Forest Resilience Declines in Face of Wildfires, Climate Change

The forests you see today are not what you will see in the future.  That's the overarching finding from a new study on the resilience of Rocky Mountain forests.

Frank Church-River of No Return Wilderness Area in Idaho

Historically, forests change over time.  But the research team said their findings suggest that it will take much longer after a wildfire for sites to return to forests, if they return at all.  In one-third of the areas studied, researchers found no seedlings growing.  The hardest-hit sites were the warmest and driest, and those where fires burned so severely that few trees survived to provide seed.

"Even if we plant trees in those areas, it's unlikely to be successful," said Stevens-Rumann.  "We need to start expecting that these landscapes aren't going to look the same in the future, whether it's reduced density of trees or no longer a forest."

One of the big surprises for the team was seeing the data for the average annual water deficit at study sites.

"In my lifetime, you can see these sites becoming substantially hotter and drier," she said.  "Many forest managers want post-fire years to be cooler and wetter, to help with regeneration, and that's just not happening anymore, or happening very infrequently."

What can be done to combat or lessen these effects?  Stevens-Rumann said that while trees similar to the ones that burned have typically been planted on a fire-ravaged site, that may no longer be the smartest approach.  She's been meeting with land managers and foresters to discuss what might be better.

"Managers may want to plant species that are adapted to the current and future climate, not the climate of the past," she said.  "There also are areas that could support certain tree species but there isn't any regeneration currently; these are the ideal places to plant after a fire."

The problem could also be addressed when a fire happens.

"Another strategy is to foster fires burning under less extreme conditions, so that more trees survive to provide seed for future forests," said Penny Morgan, professor at the University of Idaho and co-author of the study.  "When fires are patchy, more areas are within reach of a surviving tree."

Read more at Forest Resilience Declines in Face of Wildfires, Climate Change