U.S. Joint Fire Science Program


Date of this Version


Document Type



Fire Science Brief, Issue 105, April 2010


US government work.


On the southeastern edge of the Klamath Mountains in northern California, Whiskeytown National Recreation Area’s low elevation plant communities are characterized by an assortment of oaks and conifers with an understory of dense chaparral. Mechanical mastication of shrubs and small trees has become a popular method of fuels management. Although mastication expands the list of options for fire managers, the ecological impacts and long-term effects are virtually unknown. In particular, mechanical mastication essentially rearranges fuels and leaves behind a dense layer of slash on the ground. Burning this debris can potentially heat the soil and adversely affect the roots of woody plants and mycorrhizal fungi. Upper layers of soil are active sites of fine root growth, mycorrhizal hyphae, and nutrient cycling. Mycorrhizal fungi are the primary source for transfer of carbon to underground ecosystems and the transfer of soil nutrients to the trees. It was the goal of researchers to address information gaps on fuel treatments and to examine how mycorrhizal fungi and truffl es are affected by mechanical mastication followed by prescribed fire.