Clear-cut logging and related road-building in the 1950s and 1960s in southern Oregon’s Siskiyou Mountains disrupted soil stability and led to unprecedented soil erosion made worse during heavy rainstorms, report University of Oregon researchers. While logging practices have improved dramatically since then, the damaged landscape — the removal of low vegetation that helps to protect hillsides during fires and rain — continues to pose a threat into the foreseeable future, said Daniel G. Gavin, professor of geography, and postdoctoral doctoral researcher Daniele Colombaroli.
Their research — funded by the Swiss National Science Foundation and the UO — involved the analyses of charcoal, pollen and sediment taken from 30-foot-deep cores drilled below Upper Squaw Lake in the Rogue River-Siskiyou National Forest. Their findings, which provide a look at the impacts of fires over the last 2,000 years, appeared online Oct. 18 in the Early Edition of the Proceedings of the National Academy of Sciences. The data, which provided for greater scrutiny than that of tree-ring records, allowed the researchers to analyze conditions at different time periods and compare soil conditions during fire and flooding events over time.