Cumulative effects of forestry practices: An example framework for evaluation from Oregon, U.S.A.

Cumulative effects of forestry operations accumulate over time and space in forested landscapes where harvesting and management occur. We review the literature and concepts associated with cumulative effects and propose a framework for evaluating them. In order to evaluate potential adverse effects of forestry on vegetation, soils, streams, aquatic organisms, wildlife and air, baseline conditions and natural variations of resource characteristics must be known. Cause-effect relationships must be documented. Systems of measurements and monitoring must be implemented along with databases and geographic information systems for displaying information at spatial scales from individual sites to landscapes and regions. Systems for decision-making must be implemented. We provide an example of a framework for such a system in a mountainous, forested river basin in northwest Oregon, U.S.A. We conclude that knowledge and technologies for preliminary systems exist now, but that for more refined systems more knowledge of details of cause-effect links and of simulation models should be developed.