Impact of clear-cutting and road construction on soil erosion by landslides in the western Cascade Range, Oregon

Abstract

Research Article| July 01, 1975 Impact of clear-cutting and road construction on soil erosion by landslides in the western Cascade Range, Oregon F. J. Swanson; F. J. Swanson 1Department of Geology, University of Oregon Eugene, Oregon 97403 Search for other works by this author on: GSW Google Scholar C. T. Dyrness C. T. Dyrness 2USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Corvallis, Oregon 97331. Present address: USDA Forest Service, Institute of Northern Forestry, Fairbanks, Alaska 99701 Search for other works by this author on: GSW Google Scholar Author and Article Information F. J. Swanson 1Department of Geology, University of Oregon Eugene, Oregon 97403 C. T. Dyrness 2USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Corvallis, Oregon 97331. Present address: USDA Forest Service, Institute of Northern Forestry, Fairbanks, Alaska 99701 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1975) 3 (7): 393–396. https://doi.org/10.1130/0091-7613(1975)32.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation F. J. Swanson, C. T. Dyrness; Impact of clear-cutting and road construction on soil erosion by landslides in the western Cascade Range, Oregon. Geology 1975;; 3 (7): 393–396. doi: https://doi.org/10.1130/0091-7613(1975)32.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The H. J. Andrews Experimental Forest can be divided into two zones of approximately equal area, each with strikingly different susceptibilities to erosion by rapid soil movements. A stable zone occurs at elevations above 900 to 1,000 m in terrain underlain by lava-flow bed rock. Since logging and road cutting began in 1950, only two small road-related slides have taken place in the stable zone. In contrast, the unstable zone, located at elevations below 1,000 m and underlain by altered volcaniclastic rock, has been the site of 139 slides during the same period.Slide erosion from clear-cut areas in the unstable zone has totaled 6,030 m3/km2, or 2.8 times the level of activity in forested areas of the unstable zone. Along road rights-of-way, slide erosion has been 30 times greater than on forested sites in the unstable zone; however, only about 8 percent of a typical area of deforested land in the unstable zone is in road right-of-way. At comparable levels of development (8 percent roads, 92 percent clear-cut), road right-of-way and clear-cut areas contribute about equally to the total impact of management activity on erosion by landslides in the unstable zone. The combined management impacts in the unstable zone (assuming 8 percent road right-of-way and 92 percent clear-cut) appear to have increased slide activity on road and clear-cut sites by about 5 times relative to forested areas over a period of about 20 yr. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.