U.S. Joint Fire Science Program


Date of this Version


Document Type



Fire Science Brief, Issue 146, November 2011


US government work.


This study involved a chronosequence of 68 stand-replacing wildfires that happened between 1970 and 2007 in dry coniferous forests of eastern Washington and Oregon. The authors compared snag decay and surface fuel accumulation with and without post-fire logging. Without logging after a fire, woody fuels accumulate for 15–30 years because the rate of fuel deposition on the ground is greater than the rate of wood decay. Stands that were more dense prefire have greater accumulations of fuel. Predominant tree species and size influenced rates of fuel deposition and snag decay. Thin trees fell before larger trees and ponderosa pines typically fell before Douglas-firs. Within about 30 years of the fire most downed logs (>7.5 centimeters diameter) were rotten and soft. Cavity-nesters used various tree species and sizes for nests, but cavities occurred most frequently in snags with broken tops and in trees of at least 30-centimeter diameter. Post-fire logging that did not include slash removal at first increased surface fuels. But within 10 years after the fire, fuel loads were lower on logged sites than unlogged sites, and remained thus for at least 35 years. The researchers found no evidence that post-fire logging hindered tree regeneration on the study sites.