Even-aged restrictions with sub-graph adjacency

Restrictions on the size and proximity of clearcuts have led to the develop ment of a variety of exact and heuristic methods to optimize the net presen t value of timber harvests, subject to adjacency constraints. Most treat ha rvest units as pre-defined, and impose adjacency constraints on any two uni ts sharing a common border. By using graph theory notation to define sub-gr aph adjacency constraints, opening size can be considered variable, which m ay be more appropriate for landscape-level planning. A small example data s et is used in this paper to demonstrate the difference between the two type s of adjacency constraints for both integer programming and heuristic solut ion methods.