after treatment As with mean percent survival, seedlings which were in best physical condition were those with manual weeding and with the application ofReleaseTM with Touchdown 480TM, both at 0.91/ha (0.43 and 0.30 kg aelha, respectively) (Table 12). In general, herbicide mixtures ofRelease mwith Touchdown 480TM, where either one or both herbicides exceeded 4 1/ha (1.92 and 1.32 kg aelha, respectively), the RC"#dling physical condition was poor (Figure 17). Overall, with exception of the manually weeded control, the application of VisionT M alone or in mixture with Release TM resulted in better ~ n physical condition than all other herbicide treatments and the unweeded control. The exact implications ofr educed needle lengths from herbicide application is not known. However, reduced needle length results in reduced needle surface area capable of producing photosynthate (Kramer & Kozlowski, 1979). 1bis subsequently impacts on the vigour and growth Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 81 oft he seedlings. Mean needle length ofs eedlings was highest in the manually weeded control (79 mm). The second highest mean needle length was observed after the application ofRelease1M and VisionT M, both at 2 1/ha (0.96 and 0. 71 kg aelha, respectively). The shortest mean needle length was observed after the application of 3 1/ha (1.44 kg aelha) ofReleaseTM mixed with 6 1/ha (1.98 kg ae/ha) of Touchdown 480TM (28 mm) (fable 12). Applications ofReleaseTM at rates ~ 41/ha (1.92 kg ae/ha); VisionT M at rates ~ 41/ha (1.42 kg aelha); or Touchdown 480TM at any rate alone or in mixture, resulted in shorter jack pine needles than the tmweeded control (Figure 18). These results appear to coincide with the label warnings for ReleaseTM and VisionT M. Touchdown 480TM also appeared to cause detrimental effects to needle growth. Substantial volume increment per hectare was observed in the manually weeded control relative to the unweeded control (fable 12). This volume growth coincides with the highest observed survival rate, the best physical condition and the longest needles of the manually weeded seedlings. It can be speculated that these seedlings achieved full growth potential. The application oftriclopyr ester both alone and in mixture with glyphosate at rates ~ 3 1/ha (Touchdown 480 TM- 0.99 kg ae/ha; VisionT M- 1.1 kg aelha) resulted in higher volume increments/ha than the unweeded control or the glyphosatetreatments alone (Figure 19). The application ofTouchdown 480 TMgreatly reduced growth, likely because of reduced survival and needle lengths. As volume increment responses can not be accurately assessed one year after treatment, no meaningful conclusions can be drawn. The application oftriclopyr ester at rates ~ 41/ha (1.92 kg aelha) was detrimental to seedling survival, physical condition, needle length and volume increment. These observations coincide with those made on other Pinus spp.. Saville (1989), who reported that release treatments for dormant radiata pine should not exceed 3.751Jha (1.8 kg aelha). Boyd eta/. (1985) indicate that fall foliar applications oftriclopyrestercaused severe damage to lodgepole pine at a rate of3.5 1/ha (1.67 kg ae!ha). Willis et a/. (1989) noted that jack pine was susceptible to injury from application of triclopyr ester at a rate of3.11/ha (1.5 kg aelha). It was found that jack pine was more tolerant to glyphosate than to triclopyr ester. Willis eta/. (1989) explain that tolerance to triclopyr ester and glyphosate varies depending on the amount ofe picuticular wax on the needles. As the needle matures after budbreak, the stoma become occluded with wax, while the swrounding needle surface becomes only sparsely coated with wax. The thin needle cuticle ofj ack pine may allow for the absorption oftriclopyr and glyphosate Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 82 (Lebala et al. 1972). It has been determined that regardless of dormancy, triclopyr always induces some damage; while jack pine seed1ings are more resistant to glyphosate (Willis et a/. 1989). Inadequate information regarding Touchdown 480TM makes it difficult to compare its effects on vegetation and on seed1ings to those of VisionT M_ The label directives for Release1 Me xplicitly indicate that the probability ofi njury to jack pine seedlings is greater when the application is made in the same year as planting (refer to Appendix A). The seedlings in this field study were planted in the spring of 1992 and the herbicide treatments were applied in late August oft he same year. The label also indicates that needle damage to jack pine may be unacceptable with applications above 4 1/ha (1.92 kg aelha) (DowElanco, 1995). The label directives for Vision' I'M indicates that it too should only be applied to conifers which have been established for more than one year and that the target vegetation should not be disturbed prior to application (Monsanto, 1992). The herbicide treatments should not have been made in the same year as planting. This likely would have alleviated many of the negative effects on seedling survival, physical condition and needle length. Ift he treatments were applied at least two seasons after planting, perhaps then some oft hem would not have been so detrimental to the seedlings and they likely would have been more effective in controlling the vegetative reproduction of non-crop species. Summary of Recommended Herbicide Treatments for Jack Pine Release Five herbicide treatments were chosen which resulted in the least damage to the crop and provided the most control ofboreal non-crop vegetation one year after treatment These herbicide treatments are recommended only for the release ofj ack pine seedlings in the same year ofp lanting. Other post-planting treatments might prove suitable ifa pplied after more than one year. The herbicide treatments which reduced the total vegetation index to less than 35% of that observed in the lDlWeeded control (fable 13), and which met the crop damage tolerance levels, were: 1) 3.0 1/ha (0.99 kg aelha) ofTouchdown 480TM 2) 6.0 1/ha (2.14 kg aelha) of VisionT M 3) 3.0 lJha (1.44 kg a.elha) ofReleasemmixed with 1.0 1/ha (0.33 kg ae/ha) of Touchdown 4801M 4) 3.0 1/ha (1.44 kg aelha) ofReleasem 5) 2.0 lJha (0.96 kg aelha) ofReleasem mixed with 2.0 1/ha (0.71 kg aelha) ofVisionm Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 83 Touchdown 480™ is currently not registered for use in Canadian forest vegetation management. Release' I'M can not be used for the control of graminoids or bracken fern; two types ofn on-crop vegetation which often occur on boreal mixedwood sites similar to the one in this study. Subsequently, VisionT M applied alone or in mixture with Release™ remains the only two feasible herbicide treatment options for jack pine release activities, in the same year as planting. In general, the herbicide mixtures tested offered no advantage over herbicides applied alone for jack pine plantation release because of the detrimental effects induced on the crop. The poor representation of Vision™ in the mixtures did not allow for a comprehensive evaluation of its potential. CONCLUSIONS AND RECOMMENDATIONS The objective oft his field study was to provide additional baseline information about the use ' oftriclopyr ester for jack pine plantation release. As with the first field trial, several weaknesses in the methodology make it difficult ~ directly apply the results obtained to operational settings. However, the observations and experiences gained from this study have lead to the following conclusions and recommendations that deserve further scientific study and operational testing. • The results of this study apply to a mixedwood site in Northwestern Ontario. The site selected for the study was rich and very diverse in species composition. • Jack pine crop tree swvival, physical condition and needle length were greatly affected by the composition oft he herbicide treatments. The application oftriclopyr ester at rates ~ 4 1/ha (1.92 kg aelha) was detrimental to seedling