Fire Induced Tree Mortality in a Colorado Ponderosa Pine/Douglas-Fir Stand

The impact of a fall season prescribed surface fire on Douglas-fir and ponderosa pine mortality during the first 22 months following fire was evaluated using discriminant function analysis. Crown scorch, expressed as a percentage of the prefire live crown length, was the single best determinant of tree mortality. Stem charting on the least impacted quadrant is also a relevant variable in mortality determinations. Larger diameter trees of both species withstood proportionally greater stem and crown damage than smaller trees. Crown consumption indicators added substantially to the discriminating power of the functions, but prefire live crown and maximum scorch height were not important variables. Within the same size range, there was little evidence of important differences between ponderosa pine and Douglas-fir in the levels of crown and stem damage that induce mortality