Invasive annual grasses have long been known to increase wildfire danger in shrublands and woodlands of the American West. Ventenata (Ventenata dubia) is one such grass. First reported in North America in 1952 in Washington state, it is now expanding into previously invasion-resistant forest landscapes. Unlike cheatgrass, another invasive grass, ventenata can grow in sparsely vegetated rocky meadows. These forest scablands, often embedded within a forested landscape, have historically served as natural fire breaks. Lacking sufficient fuels, the scablands usually stopped fire from spreading into neighboring fireprone forests. However, when ventenata invades scablands and other open areas, it can create a highly flammable bridge between adjacent forested areas and act as a “ fire conveyor belt” that facilitates the spread of fire across a landscape.

Becky Kerns, a research ecologist with the USDA Forest Service Pacific Northwest Research Station, calls the ventenata invasion a “perfect storm” that is threatening forest resilience in the Blue Mountains Ecoregion. Not only is it contributing to wildfires, but those very fires may exacerbate the ventenata invasion.

Forest managers in eastern Oregon are using maps, study findings, and other information developed by Kerns’ research team and incorporating this information into proposed activities and other planning efforts to aid restoration and fuel reduction efforts while minimizing further invasion.

For the full story click here. 

Science Findings is a publication of the U.S. Department of Agriculture and U.S. Forest Service. Find Pacific Northwest articles at www.fs.usda.gov/pnw.