PARENT SESSION
Poster Session #15: Paleoecology.
Monday, August 5. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

A 2,500-year record of fire mystery from small hollows, Orcas Island, Washington, U.S.A.

Fujikawa, Wendy¹, Higuera, Philip¹, Brubaker, Linda¹, Sprugel, Douglas^*,1, ¹ University of Washington, Seattle

ABSTRACT- Pollen and charcoal records from three small hollows provide information on fire history and vegetation change over the past 2,500 years for a Douglas-fir - western hemlock - lodgepole pine ecosystem on Orcas Island, Washington. Records were constructed through fine-resolution sampling of macroscopic charcoal, and interpretations are supported by results from a calibration study that compares charcoal records with tree-ring evidence of past fires. Each small-hollow record suggests 2-6 moderate- or high-severity fire events. The calibration study indicates that low- and moderate-severity fires may be underestimated by up to 50%. However, even when doubling the number of fires estimated from the charcoal record, fire frequencies are much lower than expected for an ecosystem with well-drained soils and a large component of lodgepole pine. High-resolution pollen records are being developed to corroborate inferences made from the charcoal records.

KEY WORDS: fire history, paleoecology, forest ecology