survival, physical condition, needle length and volume increment. The n~ were very sensitive to the application of Touchdown 480™ at rates ~ 4 l/ha (1.32 kg aelha). • There was no significant seedling volume incrementlha response one year after the application of the twenty-three treatments. It is expected that there will be considerable change in the effects oft he treatments over the next few years. The most important effect will likely be observed in seedling growth response. • The manually weeded control (Control B) was an ideal treatment which resulted in: I) excellent vegetation control, 2) 100% jack pine SC"#dling swvival, and 3) maximum volume incrementlha. The method ofboth stem and root removal ofa ll non-crop vegetation coupled Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 84 with a mixing oft he soil would not be a feastble alternative for releasing established conifers in the boreal forest. It is speculated that vegetation control with this treatment would be very short term. • The unweeded control (Control A) had: 1) the highest vegetation index, 2) poor survival after the first growing season, and 3) very low seedling volume incrementlba, relative to the manually weeded control and some of the herbicide treatments. • The five recommended herbicide treatments which were found to be the most effective in reducing the total vegetation indices and which were the least detrimental to the jack pine crop trees were as follows: 1) 3.0 1/ha (0.99 kg aelha) of Touchdown 480TM. 2) 6.0 1/ha (2.14 kg aelha) ofVision™ 3) 3.0 Ilba (1.44 kg ae/ha) ofRelease™mixed with 1.0 1/ha (0.33 kg ae/ha) of Touchdown 480™ 4) 3.0 1/ha (1.44 kg aelha) ofRelease™ 5) 2.0 1/ha (0.96 kg aelha) ofRelease™ mixed with 2.0 1/ha (0.71 kg aelha) of Vision™ • Because ReleaseTM did not effectively control graminoids or bracken fern on this boreal forest site, and because Touchdown 480™ is not currently registered for use in forest vegetation management, herbicide treatments of Vision TM applied alone or in mixture with ReleaseTM appear to be the only two available options, at this time, for similar site and vegetation conditions. • Similar trials should be conducted on an operational scale to verify the results obtained. Such trials should be designed to evaluate mixtures ofRelease ™and Vision ™as they were not well represented in this study. In addition, the difficulties encountered in the methodology oft his field study should be avoided so that results could be better applied to operational settings. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 85 LITERATURE CIIED Allen, H. and T. Wentworth. 1993. Vegetation control and site preparation affect patterns of shoot elongation for 3-year-old loblolly pine. Canadian Journal of Forest Research, 23: 2110- 2115. Anderson, V.L. and R.A. MacLean. 1974. Design of experiments - a realistic approach. Marcel Dekker Inc. New York. 418 p. Anjou, B.N. and F. T. Pendl. 1986. Efficacy and crop tolerance of triclopyr ester. British Columbia Ministry ofForests. Vancouver Forest Station. Internal Report No. SX86702U. 21 p. Anonymous, 1989. 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Towill, K.A Baldwin and G.M Wickware. n.d. . Field guide to the forest ecosystem classification of Northwestern Ontario. Northwestern Ontario Technical Development Unit. Thunder Bay, Ontario. 191 p. Smith, D.M 1986. The practice of silviculture. John Wiley & Sons. New York. 527 p. Smethurst, P.J. and E.K. Nambiar. 1989. Role ofw eeds in the management of nitrogen in a young Pinus radiata plantation. New Forest, 3:203-224. Snedecor, G. and W. Cochran. 1967. Statistical methods. Iowa State University Press. 593 p. Stasiak, MA, G. Hofstra, N.J. Payne, R Prasad and RA. Fletcher. 1991. Alterations of growth and shjJrimic acid levels by sublethal glyphosate apPlications on pin cherry and trembling aspen. Canadian Journal ofForest Research, 21: 1086-1090. Steel, R.G. and J. Torrie. 1981. Principles and procedures of statistics: a biometrical approach. McGraw-Hill Book Co. Toronto, Ontario. 683 pp. Stephenson, G.R. 1992. Selectivity, uptake and translocation. Lecture notes from the Advanced Forest Herbicides Course Manual: 1992. Sault Ste. Marie, Ontario. Module 2 (5): 1-8. Sterrett, J.P. andRE. Adams. 1977. The effect of forest conversion with herbicides on pine (Pinus spp.) establishment, soil moisture and understory vegetation. Weed Science, 25: 521-523. Stewart, R. 1987. Seeing the forest for the weeds: a synthesis of forest vegetation management. pg 431-480 in Forest vegetation management for conifer production. J. Walstad and P. Kuch (eds). John Wiley & Sons. New York. 523 p. Stiell, W.M 1970. Some competitive relations in a red pine plantation. Department ofFisheries and Forestry. Canadian Forestry Service. Publication No. 1275. 10 p. Sutton, RF. 1982. Plantation establishment in the boreal forest: planting season extension. Canadian Forestry Service, Great Lakes Forest Research Centre, Sault Ste. Marie, Ontario. Info. Report 0-X-344. 129 p. Sutton, R.F. 1985. Vegetation management in Canadian forestry. Great Lakes Forest Research Centre. Information Report 0-X-369. 35 p. Sutton, RF. and T.P Weldon. 1993. Jack pine establishment in Ontario: 5-year comparison of stock types± Briicke scarification, mounding, and chemical site preparation. Forestry Chronicle, 69: 545-553. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 96 Sutton, R.F., T.P Weldon, G.K. Smith and R.A Haig. 1991. Mounding and herbicide treatments increase performance ofp lanted jack pine. Forestry Canada, Ontario Region. Technical Note No.7. 3 p. Toumey, N.B, J.W. Toumey Jr. and C.F. Korstian. 1947. Foundations of silviculture upon an ecological basis. John Wiley & Sons, New York. 468 p. Toumey, J.W. and R Kienholz. 1931. Trenched plots tmder forest canopies. Yale University Press. School ofForestry Bulletin No. 30. 31 p. Towill, W.D. 1992. Ecological principles. Lecture notes from the Advanced Forest Herbicides Course Manual: 1992. Sault Ste. Marie, Ontario. Module 4 (2): 1-26. Towill, W.D. and D.A. Archibald. 1991. A competition index methodology for Northwestern Ontario. Ontario Ministry ofNatural Resources. Northwestern Ontario Forest Technology Development Unit. Thunder Bay, Ontario. n ~ Note TN-10. 12 p. Vidrine, C.G. and J.C. Adams. 1993. Machine application of cut-stump treatments. Applied Engineering in Agriculture, 9: 205-208. Wagner, RG. 1994. Competition thresholds for conifer swvival and growth. Ontario Forest Research Institute. Sault. Ste. Marie, Ontario. Vegetation Management Alternatives Program Report, 3(2): 3-5. Wagner, RG., LJ. Buse, RA Lautenschlager, C. Hollstedt, A Morneault, S. Pickering, S. Strobl, F.W. Bell and M T. Ter-Mikaelian. 1993. Vegetation management alternatives program: annual report 1992-1993. Ontario Forest Research Institute. Sault Ste. Marie, Ontario. 62 p. Wagner, RG. and S.R Radosevich. 1991. Interspecific competition and other factors influencing the performance ofDouglas-fir seedlings in the Oregon Coast Range. Canadian Journal of Forest Research, 21: 829-835. Wagner, R.G. and J.C. Zasada 1991. Integrating plant autecology and silvicultural activities to prevent forest management problems. Forestry Chronicle, 67: 506-513. Walstad, JD. andP. Kuch. 1987. Introduction to forest vegetation management. pg 3-14 in Forest vegetation management for conifer production. J. Walstad and P. Kuch (eds). John Wiley & Sons. New York 523 p. Walstad, J.D., M. Newton and D.H. Gjerstad. 1987. Overview of vegetation management alternatives. pg 157-200 in Forest vegetation management for conifer production. J. Walstad and P. Kuch (eds). John Wiley & Sons. New York. 523 p. Warren, LE. 1982. Control ofbrush on conifer plantations with triclopyr ester. Proceedings of the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 97 Western Society of Weed Science, 35: 38-45. Weed Science Society ofA merica. 1989. Herbicide handbook (sixth edition]. Weed Science Society ofA merica. illinois, USA 301 p. Weetman, G.F. and RM Fournier. 