MYSTERY WIRE — The future looks bleak for one of the most iconic images of the American Southwest — the Joshua tree. The odd-shaped trees have popped up in movies and TV shows, inspired artists and musicians, and in earlier times were a vital source of food and fiber for indigenous tribes, as well as hundreds of plant and animal species.
Scientists are now worried that the Joshua trees days are numbered. For many years the reason these iconic plants were dying off was a mystery. Now, scientists say they know what’s happening.
Anyone who has driven the long dirt road across Tikaboo Valley toward Area 51 has seen the silent sentinels off to the side, gnarly gargoyles with gangly arms uplifted, almost as a warning. Yucca brevifolia has had many names but the one that stuck is Joshua tree. The harsh landscapes where it grows look extraterrestrial, if not Mars maybe Tatooine. It’s closer to asparagus than a cactus, and like snowflakes, each one is different, almost humanoid.
“A lot of native legends, creation stories for the Joshua tree that involve them being people who were turned into trees,” said Chris Clarke, writer and Joshua tree researcher.
Clark has been writing and speaking about Joshua trees for 20 years. He’s at the Desert Yeti Ranch in Pioneertown to check out a healthy 40 acre forest. The altitude and climate make this one of the few areas in the world where Joshua trees can still thrive. In general, though, they’re in trouble.
“Joshua trees are relics of a Mojave Desert that used to be, back before 8,000 years ago,” Clarke said. “As the desert and the rest of the world continues to get warmer on average, they are likely to do worse and worse.”
By the end of this century, about 90 percent of the current habitat for Joshua trees will be too hostile for them to survive. They look tough and hardy, but need a very delicate balance of conditions to propagate. The tree itself isn’t very efficient at reproducing. Centuries ago, its seeds were spread by ground sloths, but they’re long gone.
“The Joshua tree, you’re not finding it down at the 3,300 foot level in Twentynine Palms anymore. There hasn’t been a lot of recruitment of new plants in the last few decades because it’s getting warmer,” said David Smith, superintendent of Joshua Tree National Park.
As a boy, Smith climbed the dramatic rocks in Joshua Tree National Park. Today he’s the superintendent. The 800,000 acre park is home to a million or so Joshua trees, along with 1,000 other unique plant and animal species that depend on the tree in one way or another. More than 2.5 million people visit the park each year. Photographers and models can’t resist Joshuas as backdrops. Musicians have likewise been inspired, resulting in one of the biggest selling albums of all time.
The National Park Service has moved well beyond the question of whether climate change is real, because it’s already here. Joshua trees won’t disappear anytime soon. Individuals can live for hundreds of years. But human activity is already killing them off. Smog from cars deposits nitrogen in the desert soil, which causes invasive weeds to flourish, fuel for wildfires.
Now what happens, because we have so many exotic weeds in the park, we get a lightning strike from the monsoon season, we get fires, we get 100, 5,000 acre fires inside the park in an environment where fire has never existed before. So the Joshua trees, they don’t come back for centuries and centuries after they burn.DAVID SMITH, SUPERINTENDENT OF JOSHUA TREE NATIONAL PARK
A year ago, filmmaker Jeremy Corbell recorded the devastation as fire raced across the hills near the Desert Yeti Ranch, charring thousands of acres. Similar fires outside of Las Vegas in recent years have wiped out Joshua forests that will take a long time to replace. Joshua trees will survive, somewhere, but like their yucca cousins in the movie Rango, they might have to somehow get up and move.
Scientists think Joshua trees will have to somehow migrate north in both Nevada and California. One place that is crucial to its survival is Tikaboo Valley, near Area 51. It’s the only place in the world both subspecies exist. There’s hope that a hybrid of the two could evolve and have a better chance of hanging on.