A review and evaluation of growth response, stand value and profitability of pre-commercially thinned Jack pine stands in Northwestern Ontario

Abstract

This thesis will be a literature review with the purpose of evaluating the impact precommercial thinning (PCT) has on the tree growth response and if it can meet the objective of profitability in Jack pine (Pinus banksiana Lamb.) stands in Northwestern Ontario. Timing and thinning intensity have been identified as two major factors which influence the success of PCT. A general conclusion that can be made from the literature reviewed is that there is no specific threshold for timing and thinning intensities. Both are dependent upon the management objective and success can only be attained when used properly. If the goal is to achieve high-quality logs, then applying PCT at a low intensity and later in the stand’s development will help meet this goal. However, if the goal is to produce high volume with the shortest rotation age, then applying PCT at a high intensity at an early stage in the stand’s development will yield positive results. Additionally, tree growth response is clearly impacted by PCT. Greater thinning intensities can cause rapid diameter growth at the cost of increasing the abundance of more severe defects and reduce the overall quality of wood. When applied appropriately, PCT was found to decrease the total stand volume however, it can increase the total merchantable volume. Furthermore, it was estimated that in some cases, PCT can produce approximately $2,880 more average lumber recovery per hectare when compared to control stands. From the literature reviewed, it appears that PCT can meet the objective of profitability in Jack pine stands in Northwestern Ontario when used correctly.