Learning to Adapt
Most actions proposed to deal with global climate change have focused on mitigation, on strategies to reduce the greenhouse gases that contribute to warming. But now many, including Forest Service researchers, are looking at ways to adapt to uncertain future conditions. For managers of natural forested lands, this could mean using silvicultural methods—including prescribed fire—to give species more adapted to drought and higher temperatures the advantage. A recent study by SRS research forester Martin Spetich in the Boston Mountains of northern Arkansas offers a prime example.
Spetich and Hong He, associate professor of forestry at the University of Missouri – Columbia, recently completed a study that projected oak decline in the Boston Mountains over a period of 150 years. Using LANDIS, a well-known forest succession and disturbance model, they were able to compare potential oak decline sites under current and historic fire regimes and establish risk ratings for the areas they studied.
“This process represents a further step towards the kind of precision planning and management we’ll need to maintain the ecological services forests provide under scenarios of drought, higher temperatures, or other disturbances,” says Spetich.
The complex ecosystems of the Boston Mountains have been modified over the last few centuries by both human and natural factors, including drought, fire suppression, and oak decline. Oak decline, which is not really one disease but a response to multiple stressors, has had a severe effect on the forests of Arkansas and Missouri, impacting almost 300,000 acres over the last 8 years. Spetich and He found that oak decline operates over long time scales in association with forest succession—and that white oak survives these stressful conditions better than red oak.
If climate conditions in the Boston Mountains become even more severe, the moister north slopes and coves that have been relatively untouched by oak decline during droughts could be affected in the future, stressing and killing red oaks.
“We’ve shown that we can explicitly identify areas at high risk for oak decline,” says Spetich. “These hot spots could be given high priority in landscape management strategies. In some cases, this would mean using fire at historical levels to get white oak well established before climate impacts.”