Potential Recreation Displacement by Wildfire in Southern California National Forests
A landscape photo of the Angeles National Forest. USDA Forest Service photo by Alyssa Thomas.
Researchers initiated this project to provide land managers with spatial information on the potential for recreation destinations to be closed or disrupted due to wildfire. Wildfires are a common occurrence in fire prone landscapes including much of Southern California. Wildfires of any size can close national forests to the public for short durations due to safety concerns for forest visitors while the fire is active.
However, larger, more destructive wildfires can lead to long-term recreation displacement by removing trail and campsite infrastructure, killing surrounding vegetation leading to safety concerns (e.g., falling trees), and increasing the time for recreation site repair and maintenance. This project created spatial data to show where the greatest risk of long-term recreation displacement due to wildfire lies.
In the following sections we discuss the data and processes we used to create our potential for recreation displacement by wildfire spatial datasets.
Background Information and History
Devil’s Punchbowl located in the San Gabriel Mountains. This image displays burn scars of the 2020 Bobcat Fire in the Angeles National Forest.
The four Southern California national forests: Los Padres National Forest, Angeles National Forest, Cleveland National Forest, and San Bernadino National Forest span approximately 3,500,000 acres across ten counties, extending as far north as Monterey and as far south as the Mexico border. Together these forests contain more than 500 animal species, thousands of plant species, and over a dozen designated wilderness areas across a vast array of ecosystems including deserts, grasslands, and conifer forests. This unique environment and landscape provide a wide range of recreational opportunities across the forest landscapes which include hiking, camping, skiing, boating, fishing, off-roading, and scenic drives.
To understand the potential for fire to impact recreation on the four national forests of Southern California, we collected data and modeled recreation displacement likelihood using two weather scenarios. A "dry" and "moderate" scenario following Scott and Burgan (2005). Each recreation displacement likelihood map was created using the following five spatial data inputs: canopy height, flame length probability, heat per unit area, burn probability, and fire severity.
- Canopy height was used as a measurement of vegetation type most likely to cause long-term disruption to recreation, that is tall trees killed by fire are more likely to disrupt recreation than shrubs or grass fuel types.
Flame length probability and heat per unit area were used to
measure fire intensity and amount of energy released from a fire.
Burn probability conveys the likelihood of a fire occurring at a
given location across the landscape.
Fire severity indicates how damaging a fire would be if an ignition
occurred.
A set of interactive map tools were created for land managers and staff to better understand the impacts of fire on recreation in Southern California national forests. The following section contains the links to those map tools. The first link in each section is to a story map about fire related recreation displacement on each of the four Southern California national forests. The second link is a simple map tool and includes the dry and moderate weather scenarios for the impact of fire on recreation. This map also included the data inputs that went into those two scenarios. The third link in each section contains a map with the above-mentioned data, and in addition, includes some more datasets such as rate of spread, canopy base height, and existing vegetation.
These maps are interactive. You can turn on and off layers and overlay past fire boundaries with the different datasets. You can also use a measurement tool to draw polygons and calculate the size of a specific area you are interested in, or the distance between two high or low severity regions. Finally, you can also use a print tool to export an image of a specific region of the map. This output can have a detailed legend if you wish it to, and the map outputs a georeferenced image for Avenza which can be helpful during field work.
Angeles National Forest
A section of the Gabrielino Trail on the Angeles National Forest.
Cleveland National Forest
A section of the Sunset Trail to Big Laguna on the Cleveland National Forest.
Los Padres National Forest
A section of the Pine Ridge Trail on the Los Padres National Forest.
San Bernardino National Forest
Trailhead sign for the Big Falls Trail on the San Bernardino National Forest.
Story Map for San Bernardino NF
We used multiple different data sources and methodologies to produce the dry and moderate condition scenarios for the potential for fire to impact recreation. The data sources include LANDFIRE, Salo Science, USGS, MTBS, USGS National Elevation Dataset, BCM, FRAP, USDA Hazardous Fuel Treatment Reduction polygons, GRIDMET, and Landsat.
FlamMap FBO and MTT models were used to produce desired dry and moderate condition data outputs: burn probability, flame length probability, and heat per unit area. Following Scott and Burgan (2005), dry conditions were set to very low dead fuel moisture content and fully cured live herbaceous and woody fuel. Moderate conditions were set to moderate dead fuel moisture and moderate live herbaceous and woody fuel. Salo Science canopy height data was used when creating the potential for fire to impact recreation dry and moderate scenarios. Fire severity was calculated through a multistep Google Earth Engine and R process. Esri ArcGIS Pro ArcGIS Desktop Suitability Modeler was used to create the potential for fire to impact recreation dry and moderate condition models. Burn probability, fire severity, canopy height, flame length probability, and heat per unit area were entered in with equal weight on the models to create the dry and moderate condition scenarios.
The points of interest, trails, and roads shapefiles were either downloaded from the USFS clearinghouse or Caltrans.
Angeles National Forest Data Archive
Cleveland National Forest Data Archive
Los Padres National Forest Data Archive
San Bernardino National Forest Data Archive
People
-
Person
Stacy Drury, PhD
Research Fire Ecologisthttps://research.fs.usda.gov/about/people/stacy..drury -
Person
Alyssa Thomas, PhD
Social Science Analysthttps://research.fs.usda.gov/about/people/alyssa.thomas