Dr. Seuss’s Truffula Trees are real(ish), and they’re in danger of extinction.

Western Joshua trees in the Mojave Desert. © Glen E. Goodwin

If you grew up reading Dr. Seuss, you likely remember the tall, spindly “Truffula” trees from The Lorax, with striped trunks and colorful pompom foliage. People have long debated Theodor Seuss Geisel’s inspiration for these beloved trees, with some believing that a California Monterey cypress was responsible for capturing his creative attention.

But no matter the origin, one thing’s for certain. The American West has its own version of Truffulas: Joshua trees, ancient, otherworldly, and in danger of winking out.

Joshua trees grow in arid desert ecosystems across California, Nevada, Utah and Arizona. Thanks to the rise in popularity of photo-based social-media platforms like Instagram, this tall, long-lived species has become a plant celebrity in places like the Mojave Desert. The tree’s diverging branches and fuzzy trunk give us something to write home about. But even more importantly, it provides habitat for everything from birds to rodents to bobcats to pollinating moths.

In The Lorax, Seuss poses a question: What will the world look like if we don’t protect the environment, value our trees, keep our water and air clean? What if greed compelled industry to cut down all the Truffula trees for profit and development?

We won’t have to wait long to find out. Truffula trees may not be real, but Joshua trees are, and they’re succumbing to human-driven climate change at a terrifying rate. In fact, scientists predict, the trees will be largely gone from their namesake Joshua Tree National Park by century’s end.

But Joshua trees won’t go gently into that good night — or at least, the conservationists who love them won’t. Brendan Cummings, conservation director at the Center for Biological Diversity, believes there’s still time to protect the species in California under the state’s Endangered Species Act. And his passion for the species is no joke: He’s been working to save habitat for this dazzling Mojave Desert gem for decades — and to save the tree itself since writing the state listing petition for western Joshua trees in 2019.

I recently had the chance to visit with Brendan in his hometown of Joshua Tree, California. We discussed some of the most-asked questions about this species — and I tracked down what the public can do to, in the words of Seuss, “speak for the trees, for the trees have no tongues.”

First, for those who don’t know: What are Joshua trees?

People often ask me, “Is a Joshua tree a tree?” While people commonly say “no,” it all depends on how you define a tree. I’d say a Joshua tree is as much a tree as a palm tree is. It has the structure of a tree, which means it has a woody trunk and a canopy. So, whenever anyone says to me, “Joshua trees are not trees,” I often politely disagree. They are indeed trees.

Unlike most trees, Joshua trees are monocots. They’re more closely related to lilies and grasses than to other things that we think of as trees: conifers, oaks, elms, and other dicots.

As far as I can tell, the fact that they’re not typically considered a tree goes back to a publication in American Forests in 1971 titled “The Tree that is Not a Tree.” And that kind of stuck in people’s brains ever since.

[Author’s note: Wondering what a monocot is? Monocots refer to flowering plants with seeds that have only one embryonic leaf. If you’ve ever started a plant from seed, this leaf is the first one that appears after the seed sprouts.]

Are Joshua trees considered yuccas?

Joshua trees are in the genus yucca. Several yucca species have a tree form, but Joshua trees are the most tree-like of the yuccas.

I’m curious. How do you date a Joshua tree?

There’s no scientific way to date Joshua trees. Unlike conifers or hardwood trees, Joshua trees don’t have annual growth rings. So you can’t really date them unless you have things like historical photos or you’re doing a long-term study of Joshua trees where you can watch them grow.

[Author’s note: Joshua trees can live upwards of 300 years under the right growth conditions.]

Is there more than one species of Joshua tree?

Yes, there are two species of Joshua tree. There’s the western Joshua tree, or Yucca brevifolia. And there’s the eastern Joshua tree, or Y. jaegeriana. The western Joshua tree is only found in California and Nevada. The eastern Joshua tree is found in parts of California, Nevada, Utah, and Arizona.