1984. Ten-year growth and nutrition effects of a straw treatment and ofr epeated fertilization on jack pine. Canadian Journal ofForest Research, 14: 416-423. Willis, RG., G.R Stephenson, RA fletcher and R. Prasad 1989. Seasonal variations in jack pine (Pinus banksiana) and white spruce (Picea glauca) tolerance to glyphosate and triclopyr. Weed Technology, 33:33-38. Wood, J.E, and S.W.J. Dominy. 1988. Mechanical site preparation and early chemical tending in white spruce: 19-year results. Forestry Chronicle, 64: 177-181. Wood, J.E. andF.W. vonAlthen. 1993. Establishment ~ spruce and black spruce in boreal Ontario: effects of chemical site preparation and post-planting weed control. Forestry Chronicle, 69: 554-560. Wood, J.E., F. W. von Althen and RA Campbell. 1990. Black spruce outplant performance: effect ofw inter application ofhexazinone on shear-bladed sites in boreal Ontario. Canadian Journal of Forest Research, 28: 1541-1548. Yang, RC. 1991. Growth ofw hite spruce following release from aspen competition: 35 year results. Forestry Chronicle, 67: 706-711. Yeiser, JL. 1991. June, July and August applications of glyphosate tank mixes for site preparation. pg 250-255 in Proceedings oft he 44th annual meeting oft he Southern Weed Science Society. Southern Weed Science Society. Zeneca Agro R&D. 1989. Touchdown 480TMtechnical information. ICI Agrochemicals-Chipman. Stoney Creek, Ontario. 5 p. Zwiazek, J.J. and T.J. Blake. 1990. Physiological and biochemical responses ofp lants to glyphosate: a literature review. Canada-Ontario Forest Resource Development Agreement Report 3305. 13 p. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIX A DETAILED INFORMATION WITH RESPECT TO THE USE OF RELEASETM (TRICLOPYR ESTER) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. .DowEianco 1 Release* : Silvicultural Herbicide For the control of undesirable woody plants and annual and perennial broadleaved weeds in forest and woodland management sites. COMMERCIAL CAUTION POISON READ THE LABEL BEFORE USING. KEEP OUT OF REACH OF CHILDREN. POTENTIAL SKIN SENSITIZER. GUARANTEE: triclopyr ••••••••••••••••••••••••••••••••.•••••••••••••••••..••• 480 g acid equivalent/L (present as butoxyethyl ester) REGISTRATION NUMBER 22093 PEST CONTROL PRODUCTS ACT Net Contents: 10 L & 110 L Returnable Container OPERATOR USE PRECAUTIONS PHYSICAL OR CHEMICAL HAZARDS HARMFUL IF SWALLOWED. COMBtJ.SllBLE. Do not use or store near heat or open llama. MAY CAUSE SKIN IRRITAllON. MAY BE HARMFUL IF ABSORBED THROUGH SKIN. POTENllALSKIN SENSITIZER. ENVIRONMENTAL HAZARDS This product il highly toxic fD fiSh, aquatic plants and aqualic: Avoid conlact with eyes. akin and clothing. Wah lhoroughly after invert8btal.es and il not labelled for ~ n eo waller swfaces. Keep handing. Avoid bntalhing ~ r r r milt WheN hquMtlnhalation out of lakes, ponds and slreaml. Do not c:ontaminallt walllr by cleaning of of spray mist cannot be avoided, OCCIIpalionaJ exposure ro pesliddes can equipment or disposal of wastes. be raduced by uae of an u pwifying rupirarar eqc lipped wilh organic vaporcartridgn. Avoid contact with IIUI8dfolage and olher FIRST AID contaminaled surfaces while "l When apraying, follow a -w.lkin, spray If nwallowed: Do not induce vomiling. Cal a physician or =ntact a out' patr.em 10 avoid contact wilh trea'-d bnlsh. Tak8 prec:aulion& eo avoid poison conlnll cancra andlortransport to emergency facility spray drill. Oiract spcay outward and INlaY from Hlf. Aw id OWifiNd lmmeciately. spraying. Select spray nozzlalype& and pnm&ns ro minimize drift If in ey•: lrrigatelmmediallelywith flowing water for fifteen minutes. po18nlial. If on akin: Wash off rn flowing water or shower. If l'nhaled: Remove 10 fnt&h u if effects occur. Consulle physician Practice good personal hygiene. At all lime& when handling Mlblcide or a poison control cencre. concenltale or applying the dilute ml=nt. plan IIYWIIS rn suc:fla way u to mininlze parsonalexposUnt. Loca118 wash stations with an adeq •ell8 TOXICOLOGICAL INFORMATION supply of fntsh waller on wortt whiclas. Wash thoroughly with soap and The decision of whelher ro Induce vomiting or not should be made by an waller efterhandling and befont eating or smoking. Balhe or take a hot all8nding physician. If lavage Is petformed. suggastendonc:heal and'or ~ eflerwork using plenty of soap. esophageal c:cnlrOI. Danger from kmg aspiration must be "ighad against loxic:itywhari oonsidering emptying the stornach.. This product contains To minimize exposure when handing and applying Release Silvicuhural petroleum disti'llates. No specific anlidolle. Supponiw care. Treatment Hertlicida: based on judgment of the physician rn ntapOnHio reactions of the patient • Read and follow directions In the Prollctive Equipment RequirMients ForfurlherlnformalionconsulttheMATERIALSAFETYDATASHEET. and Opetaror Use Precautions sec:tiona on the label. • Applicalots should recaiw lralning on how ro minfmlza personal exposunt while applying high volume Sliem·foug. appliedhectlicidas, NOTlCE TO USER: This conll'al product 1$ ro be used only In lnc:ludng the "Walt-inllpray-out'"llc:hniqua and on how 1o nilimiD aocardance with the dnctions on lhlslabel. It Is an offense under THE contact with trur.ed foliage. PEST CONTROL PRODUClS ACTID UM a conlnll product under unsafe conditions. • Applicators should be supar.;sed ID ensure lhal d label dRc:tions and proper application techniques are followed. NOTlCE TO BUYER: Selefs guaranll88 &hal be linit.ed eo lhatanns set out on the label and subjecllherelo,lhe buyer usumeslhe risk to OowEianco Canada Inc. • 17705 Lallie Street pet'ICIM or property arising from the use or handing of this product and Newmatket. Ontario L3Y 3E3 (905) 836-oc36 accepiS the product on lhal condition. "Trademark of DowElanco Do not ship or store with food, feeds, drugs or OowEianco Canada Inc:. is a licensed user. clothing. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. GENERAL USE PRECAUTIONS DIRECTIONS FOR USE: Do not apply lhis procllct in a mamer inconsistent with f1elabel. Ground Applications Do not apply Release Silvicuhural H-1licicfe dir8CUy 10, or oth«wise WOODLAND MANAGEMENT SITES permit it 110 come into ciract coru.ct with de&irable crops orolher (500 hec:W'ft or leu) desirable bnJadfeaf plants or non-tatget species 8nd do not permit spray mists contamg Release Silvlcultu...r Hettlic:ide 110 drift onto them. Release ~ ur Hertliddlt Is not registered forapp&cation to water ufacellncbing !Mel, ponds and strums and is highly toxic to fish. Sensiliw fllrr8strial and aqualic habitat must be proe.c.d (referiD ~ n 8nd aquatic lnwr18brallll. Do not ov.spray IUch antu. GroundApp&calion and/or Aerial Application MCfona on buffer zane In order ID reduce the hazards 10 drift ID non-r.get plants, aquatic species requintmentsand&pqydriftcontrofrecommeudationa). or&enlitMt habftat. ensura that appropriate buff•zonu.,. maintained and refer to lhe sec:tion "Spray Drift Control•. AVOID SPRAY DRIFT: Apply only when 1here is &ale or no haard frDrn spqy drift. Smal quantities of lhe apraywhidl may not be vi&IM, may Spray Drift Conlrl:ll: The pof8r.tial for spray drift can be recllced by Mriously injure &U&Ceplible plants and duMge &enliiM n n ~ epplying a coane apray using large droplet procilc:ing nozzle tips: by lhe habital A method must be used 10 detect* mowment. ..,_ use ollhe ~ r~T rollltoranequivalentdriftcontrof &y&tem condlions, or lilmperatan inYw&iona ~ r IUdl u the use of a oredditiw; by liMping the spray boom ulow u poullle; by using a spotter p!Me, baloons or a continuous IIIIOM column ator,_,.lhe spray preuure no greater than Is IWqUhd to oblak1 a n ~ spray pattam spqy lite or a smoke generator on the 1Pf8Y equipment.. If the smoke foredequalll n ~ and by applying when the wind wlocity Is dewlops Into layers orlndicaras a potenlial tor hazatdoua spray drift. DO law.lf a spray thickening agentia used, follow 1111 use chctionl8nd NOT SPRAY. ~ n lhe productr.bel When Uling a power sprayer 8nd handg&n. chct sprays no higher1Mn the aop. oflhe target plants. GENERALINFORMAnON BROADCAST FOUAR APPUCATIONS Release Silllic:Utlnl Herbicide is recommeclded for !he conlrol of General Information and Mixing Instructions unde&irablewoodyplantsandannual n ~ r C in forest8nd woocland management lites. AppriC&Iions may beiNide for AfJply Releue Silvicullural Hedlic:ide mixed wilh ...... , malclt at leut woodland &it8 preparation prioriD natural orar111c:W .