Maciej Jamrozik  

MSc candidate, 2011 - present
Influence of a large deciduous tree species, bigleaf maple, on the growth of mature conifers in the Pacific Northwest


Bigleaf maple (Acer macrophyllum) is one of the largest and most prominent hardwood trees growing in the temperate rainforest along the western coast of North America. The litterfall, throughfall, and stemflow originating from bigleaf maple result in mineral soil conditions that have higher concentrations of N, K, Ca and Mg as well as a forest floor with higher mineralizable NO3-N and pH. Our research examined whether the beneficial soil conditions created by bigleaf maple lead to an increase in the rate of growth in commercially valuable coniferous tree species such as Douglas fir (Pseudotsuga menziesii). Within Malcolm Knapp
Research Forest, located east of Vancouver British Columbia, we conducted a paired plot analysis comparing conifer growth in proximity to bigleaf maple with conifer growth not in proximity to bigleaf maple. Tree cores were extracted, and with the use of dendrochronological methods, the annual growth increments of the paired plots were compared to assess the difference in accumulated wood volume over time. Tree height was measured and site index was determined and compared between site types to assess whether bigleaf maple has an influence on conifer productivity. Given the expected increase in occurrence of bigleaf maple with climate change, the results will provide information about how forest ecosystem function may be affected by a shift in species composition.