California Fires Threaten Endangered Joshua Trees

These iconic desert plants face many other dangers.

Joshua trees
Joshua trees have survived since the Pleistocene era, about 2.5 million years.

 Jim Steinfeldt / Getty Images

Peculiar and iconic, Joshua trees are easy to spot. They have a long trunk ending in a maze of branches topped by clusters of spiky leaves. Most of these Seuss-like desert plants are found in California's Mojave desert. They've survived since the Pleistocene era, about 2.5 million years; Joshua Tree National Park is named for them because they are such a key part of the area landscape.

But recent wildfires are just one of the many threats to these beloved plants. The Dome Fire that tore through the Mojave National Preserve in late August has burned 43,273 acres. As of Aug. 26, it was 95% contained, but the damage to Joshua trees has been done.

"Fire is always a concern with Joshua trees of any kind, and the Dome Fire in Mojave National Preserve has killed perhaps a couple million trees," Chris Clarke, associate director of the California Desert Program of the National Parks Conservation Association, tells Treehugger.

"Fire is one of the major reasons to worry about Joshua trees' survival: the trees on the western edge of the range seem a little more likely to survive fire but all Joshua tree populations are at risk from wildfire, which is on the increase in the deserts due to a combination of invasive introduced grasses and other weeds, as well as increased storm activity due to climate change."

The Mojave National Preserve is a 1.6 million-acre park located between Los Angeles and Los Vegas.

Unlike some trees, like redwoods, that are more resilient during wildfires due to thick bark, height, and natural flame retardants, Joshua trees are more fragile when the flames hit.

Debra Hughson, chief of science and resource stewardship at the Mojave National Preserve, told the Palm Springs Desert Sun that the fire swept through a “phenomenally large and phenomenally dense Joshua tree woodland,” which was one of the largest in existence.

“The Joshua trees are very flammable. They’ll die, and they won’t come back,” she said. She called the burning of the Joshua trees a “tragic loss.”

Facing Many Threats

A Joshua Tree in an arid landscape
Joshua trees are actually succulents that retain water. Sean Russell / Getty Images

Joshua trees (Yucca brevifolia) — which are actually succulents — are bombarded by other threats. In a study published in 2019 in Ecosphere, researchers found that the plants could face extinction by 2070 due to climate change.

With the help of a team of volunteers, they gathered data on more than 4,000 trees in Joshua Tree National Park. They found that the trees have been migrating to parts of the park with higher elevations that offer cooler weather and more moisture in the ground. These are safe, protected zones for the trees. Adult trees that are located in hotter, drier locations don't produce as many young plants, and the ones they do produce aren't surviving.

Taking into account the predicted effects of climate change, the researchers estimated how many of these safe zones would remain. They predicted that even if major steps were taken to lower carbon emission, only about 19% of Joshua trees would survive after 2070.

If temperatures continue to rise and no serious efforts are made to reduce carbon emissions, they predicted only .02% of Joshua trees would remain.

"Our study brought a great deal of attention and made real the urgency of the situation for not just Joshua trees but many Mojave Desert species that are vulnerable to climate change. I was pleased to see that the science was presented in a way that made the findings tangible for many people," lead author Lynn Sweet, a plant ecologist at the University of California, Riverside, tells Treehugger.

"For many people, seeing, living among and recreating in the Joshua tree woodlands, and the risk of not being able to do so, for them or their children, is important and personal to them. Since our study came out, many people with personal connections to the Mojave, documentary filmmakers, artists, recreationalists have all spoken to us about the issue and it is heartening to know how many people care about this desert."

Waiting for Legal Protection

In October, 2019, the California Fish and Game Commission received a petition from the Center for Biological Diversity to list the western Joshua tree as endangered under the California Endangered Species Act. The California Department of Fish and Wildlife recommended the commission accept the listing, but the vote has been delayed several times.

There has been opposition to the listing from industry groups, including the California Wind Energy Association.

"If all species are to be listed as threatened and endangered on the basis of anticipated climate change impacts, the list will be exceedingly long," writes Executive Director Nancy Rader in a letter to the commission. "And the impact of such listings will undercut the very solutions to climate change that we need."

At a recent commission meeting, many Yucca Valley residents testified that illegal removals of the trees were tolerated by local officials, Clake tells Treehugger.

"Joshua trees on public land sometimes have some measure of protection, especially in national parks, though being in a national park didn't help the trees caught in the Dome Fire," he says. "Some municipalities have ordinances protecting the trees. They are generally not too protective, and rarely enforced."

He thinks the Joshua tree will eventually make the endangered list.

"I'm not too concerned about opposition to listing. We have science on our side."