-ge1'181'81ionof 100 iiNs per hectare of lOCal delivwyvalurne.ln 1111 cues. use equipment conifen:x.11 crop tree&, for conifer release in piMtalions and e&tlbilhed lhat wll u~n uniform cowqge of the folage of the plants 10 be stands and for forest roadside vegetation control. Among the woody controlecl.. An application .-m or.cicltiva lhould be used to ~ plants controlled ant: off-target spqy pat1icle drift. Nozzles or. .:fclliws lhat procllce larger ~ ..-quire highervalurnu oftacal cW'MtY wlumeperhect8re alder, red INPie.red 10 obllin uniform coverage of 1he nar.d 'Ngetalion (See Dinc:tions for alder, speckled fNPie, sugar- Use, Spray Drift Contra). uh,white oM, red upen.lnlmbling poplar, balurn Site Preparation birch, whit8- rupbeny To control rupbeny and woody species apply 3 ID 8 L per Mc:tare of cheny,pin &alai- Release Sllvlcultural Hertlicide in at least 100 L of total de&v.ry volume. rqple, bigleat- willow Use of a rate in lhe upper end of the rec:onunended range Is suggested for control of bual sprouting Md root suckering specie& and for tall, dense -White birch is belt controlled n ~ the use ot any one otlhe foiar bnl&h.. Appicalions should be made folowing full leaf-out. but before application melhods. autumncolouration. Conifer planting should be delayad until the following -Sugar maple and big leaf maple ant belt controlled ttvaugh 1he use of year. any one of lhe basal barit application methods. -For control of salal, refer to lhe Dintctions For Usa • Broadcast Foliar Conifer Release sec:tion. To release conifers. n u ~n white spruce, black spn.oca, and jac:X pine PROTECTIVE EQUIPMENT REQUIREMENTS from raspbeny and deciduous woody &peQel, apply 3 to 6 L per hec:tanl of Release Sivic:ultu...r Hertic:idll with water in atleut100 L of total HAN DUNG CONCENTRATE: When handing concennra, wear deivllry volume. Uu of a rare in lhe upper 8nd of lhe recommended r ru n n r r~n range ia "''IQfttad for control of bual sprouting 8nd root sucbring dean c::owralls owrnonnal wotkclothn, impermuble head CXMiring apec:ia and for tal, dense brush. Applicalionllhoukl be made in late and chemical ruistantboots (rubbet) cilring al mildngllaadng ac:dvities. summer, alter conifers ha. .. hardened off (bud& firm and sharp 110 lhe Remo. .. clothing contaminated with concenltat8 prompCiy and wah touch) and deciduous species are in fulleaf, but prior to autumn before re-use. Exercise c.nt in removal of cantaminalled clolhing 110 colourUon. Jack pine needle damage at rallll greaterlhan • L per avoid secondary lkfn contact. Segregate contamlnalled ar1ideaand hectare may be unacceplabkl. To minimize j.ck pine injury, applications launderseparalaly from other clothing using a double rinM. Lealher lhould not be made whie lhe jack pine tree1 are in lhe Jammu or atticle& such u boots, belts orwald\band. ahould be destravecf H secondary growth stage. The probablity ol qury Is greater when contaminated by concentrate. appication is made in lhe same v-r u planting. APPLYING DILUTE SPAAY SOLUTION: When spraying dilute solution Salal Control andcllringequipmentmaintenanceandrepair,wurdeaneo......rlsowr To provide c:ontrol of &alai. apply 8 L per hectare of Release Silvicuhural normal woridng clolhu, impermeable head c:IDWI'fng, chemical reli&tant Hertlic:ide in an ol c:atrier (dieul, karosene or mineral) and at leut 100 glova& (nirie or neoprene) and chemical re&i&tant footwear IUch as Ins of total deiwryvolume. ~ n should be made to avoid rubber boots. spqying MY desirable conifers. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LOW VOLUME FOUAR APPUCATIONS Thlnllne General lnfonnatlon and Mixing Instructions To control woody plants wi1h stamalasslhan t5 em in basal diameter. For conifer release and site praparalion. uselhis IIChnique with knapsadt app!y undiluted Release Silvicultural Hertlic:lde in alhin stream to aD sides or baciq)adt sprayatS equipped with lat r.n or IOiid cone nozzles. For of lha Joww parts of ..en stem. 'The strum should be dirac:tad site preparation. power &prayatS and handguns may also be used. Do not horizontally to apply a narrow band of Relaasa Sllvicultural Herbicide apply lha prockldwith ~ around lhe enlire c:Rumr..nc:e of each stem about t 5 em above lhe ground. From 2 ID 15 mL of che.mc.! wil be ~ for treatment ol Site Preparation single seems Md from 25 a 100 ml ID nat clumps of ac.ms. A straight slr'Nm nozzle and an applic:aror ~ r calibrated ID dai"Mtr lha small Mix 1 to 5 L of Rareasa SilvicuhuqJ Hettic:ide In enough _,..to mak8 amounts othertl· ·1 NqUired should be used. Apply at any lime. 100 Lo f spray IOiu1ion. Uae of a rail fn ._ upper end of N auggeSIId including lhe winlwmonlha. exceptw hen snow r r ~ spraying NCOmmandad rMgals farcanlrDDI ohlbcat.u_l a prautng end root allheclesir.cfhefght-.groundle¥81. IUCicaring species and for IIIII. dlnH bfwh. IPIIYICfulian a thoroughly wet lhe fobge of lhe a.rgetplanla but nota N point of MIOff. Streamline Applyatt.rfullaaf-out. butbeforw .uunn oolocntian. Conlerplanling lhoUcl ~ unlllhe lallowlngyaar. n ~mana ao 30 LoiReleaH SivfQ.Ihuraf Herbicide Conifer Release In enough oil!) 100 lilrel of IP'8Y m:::::.n. Appt'f wilh a bac:kpadt =·1, or knapsadt spraywusing a flat fan or a solid cone nozzle. Apply Mix 1 to 5 L of Release Silvict*uraJ Haiti. wilh _,... . mM8 tOO Lof sufficient spray'» one.-of st.ma lesalhan 8 em in bual diMietarto spray IOiution. u .. of a rata in lhe upper end of ._IWCIOIIIIMIIded rM88 tonn a a-nd lhatla S em In wid1h.. \\'hen the opMium amount of spray Is wggesl8d for conlrOI of bualsprouting and rootsudt1ring species and mixlln lsappled, lha .....S zane lhoUclwlden a encircle lhe stem fared. dlnu brush. ou.ct the spray solution alhoraughlyMtlhe foliage wilhinapproxirna181y30111irMMs. Treatbolh uasotams whicn are &to of the target plants but notiO lha point of n~n Applyablrfulleaf-out. 12 em In basal diameler. Dnct the apray ala point on lha stem that is but before autumn colouralion. Avoid spraying the canlf.-s. especially If approximar.ly 30 to 50 em ebow ground .... OptirMiresults are application occurs before hardanlnf off (buds firm and IMrp 10 lhe toucn) ac:tliewd when appicationa .. made to young vigorously growing stems or if they ant in lammas growth stage (jack pine). which hav. not dewloped the thicker balk c:harKI8ristic of slower growing. understory lrHs in older stands. Apply at any lime. including the BASAL BARK APPLICATIONS wintermonlhs, except when snoworwaterprewntspraylng at the desired height above ground lev81. General lnfonnatlon and Mixing Instructions For sic. praparalion.f89anaralion ralaaae. or thinning. uae Release Silvicultural Herbicide in oil un ~ ~ and appi"'Mid a desc:ribad Cut Stump Treatment below. ~ a diluent such as diesel fuel. k8ronne. or mineql oil. Add Release Silvicultural Herbicide 10 the r.quirwd amount of ollln lhe mixing To oonlrol rasprouling of cut stumps of woody species. mix 20 to 30 L of tank and mix thoroughly. When mixing with oils commera.lly formulated Release Silvicultural Herbicide In enough oil ID make 100 L of spray for basal bark herbicide applications. read and foDCJW lha uae dirac:tions mixture. Apply with a badr.piiCk or kMpsack sprayer using a tlat fan or a and prac::aulions on the procl.lct lat».. prapar.d by the oil"s manufacturar. solid cone nozzle. 