Dead Wood Dynamics in Stream Ecosystems

Large woody debris (LWD: > 10 cm diameter and > 1 m in length) in stream channels of forested regions in North America is an essential ecosystem component. This article summarizes information from the literature on the spatial and temporal variability of LWD abundance, distribution and age; the processes of LWD delivery and elimination; and the influence of LWD on material retention, habitat formation, and productivity of streams. Examples are drawn mostly from the Pacific Coastal Ecoregion, but the fundamental principles learned from this region have application over the broad, forested regions of the Temperate Zone. Key studies show that LWD is an integral component of stream and river corridors, positively affecting material retention, habitat formation, and productivity. It is abundant in streams of all sizes flowing through forested regions, although the density and form of accumulation changes with forest type, landscape topography, and flow regime. The management implications of maintaining natural stream LWD dynamics are significant. Overall, LWD is a fundamental component of streams in many western states. This suggests that measures assuring a continued supply of LWD of appropriate size, volume, and species composition are essential for maintaining the long-term integrity of stream and river corridors.