Crown scorch volume and scorch height: estimates of postfire tree condition

Abstract

In salvage operations after wildfire, timber managers need to identify those trees most likely to die. Crown scorch volume and scorch height are commonly used to estimate damage to conifers after fire. Calculated crown scorch volume based on scorch height and tree dimensions was compared with observed crown scorch volume for four common conifer species of the northern Rocky Mountains. Calculated crown scorch volume was significantly greater than observed crown scorch volume for all species. The overestimates are the result of differences among species and trees of varying crown shape. When postfire tree condition was evaluated from observed crown scorch volume rather than from measured scorch height, crown damage was estimated with greater accuracy. Functions that estimate postfire tree mortality based on crown damage should be based on observed crown scorch volume rather than scorch height.