Fire is an important historical disturbance factor in most stands of British Columbia interior Douglas-fir (Pseudotsuga menziesii var. glauca). Evidence of fire history was studied at the Pothole Creek Research Site (IDFdk1 biogeoclimatic subzone) near Merritt, B.C., as part of a larger project investigating stand development and growth and yield. A master chronology, constructed using samples taken from climatically sensitive trees, was used to cross-date samples collected from fire-scarred wood. The resulting pattern of past fire intervals was then employed to speculate about the historical fire regime at Pothole Creek. Evidence was found of fires occurring as long ago as 1693 and as recently as 1967. The mean fire interval was 13 years, within the expected range for interior Douglas-fir forests. The minimum and maximum intervals were 1 year and 46 years, respectively, indicating varying periods of both low-intensity/high-frequency fire and higher-intensity/low-frequency fire. This high disturbance frequency promotes plant species with adaptations to fire, such as Douglas-fir and pinegrass (Calamagrostis rubescens), and an open stand structure with sparse, patchy regeneration. The most severe fires identified on the site were not sufficiently intense to destroy the
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Updated July 24, 2015