Joshua trees were first declared two separate species in 2007, when a scientist published a study differentiating the Joshua tree based on structure. The western species is more tree-like: It usually has a singular trunk, bifurcates [branches out] where flowers grow or where there’s disturbance to the trunk, and its leaves are longer. The eastern species, on the other hand, splits more readily and can end up taking a shrubbier form. Its leaves are shorter.

What really made people start to recognize Joshua trees as two different species were studies on the moths that pollinate the trees’ flowers. As it turned out, the yucca moths that pollinate the western Joshua tree are different than the ones that pollinate the eastern Joshua tree. The flowers on each species have adapted to be pollinated by these distinct endemic moths.

[Author’s note: Brendan shared with me that Joshua tree reproduction is a delicate balance of temperature, precipitation (in the form of rain or snowfall), and the presence of these moths. So, the future of Joshua trees also relies on the future of these pollinating moths.]

A western Joshua tree in shadows against the sun. © Glen E. Goodwin

You’re primarily focused on the western Joshua tree right now. Why is that?

Even though the ecological impacts on both species are similar, I sought protection of the western species because the species is more imperiled — certainly in California. So let’s talk about the threats facing the western Joshua tree.

One of the direct threats is development. About 50% of the tree’s range is on unprotected, nonfederal land, so western Joshua trees could lose thousands of acres of habitat to sprawl if they aren’t protected by state law. Joshua trees are also vulnerable to desiccation, fire, and heavy windstorms caused by climate change.

But perhaps the most significant long-term threat to the Joshua tree is that they’re largely not reproducing. The trees are still flowering and fruiting, but juveniles aren’t surviving. In other words, the trees you see today in this area — that are probably between 40 and 150 years old — were recruited into the population under a climate that no longer exists.

So, when you layer the climate threat, the fire threat, the lack of reproduction, and losing a lot of habitat to development, it all has cumulative impacts on this species’ survival. Which means if we stay on our current climate trajectory, we’ll likely lose Joshua trees in the Mojave Desert for good.

What’s being done right now to protect the western Joshua tree?

In September 2020 the California Fish and Game Commission voted to grant western Joshua trees candidate status under the California Endangered Species Act. Candidacy means protection “may be warranted,” the equivalent of a federal 90-day finding. The next step is to list the species.

For each step the Commission makes, the California Department of Fish and Wildlife prepares a report and a recommendation. At this stage the Department status review says the western Joshua tree is not threatened — and recommends the Commission vote “no” when they meet.

The Commission will vote on whether to list the western Joshua tree under the California Endangered Species Act on June 15, 2022 in Los Angeles. Right now, we need to convince the Commission that the Department and the experts it relied on were wrong and that they should vote “yes” to list the species.

What happens if — worst-case scenario — we lose the western Joshua tree?

We’d likely see a homogenization of the landscape: a Joshua tree woodland becoming a non-native grassland. Some life, like California ground squirrels, would still exist here. But Joshua trees provide important ecological roles: Woodpeckers peck holes in their trunks, animals nest in them and eat the seeds, local bobcats climb them to get away from coyotes…. We would lose the visual identity of the Mojave Desert, but other species would be affected, too.

Joshua trees are an indicator species here. What’s happening to them is the litmus test of if we’re protecting the Mojave Desert from climate change. It’s also an umbrella species: what we do to save the Joshua tree will also help the Mojave Desert and its ecosystem.

Joshua trees are recognized; they’ve become a global symbol of the Mojave. But they’re now in danger of becoming a symbol of our failure to address climate change.

However, if we take the necessary steps to protect them under the California Endangered Species Act, Joshua trees can instead become a symbol of society doing the right thing — a symbol of all of us responding to the very difficult problems climate change throws at us.



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Anna Sofia

Anna Sofia

I solve writing conundrums like puzzle pros solve a Rubik’s cube. Science writer & Johns Hopkins grad. Social media strategist at Center for Bio Div.