Burned area emergency response team releases soil burn severity map on the Town Gulch Fire
By Shannon Weidemann (McKone) on Tuesday, September 10th, 2024 in More Top Stories Northeastern Oregon News
BAKER CITY – (Release from the U.S. Forest Service) Forest Service Burned Area Emergency Response (BAER) specialists recently completed their field data evaluation to produce the Soil Burn Severity (SBS) map for the Town Gulch Fire. This map verifies unburned/very low, low, moderate, and high SBS categories from satellite imagery.
The SBS map estimates the following approximate acreages:
· 337 acres (2%) of the fire is unburned/very low
· 13,707 acres (74%) have low SBS
· 4,396 acres (24%) have moderate SBS
· 86 acres (<1%) have high SBS
The SBS map product is an estimate of fire effects to soils, not fire effects to vegetation. SBS characterizes fire effects to the soil surface and below ground. Fire effects to vegetation would include an estimate of vegetation mortality and does not always correlate with degree of SBS.
Moderate and high SBS can alter or damage physical, chemical, and biological soil properties. This may result in increased runoff, erosion, and negative effects to soil productivity. Common changes to the soil used to determine SBS include loss of effective ground cover due to consumption of litter and duff. Soil color may change due to char, ash cover, or soil oxidation. Additionally, loss of soil structure can occur due to consumption of soil organic matter and fine roots may be consumed in the topsoil. Water repellent layers may also form that reduce the ability for water to seep into the ground.
Changes to these soil properties determine the degree of SBS. Loss of effective ground cover, especially on steep slopes, greatly increases the chances of soil erosion and runoff.
The Town Gulch BAER team used remote sensing imagery with field-validated soils data to produce the final SBS map. The BAER team will use the SBS map as an analysis tool. It helps to estimate post-fire erosion with subsequent sediment delivery, stream flows and debris flow probabilities. The map is also shared with cooperating agencies.
The Town Gulch Fire SBS map is attached to this press release and found online.
For more information on the Burned Area Emergency Response Program, visit: Burned Area Emergency Response – BAER.
