Fact Sheet / Brief
Wildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can produce dangerous flash floods and debris flows. The USGS conducts post-fire debris-flow hazard assessments for select fires in the Western U.S. We use geospatial data related to basin morphometry, burn severity, soil properties, and rainfall characteristics to estimate the probability and volume of debris flows that may occur in response to a design storm.
Since its 2018 launch, the Rangeland Analysis Platform (RAP) has revolutionized rangeland management and monitoring. This free, powerful technology puts vegetation cover, productivity, historical tree cover, and more in the digital hands of anyone with a computer or smartphone.
But RAP isn’t just for landowners and managers. It’s also being used by scientists and researchers who are leveraging its cutting-edge technology to inform conservation planning. Recent research highlights just how beneficial RAP is proving to rangeland scientists and, in turn, to managers working to restore and maintain productive working rangelands from the Great Basin to the Great Plains.
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Communities across the United States and the globe rely on clean water flowing from forested watersheds. But these water source areas are impacted by the effects of wildfire. To help water providers and land managers prepare for impacts from wildfire on water supplies, the U.S. Geological Survey is working to measure and predict post-fire water quality and quantity.
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Katherine Zeller, a research biologist with the Aldo Leopold Wilderness Research Institute housed within the Rocky Mountain Research Station, was part of a team of researchers who created a series of species distribution models to determine whether this concern was warranted. “What we wanted to know is how these conifer treatments might affect a greater suite of species,” she explains. “Not just the sage grouse but these other species of conservation concern.”
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Lower treelines in the Intermountain West are often defined by the boundary beyond which conditions are too dry for trees. Scientists are observing tree mortality in response to global climate changes and associated increased aridity in some places. Land managers are keenly interested in these changing ecological dynamics and how forests will shift in response to climate change.
Extensive research shows us that native conifer trees, primarily juniper and pinyon pine, but also other conifers, have been increasing their footprint on the landscape at an unprecedented rate over the last 150 years or so, especially in places like the Great Basin. This is part of a global phenomenon of trees encroaching into and replacing adjacent grasslands and shrublands.
Some of that change is expansion in the traditional sense, that is, trees moving from higher elevations or fuel-limited sites protected from fire where they historically existed into areas where they never grew before. But much of the change is what we call ‘infill,’ which is what happens after trees colonize and continue to populate previously tree-less landscapes, turning them from sagebrush or grasslands with just a few trees per acre into closed-canopy woodlands – what you might think of as a forest.
Large wildfires need four key ingredients to burn, not just one. Ignitions, fuels, and drought thresholds must be crossed at the same time, enhanced by anomalous weather events such as foehn winds. But how do these ingredients, or drivers, fit together in various ecosystems? In this important concept paper, Pausas and Keeley (2021) outline the mechanistic flow of these complex drivers for fire prone ecosystems and illustrate this in the figure below (Fig.1). In brief, the fire weather for a given ecosystem helps to push the other three essential driver thresholds, or saturation points, down. With ignitions, fuel continuity, and drought saturation points simultaneously lowered by the right weather, wildfire will be triggered.
WindNinja, a tool developed by RMRS scientists, delivers high-resolution wind predictions within seconds for emergency fire responders making on-the-ground decisions. The program computes spatially-varying wind fields to help predict winds at small scales in complex terrain. These predictions are extremely important in fire-prone landscapes where local changes in the near-surface wind are not predicted well by either operational weather models or expert judgment but are extremely important for accurate fire behavior predictions.
Because three key thresholds must be crossed all at once for a wildfire to start, avoiding just one of these thresholds─ ignitions, drought, or continuous fuels (Fig.1)─ could significantly reduce the likelihood of wildfire. As climate change makes fire weather more common everywhere, managing ignitions where wind is problematic and managing fuels where drought is problematic will help to keep stochastic, out-of-regime fires contained. Where fire management tools won’t help, a fire danger zone should be designated to reduce human activity and development, much like volcano or flooding zone designations.
Timing is everything, especially when it comes to the complex ecological interactions between plants and the environment. For range managers concerned with maintaining the integrity and productivity of rangelands, it is critical to monitor the seasonal development and condition of grasses and other vegetation on which cattle graze. PhenoMap is a new Web-based tool that managers can use to assess the production and location of high quality forage. It uses satellite imagery to address the need for near-real-time information about plant life cycle events over large spatial areas.