Relations between peak snow accumulation and canopy density

Snow was monitored for five years in plots from which 30% of the timber had been previously removed in the form of group selection and in an unlogged control at a sub-alpine site in British Columbia. Average peak snow water equivalents (SWE) ranged from 38 to 52 cm and occurred between late March and mid-April. Canopy density was measured in circular areas of sky in 10-degree increments from the zenith to the horizon. The optimum parameter for explaining the variability of peak SWE was canopy density within a 60- to 80-degree-wide cone. Results suggest that where openings are 1 ha or less, peak SWE approached a locally consistent maximum value when canopy density approached zero. This improves our ability to predict the effects of group selection on snow accumulation in high elevation forests. Key words: forest canopy, snow interception, snow accumulation, group selection