'Thoroughly at the outarporlion of lha cut surface aqac:ant ID lhe cambium and lha sides of lhe stumps. induding lh8 root Uselha higher spray mixture corantration of Release SiMQ.Ihural collar ani&. but not IDa. point of runoff. Apply at any time, including the Harbicidl when !rUling basal sprouting and root sucbring species or winc.rmonlhl. except when snow orwatar prawnt apraying 10 lha ground when applying during lha dormant I8UOil. Uaelow nozzle pressure 1D line. Cant must be tak8n to ensure 1r'Hbnant of aD c:ut stems within a minimizespaltarlng of spray solution off the target a.m. dump. Conventional Volume To control woody plants with slims lea than 15 em in baul diametar. mix 1 ID 5 L of Release SiMc:uluaJ Herbicide In enough oil to mak8 100 L of spray mixture. Apply wilh baclql.:k or kMpsack sprayer using allat fan or solid cone nozzle. Spray lha basal parts of aacn stem from a height of 50 em down ID the root coDar. Thorough wetting of lha in 105 oc (setaflash cc) Cold Stability: < -28 oc pH: 3.8 -5.0 (1 g/20 ml water) 1.2 FORMULATION Solution Concentration: a. salt 480 gil b. acid equivalent 330 gil Transport Hazards: a. ground Not Restricted b. air Not Restricted 2. TOXICOLOGY (TECHNICAL MATERIAL) Glyphosate 1MS has low oral and dermal toxicity to mammals. The data indicates that there should be very little hazard from the recommended use of the product. 2.1 ACUTE TOXICITY 2.1.1 r ~ The acute oral ~ in male and female rats are 748 and 755 mglkg respectively. In male and female mice. it is 1383 and 1250 mglkg respectively. When formulated as TF1242 the acute oral ~ in male and female rats are 1760 and 1298 mglkg. respectively. 2.1.2. Dermal ~ The acute dermal LD50 in rabbit is 2000 mglkg and greater than 2000 mglkg of the TF1242 formulation. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 110 2.1.3. Skin and Eye Irritation Glyphosate 1MS is a mild skin and eye irritant The 1F1242 formulation is non-irritant. 2.1.4. Inhalation The iohalation LC50 in rats is greater than 0.81 mg/1 Glyphosate TMS and its formulations pose no inhalation hazard. 3. ENVIRONMENTAL PROFILE 3.1 Birds GJ;ypbcsate TMS does not represent a dietmy hazard to birds. The agricultural uses of glyphosate TMS normally results in zero or negligible residues in food consumed by birds. 3.2 Bees Glyphosate TMS represents no hazard to honeybees. In toxicity tests, 62 micrograms/bee was applied to groups of honeybees which were observed for 96 hours. No mortality occurred. 3.3 Fish and Aquatic Invertebrates Although the extremely low toxicity to fish of glyphosate 1MS is increased when formulated, it does not increase to a level where it becomes hazardous to fish as a result _of normal use. Studies are incomplete against aquatic invertebrates, but data so far indicates that formulated material is less toxic than active ingredient. 3.4 Fate in Soil Glyphosat.e 1MS is rapidly and ultimately degraded to carbon dioxide and mineral compotmds within days or at most a few weeks of application to soil There is no risk ofleacbing or grotmd water contamination. 3.5 Residues in Crops No residues were fotmd in crops following the majority of use patterns (pre-crop sowing. pre-emergence and directed spray). Slight accidental contamination of growing crops by drift from directed spray may occur but residues in harvested crops are n ~ When used in cereals as a pre-harvest application, measurable residues may be found but these are of no toxicological significance since the majority of the residues are destroyed or removed during the processing of the cereals. 4. BIOLOGICAL AcnviTY GJypbosate 1MS is absorbed into plants via leaves and stems. Uptake is thought to occur by diffusion and can be enhanced by favourable environmental conditions such as high relative humidity. It is possible that light mist will re-wet glyphosate TMS deposits on leaf surfaces and give secondacy uptake. Uptake via roots and woody stems is minimal, although spray additives have been shown to assist uptake through "difficult" \WOdy and waxy stems. Inside the plant. glyphosate TMS is readily transported with the phloem and xylem. Movement can be very rapid and is typically toward the most actively growing parts of the plant. Accumulation at actively dividing meristems result in symptoms being seen here first, followed by a gradual die-back of more mature parts of the plant. If applied when root systems are actively growing. glyphosate TMS will accumulate ai ih.:se sites and give excellent control of regrowth. The primacy mode of action of glyphosate TMS is inhlbition of production of aromatic amino acids, preventing protein synthesis. Although this is the primary explanation for herbicidal effects, other processes are involved which include inlnbition of photosynthesis. and reduction in level ofiAA produced. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 111 5. APPilCATION 5.1 Weather Conditions Optimum effect will be achieved when soil and air moisture are high. Plants suffering drought stress may not be controlled effectively. Glyphosate 1MS is only slowly absorbed into the plant, thus rain falling shortly after spraying will reduce amount taken up. Ideally a rain free period of 6 hours is required to maximize herbicidal effect 5.2 YJJDing Best results are obtained when weeds are actively growing. Species differ in their susceptibility according to growth stage, but generally, good control will result when plants are established with sufficient target foliage to receive spray. Broadleaf weeds are often the least susceptible. Optimum timing for control is at or near flowering. Effective long term control of perennial species is most likely to occur when applications are made to 1Dldisturbed planted during the growth of new dlizomesfroots. 5.3 Trial Uses When trials compare TOUCHDOWN and ROUNDUP, they should do so as salts, not as acid equivalents. Trials to date indicate that TOUCIIDOWN performance is equal to or better than ROUNDUP in comparative tests. Rates of 1 to 2 kg ailha provides control of annual grasses and broadleaf weeds and 1 year's control (suppression) of perennial weeds such as Quack grass. For perennial grass and broadleaf weed control. 2 to 3 kg ailha is required. Spray volumes of 150 to 300 Llha have proven effective. More work is needed on the interaction of spray volumes and selected adjuvant systems such as FRIGATE and ammonium sulphate. 6. HANDLING PRECAUfiONS When handling the concentrate, wear protective gloves and eye protection. Wash splashes from skin or eyes immediately. When spraying, avoid working in spray mist After spraying, wash clothing. When using, do not eat, drink or smoke. Wash hands and exposed skin before meals and after work. Keep out reach ofc bildren. Keep away from food, drink and animal food. Do not contaminate ponds, waterways or ditches with the chemicaL Store in original container, tightly closed, in a safe place. Wash out container thoroughly, empty washings into spray tank and dispose of safely. 7. FIRST AID If swallowed, DO NOT INDUCE VOMITING. Ifo n skin, wash thoroughly. If in eyes, flush out thoroughly with clean water for at least 15 minutes. For all cases, seek medical attention immediately. Treat symptomatically. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIXD THE LOCATION OF FIELD STUDY #1 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 113 LOCATION OF FIELD STUDY #1 Figme D-1 illustrates the general location of the field study #1 in relation to Thunder Bay, Ontario. HORTHWESTER.H ONTARIO Figure D-1. The general location of field study #1 in relation to Thunder Bay, Ontario. Figme D-2 presents a more detailed map oft he location off ield study#1 . The site is located to the west ofKakabeka Falls, Ontario. Kakabeka Falls is located approximately 30 km west of Thunder Bay en Highway 11117. To access the study area, one must travel west on Highway 590 for approximately 10 km to the Boreal Timber Road and west on this road for 20 km. The plots were established in a cutover adjacent to the Ontario Ministry ofNatural Resources 'Mattawin Seed Orchard'; east of the Mattawin River. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. •' t · ~ ·F'c '• I ...... ~ I I \ : .. r. I • I'_ ,, --... , .