Cutting patterns and the condition of riparian zones may influence where debris flows start and stop.

In many mountainous regions, landslides and debris flows are the prime movers of sediment from hillslopes to the channel network and therefore control how natural and anthropogenic disturbances, such as wildfires and clearcuts, are transmitted downstream to fish-bearing streams and inhabited valley bottoms. In forested landscapes the vegetation can play many geomorphic roles, including anchoring soil on steep slopes with roots, influencing the runout behavior and the depositional patterns of landslides and debris flows once they initiate, affecting the morphology and habitat quality of downstream channels, and mediating long-term sediment transport to downstream reaches. These many roles are a primary rationale behind recent implementation of extensive riparian reserves in channel networks throughout the west to protect endangered aquatic ecosystems. Although central to these protection and restoration strategies, the underlying dynamics of wood, mass movements, and the condition of the channel network in response to both new and old land management practices are very poorly understood. In order to learn more about the complicated interactions of wood, debris flows, and downstream channels we are developing and testing a physics-based landscape model that is sensitive to vegetation influences on landslide initiation, debris flow runout, and channel change in the Oregon Coast Range as part of the Coastal Landscape Analysis and Management Study (CLAMS).