By removing low-intensity fires, humans may be changing the course of evolution. Without exposure to low-intensity fires, species can lose traits crucial for surviving and recovering from such events.

After extreme fires, landscapes have fewer seed sources and less shade. New seedlings have a harder time becoming established, and for those that do, the hotter and drier conditions reduce their chance of survival.

In contrast, low-intensity fires free up space and resources for new growth, while still retaining living trees and other biological legacies that support seedlings in their vulnerable initial years.

By quickly putting out low-intensity fires and allowing only extreme fires to burn, conventional suppression reduces the opportunities for climate-adapted plants to establish and help ecosystems adjust to changes like global warming.

As the climate becomes hotter and drier, more area is burning in wildfires. If suppression removes fire, it should help slow this increase, right?

In fact, we found it does just the opposite.

We found that while conventional suppression led to less total area burning, the yearly burned area increased more than three times faster under conventional suppression than under less aggressive suppression efforts. The amount of area burned doubled every 14 years with conventional fire suppression under simulated climate change, instead of every 44 years when low- and moderate-intensity fires were allowed to burn. That raises concerns for how quickly people and ecosystems will have to adapt to extreme fires in the future.

The fact that the amount of area burned is increasing is undoubtedly driven by climate change. But our study shows that the rate of this increase may also be a result of conventional fire management.

The near total suppression of fires over the last century means that even a little additional fire in a more fire-prone future can create big changes. As climate change continues to fuel more fires, the relative increase in area burned will be much bigger.

This puts more stress on communities as they adapt to increased extreme wildfires, from dealing with more wildfire smoke to even changing where people can live.

To address the wildfire crisis, fire managers can be less aggressive in suppressing low- and moderate-intensity fires when it is safe to do so. They can also increase the use of prescribed fire and cultural burning to clear away brush and other fuel for fires.

These low-intensity fires will not only reduce the risk of future extreme fires, but they also will create conditions that favor the establishment of species better suited to the changing climate, thereby helping ecosystems adapt to global warming.

Coexisting with wildfire requires developing technologies and approaches that enable the safe management of wildfires under moderate burning conditions. Our study shows that this may be just as necessary as other interventions, such as reducing the number of fires unintentionally started by human activities and mitigating climate change.

This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Mark Kreider, University of Montana

Read more:
The West’s iconic forests are increasingly struggling to recover from wildfires – altering how fires burn could boost their chances

The US is spending billions to reduce forest fire risks – we mapped the hot spots where treatment offers the biggest payoff for people and climate

How years of fighting every wildfire helped fuel the Western megafires of today

Mark Kreider receives funding from the National Science Foundation and the USDA Forest Service.