Relating Landscape Factors to In-Stream Patterns of Large Wood in Anadromous Streams of Southeast Alaska

It’s well-known that stream characteristics are controlled by features of landscapes, and local conditions within streams are influenced by hydrologic and geomorphic processes occurring within watersheds.  In southeast Alaska, a local habitat factor accepted as improving a stream’s ability to support salmonids is large wood.  Historically, research on wood in the region’s streams has occurred at localized scales, but to our knowledge, little work has characterized how landscape factors, including timber harvest in watersheds, affect wood within stream systems.  To address this need, wood size and abundance were quantified from 28 stream reaches in southeast Alaska having experienced varying degrees and timing of timber harvest. We summarized harvest factors at two spatial scales, local and network stream catchments, along with other natural and anthropogenic landscape factors important to fluvial habitat.  Multiple regressions were used to predict various measures of large wood such as densities and size distributions of pieces within streams from landscape variables, and results show influences of both timber harvest and other factors on metrics. Because timber and fisheries resources are essential to the region’s economy, better understanding interrelationships between aquatic and terrestrial systems will be essential for sustainably using and conserving these resources into the future.