DANIELS, L.D.

Department of Geography, University of British Columbia, 1984 West Mall, Vancouver, BC CANADA V6T 1Z2

Historically, fire was a primary factor influencing the structure and dynamics of Douglas-fir – lodgepole pine forests of central British Columbia, Canada. The historic fire regime included low-severity, stand-maintaining fires and less frequent, stand-replacing fires. At the stand level, fire intervals ranged from two to 59 years, with median intervals of 13 to 22 years. Fire intervals doubled when considering only fires that scarred at least two recorder trees per plot. Fire scar records, precipitation reconstruction, and El Niño-Southern Oscillation (ENSO) indices were used to test for climatic influences on fire occurrence between 1700 and 1970. Links between climate variation (ENSO) and fire in the Cariboo region were consistent with climate-fire relationships in other dry forests in North and South America. Fires related to drought at the onset of La Niña events. Years of above average precipitation preceded fire years, perhaps increasing understory vegetation cover and fine fuels. These results are regionally important given the current mountain pine beetle outbreak in British Columbia. The risk of catastrophic fire in the Cariboo forests will be greatest if a strong La Niña event coincides with peak fuel accumulations resulting from the current outbreak.