Fuel weights of understory-grown conifers in southern Oregon

Abstract

Fuel weight by size classes for five understory coniferous tree species in southern Oregon was estimated using regression equations. Species included Abiesconcolor (Gord. and Glend) Lindl., Abiesmagnified Murr. var. shastensis Lenin., Pinusponderosa Dougl., Pinus contorta Dougl. var. murryana Grev. and Balf., and Tsugamertensiana (Bong.) Carr. Trees ranged from 0.1 to 3 m tall and were selected from "open" and "dense" overstory classes. Live and dead fuels from each tree were segregated into five diameter size classes. Regressions for foliage and total fuel weight are presented using as independent variables groundline diameter, total height, diameter2 × height, and basal area. Coefficients of determination (r2) were high, exceeding 95% for total weight in every case, but tended to decrease as diameter size class increased. Relative shade tolerance of the five species is estimated by comparing open- and dense-grown foliage weight ratios for each species.