Wildfires Are Speeding Up Climate Change—and Shifting What Grows Where

The range of native plants is moving northward after wildfires, and agriculture may follow.
Vicente fire, August 2014. (Photo: Flickr)
Aug 14, 2015· 3 MIN READ
Dan Nosowitz is a freelance writer based in Brooklyn. He has written for Popular Science, The Awl, BuzzFeed, Modern Farmer, Gawker, Fast Company, and elsewhere.

California is having a very bad year, ecologically speaking. With 92 percent of the state in severe drought and wildfires raging from the Oregon border to the Mexican border, California can’t seem to catch a break. Now comes new research from the University of California, Davis, that suggests the wildfires may be accelerating the process of climate change, moving the state faster into the future.

“Our goal was to describe how forest thinning and fire are affecting the plant diversity underneath California's conifer forests,” Jens Stevens, the lead author of the paper, which was published in the Journal of Ecology, wrote in an email. “In other words, how many species do we have, and what kind of species are they?” Stevens measured a new process, recently named and not particularly thoroughly studied, called thermophilization.

Thermophilization is a term coined in 2012 to describe the predominance of species from warmer climates wresting control of habitats in which they’d normally be minorities. In other words, it seeks to describe the changes in flora that result in, say, plants more commonly seen in Mexico suddenly being found in the San Francisco Bay Area. This isn’t quite the same as plants shifting their territories or farmers moving their plants to cooler planting grounds; this isn’t a banana tree turning up somewhere it’s never been seen before, like, say, Michigan.

“The southern species are already in the area of these fires, so it's not that they're ‘moving’ necessarily, it's just that they are becoming more abundant,” Stevens wrote. The fire areas examined included the Angora Fire in 2007 and the American River Complex Fires in 2008, so the plant life has had a chance to recover. Also, many wildfires are currently burning, which does not provide a particularly nice environment for study.

Stevens’ work is not in the agricultural field and doesn’t directly comment on agriculture, but it’s not hard to draw a parallel between what’s happening in the natural world and what could happen in agriculture. In 2012, researchers at CGIAR took a look at the production of the world’s biggest cereal crops, among them wheat, rice, and corn, and found that many developing countries will find that their ability to grow them will decrease in the wake of climate change. One particularly interesting prediction is that potatoes, which rely on cool temperatures and especially thrive at high altitudes, will prove tricky to grow. CGIAR predicted that bananas, or plantains, could end up replacing potatoes at these altitudes.

Farmers would essentially be imitating the effects of these wildfires: scrapping their fields and starting over with new crops. In the coming years, that’ll come in stages, the same way Stevens’ study shows it happening in the natural world. A farmer in Northern California might start planting more almond trees, then citrus—both crops more popular in the South.

On the other hand, just because the crops will shift doesn’t mean times will get any easier. Studies have indicated that pests will also move toward the poles in response to climate change, in essence following their favorite crops. Farmers can’t outrun pests, it seems.

This isn’t a phenomenon limited to plants. Many bird species are shifting northward, though as the Cornell Lab of Ornithology found, despite their ease of movement, they’re not shifting quite as fast as climate change. Most categories of marine life have moved, to some extent, to cooler waters.

Plants have a harder time moving than animals, relying on seed dispersion from northern-shifting animals to plop their seeds somewhere more conducive to life. But in California, the wildfires accelerate that process. “Over the long-term, more fires might facilitate the northward movement of these species under climate change,” wrote Stevens, though he’s careful to note that that’s an inference based on the data.

What Stevens’ data shows is that in the post-wildfire landscape of California’s conifer forests, most common in Northern California, times are changing. Plants that were more often found in Mexico and the very southern part of California, like manzanita and monkey flower, are showing dominance over plants that controlled the forests in Northern California, like some species of lupine and violets, before the fires.

Given a blank slate, in other words, it’s the southern plants, which are predisposed to hot weather and drought in a way that many northern species are not, that are thriving. It gives a sense of how nature is rearranging itself to accommodate climate change in much the same way farmers and agricultural professionals will have to adjust. It’s a wide-ranging study, one that takes a broad view of the various ways in which California forests can be burned and recover, and it doesn’t state that the better-known Northern California plants will be going away anytime soon. But it’s kind of a glimpse into the near future, a slightly fast-forwarded look at the state of things after a few hikes in temperature.