The footprint of Alaskan tundra fires

May 20th, 2013 @

Scientists at the Arctic Long-Term Ecological Research project, which is based at the Ecosystems Center, are studying the increase in wildfires on the Arctic tundra. A recent paper by Adrian Rocha, Ed Rastetter, Gus Shaver and others reports that recently the size and frequency of wildfires in Alaska’s arctic north has increased dramatically because of changes in climate and dryness of the tundra.

When a wildfire occurs, there are both positive and negative effects on future climates.  One effect is that the soil gets darker, which leads to warming, more decomposition of organic carbon, and release of CO2; yet it also leads to growth of more plants that will take up CO2 and preserve the carbon in plant parts for many years.

Another effect is that the tundra is shaded by the increased leaves and plant litter, which leads to cooling, but a counteracting warming of the soil in winter caused by an increase in snow thickness trapped by more shrubs.

There is also an increase in the depth of thaw each summer that leads to increased erosion and breakdown of soil organic matter.  Our current research in arctic Alaska investigates the balance of these and other processes that will change the effect of the tundra on the climate.

Rocha, AV; Loranty, MM; Higuera, PE; Mack, MC; Hu, FS: Jones, BM; Breen, AL; Rastetter, EB; Goetz, SJ; Shaver, GR. 2012. The footprint of Alaskan tundra fires during the past half-century: Implications for surface properties and radiative forcing. Environmental Research Letters. doi:10.1088/1748-9326/7/4/044039