Options for harvesting timber to control snowpack accumulation

Past research in the subalpine forest indicates that the effect of timber harvest on snowpack accumulation patterns and subsequently on streamflow can be optimized when 30-40 percent of the area is clearcut using 5-8 tree height openings. This paper will present the results of several recent studies looking at the effects of other harvesting practices on snowpack. Two years of post-harvest data indicate that large openings (26-tree height) can be created and a 25-30 percent increase in peak water equivalent (relative to undisturbed control) can be obtained through the use of residual stems and slash to create roughness and prevent scour. In another study five years of data on replicated plots of varying growing stock levels indicate that peak water equivalent in the pack can be increased up to 13 percent following thinning. Observations on a 40 ha subwatershed of the Fraser Experimental Forest where 35 percent of the basal area was removed by individual tree selection and 3 years of postharvest data is available, indicate peak water equivalent increased 10-15 percent over the entire area.