In a Nutshell: The Smokey Bear Effect

For most of the last century, land management agencies in the U.S. and Canada have fought to suppress wildfires ravaging their natural landscapes. For every fire that burns, it leaves a blackened and barren landscape where there was once dense vegetation. It’s undoubtedly tragic, and the fact that fires can be prevented makes it even more so. At least, this was the assumption for most of the 1900s until scientists realized that fire is a natural process and vital for maintaining biodiversity like rain or wind. 

“We often talk about wind and rain as just natural processes, but fire is often described as a disturbance–something not normal. So I’ve been starting to describe fire as just one of those necessary elements in our environment. And many ecosystems evolved with both lightning ignitions and cultural fire, and as such they’re dependent on fire,” Susan Prichard, a Fire ecologist at the University of Washington, says.

How do we keep our ecosystems healthy? Fire isn’t the answer that most people expect; however, periodic low-intensity wildfires were once an innate part of North American ecosystems. For this reason, many native species have adapted to fire, and some are even dependent on it.

For example, the Lodgepole pine, which ranges from British Columbia to Colorado, demands fire to release its seeds. The tree’s cones have a meltable resin that seals the seeds inside, which can only be freed by fire’s high temperatures. Closed-cone species like this have fire-dependent reproductive cycles, otherwise referred to as serotinous.

Fire also clears underbrush–an overgrowth of shrubby plants on the forest floor–and recycles nutrients into the soil, allowing a diverse set of plants to thrive. By preventing certain plant species from growing while others overtook the forest floor, animal populations dependent on variable ecosystems for food or shelter also suffered. The advantages of periodic wildfires aren’t limited to individual species but the entire ecosystem.

The succession of various plant and animal species across North America halted as land management agencies suppressed a keystone process. What was once a patchwork of diverse habitats has become a homogeneous, closed-canopy, nutrient-depleted environment no longer hospitable to many of the organisms that once resided there.