We present results and inferences from 15 soil-monitoring projects by the USDA Forest Service (USFS) after logging in the interior Columbia River basin. Details and comments about each project are provided in separate appendixes. In general, application of past protocols overestimated the percentage of “detrimentally” disturbed soil in harvested units. Based on this past monitoring experience, we recommend changes to existing protocols, and further validation and revision of USFS numerical standards for judging change in soil quality and for defining “detrimental” soil disturbance. A proposed visual-assessment protocol was tested at some locations by comparing results of its application among observers, and by verifying visual assessment of compaction against quantitative estimates of bulk density. Consistent disparity between experienced and recently trained observers emphasizes the need for more intense training to teach individuals to recognize and correctly classify types and severity of soil disturbance. Because growth response of trees to soil disturbance is so variable and dependent on climate and other nonsoil factors, designating some visual classes as “detrimental” to soil productivity is problematic. We propose an alternative key for visually classifying a wider continuum of soil disturbance without assigning consequence for productivity to any class.
interior Columbia River basin.
Miller, Richard E.; McIver, James D.; Howes, Steven W.; Gaeuman, William B. 2010. Assessment of soil disturbance in forests of the interior Columbia River basin: a critique. Gen. Tech. Rep. PNW-GTR-811. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 140 p.