Brush Mapping Data
This glossary provides definitions and fire risk assessments for various brush mapping data metrics. The information is based on data provided by the California Department of Fish and Wildlife (CDFW), which can be used to understand and analyze different vegetation types and their associated fire hazards. The CDFW data is a valuable resource for land management and fire prevention efforts in California.
For more detailed information, you can refer to the original metadata: https://map.dfg.ca.gov/metadata/ds1327.html.
You can download the source data here: https://filelib.wildlife.ca.gov/Public/BDB/GIS/BIOS/Public_Datasets/1300_1399/ds1327.zip.
Brush Mapping Data
| Term | Impact on Fire Risk | Short Description |
|---|---|---|
| Agriculture | Variable; higher risk when dry, lower when tilled or irrigated. | Land used for farming and ranching. |
| Barren | Very low to negligible risk. | Areas with minimal to no vegetation. |
| Conifer | Higher risk. | Areas dominated by cone-bearing trees. |
| Desert | Low risk; higher with invasive grasses. | Arid land with sparse, drought-resistant vegetation. |
| Hardwood | Lower to moderate risk. | Areas dominated by broadleaf, deciduous trees. |
| Herbaceous | Higher risk when dry. | Non-woody plants like grasses and forbs. |
| Shrub | Higher risk. | Areas dominated by dense, woody plants. |
| Urban | Low risk; higher for structures at the wildland interface. | Developed areas with high human infrastructure. |
| Water | No direct risk. | Bodies of water that act as natural firebreaks. |
| Wetland | Very low risk; can be high if dried out. | Land saturated with water, supporting specific vegetation. |
Agriculture
Definition: Land primarily used for farming, ranching, or other cultivation. This includes a wide range of vegetation types, from row crops to grazing pastures.
Fire Risk Assessment: The fire risk for agricultural land is highly variable. Dry, cured grass or grain fields can act as fine fuels, posing a high to extreme surface fire risk during dry seasons. Tilled fields or irrigated crops, however, have very low flammability and can act as effective firebreaks.
Barren
Definition: Areas with little to no vegetation, such as rock, sand, gravel, or exposed soil.
Fire Risk Assessment: Barren land has an extremely low fuel load. It poses a negligible fire risk and can act as a natural firebreak, stopping the spread of fire.
Conifer
Definition: A vegetation type dominated by cone-bearing evergreen trees like pines, firs, and spruces.
Fire Risk Assessment: Coniferous forests are considered highly flammable. Dense stands and continuous canopies allow fire to spread from the ground into the treetops, leading to dangerous crown fires. They have a very high to extreme fire risk due to the presence of highly combustible resins and oils in their foliage and a significant accumulation of dead surface fuels like pine needles and cones.
Desert
Definition: An arid land type characterized by sparse vegetation, often consisting of drought-resistant plants, grasses, and shrubs.
Fire Risk Assessment: Undisturbed desert landscapes generally have a low fire risk due to widely spaced vegetation and low fuel loads. However, the introduction of invasive grasses (like cheatgrass) can create a continuous, flammable fuel bed, dramatically increasing the fire risk to moderate or high, allowing fire to spread rapidly across the landscape.
Hardwood
Definition: Areas dominated by broadleaf, deciduous trees such as oaks, maples, and aspens.
Fire Risk Assessment: Hardwood forests are generally less flammable than coniferous forests. Their high moisture content and tendency to resist crown fires make them a moderate fire risk. Hardwood stands can also be effective fuelbreaks.
Herbaceous
Definition: Vegetation composed of grasses, forbs (herb-like flowering plants), and other non-woody plants.
Fire Risk Assessment: The fire risk of herbaceous vegetation is heavily dependent on moisture. Live, green herbaceous plants are not a significant fire threat. However, when these plants dry and “cure,” they become a fine, highly flammable surface fuel. Dry herbaceous areas, particularly grasslands, can have a high to very high fire risk and are prone to fast-moving surface fires.
Shrub
Definition: A collective term for areas dominated by shrubby, woody plants or low-growing trees, often referred to as brush. Chaparral and sagebrush are common examples.
Fire Risk Assessment: Shrublands, especially dense types like chaparral, are extremely flammable. They pose a very high to extreme fire risk due to their high volume of dense fuel, which can produce high-intensity fires and create abundant embers for spotting.
Urban
Definition: Areas with high human development, including cities, suburbs, and industrial zones.
Fire Risk Assessment: The urban environment itself contains very little vegetative fuel. However, the primary fire risk lies in the wildland-urban interface (WUI), the zone where development meets wildlands. In these areas, structures and property are at extreme risk from embers, radiant heat, and direct flame contact from a fire in the adjacent wildlands.
Water
Definition: Any large body of water, such as an ocean, lake, river, or large reservoir.
Fire Risk Assessment: Bodies of water contain no flammable fuel and therefore pose no fire risk. They act as absolute firebreaks, halting the spread of any fire that reaches their edge.
Wetland
Definition: An area where the land is saturated with water, either permanently or seasonally, supporting a unique ecosystem of specialized vegetation.
Fire Risk Assessment: Due to the high moisture content of both the soil and the vegetation, wetlands typically have a very low fire risk. They can act as natural barriers to fire spread. However, if a wetland becomes completely dried out, especially one with a high peat content, it can pose a significant and difficult-to-extinguish fire risk.
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