Trees facilitate wildfires as a way to protect their habitat

Oct 28, 2009
Savanna trees such as these pines may help facilitate frequent fires in order to prevent other trees from displacing savanna trees and shifting the community from an open savanna to a closed forest. Credit: Brian Beckage/UVM

Fire is often thought of something that trees should be protected from, but a new study suggests that some trees may themselves contribute to the likelihood of wildfires in order to promote their own abundance at the expense of their competitors.

The study, which appears in the December 2009 issue of the journal The American Naturalist, says that positive feedback loops between fire and trees associated with savannas can make fires more likely in these ecosystems.

"We used a to show that positive feedback loops between fire frequency and savanna trees, alone or together with grasses, can stabilize ecological communities in a savanna state, blocking conversion of savannas to forest," said the study's leading author Brian Beckage, associate professor in the Department of Plant Biology at the University of Vermont. The study's co-authors are William Platt, professor of biology at Louisiana State University, and Louis Gross, director of the National Institute for Mathematical and Biological Synthesis and professor of ecology and and mathematics at the University of Tennessee. Beckage was a short-term visitor conducting research at NIMBioS in 2009 and will be on sabbatical at NIMBioS in 2010.

The promotion of fire by the savanna trees increases their own abundance by limiting the establishment and growth of tree species that are better competitors for resources and that might ultimately displace the savanna trees. The research results suggest that some trees may modify or "engineer" their environment, including the characteristic fire frequencies in a landscape, to facilitate their own persistence at the expense of their competitors, Beckage said.

The research proposes a scenario for the development of savannas in landscapes that would otherwise become closed forests. Examples of savanna that facilitate frequent low-intensity fires include the longleaf pine and the south Florida slash pine, both of which frequently shed their needles providing fodder for wildfires. The tree initially invades grassland, but by facilitating frequent fires, it limits its own density and thus prevents conversion to a forest.

More information: The study was recently published in the journal The American Naturalist. It can be viewed at www.journals.uchicago.edu/toc/an/0/0

Source: National Institute for Mathematical and Biological Synthesis

Explore further: More wolf spiders feasting on American toads due to invasive grass, study shows

add to favorites email to friend print save as pdf

Related Stories

Study identifies two types of savannas

Dec 08, 2005

Colorado State University scientists have determined the Earth maintains two types of savannas, which cover a fifth of the planet's surface.

Large trees declining in Yosemite

Jul 29, 2009

Large trees have declined in Yosemite National Park during the 20th century, and warmer climate conditions may play a role.

The vicious cycle of rainforest destruction

May 22, 2006

Rainforests and savannas contain 70% of the world’s plants and are critical to the health of our planet. A new £1.6m international project involving researchers from the Leeds Earth and Biosphere Institute is looking at ...

Recommended for you

Wolves susceptible to yawn contagion

13 hours ago

Wolves may be susceptible to yawn contagion, according to a study published August 27, 2014 in the open-access journal PLOS ONE by Teresa Romero from The University of Tokyo, Japan, and colleagues.

User comments : 0