Assessing the impact of management unit design and adjacency constraints on forestwide spatial conditions and timber revenues

Spatial considerations in ecosystem management are addressed within the fra mework of the forest management scheduling adjacency problem. Emphasis is o n both the effectiveness of adjacency regulations and the consequences of s trategies for management unit design. Four strategies are presented that su bdivide stands into maximum-sized harvest units. A dynamic-programming heur istic is used to plan harvest schedules that comply with adjacency constrai nts over temporal horizons extending up to eight 10-year periods. The impac t of stand design and adjacency constraints upon the output of the forest m anagement problem is assessed. Specifically, timber revenues and spatial co nditions generated by combining adjacency constraints with alternative stra tegies are analyzed. Results from test computer runs are discussed for appl ications in nine scenarios. Results suggest that timber adjacency costs are not overly sensitive to alternative strategies for management unit design that emphasize the generation of specific spatial conditions (e.g., amount of edge and interior space). They further indicate that emphasis on timber production when designing the management units' boundaries substantially re duces adjacency costs. They show that adjacency constraints contribute to m aintain spatial heterogeneity and yet may be inadequate for addressing othe r spatial concerns.