-y'\ D •p ; ""V"--J p •. • (:/J~ ~ \ 1\ Figure 1) -2. A detaHed map of the location of field study ##1. NOT TO SCALE Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIXE FIELDSTUDY#l: RESULTSOFTHEANALYSISOFVARIANCE I Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 116 Table E-1 presents a summary oft he probabilities ofo btaining a larger F-ratio for herbicide treatment effects, planting time treatment effects and interaction effects, which resulted from the ANOVA , for each mean seed1ing response variable. Table E-1. A summary oft he probabilities of obtaining a larger F-ratio for herbicide effects, planting time effects and interaction effects for each mean seedling response variable. An asterisk (*) denotes significant and '**' denotes highly significant effects, at p = 0.05. SOURCE OF DF TRANSFORMED PHYSICAL NEEDLE VOLUME VARIATION SURVIVAL CONDmON LENGTH INCREMENT Block (B) 2 - - - - Herbicide_ (H) 1 0.000 ** 0.005 ** 0.990 0.018 * r~~~~ 4 0.000 ** 0.000 ** 0.016 * 0.000 ** BUI 2 0.010 ** 0.015 * 0.071 0.132 B:s:T 8 0.003 ** 0.006 ** 0.488 0.050 * H:s:T 4 0.006"** 0.001 ** 0.206 0.112 B:s:H:s:T (Error) 8 - - - - I Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIXF THE LOCATION OF FIELD STUDY #2 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 118 LOCATION OF FIELD STUDY #2 Figure F-1 illustrates the general location of the field study #2 in relation to Thunder Bay, Ontario. NORTHWESTERil OllTAIUO Figure F-1. The general location of field study #2 in relation to Thunder Bay, Ontario. Figure F-2 presents a more detailed map oft he location of field study #2. The site is located to the west ofKakabeka Falls, Ontario. Kakabeka Falls is located approximately 30 km west of Thunder Bay on Highway 11/17. To access the study area, one must travel west on Highway 590 for approximately 9.5 km to the Adrian Lake Road (just north oft he Boreal Timber Road) and then northwest on this road for 9 km to the Adrian Extension Road (at Adrian Lake). The plots were established in a cutover approximately 1 km up the Adrian Extension Road, on the right hand side (see Figure F-3) for detailed road map. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. .... 0 c :;0: ; ItS -(.) 0 (I) .s:; .+..". 0 c. ItS E -"0 (I) "iii +" (I) "0 c( C\1 I 1,.1- (J) L.. ::l ..C...l IJ.. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ~ ~ ~ . ,, \\ \\ ~ \ •• ~~II.,. ,. .,.. "' """' -- J "'\..._ ADRIAN EXTENSION R;D- ...... "' ,.' '• • '\. I.~I I .,. -II ,- ~ ' '' q \ \\ ..,., ... ,\,\ ~ .... ' ,,/ J ~ ' I ~ ,' ,',, It sI ~ .,$~ n ~ "v' \ I/ - ~~ ..' .,--1}, ;' ;;. --"'"' _, I - - ,. !"' "' q I' ' I ~ / ...' {[ 1/ ' - ~ I /J I ~ II '-II \ qn ' \ ~ I N /.~ 'I '~ I SCALE 1 : 15840 Figure F- 3. A map of the location of cutover and the plots for field study :# l. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIXG FIELD STUDY #2: RESULTS OF THE ANALYSIS OF VA IUANCE FOR THE VEGETATION INDICES Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 122 Table G-1 presents a summary oft he probabilities ofo btaining a larger F-ratio for herbicide treatment effects, tested against a residual error term with 44 degrees of freedom; and with block effects removed (p = 0.05); for each oft he vegetation type response variable, which resulted from the analysis of variance (ANOVA). Table G-1. Summary of the probabilities of obtaining a larger F-ratio for treatment effects tested against residual error for mean vegetation indices for each vegetation type (variable); one year after each treatment. An asterisk (*) denotes significant and '**' denotes highly significant effects at p =0.05. VEGETATION RESPONSE F-RATIO VARIABLE PROBABILITY Total Vegetation Index 0.011 * Shrub Vegetation Index 0.000 ** Herb Vegetation Index 0.76 Graminoid Vegetation Index 0.331 Bracken Fern Vegetation Index 0.414 I Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIXH FIELD STUDY #2: MEAN VEGETATION INDICES FOR EACH OF THE VEGETATION TYPES, IMPORTANT INDIVIDUAL SPECIES AND CORRESPONDING RESULTS OF MULTIPLE RANGE TESTING Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 124 Figure H-1 illustrates the mean total vegetation indices ofa ll vegetation observed on the site one year after each treatment Letters denote any significant differences between the treatment means as determined by the Tukey's - HSD Multiple Range tests at p = 0.05. ~~ ~ 1000 Figure H-1. The mean total vegetation indices observed one year after each treatment. eatment List [R elease-Touchdown-Vision in l/ha] 1)CTLA 9) 4-0-0 17) 3-1-0 2)CTLB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 S) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6) 0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 125 Figure H-2 illustrates the mean shrub vegetation indices observed on the site one year after each treatment Major shrubs were those of most interest to DowElanco Canada Inc. while minor shrubs include all others (Table 9). Letters denote any significant differences between the treatment means as determined by the Tukey's- HSD Multiple Range tests at p = 0.05. 3400 c 3200 3000 2800 rl ~ 2600 >< 2400 ~ BC cw ,., z 2200 ~ 2000 ~ V1 z 0 1800 ~ ~ i= ~ ~ ABC 1600 c( ~ ABC tw- 1400 ~ ~ % ABC 1200 t% ~ w~ 1000 / ~ ABG ~ - ' AB ~ > BOO ~ ~ AB ~ A8 ~ / AB 600 ~ AB!III '/. v. I/: /. ~ ~ ~ ~ AB ~ ~ % AB ~ ~ 7 '/ AB ~ :% AB ~~ -400 ,., /. .... / ~ ~ ~ '/ 200 '/ ~ ~ /, /. '/ 'Z ~ I ~ A r./. '/ /. ,/. /. '/ / '/. 0 1 2 3 4 5 6 7 8 9 10 1112 13 141516 1718 19 20 21 22 23 TREATMENT ~ MAJOR SHRUBS - MINOR SHRUBS Figure H-2. The mean vegetation indices of the major and minor shrubs observed one year after each treatment Tre atment List [R elease-Touchdown-Vision in llha] 1)CTLA 9) 4-0-0 17) 3-1-0 2)CTLB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 5) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6) 0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 126 Figures H-3 through H-8 illustrate the mean vegetation indices by treatment for each of the six major shrubs. Letters denote any significant differences between the treatment means as determined by the Tukey's - HSD Multiple Range tests at p = 0.05. Trembling Aspen Figure H-3 shows that, with the exception of treatments #11 (6-0-0), #12 (0.9-0.9-0), #22 (5.1-5.1-0) and #23 (6-3-0), all the treatments controlled trembling aspen relative to Control A. Mixtures of triclopyr and glyphosate reduced the vegetation index of trembling aspen to a greater degree than did either of the two herbicides applied alone. The best control was achieved with treatment #20 (3-6-0). Mountain Maple Figure H-4 shows that all the treatments, except #16 (2-2-0), reduced the vegetation index of mmmtain maple relative to Control A The high index which resulted in treatment # 16 seems to be an anomaly and could not be explained Although the differences were not significant, herbicides applied alone tended to provide better control of mountain maple than did the mixtures. Beaked Hazel Figure H-5 shows that, with the exception oft reatment #9 ( 4-0-0), all treatments significantly reduced the mean vegetation index of beaked hazel to less than half of that found on Control A. Treatments #4 and #7 (6l/ha ofVision and ofTouchdown, respectively) eliminated the beaked hazel completely. Treatment #9 was not as effective in reducing the mean index of beaked hazel as the rest of the treatments. Prunus L spp. Figure H-6 shows that all the treatments, with the exception of treatment #23 (6-3-0), were effective in reducing the mean vegetation index ofP runus L spp. Treatments #5 (0-3-0) and #9 ( 4- 0-0) were not as effective in reducing Prunus spp. as the remainder of the treatments were. It is not known why treatment #23 resulted in more than twice the index observed in Control A The Tukey's - HSD Multiple Range Test identified that there were significant difference between the poor result in treatment #23 and several of the other herbicide treatments. Bush Honeysuckle Figure H-7 shows that the mean vegetation index ofbush honeysuckle was significantly reduced by all herbicide treatments and by the manual vegetation control treatment; relative to the unweeded control. However, the manual weeding (Control B) was not as effective as the other herbicide treatments. Generally, lower rates oft riclopyr and glyphosate applied singly and in mixture did not control bush honeysuckle as effectively as did higher herbicide rates. