Informing sustainable forest management: Remote sensing strategies for assessing soil disturbance after wildfire and salvage logging
Land managers must perform a balancing act as they consider the positive effects of wildfires on landscapes with potential challenges to surrounding communities and the secondary effects of severe wildfire. Following a fire, salvage logging can be used to recover timber value and to remove excess fuels. Land management planning agencies have protocols in place to manage, minimize, and mitigate potential disturbance from logging activities.
Forest Service directives limit the amount of detrimental soil disturbance from such activities to maintain soil productivity. Satellite imagery is used to monitor the disturbed environment after wildfire and salvage logging, while the Normalized Difference Vegetation Index (NDVI), or "greenness" index, is used to visualize exposed soil. This provides estimates and maps ground disturbance and its potential effects on soil erosion.
Researchers used high-resolution satellite imagery of post-salvage logging landscapes to look for soil disturbance 4 to 5 years post-logging and related ground-disturbance conditions. The relationship between NDVI and ground cover was used to classify and map soil conditions from the pre-fire to the current period and identify areas at greatest risk to significant soil disturbance following salvage logging. This is a repeatable and scalable method for mapping and monitoring logging disturbance over large areas and time scales.
This research will aid land managers in preventing soil degradation after wildfire and salvage logging. The classified NDVI maps can also be used to evaluate salvage disturbance, delineate existing skid trails, and eventually incorporate skid trails and soil-disturbance information into watershed-modeling tools.
Forest Service research delivers the best available science to maintain, enhance, and restore public and private forests and grasslands. Our scientists and others are on the leading edge of research in forestry, rangeland management, biological and physical sciences, and socioeconomics to guide the agency’s land management work.