Kirtland’s Warbler on the Hiawatha National Forest: a spatial and temporal management problem

Abstract

The Kirtland's warbler (Setophaga kirtlandii) utilizes actively managed breeding habitat on the Hiawatha National Forest in Michigan's Upper Peninsula. Managing the spatial arrangement of future breeding habitat is a complex forest management problem. While it is relatively simple to identify good areas to create habitat in the near future, it is difficult to foresee, without analysis, whether good habitat patches and amounts can be maintained through a full forestry rotation. Additionally, financial investments required to create suitable habitat are substantial, and managers should carefully consider habitat designs that increase breeding success.A harvest scheduling model was applied on the Hiawatha National Forest to explore opportunities for habitat management. Results help support implementation of the 2006 Forest Management Plan, which identified goals and objectives to create and maintain 6700 acres of age 6-16 Kirtland's warbler (KW) habitat within a larger 33,500 acre KW habitat system. Applications addressed a mid-sized landscape (174,808 acres), comprised of 12,307 stands and a 60 year planning horizon, consisting of 30 two-year planning periods with KW habitat production objectives. Three major model explorations are documented. First, a heuristic is developed to solve an intractable dynamic programming (DP) problem. Secondly, a pre-processing heuristic is developed to pare down the number of stand-level management options that must be included in the harvest scheduling model. Finally, the modeling system is applied to the problem to identify a management strategy and show financial and spatial trade-offs of alternative management strategies. Results of the first exploration indicate that an optimal DP solution can be identified with the proposed heuristic with improved solution times. The second exploration shows substantial time savings from eliminating many KW management options without compromising solution value. The third exploration determines a management strategy for where and when to generate habitat on the Hiawatha National Forest along with the associated spatial and financial tradeoffs.