Chapter 1 - Setting the Stage for Mixed- and High-Severity Fire

Abstract

Drier montane forest ecosystems and some shrub habitats are assumed to have historically been maintained by lower-severity fires that created open and park-like structures in western North America. High-severity fires—especially larger patches—also often are assumed to be unnatural and ecologically damaging. These assumptions drive current land management policies where fires burn in higher severities. However, evidence indicates that montane forests, including ponderosa pine and mixed-conifer forests, were historically far more variable in tree densities and fire regimes and were maintained by a mixed-severity fire regime. Though the unique complex early seral forests created by higher-severity fires are important for a wide variety of biota, they may now be relatively rare because of fire suppression, land use alterations, and postfire logging. Management designed to encourage primarily homogeneous, low-severity fire in areas that historically had mixed-severity fire is a poor substitute for the ecosystem benefits created by these fires.