Many people have recommended Joshua Tree National Park to visit, so we drove here from Flagstaff. The 340 mile drive was the longest we have driven in a day in months. It was tiring but we made it to nearest campground just as the rangers were closing up. By this point in our trip we do minimal planning ahead of time, arriving at our destination with open minds about what to do while we are there. So we arrived at closing time on a Saturday night to Indian Cove campground with no reservations. We were very lucky that the campground had had a cancelation, so we got a spot that night. The campground cleared out a bit on Sunday. Indian Cove and Black Rock campgrounds are on the perimeter of the park and are both reservation campgrounds, but all the campgrounds on the interior of the park are first-come, first-serve, so we would have a chance to get spots in the middle of the week. Altogether the not-planning plan worked out through luck.
Joshua Tree is a famous rock climber destination, and after clambering around on some of the smaller rocks we understand why. The rocks are super grippy (I’ll give a more scientific description in a future post) and easy to get traction on.
After a few days we left Indian Cove to see what Black Rock Canyon campground was like. On the way we stopped to hike a trail to an oasis on recommendation from a friend. Oases in the desert can be spotted by the trees growing around the water source. The oases in Joshua tree are fed by springs where the ground water seeps through faults. These springs are affected by tectonic activity, and even far away earthquakes can cause the springs to dry up or deliver 10 times as much water; both of these scenarios have happened in the park.
On an interpretive trail at the Indian Cove campground we read about chuckwallas. The chuckwalla is a large lizard that reaches nearly 16 inches in length. It’s defensive strategy is to wedge itself between rocks by inflating its lungs so it can’t be pulled out by predators. In short, it is a giant inflatable lizard. We just had to see one! Chuckwalla did not disappoint – we saw one together on our oasis hike and I saw another one later in by Arch Rock.
Joshua Tree National Park straddles two different desert ecosystems, the Colorado desert and the Mohave desert. The Colorado desert is a sub-region of the Sonoran desert, which we had been traveling in for weeks before reaching Joshua tree, so the landscape at Indian Cove campground was familiar. As the topology changes, so does the desert – the Colorado desert transitions into the Mohave desert around 3000 feet in elevation. Black Rock campground is solidly in the Mohave desert, and here many Joshua Trees stand.
Legend has it that Mormans migrating west named the tree after the biblical figure, because the tree appeared as a man raising his arms in worship, guiding the immigrants west. The scientific name is Yucca brevifolia; the tree is in the yucca genus. Joshua trees are thought to live 250-300 years, but they do not have annual growth rings like other trees so aging them is difficult. The species is a relic of the last ice age, and was a favorite food of giant ground sloths (which is known from analyzing fossilized dung!). Because the ground sloths preyed on the yucca, a theory posits that the yucca adapted into tree-form as the sloths ate the shorter plants.
Joshua trees can reproduce by both seeds or by sprouting clones from the roots. Blooming takes a lot of resources (energy and water) so these trees that grow in the resource-constrained desert do not bloom every year. Not all the branches bloom at the same time so a multi-branched Joshua tree may have flowers for several successive years, but from different branches each year. Last year was a record blooming year for the Joshua trees, with just about every tree in bloom, but no one knows why. Even with the unprecedented blooming last year, this year was a normal blooming year and we were lucky to be in the park in the right season to see the flowers. Like many yuccas, the Joshua tree depends on the yucca moth to pollinate its seeds. Flowers left not pollinated will develop into unviable seed pods, which remain on the trees for a year or more while the pollinated seed pots drop from the tree to disperse.
Yucca moth populations are plummeting, likely due to pesticide use, limiting the number of viable seeds the trees produce. On top of this challenge, the trees depend on rodents to distribute the seeds, and rodents don’t travel very far, so the potential range migration is very slow. The Joshua tree survived a major climate change once before, when ground sloths were present to distribute the seeds widely and some landed in a region where the trees could survive. With the current changing climate, especially the diminishing rainfall, the Joshua tree cannot migrate its range fast enough to keep trees growing in favorable habitat. The range of the trees is shrinking, as evidenced by the lack of baby trees at the southern edge of the range. On top of all that, adult trees are decimated by wildfires, which are being made worse by invasive grasses. Due to all of these challenges, Joshua trees are predicted to go extinct within our generation.
From Black Rock campground we took a 9.6 mile hike to Eureka peak and back. This was a nice relatively short day hike offering stunning view of the nearby mountain ranges, including Mount San Jacinto. Despite the dry winter and warmth of southern California, San Jacinto’s summit was covered with snow, the only snow in sight (according to the locals, the other mountains around are covered with snow in non-draught winters) . At 10,834 feet in elevation, the peak is the tallest in the region and one of the most prominent on the continent (a mountain’s prominence is basically the height of the peak compared to the surrounding land).
When we left Black Rock campground, we finally ventured to the interior of the park, four days into our visit. First stop was the Lost Horse Mine trial for a ranger-led tour. The trailhead is a small parking lot at the end of a dirt road. Arriving an hour early we were surprised at the number of people there on a Thursday morning for a four mile ranger hike. It turned out another organized group was hiking the same trail. A big crowd also arrived for the ranger hike, so that parking lot was overflowing by the the time we set out.
Many attendees stayed for lunch at the end of the tour, so overall this was a five hour program. We really enjoyed the presentation by Ranger Lacy, a young and energetic ranger. She provided a lot of natural and human history about the region, and was open to all of our many questions. Her answers were always informative as well as entertaining. For example, when we spotted a lizard and it stopped to do pushups I asked why they do that behavior. She explained that it is a territorial display, and that they are “showing their guns”. Most of the information about the Joshua tree I explained above came from this tour, and she also shared the background on the Lost Horse Mine. The mine was named because the developer Johnny Lang learned of the gold deposit while in search of his stolen horses. If you are interested to learn more of this sordid wild west tale, the full story is on the park’s website.
A large fire burned through the area a few years ago, and while the park service generally lets fires run their course as a part of the natural cycle, a lot of effort was spent to save the historic mine equipment. Desert areas cleared from fire take long to regenerate because desert plants are slow-growing and many depend on a nursery plant. In some cases park ecologists will help the regeneration along by planting sticks upright in fire-ravished areas. The sticks serve to catch wind-blown seeds and even provide a little shade that helps germination.
We had really amazing luck at getting campsites in Joshua Tree National Park, and the ranger program we attended with Ranger Lacy was the most informative of any that we’ve been to (and we have been to a lot!). It was interesting to learn about the Mohave desert and the history of the land. In the next post, I will share more about the geology of the park.
March 15 – 20, 2014