One side effect of many land management activities is an increase in the amount of available fuel. Fuels resulting from, or altered by, forestry practices such as timber harvest or thinning, as opposed to naturally created fuels are called Activity fuels. Branches and unmerchantable bolewood left on site after timber harvesting (slash) is the quintessential activity fuel. Other land management activities, such as pruning, herbicide application, non-commercial thinning, and even prescribed burning, also create activity fuel. Even prescribed burning in some cases creates “activity fuels” killing tree branches or whole trees.