SPR-794

Description:

This study will explore whether ADOT landscaping and vegetation-management practices that encourage the recovery of native plant communities following wildfires can reduce both repair and maintenance costs for adjacent roadways. Wildfires can leave roadways susceptible to further damage from flooding, erosion, and debris flows over the long term because slow-growing native plant communities can take several years to fully recover. ADOT incurs significant expense when roadways are damaged by erosion or debris flows. In the meantime, non-native plant species that grow in disturbed ecosystems—such as buffelgrass, Sahara mustard, wild oats, and red brome—are often flammable and can actually increase the risk of future wildfires when they replace more fire-resistant native plant communities. The need to manage flammable vegetation by applying herbicides, mowing, or other treatments, creates further expense for ADOT. The agency’s construction and maintenance projects along roadways can have a sizable influence on the success of landscape-scale vegetation-management projects led by other land-management agencies, such as the Arizona Department of Forestry and Fire Management, in conjunction with the Arizona State Land Department, the U.S. Forest Service, the U.S. Bureau of Land Management, and others. These agencies may partner with ADOT to reduce the risks of starting additional wildfires near roadside fire starts and improve resilience to wildfire. Current guidelines for vegetation maintenance address post-construction activities but not post-wildfire recovery. As a result, there are no clear best practices to follow for roadway repair and maintenance following wildfire-related damage, and repair and maintenance teams are not certain what ADOT can or should do to encourage recovery of native plant communities. The research study will correlate roadway damage and maintenance costs in areas where wildfires have occurred to post-wildfire vegetation recovery. The study will assess how plant communities have recovered in areas that have burned within the past 10 years and determine whether the full recovery of native plant communities is associated with lower wildfire risk and, thus, lower maintenance costs for adjacent ADOT roadways.

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