Dense forests and drier climate conditions have facilitated a widespread outbreak of the mountain pine beetle, a bark beetle native to western North America. Fire and fuel managers need up-to-date information regarding the location and nature of beetle attacks because beetle attacks can substantially alter fuel conditions, which can increase risks to firefighters and communities in affected areas.
U.S. Forest Service personnel have hand-mapped beetle attacks from aircraft for many years, but the extent of the land area makes it difficult to comprehensively map all areas each year, and differences between observers can also complicate analysis. To resolve this, the Western Threat Center is providing support for researchers from the Rocky Mountain Research Station and University of Montana to develop a system to map the progression of beetle attacks over time using MODIS satellite imagery and field-measured fuel changes (below). They developed and tested a system to apply the field-measured fuel changes to fuels maps used for modeling fire behavior. Maps show the progression of beetle attacks in 2001, 2005, and 2009. Click to enlarge.
Satellite imagery provided consistent and geographically comprehensive maps of beetle attacks over time, which compared favorably with field-measured data. Fuel changes associated with beetle attacks were found to vary depending on time since attack. Comparisons of fire behavior using fuel maps with and without beetle-induced fuel changes over time (below) suggested significant increases in predicted fire behavior with beetle-induced fuel changes.
Images show comparisons of fire behavior using fuel maps with and without beetle-induced fuel changes over time. Click to enlarge.
Beetle effects on fuels and fire behavior are an area of active research. As this work advances, it has potential to be integrated with current fire and fuel management and future planning and to be extended to other geographic regions.