I am walking through the Hexie Mountains, a small range composed mainly of metamorphic rock in Joshua Tree National Park. The Hexies are perhaps a couple miles north of the southernmost wild Joshua tree in the entire world. The Joshua trees in the Hexies look pretty healthy, but they’re in trouble.
Two sides of the Hexies, on the north and west, lie in the southern Mojave Desert. The other two sides are in the Sonoran Desert, a.k.a. the “Colorado” or “Low” desert where for perhaps 15,000 years it has been too hot for Joshua trees to grow. These trees are right at the verge, above a canyon that slopes circuitously downward to the Sonoran.
Surrounding them are the usual complement of plants to be found in washes and on hillsides in the lower elevational range of Joshua trees. There is creosote, desert senna, desert willow and Senegalia in the washes, chollas of various kinds, incongruous blackbrush in a couple places, and a healthy population of barrel cacti.
There’s also this sweet little thing: the smallest horned lizard I have ever seen, approximately the size of a Brazil nut without the shell.
…and the usual zebra-tails and side-blotcheds and leopard lizards.
Like I said, the Joshua trees along my hike look like they are having a reasonably good life, but something is amiss. There are a few dead trees, not unusually frequent, and quite a few mature ones, including these growing in a clonal group:
What I do not see were Joshua tree seedlings of any kind. Every youngish, unbranched tree under five feet in height is within a few feet of an older tree, or of a clump of similar trees, meaning that those “youngsters” are clonal sprouts of older plants, not a new generation of trees.
As we have discussed here before, Joshua trees need rainy, cool winters in order to grow fruit (and thus seeds, and thus baby Joshua trees). The warmer the desert gets, the less often those rainy, cool winters happen. There are still places in the upper elevations of Joshua Tree National Park where new baby Joshua trees are being born, but not so much here on the southernmost edge of the plant’s range.
That’s why, as I mentioned here, an environmental group petitioned the US Fish and Wildlife Service to list the Joshua tree as Threatened in 2015, and it’s why we were disappointed, though not even a little surprised, when the current executive branch chose not to take steps to protect the tree.
Fun fact, however: in the process of declining to step in to help the Joshua tree Fish and Wildlife did weigh in on the issue of whether the trees make up one species or two, siding with the “two species” partisans.
And then Brendan Cummings took that decision and ran with it. Conservation Director at the Center for Biological Diversity and a neighbor of ours here in Joshua Tree, Cummings took US Fish and Wildlife’s decision on how many species make up the general concept of “Joshua tree” (which decision, for what it’s worth, has little sway with the botanists who will actually be making that decision at some point, but oh well) and then wrote a petition asking the California Fish and Game Commission to list one of those two species, Yucca brevifolia, as Threatened under the California Endangered Species Act, a stronger law.
Cummings and the Center cite the relatively greater threat from climate change to Yucca brevifolia than that facing Yucca jaegeriana, its eastern counterpart. Borrowing another idea from the USFWS, Cummings suggests the state consider treating western Joshuas as comprising two smaller populations, “Evolutionarily Significant Units” (ESUs) in the north and south parts of the range. If the commission is reluctant to list all Yucca brevifolias in the state as Threatened, they could choose to list just the southern ESU, which is under greater threat from climate change.
That southern population, somewhat boomerang-shaped on the map, has one end in the vicinity of Ridgecrest. The population’s range runs along the eastern edge of the Sierra Nevada and Tehachapi mountains to an apex near Gorman, California, where the trees grow within shouting distance of Interstate 5. The population then turns southeastward to run along the northern edges of the San Gabriel and San Bernardino mountains, sometimes as high as 8,000 feet in the latter. The eastern end? That would be more or less where I’m standing right now, panting for lack of shade in the Hexie Mountains.
In the middle of the bracket formed by the outermost edges of the population’s range there are outliers, slightly disjunct populations in Boron and Barstow and Red Mountain. North of those, the Joshua trees belong to the northern proposed ESU. Farther east there be jaegerianas.
This prioritizing makes sense. The southern edge of Joshua tree country is where climate change will strike hardest and first.
And there’s this: 40 percent of the range of western Joshua trees is on private land, almost none of it protected. Almost all of the trees’ range near Los Angeles, a shocking percentage of the whole, is under severe development pressure.
If Cummings and CBD succeed in getting the Fish and Game Commission to list even just the southern group of western Joshua trees, it would shake the desert. Despite some sentmentality regarding the trees in Los Angeles County, their eradication has long been LA’s unspoken policy. A stunning 19th Century example: a paper mill in present-day Acton was founded with a business plan involving cutting down the extensive Joshua tree forests of the West Mojave to print London newspapers. As David Earle writes at SCVHistory.com:
In connection with the availability of railroad transport, a rather bizarre manufacturing experiment was set up in Ravenna in 1885. A paper mill, designed to process Joshua trees into paper pulp, was briefly in operation at that time. The trees were obtained from vast tracts of land in the Antelope Valley that the company operating the mill had bought. The company had been designed to ship newsprint to England for publishing use. This project was to end in failure after a few years on account of the poor quality of the paper produced at the mill. The mill lay idle by 1889.
That story, which explains why you don’t see Joshua trees in Acton, may seem like shudder-inducing bad news from a time long dead. But take a look at this local news story from 2015, in which a solar developer, following the letter of the law, was able to cut down hundreds of Joshua trees to make way for a solar project.
Even here in Joshua Tree, next to Yucca brevifolia’s namesake national park, we sometimes prevent subdivisions in Joshua tree forests only by luck, or with the help of economic collapses at the right time.
List the trees as Threatened and that changes. The California Endangered Species Act prohibits “take” of plant species. “Take” is jargon for “killing” or “harming.” Harming is usually interpreted broadly. Bulldozing Joshua trees to build a payday loan business would likely be considered a “take.” Spraypainting Joshua trees for your music video might be as well.
There’s this: protecting Joshua trees in their habitat may well mean protecting other things, as the Joshuas act as a keystone species to prevent random Californication of the desert environment. This may turn out to be good news for bobcats, badgers, and blackbrush as well.
Also, if this adds more impetus to the state to push for national and global climate policy, that gives these Joshua trees in the Hexie Mountains at least some chance of surviving until they can flower and set seed again. That would be nice.
And if the Fish and Game Commission could explain why Yucca brevifolia, which means the short-leaved yucca, has longer leaves than Yucca jaegeriana, I would be a happy man.