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 127 ~~ ~ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TREATMENT Figure H-3. The mean vegetation indices oft rembling aspen observed one year after each treatment Tre atment List [R elease-Touchdown-Vision in 1/ha] 1)C1LA 9) 4-0-0 17) 3-1-0 2)CTLB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 5) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 128 800 ~ 700 ~ ~ ~ 600 % t1 ~ ~ 0 -z 500 I z ~ ~ 0 400 ~ tc= ~ .w.... . ~ ~ I 300 >w ~ ~ ~~ t% ~ I ~ 1: ~~ -. ~ ~ 200 ~ ~ ~~ ~ % ~ :~% ~~ ~ ~ ~ I 100 ~ ~ ~ 1%r7 ~ ~ ~ ~ I ~ ~ ~ ~ /_ ~ ~ ~ :1 :~% % /~ 0 ~ ~ ~ "A I"A I.? .! ~ ~ 1 2 3 4 5 6 7 8 g 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TREATMENT Figure H-4. The mean vegetation indices ofm ountain maple observed one year after each treatment. Tre atment List [ Release-Touchdown-Vision in 1/ha ] 1)CTLA 9) 4-0-0 17) 3-1-0 l)CTLB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 S) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 129 ~~ ~ z 0 ic= IU >2 Figure H-5. The mean vegetation indices ofbeaked hazel observed one year after each treatment. Tre atment List [ ~ Touchdown-Vision in 1/ha] 1)C1LA 9) 4-0-0 17) 3-1-0 2)C1LB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20)3-6-0 S) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14)2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 130 ~~ B ~ ~ ~~ ti 500 zQ z 4CJO 0 ic= ~ 300 Ill ~ >Ill 200 1 2 3 4 5 6 1 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TREATMENT Figure H-6. The mean vegetation indices of Prunus spp. observed one year after each treatment. Treatment List [Release-Touchdown-Vision in 1/ha] l)ClLA 9) 4-0-0 17) 3-1-0 2)C1LB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 S) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7) 0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 131 450 8[% 400 ~ ~ 350 ~ ~ t1 300 ~ -0z ~ ~~ z ~ Q ct= ~ .... ~ . 200 UJ ~ ~ w~ 150 % > ~ 100 ~ A ~ A ~ A ~ ~ 50 ~ .A ~ ~ A ~ ~ :1. % ~ ~ % ~ ~~~~~ ~ A ~ ~ ~ ~ ~ ~ V/IA A A A A .A 0 ~ ~ ~ ~ :A. I 1 2 3 4 5 6 1 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TREATMENT Figure H-7. The mean vegetation indices of bush honeysuckle observed one year after each treatment. Tre atment List IR elease-Touchdown-Vision in 1/ha] 1)CTLA 9) 4-0-0 17) 3-1-0 2)CTLB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 5) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7) 0-6-0 1S) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 132 RubusLspp. Figure H-8 shows that there was very little or no Rubus L. spp. observed one year after most treatments. There were no significant differences between mean indices identified by Tukey's- HSD Multiple Range Test. As with the control of mountain maple, treatment #16 (2-2-0) had an extremely high index relative to the rest of the treatments. 600 ~ 500 ~ ~ ~ ~/j -c t1 400 z % z ~ ~ 0 300 ~ ic= ~ 1w- ~ ~ w~ 200 ~ > ~ ~ % ~ % 100 ~ ~ % %~ ~ % % ~ ~ ~ 0 1'7"'2 ~ ~ 1"'71 ~ I I I I I I 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TREATMENT Figure H-8. The mean vegetation indices of Rubus spp. observed one year after each treatment. Treatment List [Release-Touchdown-Vision in lJha] 1) CTI..A 9) 4-0-0 17) 3-1-0 2) CTI..B 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 5) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 133 Figure H-9 illustrates the mean herb vegetation indices observed on the site one year after each treatment With the exceptionoftreatment#21 (5.1-0.9-0), all the treatments reduced Aster L. spp. to some degree, relative to Control A. There were no distinguishable trends in the degree of control, treatment#22 (5.1-5.1-0) was the most effective in reducing the mean vegetation index ofA ster spp.. All the herbicide treatments did control fireweed to some degree. The least effective treatments were: #10 (5-0-0), #13 (0.9-5.1-0), #4 (0-0-6) and #7 (0-6-0). Generally, high rates of Release and Touchdown in mixture tended to be the most effective. Overall, there were no significant differences in mean vegetation indices for aster, fireweed or for all herbs combined. Figure H-1 0 illustrates the mean graminoid vegetation index indices observed on the site one year after each treatment The mean indices of Canada blue-joint grass was very low (vegetation indices <60). Treatment #6 (0-4-0) was the least effective in controlling grass. Herbicide treatments with triclopyr ester applied alone and in mixture with low rates of glyphosate did not effectively control grass, relative to no vegetation control. The mean indices of Carex (Dill.) L. spp. were relatively high with treatments of triclopyr applied singly and in mixture with lower rates of glyphosate. Treatments with the higher rates of glyphosate controlled Carex spp. most effectively. Overall, there were no significant differences in mean vegetation indices of Canada blue-joint grass, Carex spp. or ofboth graminoids combined. Figure H-11 illustrates the niean vegetation indices for bracken fern observed on the site one year after each treatment Several treatments resulted in an increase in index relative to Control A. Although differences between means were not significant, treatments #14 (2-0-2) and #11 (6-0-0) resulted in the highest mean indices. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 134 >w< -zc z 0 i= ~ >fi1 TREATMENT ~ IIIFIREWEED ~ OTHER HERBS Figure H-9. The mean vegetation indices ofA ster spp., fireweed and other herbs observed one year after each treatment. Tre atment List [ Release-Touchdown-Vision in 1/ha] 1) CTLA 9) 4-0-0 17) 3-1-0 2)CTLB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 S) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 135 -...-... •-o-r-A %/:: ,_ :% ~ ~ w>< -- % I % ~ 0 -- ~ %~ ~~ ! ~ ! z ~ .. ~ 1- /'.: ~ ~ 0 -~-- ~ ~ ~ % ~ t= ~ I' ~ - -- ~ ~ .- ~ ~ ' I. '~l 7 ~ ~ ~ w ~ ~ ~ ~ I~ /. 150 . ~/:: ~ > ~ ~ ~·- ~ ~ ~:,1 IZ ~ ~ ~ ~ '~/. ~~ ~ ~ '/. ~ ~ ~ ~ ~ ~ '/ n,a, ~ t% t% ~ ~ '"" %: ~~ '~ ~ /. ~ -'l ~~ v. lj %: '/1 lj - '/ '/ ~ '/ :~% ~ A ~ ~ / 123456 8 9 12 13 14 1516 18 19 20 21 22 23 TREATMENT 11\1 Blue-joint Greae Figure H-10. The mean vegetation indices ofCarex spp. and Canada blue-joint grass observed one year after each treatment. Treatment List [Release-Touchdown-Vision in 1/ha} 1)CTLA 9) 4-0-0 17) 3-1-0 2)CTLB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 5) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 136 500 450 r7 ~ 400 ~ ~ 350 ~ ~ t1 ~ -c ~ z ~~ 300 ~~ z !% ~ 0 ~ ~ ~ 250 c ~ ~ ~ ~ w~ 200 ~ ~ ~ w~ ~~ r% ~ > 150 !'/ ~ ?/ ~ [% ~ ~ ~ ~ 'l; ~ ~ ~ 100 ~ f:3 ~ ~ ~ ~ ~ ~ ~ t% ~ ~ ~ ~ ~ ~ ~ :% r-:%~ ~~ ~ ~ t% ~ 50 ~ ~ ~ ~ ~ ~ ~ ~ ~ P? ~ ~ ~ ~~~ ~ t% ~ ~r ~~ t% ~ ~ ~ t% 0 ~ ~ ~ ~~~~~ ~ ~ ~ ~~~~~ - ~ ~ ~ 1 2 3 4 5 6 7 8 g 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TREATMENT Figure H-11. The mean vegetation indices for bracken fern obseiVed one year after each treatment. Tre atment List [Release-Touchdown-Vision in 1/ha] 1)CTLA 9) 4-0-0 17) 3-1-0 2)CTLB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 5) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIX I FIELD STUDY #2: MEAN VEGETATION INDICES GROUPED INTO HERBICIDE RATE CONCENTRATION GRADIENT Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 138 Mean indices for each vegetation type were calculated for herbicide treatments on the basis ofa grouped herbicide rate concentration gradient: 0, 1-3 and 4-6 Ilha This was done in an attempt to determine ifa ny trends in vegetation control existed. Tables I-1 to I-5 present this information in tabular format Refer to text for graphical presentation. Table I-1. The mean total vegetation indices grouped by herbicide rate (0, 1-3 and 4-6llha) (adapted from Table 11). The number enclosed in brackets is the number of treatments involved in calculating the mean. lt'laa TOUCHDOWN TOUCHDOWN VISION VISION 0 1-3 4-6 1-3 4-6 0 Ctl A 5162 (1) 1349 (1) 1740 (2) N/A 1624 (2) Ctl B 2183 (1) RELEASE1-3 1740 (1) 2539 (5) 