Abstract: |
Silvicultural treatments to manage fire behavior affect both forest values that can be priced (market) and those that cannot (non-market). When the purpose of the treatments is to benefit a non-market value, evaluating their net effect is complicated by difficulties in assessing their total cost. Production possibility (PP) curves illustrate the relative cost, or tradeoffs, of managing for a non-market value in terms of market or other non-market values. We combined simulation and optimization models to schedule treatments that reduce fire threat (FT) and maintain late successional forest habitat (LSF structure) for the northern spotted owl over thirty years in a 6070 ha forest reserve. We evaluated the tradeoffs between reducing FT and maintaining LSF structure by constructing a set of PP curves. Results suggest that at low and moderate levels of LSF structure in the reserve, treating non-LSF units is as effective in reducing fire threat as is treating LSF units. In this range, the treatments impose a low cost on owl habitat. In contrast, at high levels of LSF habitat structure, treating some LSF units could reduce fire threat in the reserve. In this range, treatments come at a cost to owl habitat. Treatment effects in the reserve, whether ecological or financial, need to be evaluated at scales relevant to fire and owls. Hence, we evaluated net present value (NPV) for the collection of treatment units in the reserve over thirty years rather than for each unit in each decade. Results indicate that the lowest cost to the non-market values of LSF structure and FT reduction was achieved by a mixture of treatments -- some that earned money and some that lost money in an individual unit but that collectively broke even (NPV=0). In contrast, if breaking even was required within each decade the cost was similar to requiring that treatments earn $0.5 million NPV over thirty years. This implies that constraining the time period within which the financial effect of the treatments was evaluated imposed a cost on the non-market values in the reserve. |
