Comparing Clearcutting and Alternatives in a High-elevation Forest: Early Results

The Sicamous Creek Silvicultural Systems project examines clearcutting and silvicultural alternatives to clearcutting in high-elevation Engelmann spruce – subalpine fir (ESSF) forests, motivated by concerns about the effects of forestry practices on regeneration, hydrology, and biological diversity. Treatments include: ha clearcuts, arrays of -ha openings, arrays of .-ha patch cuts, individual tree selection (), and uncut controls. The replicated experimental treatments at an operational scale have attracted many researchers to the site. We summarize the results of studies that have looked at harvest treatment effects and the effects of different opening sizes on  different resource values and ecosystem components, including: harvest economics and the residual stand, microclimate and snow, soil ecology, conifer regeneration, and biodiversity. All harvest treatments were successfully implemented under winter conditions. Harvest cost was somewhat less for -ha clearcuts than for the other treatments. Physical conditions for regeneration were generally better with and -ha openings, but .-ha openings or individual tree selection harvesting favoured many soil processes, natural regeneration, and components of biological diversity. Across all studies, most variables showed similar responses to the -ha openings and the -ha openings, but different responses to the .-ha openings or individual tree selection. Openings of  ha or more could therefore be considered ecologically similar to larger clearcuts, implying that recent increased use of to -ha openings operationally may not represent much ecological change from previous to -ha clearcuts. Harvesting with .-ha patch cuts was more often preferred for study variables than harvesting with uniform selection cuts. We recommend more operational trials with small patch cuts or patchy group selection, varying the amount of timber removed and size of gaps, as a way of increasing the ecological diversity of harvesting practices in the ESSF, and to help meet the growing list of objectives for high-elevation forestry.