Plant community and microclimate changes across forest edges created by clear-cutting

Background/Question/Methods

Forest management creates landscape mosaics of forest stands differing in time-since-harvest and successional age. Microclimate and plant communities exhibit distinct gradients across anthropogenic edges between mature forests and adjacent clear-cuts, but little is known about the temporal variability of the resulting edge effects. We quantified edge effects across edges differing in age (5 vs. 15 years old), that were created by patch clear-cutting in a maple-beech-birch forest in the Adirondack Mountains, NY. We sampled microclimate and plant community characteristics across four edges (2 per age) along twelve 60 m long transects (3 per edge).  At increasing distances from each edge (0, 5, 10, 20, 30 m; within forest or clear-cut), we measured hourly air temperature during the peak month of the growing season and cover of ground-layer plants on three 1 × 1 m plots. 

Results/Conclusions

Microclimate and plant cover exhibited steep gradients across the 5 year old edges, but did not change across 15 year old edges. Species richness did not show a gradient across either edge, but was highest in 5 year old clear-cuts, intermediate in mature forest, and lowest in 15 year old clear-cuts. Mature forest adjacent to 5 year old clear-cuts was more species rich than mature forest adjacent to 15 year old clear-cuts. Thus, edge-related gradients in microclimate and plant cover appear to be transient and obscured by forest regrowth within clear-cuts 15 years after timber harvest. In spite of this, species richness remains affected by time since harvest and the successional age of adjacent stands.