1871 (2) 2361 (2) N/A RELEASE4-6 2820 (3) 3387(2) 1458 (1) NIA NIA Table I-2. The mean shrub vegetation indices grouped by herbicide rate (0, 1-3 and 4-6IIha) (adapted from Table 11). The number enclosed in brackets is the number of treatments involved in calculating the mean. 1/ha TOUCHDOWN TOUCHDOWN VISION VISION 0 1-3 4-6 1-3 4-6 0 Ctl A 3023 (1) 409 (1) 312 (2) NIA 432 (2) Ctl B 317 (1) RELEASE1-3 323 (1) 1043 (5) 624 (2) 587 (2) N/A RELEASE4-6 900 (3) 1217(2) 641 (1) N/A N/A Table I-3. The mean herb vegetation indices grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 11 ). The number enclosed in brackets is the number of treatments involved in calculating the mean. 1/ha TOUCHDOWN TOUCHDOWN VISION VISION 0 1-3 4-6 1-3 4-6 0 Ct1 A 2140 (1) 870 (1) 1255 (2) N/A 1092 (2) Ct1 B 1526 (1) RElEASE 1-3 919 (1) 1167(5) 1071 (2) 1302 (2) N/A RELEASE4-6 1364 (3) 1873 (2) 704 (1) N/A N/A Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 139 Table I-4. The mean graminoid vegetation indices grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 11). The number enclosed in brackets is the number of treatments involved in calculating the mean. IJba TOUCHDOWN TOUCHDOWN VISION VISION 0 1-3 4-6 1-3 4-6 0 CtlA227(1) 77(1) 105 (2) N/A 48 (2) Ctl B 206 (1) RELEASEl-3 433 (1) 208 (5) 225 (2) 198 (2) N/A RELEASE4-6 386 (3) 825 (2) 83 (1) N/A N/A Table I-5. The mean bracken fern vegetation indices grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 13). The number enclosed in brackets is the number of treatments involved in calculating the mean. llba TOUCHDOWN TOUCHDOWN VISION VISION 0 1-3 4-6 1-3 4-6 0 CtlA 54 (1) 0 (1) 65 (2) N/A 60 (2) CtlB 138 (1) RELEASEl-3 15 (1) 32 (5) 82(2) 291 (2) N/A RELEASE4-6 183 (3) 244 (2) 54 (1) N/A N/A Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIX.J FIELD STUDY #2: RESULTS OF THE ANALYSIS OF VARIANCE FOR THE .JACK PINE CROP TREE RESPONSES Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 141 Table J-1 presents a summary of the probabilities of obtaining a largerF-ratio for herbicide treatment effects, tested against a residual error term with 44 degrees of freedom; and with block effects removed (p = 0.05); for each of the scOOting response variables, which resulted from the analysis of variance CANOVA). Table J-1. Summary of the probabilities of obtaining a larger F-ratio for treatment effects tested against residual error for the mean seedling response variables; one year after each treatment. An asterisk (*) denotes significant and'**' denotes highly significant effects at p = 0.05. SEEDLING RESPONSE F-RATIO VARIABLE PROBABILITY Survival 0.019 * Physical Condition 0.241 Needle Length 0.021 * Volume incrementlha 0.187 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIXK FIELD STUDY #2: JACK PINE SEEDLING RESPONSES ONE YEARAFfEREACHOFTBE TWENTY-THREE TREATMENTS Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 143 Figure K-1 illustrates the mean percent survival rates of the jack pine seedlings one year after each treatment ...J >> cl: a: ::J tD ~ Ill a0: Ill 0- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TREATMENT Figure K -1. The mean percent survival rates oft he jack pine seffilings one year after each treatment Tre atment List IR elease-Touchdown-Vision in l/ha] 1)C1LA 9) 4-0-0 17) 3-1-0 2)C1LB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 S) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6) 0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 144 Figure K-2 illustrates the mean physical condition codes of the jack pine seedlings one year after each treatment. ~ ~ ~~ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TREATMENT Figure K-2. The mean physical condition codes of the jack pine seedlings one year after each treatment Tre atment List [R elease-Touchdown-Vision in 1/ha] 1)CTLA 9) 4-0-0 17) 3-1-0 2)CTLB 10) 5-0-0 18) 3-2-0 3)0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 5) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 145 Figure XI-3 illustrates the mean needle lengths of the jack pine seedlings one year after each treatment. ~~~ ~ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 TREATMENT Figure K-3. The mean needle lengths (in mm) of the jack pine seedlings one year after each treatment. Tre atment List IR elease-Touchdown-Vision in 1/ha] 1)CTLA 9) 4-0-0 17) 3-1-0 2)CTLB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 5) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6) 0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16)2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 146 Figure K-4 illustrates the mean volume incrementslha of the jack pine seedlings one year after each treatment. 800 - ~ 100 (I) ~ < ~ -E 600 I' 0 ~ - ~ .cG: 500 / z~ ~ Ill ~ ~ 400 I' Ial:l ~ ~ ~ ~ I- (z) ?. 300 ~ v~ v. ~ ~ ll ~ ~ ~ ~ ~ ::i ~ ~ v. ~ v~ .... 200 ~ v. ? ~ 0 /~ ~ ~ ~ ~ ~ > I' / 100 ~ ~ ~ v ~. ~ ~ ~ / ~ ~ v~. ~~~ ~ ~ ~ ~~ I I' ~ ~ ~ ~ ~ ~ ~~~ ~ ~ ~ ~ ~ ~ ~ ~ !I' 17.1 ~ v~ ~ ~ v. 0 ~ ~ 1 2 3 4 5 6 1 8 9 10 11 12 13 14 1516 1718 19 20 21 22 23 TREATMENT Figure K-4. The mean volume increm.entslba in cm3 ofthe jack pine seedlings one year after each treatment. Tre atment List [Release-Touchdown-Vision in 1/ha] 1)C1LA 9) 4-0-0 17) 3-1-0 2)C1LB 10) 5-0-0 18) 3-2-0 3) 0-0-4 11) 6-0-0 19) 3-3-0 4) 0-0-6 12) 0.9-0.9-0 20) 3-6-0 5) 0-3-0 13) 0.9-5.1-0 21) 5.1-0.9-0 6)0-4-0 14) 2-0-2 22) 5.1-5.1-0 7)0-6-0 15) 3-0-1 23) 6-3-0 8) 3-0-0 16) 2-2-0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIXL FIELD STUDY #2: MEAN JACK PINE SEEDLING RESPONSES GROUPED INTO HERBICIDE RATE CONCENTRATION GRADIENT Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 148 Means for each response variables were calculated for herbicide treatments on the basis of a grouped herbicide rate concentration gradient: 0, 1-3 and 4-6 1/ha. This was done in an attempt to determine ifa ny trends in seedHng response existed Tables L-1 to L-4 present this information in tabular format Refer to text for graphical presentation Table L-L The mean percent seedling SUtViva1 grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 12). The number enclosed in brackets is the number of treatments involved in calculating the mean. IJha TOUCHDOWN TOUCHDOWN VISION VISION 0 1-3 4-6 1-3 4-6 0 Ctl A67(1) 73 (I) 54 (2) N/A 74 (2) CtlB 100 (1) REI EASE 1-3 73 (1) 68 (5) 45 (2) 84 (2) NIA RELEASE4-6 65 (3) 38 (2) ·42 (1) N/A N/A Table L-2. The mean physical condition codes grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 12). The number enclosed in brackets is the number of treatments involved in calculating the mean. IJba TOUCHDOWN TOUCHDOWN VISION VISION 0 1-3 4-6 1-3 4-6 0 Ctl A2.0 (I) 2.0 (1) 2.7 (2) N/A 1.7 (2) Ctl B 1.0 (1) RELEASE 1-3 2.0 (1) 2.3 (5) 3.0 (2) 1.8 (2) N/A RELEASE4-6 2.3 (3) 3.0 (2) 3.0 (1) N/A N/A Table L-3. The mean seedling needle lengths (in mm) grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 12). The number enclosed in brackets is the number of treatments involved in calculating the mean. IJba TOUCHDOWN TOUCHDOWN VISION VISION 0 1-3 4-6 1-3 4-6 0 CtlA68 (I) 52(1) 45 (2) N/A 60(2) CtlB 79 (I) RELEASE 1-3 15 (1) 67(5) 31 (2) 70(2) N/A RELEASE4-6 64(3) 58 (2) 51 (1) N/A N/A Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 149 Table L-4. The mean seedling volume incrementslha (in cm3) grouped by herbicide rate (0, 1-3 and 4-6 1/ha) (adapted from Table 12). The number enclosed in brackets is the number of treatments involved in calculating the mean. llha TOUCHDOWN TOUCHDOWN VISION VISION 0 1-3 4-6 1-3 4-6 0 CtlA 141 (1) 88 (1) 41 (2) NIA 132 (2) CtlB 751 (1) RELEASE1-3 339 (1) 189 (5) 30(2) 231 (2) N/A RELEASE4-6 204 (3) 190 (2) 24(1) N/A N/A Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IMAGE EVALUATION TEST ~ (QA-3) ::: I 2ll ~ ~ ~ om 2.2 I t~ ~ ~ u II& •20 ~ 25 14 6 111111. 11111 " 111111. ._-__ 150mm -- ,_... 6" -- APPLIED -..::E IMAGE .In c ...:::::: 1653 East Main Street ~ Rochester, NY 14609 USA ~ Phone: 716/482-0300 -- Fax: 7161288-5989 C 1993, Applied 1m age, Inc.. All RlghiS Reserved Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.