Fuel Treatments & Effects
Naturally-ignited Fire-use treatments
A detailed study of canopy fuel characteristics in five different forest types provided a unique dataset for simulating the effects of various stand manipulation treatments on canopy fuels. Low thinning, low thinning with commercial dbh limit, and crown thinning had similar effects on canopy bulk density (CBD) and canopy fuel load (CFL), but only the strict low thinning significantly affected canopy base height (CBH). In four of five sampled stands, CBD and CFL responded linearly to increasing treatment intensity in those three thinning treatments. The ponderosa-pine/Douglas-fir stand, with its significant understory component, showed little change in CBD with the commercial limit and crown thinning treatments. The diameter-limit harvest exhibited little consistency among sites and, hence, it is not a good silvicultural tool for creating canopy fuel reduction prescriptions. Due to fire-induced mortality, crown scorch (from prescribed fire) was more effective than mechanical pruning (to an equivalent height) at modifying canopy fuel characteristics. At achievable scorch and pruning heights, neither treatment had a significant effect on CBD or CFL.