Evaluating the impact of stand composition and competition on white spruce and aspen wood attributes in the boreal mixedwood.

I evaluated how intra- and inter-specific competition affects the development of eleven wood attributes of trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) over 34 years. My analysis was conducted in a mixedwood trial site in Northern British Columbia, Canada, that included treatments consisting of 0, 1000, 2000, 5000, and 10000 stems per hectare of aspen. Competition was found to negatively influence wood attribute development in aspen and positively impact spruce (at low levels of competition). Plot level competition indices were the best predictor of variation in aspen wood attributes, while stand level competition (population density) best explained the majority of spruce wood attributes. Maintaining aspen at lower densities in intimate mixture can have a positive effect on spruce wood quality, while incurring relatively small reductions in spruce volume production and also retaining the ecological benefits associated with managing for mixed stands.