A long-term Pacific Northwest study of landslides, clear-cutting timber and building roads shows that forest management history has a greater impact on how often landslides occur and how severe they are compared to how much water is coursing through a watershed. Findings of the U.S. National Science Foundation-supported research, led by Catalina Segura and Arianna Goodman of Oregon State University, were published in the journal Earth Surface Processes and Landforms. “The study highlights the importance of land-use dynamics on natural processes such as landslides,” said Justin Lawrence, a program director in NSF’s Division of Earth Sciences. …Probing the factors behind landslide frequency and magnitude is crucial because slides occur in all 50 states, causing an average of more than 25 deaths per year, according to the U.S. Geological Survey. The USGS puts the total annual average economic damage resulting from landslides at greater than $1 billion.