The interior wet-belt of BC consists of Engelmann spruce/subalpine fir and cedar/hemlock forests where natural disturbance is dominated by small-scale agents such as insects, pathogens, and weather. Partial cutting may better mimic natural disturbance regimes in these forests than clearcutting, which mimics large-scale disturbance such as fire. We will study the response of seedlings to a range of resources (light, nutrient) under three different partial cutting treatments in the Interior Cedar Hemlock zone. The study will examine above and below-ground limitations to growth of four conifer species (interior spruce, lodgepole pine, Douglas-fir, and western red cedar), and variation in species response to partial cutting practices. In addition to studying tree growth, we will sample seedlings for diversity and type of beneficial mycorrhizal fungi and disease-causing fungi. We expect colonization of roots by mycorrhizal fungi to suppress infection by disease fungi, while increasing nitrogen availability to the seedlings. Our hypothesis is that plant vigour will be affected not only by light and nutrients available to the plant, but also by the extent of colonization by beneficial mycorrhizal fungi. Therefore, reduced canopy retention may improve the seedling's access to light and nutrients at the expense of increasing the distance of seedlings from residual trees containing inoculum of beneficial mycorrhizal fungi. Increased knowledge of the relationships between seedling vigour and mycorrhizal fungi under different levels of canopy retention will improve our ability to predict the impacts of partial cutting and help us to determine the appropriate degree of partial cutting to optimize performance of different conifer species. Keith N. Egger.
Egger, Keith N.. 2003. Above- and below-ground processes affecting regeneration in partial cuts in interior wet-belt forests. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2003MR336