The Effects of Planting Density on the Growth and Yield of Lodgepole Pine Interior Spruce Interior Douglas-fir and Western Larch - 16 to 26 Year Results from EP964

This technical report summarizes nearly three decades of research from Experimental Project 964, a large-scale study investigating how planting density influences the development of four major conifer species in British Columbia. By evaluating 17 different sites over 16 to 26 years, the authors analyze the critical trade-offs between individual tree size and total timber yield per hectare. The findings reveal that higher densities maximize total wood volume and biomass and lower densities produce thicker trees with less taper, though vertical height growth remains largely unaffected across all treatments. This document serves as a guide for forest managers to select optimal stocking levels based on specific commercial goals, such as high-value lumber production versus biomass for carbon credits.