U.S. Joint Fire Science Program


Date of this Version


Document Type



Fire Science Brief, Issue 29, January 2009


US governmen work.


Prescribed fire and mechanical thinning have long been used as management tools in fire-excluded forests. Until recently, however, little coordinated data existed on the ecological effects of thinning versus fiire. Malcolm North and a large team of scientists working in mixed-conifer stands at the Teakettle Experimental Forest in California, examined how a range of ecosystem functions responded to commonly used fuels treatments. They found that fire is the key to restoring forest health, and thinning is best viewed as a tool for controlling fire intensity and extent. Collectively the different research studies at Teakettle found that fi re can “jump start” many ecosystem process while the additional slash and litter produced by thinning alone may actually “stall” the same processes. In current fi reexcluded forests, soil moisture is the most limiting resource. Fire exclusion has also signifi cantly changed mortality with insects, disease, and water stress selectively killing larger trees in a clustering pattern. With a broad range of studies, coordinated in a common experimental design, research at Teakettle can provide a valuable, synthesized understanding of how fire and mechanical fuels treatments affect forest health.