Is Thinning of Riparian Forests Ecological Restoration?

Riparian forest thinning is an increasing element of recent and emerging policies for private, state and federal forestlands in the Pacific Northwest and California. The premise that selective logging in riparian forests can serve purposes of restoration is based on largely hypothetical claims of future ecological benefit, underlain by the fact that larger riparian trees can be disproportionately valuable as saw timber.  We evaluate riparian thinning based on two approaches 1) stand succession simulation modeling and associated projections of woody debris recruitment to habitat, and 2) review of scientific literature on ecosystem processes and conditions potentially affected, including water temperature, sediment and nutrient retention, roads and associated erosion, and interaction with natural forest disturbance processes including windthrow and fire. Potential adverse impacts we identified have not been systematically disclosed and evaluated by the federal land management agencies now developing policies to replace the Northwest Forest Plan. Our analysis supports the conclusion that protection and passive restoration of natural successional and disturbance processes in riparian and near-stream sensitive areas is the most robust and effective ecosystem restoration policy. Riparian thinning should be allowed only on a limited experimental basis, and with full commitment to monitoring long-term outcomes and ancillary environmental effects.