n. A cultural treatment made to reduce stand density primarily to improve growth, enhance forest health, recover potential mortality, or modify canopy fuel characteristics (adapted from Helms 1998)
In fire management applications, thinning is prescribed primarily to reduce canopy bulk density and increase canopy base height, reducing the potential for crown fire. Thinning types are classified by the method of selecting trees to be removed: low thinning, crown thinning (also called high thinning), free thinning, and selection thinning.
Thinning may exacerbate surface fire behavior, however, because surface fuel load may increase, in-stand wind speed may increase, and dead surface fuel moisture content may decrease. The tradeoff between reduction of crown fire potential and increase of surface fire potential must be considered.