A recent study by U.S. Forest Service and university researchers shows that thinning and prescribed fire can protect stands of southern pines on a landscape level from infestations by southern pine beetle. The results, published online in the Journal of Forestry, also provide first-time confirmation of the effectiveness of the treatments supported by the Southern Pine Beetle Prevention Program (SPBPP) to reduce stand susceptibility to the southern pine beetle in the southeastern U.S.
The southern pine beetle (Dendroctonus frontalis Zimmermann) is a native pest which can cause huge damages in the Southeast, where wood product production is dominated by several southern yellow pine species. Major southern pine beetle outbreaks occurred across the region almost every decade until recently. The last multistate outbreak occurred from 1998 to 2002 in the Southern Appalachians, affecting more than 1 million acres of forest in five states and resulting in an estimated economic loss of $1 billion.
In 2003, after that last great outbreak, the Forest Service started the Southern Pine Beetle Prevention Program (SPBPP) to support landowners in reducing the susceptibility of their pine stands to southern pine beetle through silvicultural treatments or by restoring damaged stands with less susceptible species such as longleaf pine. Since then, funds from the program have helped treat more than 1.2 million acres on state, private, and national forest lands in the Southeast.
“It’s long been accepted that thinning is particularly effective in reducing the susceptibility of stands to southern pine beetle,” said John Nowak, the Forest Service Forest Health Protection entomologist who coordinates the SPBPP program with state forestry agencies, and lead author of the research article. “Dense, overstocked stands are inherently stressed. Thinning not only improves forest health but also helps to limit the beetle’s expansion through a stand and the formation of hot spots.”
From the USFS Southern Research Station: https://www.srs.fs.usda.gov/compass/2015/07/21/thinning-and-burning-the-best-defense-against-southern-pine-beetle/