Lodgepole pine and trembling aspen competition: Neighbourhood studies within 22 to 39 year-old pine plantations of northern British Columbia

Six lodgepole pine plantations located within the Sub Boreal Spruce (SBS) biogeoclimatic zone of the northern interior of British Columbia were chosen to study the impacts of neighbourhood aspen competition on the growth of planted lodgepole pine (22–39 years old). At each site, 30 pine trees (CP) were selected as plot centres across the observed range of aspen competition. Information on the six nearest neighbours (NN) and a variety of competition indices were evaluated using linear and nonlinear models. Competition indices based on diameter or height relative to size were found as the best overall predictors of CP growth. Proximity of NN to the CP was found to be inconsistent as a predictor of growth. Individual pine and aspen NN modelling suggested aspen competition had the greatest influence on CP growth restriction. The results do not support aspen thresholds for optimizing the growth of free growing pine plantations. It is recommended that performance-based standards be developed that account for as...