The effect of aspect on the forest edge along a power line corridor at Greenwoods Conservancy, summer 1999

The fragmentation of forest ecosystems is common in the northeastern United States (Cadenasso, 1997). Many studies have focused on the biotic factors of forest edges. These have shown that edge vegetation is different compositionally and structurally from forest interior vegetation (Brothers, 1992; Luken, 1991; Matlack, 1993; 1994). Steeper climactic gradients are created when trees are removed, the understory expands, and species distributions become edge oriented (Matlack, 1994). Trends among abiotic factors influencing forest edges, including light, temperature, and soil moisture, are much more difficult to generalize (Cadenasso, 1997; Saunders, 1999). The zone of temperature change from a clearing to the interior at a forest edge can vary by as much as 45m during a single day and by 40m for anyone time of day during a week (Saunders, 1999). Abiotic factors influencing a forest edge may not correspond with forest boundaries defined by canopy cover (Cadenasso, 1999).