Economic and fragmentation effects of clearcut restrictions

Clearcut restrictions limiting individual clearcut size affect economic outputs and alter the spatial distribution of wildlife habitat over the landscape. Simulations of different clearcutting restrictions were applied to a 47,500 ha mixed-ownership landscape in the Sierra Nevada of California. The private owner was assumed to pursue a goal of maximizing net present value (NPV), while the public owner was assumed to use a combination of low-intensity selection harvesting and long rotations to develop late-seral habitat. With a 10 yr exclusion period, maximum clearcut size limits of 4 and 32 ha reduced the private owners NPV to 79% and 91% of the unconstrained maximum, respectively; with a 20 yr exclusion period, to 65% and 88% of the unconstrained maximum. Initially, smaller clearcut size limits resulted in more mature forest [average stand diameter (ASD) greater than 30 cm], but with greater fragmentation. Ultimately, late-seral habitat (ASD > 61 cm) was insensitive to clearcut size limits because rotation lengths of 60 or 90 yr did not produce that habitat class for most forest types.