Rapid human population growth across the western USA is increasing the wildland urban interface (WUI), especially in grassland ecosystems

The U.S. Bureau of Land Management, through the Joint Fire Science Program (CFDA 15.232), awarded a $499,865 cooperative agreement to The Regents of the University of Colorado to conduct research on landscape-scale fuel reduction strategies for grassland ecosystems in the wildland-urban interface (WUI) of Boulder County, Colorado. The project aims to:

1. Measure grassland fuel characteristics to develop a custom fuel model for the region
2. Experimentally test mowing, grazing, and prescribed fire fuel treatment methods, including evaluating the use of virtual fencing for targeted grazing
3. Determine priority fuel treatment locations using fire modeling with the custom fuel model
4. Assess the effectiveness of fuel treatment strategies on fire spread, intensity, and interaction with the WUI under different weather scenarios

The results of this 3-year project are expected to substantially advance understanding of grassland fuel management approaches and provide guidance to land managers on effective landscape-scale fuel reduction strategies for this high-risk WUI environment.

This expansion of the WUI is exposing more people and structures to damaging wildfire. Importantly, there have been several catastrophic grass-FED wildfires like the marshall fire in the front range of colorado. These damaging wildfires are spurring extensive conversation of actions that can be taken to reduce wildfire risk in grassland landscapes at the WUI, exposing the fact that we know much less about grassland fuels and fuel treatments compared to forested systems, especially when thinking about fuels treatment strategies at the landscape scale. Our project will fill critical knowledge gaps for implementing landscape fuel reduction treatments in grasslands. This project has four objectives. First, we will measure grassland fuel characteristics across the landscape and across seasons to parameterize a custom fuel model for thegrasslands of boulder county, CO. Second, we will run fuel treatment experiments including mowing, grazing, and prescribed fire. We will test virtual fencing for customizable, targeted grazing for fuel reduction in landscape fire risk hotspots. Third, we will use fire models and our custom fuel model to determine fuel treatment priority locations on the landscape. Finally, we will test the effectiveness of various fuel treatment strategies on fire spread, intensity, and interaction with the WUI under various wind and weather scenarios. We expect that a custom fuel model will be important for accurate fire modeling in grasslands and that targeted grazing by using virtual fences will be the most effective landscape-scale fuel reduction method. The results of this project will substantially advance our understanding of landscape-scale grassland fuel treatment strategies and serve as a guide for fuel management treatment for land managers in boulder county. IT will also provide guidance on the effective use of virtual fences for fuels management for the broader grassland and rangeland community. We will share our results with presentations at professional conferences, refereed publications, research briefs and webinars distributed through fire exchange networks. We will also convene two workshops with local stakeholders including government officials, ranchers, and community associations to share results and share perspectives on the challenges and priorities for grassland fuel management methods.