DISCLAIMER: This website is for a class project.  The dataset used for analysis is preliminary and/or heavily modified.  Any conclusions derived from this analysis should be considered fictional.

Summary

          The mixedwood forests of Western Canada are dominated by mixtures of aspen [Populus tremuloides] and white spruce [Picea glauca] (Figure 1).  In boreal regions under forest management, silvicultural techniques like clearcutting, plantation forestry, and vegetation management shift mixedwood species compositions toward deciduous or conifer dominance.  These species shifts have the potential to lower stand productivity, reduce conifer wood quality, and increase insect damage to spruce.  Furthermore, deciduous or conifer-dominated stands fail to address the biodiversity and site-productivity concerns associated with simplified stand structures. "Intimate mixtures" provide a management alternative by allocating equivalent growing space to aspen and spruce early in stand development. Specifically, "intimate mixtures" attempt to accelerate mixedwood succession, providing shorter rotations and mixedwood stand structure.  In this experiment, intimate mixtures were established by removing aspen competition radially within 1 to 2.5 metres of planted spruce.  These radial treatments were applied in five treatment sizes at 2, 4, and 6 years after stand establishment.  Increasing radial treatment size and earlier treatment application were expected to improve spruce growth;  however, no significant trends could be extracted from the data.  Ultimately, radial treatment size and the year of treatment application poorly predicted spruce growth.  Supplementary analysis also tested spruce growth against vegetative competition.  Unfortunately, correlations were weak, contradictory, and often insignificant.

                                                                   Figure 1. Examples of aspen and spruce in the boreal 
                                                                   mixedwoods.  Coniferous spruce occupies the foreground and  
                                                                   deciduous aspen dominate the background. (Image: Phil Comeau)