CSP study pioneers a new method for identifying key areas to apply fuel treatment

A novel application of centrality metrics to fire connectivity modeling exposes high-risk areas, providing a template for an ecologically and economically efficient approach to managing landscape fuels and invasion by cheatgrass.

CSP’s Miranda Gray and Brett Dickson published a paper in the March 2016 edition of Landscape Ecology describing a new approach for developing fire mitigation strategies. The study focused on identifying optimal locations for applying fuel treatments to cheatgrass — a non-native, highly invasive, annual grass that is facilitating increases in fire activity across the arid, Intermountain West.

Gray and Dickson’s analysis is based on “centrality,” a concept repurposed from network theory. In this application, centrality measures the extent to which a patch of cheatgrass facilitates the spread of fire across the whole landscape. Centrality metrics have been used previously in analyses of many ecological processes, primarily to restore connectivity across fragmented landscapes; however, this study is the first to apply centrality metrics to fire and invasive plant management.

The researchers looked at 485 square kilometers on the Kaibab National Forest in northern Arizona and modeled fire connectivity between large cheatgrass patches across the landscape. They identified 25 patches with relatively high centrality and then simulated “greenstrips” — planted strips of fire-resistant vegetation — around these focal patches. The model results suggest that this treatment would reduce the centrality — and therefore the susceptibility to fire — for most of the modeled patches.

The results of this study show that this method can be an important step in focusing conservative mitigation actions only around focal cheatgrass patches.

The paper is entitled “Applying fire connectivity and centrality measures to mitigate the cheatgrass-fire cycle in the arid West, USA.”

Cheatgrass patches and associated area-weighted centrality estimates across the western Kaibab Plateau. The yellow and orange patches were predicted to be the most important for facilitating fire spread, while the black and dark blue patches were predicted to be the least important.