Losses in Timber Values Associated with Distorted Growth in Immature Douglas-Fir

摘要

Lumber yields from a sawmill recovery study were used to quantify variation in tree values associated with growth distortion, prevalent in two stands of late immature Douglas-fir located in the Wetter Maritime CWH biogeoclimatic subzone on the west coast of Vancouver Island, British Columbia. The objective was to gain preliminary information on the variation in timber values associated with distorted growth (sinuosity and branching), to establish sampling requirements for the development of statistically significant value-based stem distortion classes. Following preliminary sampling of 200 potential study trees, 42 were selected according to size, branching, and sinuosity. These trees were felled, transported to a sawmill, and converted to lumber. Lumber grade and volume yields were recorded and used to calculate values for each study tree. These values were found to be 43% lower than those obtained in a previous second-growth Douglas-fir study. The lower value, however, was due primarily to rapid rates of growth in the distorted trees, which resulted in lumber that failed to meet annual ring count requirements for No. 2 and higher structural grades.