Effects of Laccaria proxima and fibrous pulp wastes on the growth of container-grown conifers

Abstract

Nine conifer species, Japanese larch {Larix kaempferi), white spruce (Picea glauca) , black spruce (P. mariana), red spruce (P. rubens), jack pine (Pinus banksiana), mugo pine (P. mugo), red pine (P. resinosa),Japanese black pine (P. thunbergii) and Douglasfir (Psevdotsuga menziesii var menziesii), were tested to determine the effective host range of the ectomycorrhizal fungus Laccaria proxima and the possibility of utilizing pulp waste as potting medium for containerized seedling production. L. proxima significantly improved the growth of container grown jack pine, mugo pine, black spruce, red spruce and Douglas-fir, improved the growth of Japanese black pine and white spruce and slightly improved the growth of red pine and Japanese larch. Rye grain spawn inoculum was used for mycorrhizal establishment on jack pine seedlings. Pulp waste (33% by volume) usually had negative effects on tree seedlings except for Japanese black pine (positive) and Douglas-fir (no significant effect). The interactions of L. proxima and pulp waste varied with host tree species, but were significantly positive (P < 0.01) for jack pine and black spruce, and nearly significant for red spruce (P < 0.08) . Negative effects were found with Japanese black pine. Up to 8% pulp waste by volume without mycorrhiza improved the growth of jack pine seedlings over the controls, but over 8% pulp waste hindered jack pine seedling growth. Ten to 30% of pulp waste was effectively utilized in jack pine seedling production in association with L. proxima. Pulp waste with malt extract amendment was used as a spawn medium. Pulp waste in seedling production of black spruce, mugo pine, red spruce and Douglas-fir in association with Ii. proxima and of Japanese black pine without is feasible, but further research is needed to find out the optimal percentage of pulp waste which can be utilized in seedling production for most tree species.