GSA Annual Meeting in Seattle, Washington, USA - 2017

Paper No. 356-3
Presentation Time: 9:00 AM-6:30 PM

COMPARATIVE EFFECTS OF DIFFERENT POST-FIRE LAND MANAGEMENT STRATEGIES ON HILLSLOPE SEDIMENT YIELD


COLE, Ryan, Department of Forest Engineering, Resources, and Managment, Oregon State University, 210 Snell Hall, Corvallis, OR 97331, BLADON, Kevin D., Department of Forest Engineering and Management, Oregon State University, 210 Snell Hall, Corvallis, OR 97331, WAGENBRENNER, Joe, Pacific Southwest Research Station, US Forest Service, 1700 Bayview Dr, Arcata, CA 95521 and COE, Drew B.R., California Department of Forestry and Fire Protection, 6105 Airport Road, Redding, CA 96002, ryan.cole@oregonstate.edu

High-severity wildfire can increase erosion on burned, forested hillslopes. Salvage logging is a post-fire land management practice to extract economic value from burned landscapes, reduce fuel loads, and improve forest safety. Few studies assess the impact of post-fire salvage logging or alternative land management approaches on erosion in forested landscapes, especially in California. In September 2015, the Valley Fire burned approximately 31,366 ha of forested land and wildland-urban interface in the California’s Northern Coast Range, including most of Boggs Mountain Demonstration State Forest. The primary objective of our study is to quantify erosion rates at the plot scale (~75 m2) for different post-fire land management practices, including mechanical logging and subsoiling (or ripping) after logging. We measured sediment yields using sediment fences in four sets of replicated plots. We also estimated ground cover in each plot using three randomly positioned 1-meter quadrats. We are also measuring rainfall near each plot to understand hydrologic factors that influence erosion. Preliminary results indicate that burned, unlogged reference plots yielded the most sediment over the winter rainy season (3.3 kg m-2). Sediment yields of burned and logged (0.9 kg m-2), and burned, logged, and ripped (0.7 kg m-2), were substantially lower. Burned and unlogged reference plots had the least ground cover (49%), while ground cover was higher and more similar between logged (65%) and logged and ripped (72%) plots. These initial results contrast with previous studies in which the effect of post-fire salvage logging ranged from no measured impact to increased sediment yield related to salvage logging.