The 2002 Biscuit Fire burned at mixed-severities encompassing over 200,000 ha of publicly owned forestland,
including more than 8300 ha of conifer plantations. We used pre- and post-fire digital aerial photography
to examine how the level of canopy damage varied within these plantations in relation to
topography, weather, vegetation-cover, and management history, with an emphasis on the age of the
plantation. We examined 198 plantations that varied widely in age (5–47 years), size (1.25–47 ha), and
landscape context. The average level of canopy damage within the plantations was 77%. Based on Random
Forest variable importance values, plantation age was the best predictor of canopy damage. Average
annual precipitation, elevation and topographic position were ranked second, third, and fourth, respectively.
A model selection procedure, using geo-statistical regression models and Akaike’s information criterion,
corroborated the importance of plantation age relative to the other predictors tested and also
suggested that the influence of age varied over time. The top ranked regression model indicated that
the level of canopy damage reached its maximum around age 15 and stayed relatively high until age
25 before declining.

Keywords: Biscuit Fire, Burn severity, Land use legacy, Klamath Mountains, Random Forest analysis, Geostatistical regression