Vole use of coarse woody debris and implications for habitat and fuel management

Woody debris is an increasing management focus in forests, representing multiple and sometimes conflicting values. Fuel management may prioritize removal of coarse woody debris (CWD) to minimize wildfire occurrence, intensity, or both. Conversely, management for wildlife habitat or other ecological values often focuses on retention of CWD. We modeled and quantified CWD use by red-backed voles (Clethrionomys gapperi), tested whether voles move selectively in portions of forest stands with greater CWD, and correlated stand-level measures of CWD as habitat to fuel loads, providing a basis of comparison for CWD quantitative guidelines. Voles used CWD at a greater rate than expected based on availability and traveled in portions of stands with greater CWD coverage (21-27 trails made by individual voles in each of 5 forest stands). A strong correlation between stand-measure CWD coverage and fuel-load measure (r = +0.96) provides a basis for comparing CWD guidelines. We concluded that current guidelines from different research fields disagree. Only 2 of the 5 stands we sampled fit with guidelines for fuel management and ectomycorrhizae in the northern Rocky Mountains. Coarse woody debris coverage in all of our stands was well below recommendations for small mammals in coastal forests.