Logging and forest roads related to increased debris slides in southwestern Oregon

Abstract

Abstract - Debris slides over a 20-year period were inventoried on 137,500 acres of forested land in the Klamath Mountains of southwest Oregon. Frequency during the study period was about one slide every 4.3 years on each 1,000 acres-an erosion rate of about 1/2 yd 3 per acre per year Erosion rates on roads and landings were 100 times those on undisturbed areas, while erosion on harvested areas was seven times that of undisturbed areas. Three-quarters of the slides were found on slopes steeper than 70 percent and half were on the lower third of slopes. The study area was subdivided into nine geomorphological erosion response units which exhibited profound differences in natural erosion rates and responses to disturbance. The results serve as a guide to appraising slide risk associated with planned timber harvests or mad construction on forested slopes.

Citation

Amaranthus, Michael P.; Rice, Raymond M.; Barr, Nicholas R.; Ziemer, Robert R. 1985. Logging and forest roads related to increased debris slides in southwestern Oregon. Journal of Forestry 83(4): 229-233.