Long-term monitoring of planting density trials provides critical information about the effects of planting density on the growth, development, and yield of conifer plantations. Experimental Project 964 (EP964), which was established in the Interior of British Columbia by the B.C. Ministry of Forests between 1985 and 2000, comprises 26 standardized planting density installations distributed over nine forest districts and four biogeoclimatic zones. The installations include four commercial conifer species laid out using five planting density treatments. The installations with this Experimental Project have now been monitored for about 16-26 years since planting. In this project, we analyzed data for 17 EP964 installations planted with interior lodgepole pine, interior Douglas-fir, interior spruce, and western larch. We focussed our analyses to answer three questions of interest to forest managers that concern: (1) the consistency of planting density effects on the growth and yield for particular tree species; (2) the optimal planting density to achieve the highest timber value per area for particular timber products; and (3) the forest health effects of planting density on pine mortality.
de Montigny, L., Ahmed, S.; LeMay, V.. 2016. 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. Forests, Lands, and NR Operations. Research Report (FLNRORD). TR98