Monday, 17 November 2003
Predicting effectiveness of Nevada greenstrip fuel breaks: issues of establishment success and scale
Land managers in Nevada and the Great Basin have used greenstrips and similar vegetative fuel breaks for almost two decades in an attempt to mitigate wildfires and the spreading annual invasive Bromus tectorum (cheatgrass, downy brome). While the implementation of these fuel breaks has increased, there has been limited monitoring of fuel breaks to determine establishment success of the seeded species. Additionally, previous studies of wildfire behavior change in fuel breaks have not addressed issues of scale and resolution in either the fuel break or the fire behavior modeling programs. Establishment success was evaluated on two recently constructed greenstrips in northern Nevada, and fire behavior changes were predicted using the BehavePlus 1.0 and FlamMap 2.0 (beta version) fire behavior modeling programs. Neither greenstrip exhibited successful establishment of perennial species. For fire behavior, the reduction of the overall fuel load reduces the flame lengths and heat intensity produced on the greenstrips, but the increase in annual species composition and fine fuels produces increased rates of spread. Additionally, the increase in fine fuels points to increased ignition potential on these sites. Scale issues are addressed by comparing the fire behavior outputs on 10m and 30m grid cell-sizes, with the finer resolution giving a more accurate picture of fire behavior potential for the site. Recommendations are made for ways to increase the effectiveness of the greenstrips.