TRADE-OFFS FOR TIMBER PRODUCTION AND AQUATIC HABITAT OF HEADWATER BUFFERS FOR LARGE WOOD

Timber production in landslide-prone terrain involves an inevitable tradeoff between the value of at-risk resources, commonly fish habitat, and the costs of protecting them. Analysis tools to quantify this trade off will help policy makers and land managers to rationally evaluate their options. We will describe initial efforts to develop such tools for evaluating the costs and benefits of riparian buffers on non-fish-bearing streams designed to ensure future landslide recruitment of wood to fish-bearing streams. In particular, many headwater channels serve as debris-flow corridors from upslope landslide sites to downslope fish-bearing streams. These headwater channels are currently protected on most Federal forest lands. Conversely, such channels are not generally protected on private lands. The consequences of these policies for future wood recruitment rates are not well characterized. Can the same protection be provided with smaller buffers? Can policies be tailored to potential habitat? We will show how existing landslide and debris-flow models were used to delineate debris-flow corridors in terms of the potential for traversal by a debris flow that delivers to a downslope fish-bearing stream. We will then show how these results can link with models of wood recruitment and stream type to better evaluate consequences for fish habitat of different levels of headwater protection.