Theses and Dissertations Collection

Western larch (Larix occidentalis Nutt.) provides high-value lumber and wildlife habitat but is threatened by fire suppression and climate change. Crown foliage allocation was studied to enrich knowledge of western larch production ecology. Analysis of spatial models revealed that western larch produces foliage in an increasingly diffuse distribution as the crown lengthens. Unlike other conifers, foliar biomass increased linearly with DBH, indicating significant constraints on crown volume-filling. Specific leaf area (SLA) increased on the south side of the crown. Leaf area peaked closer to the bole in the southwest quadrant. Intrinsic variables accounted for less variance in horizontal foliage distribution compared to vertical distribution. The characteristic intrinsic dynamics of spatial foliage distribution and SLA variation are consistent with a hypothesis of plasticity to hydraulic and light conditions. The amount and distribution of foliar biomass and leaf area reflect the mesic site preference, deciduous habit, and shade intolerance of western larch.