An average of 6.5 (range: 1 - 23) stumps or trees were sampled (for origin dates, scar dates) over 359 sample sites, 30 of which lie just outside the study area. Study sites were selected to represent the range of stand age-class patches as interpreted from 1:12,000 aerial photograpy, and to include the boundaries between these patches. Since, most sites are located in clearcuts, the distribution of clearcuts strongly influenced the distribution of sample sites. Within sites, trees or stumps were sampled to include all age- classes present, to include the oldest individual present, and to include a maximal number of fire scars.
Tree origin dates and fire scar dates were recorded on stumps in the field. Increment cores were collected and used for trees in intact stands. A master fire chronology was constructed where the presence of seral tree species regeneration or fire scars for each fire year is listed for each site. Each fire episode was then mapped. Fire frequency was determined, and compared according to elevation, aspect, physiographic unit and cultural period. ANOVA and multiple comparisons tests were used for these comparisons.