Plants Could Help Override Global Warming's Effect On Wildfires

"Scientists predict that global climate change will make many regions around the world warmer and drier, a factor which, taken by itself, would seem to increase the risk of wildfires.

But a new study led by a Montana State University researcher shows that changes in the types of vegetation covering an area play a major role in determining how often that area is burned by fires and could even counteract the effects of changes in temperature and moisture.

In the study, MSU earth sciences post-doctoral researcher Philip Higuera and his colleagues show that the risk of wildfires can be either reduced or increased by changes in the distribution and abundance of plants. The study will be published in the May issue of the journal Ecological Monographs.

"Climate affects vegetation, vegetation affects fire and both fire and vegetation respond to climate change," Higuera said. "Our work emphasizes the need to consider the multiple drivers of fire regimes when we anticipate how they will respond to climate change."

Higuera and his colleagues studied fire history in northern Alaska by analyzing sediments at the bottom of lakes, some dating as far back as 15,000 years. In the samples from the lakes, the scientists measured the abundance of different preserved plant parts, such as pollen, to determine what types of vegetation dominated the region in the past. Like rings in a tree, different sediment layers represent different times in the past.

The scientists then looked at charcoal deposits in the sediments to determine how often wildfires had burned over those soils. They compared that to the kinds of vegetation that were dominant at the time and finally looked at what is known about historical climate changes in northern Alaska.

The scientists discovered that, in many cases, changes in climate were less important than changes in vegetation when it came to affecting the frequency of wildfires."

ORIGINAL SOURCE: Montana State University