Study reveals patterns that shape forest recovery after wildfires

New University of Montana research suggests recurring continent-spanning drought patterns set the tempo for forest recovery from wildfire.

A study published Nov. 9 in the Proceedings of the National Academy of Sciences shows that forest recovery from fire follows a drought seesaw, called a climate dipole, that alternates between the Northwest and the Southwest every few years.

The researchers examined the relationship between this drought seesaw and post-fire regeneration of ponderosa pine across the Interior West of the U.S. They found that severe droughts under climate change are making it increasingly difficult for tree seedlings to regenerate after fire.

"Managers and scientists are increasingly concerned that western forests won't be able to recover from wildfire under hotter and drier conditions," said Caitlin Littlefield, the study's lead author. "Forest recovery hinges on the success of tree seedlings, which are particularly vulnerable to drought. We wanted to explore how patterns in drought variability across the western U.S. affect post-fire tree regeneration to better understand where and when we can predict robust recovery—or lack thereof."

The authors used annual ponderosa pine regeneration data from a previous UM study led by Kimberley Davis, as well as U.S. Forest Service inventory data. They examined the relationship between ponderosa pine regeneration and the dynamics of the dipole.

Read the full story from Phys.org here.