U.S. Joint Fire Science Program


Date of this Version


Document Type



Fire Science Brief, Issue 25, December 2008


US government work.


Historically, frequent low-intensity, dormant-season fire shaped the landscape across a variety of forests in the United States, from eastern hardwood and hardwood/conifer mixtures to western coniferous forests. Decades of fire exclusion have resulted in heavy fuel loads and increased threat of severe wildfire compared to historic conditions in most forest types and also resulted in changes in forest composition compared to historic conditions. The Fire and Fire Surrogates Study (FFS) is the first to apply a standard experimental design to compare thinning, thinning followed by prescribed fire, and prescribed fire alone across a wide spectrum of ecological and economic variables. An important, though often overlooked, component of forest health is the soil. Recent research is demonstrating that fire has complex effects on soil composition, and thus forest health, compared to mechanical or chemical treatments.