WONDROUS PLANTS, WONDROUS ROCKS
Los Angeles, 31 March 2017
Two weekends ago, my wife and I visited Joshua Tree National Park, together with our daughter and her beau (I should quickly explain that we are currently in Los Angeles, visiting the happy couple). For those of my readers who have only a hazy idea of this National Park, let me give some background. Located some three hours’ drive east of LA, the park straddles the border between two desert ecologies, that of the lower-altitude Colorado desert, and that of the higher-altitude Mojave desert. It was created back in 1936, to protect and preserve its rare desert plants. As a tribute, I throw in here a photo of the lady, Minerva Hoyt, whose tireless efforts back in the 1930s finally led the US Congress to list the site.
The park is – at least to my European eyes – enormous: 3,200 square kilometres, the size of Luxembourg. But that’s less than 1% of the size of California. One of the difficulties I always have in the US is getting used to the size of things here (including food portions, but that is another story).
The park’s symbol, and the origin of its name, is the Joshua Tree, a member of the Yucca family.
It is related that the plant got its odd name from a group of Mormon pioneers in the mid-19th century who were heading west to what they fervently hoped would be their Promised Land. When they came across the tree, members of the party decreed that the plant’s shape reminded them of the Biblical story in which Joshua holds up his hand in prayer to stop the sun.
Personally, I have my doubts about this tale but have no better name-origin story to offer.
There are parts of the park where Joshua Trees cluster closely. Contrary to many web sites, that of the park itself included, I’m not sure I would go so far as to call these clusters a forest.
It is sad to relate that the Joshua Tree is in danger of disappearing from the park because of climate change. I suppose the trees are finicky in their locational needs, both in terms of altitude as well as of terrain. Climate change is making their current location too hot for them. But where can they escape to? The tragedy of the Joshua Tree, and indeed of all plants, is that being rooted to one place they cannot migrate to cooler climes. To migrate long distances they are totally dependent on either having their seeds sail away on the back of the winds or on animals eating their fruit and wandering far away and depositing the seeds in a nice bed of faeces. It seems that in its evolution the Joshua Tree opted for the latter form of dispersal, but it was its bad luck to create this symbiotic relationship with the Shasta ground sloth.
Note that this is an artist’s reconstruction of the animal based on fossils; it disappeared in the big wave of extinctions that occurred in North America some 12,000 years ago (perhaps hastened on their way by the first humans who arrived in North America, or perhaps not; the experts are animatedly divided on this issue). So the Joshua Tree has been nailed to the spot for the last 12,000 years.
After admiring the Joshua Tree – in my case with a point of sadness – we went for a hike through a most interesting geological formation that the park hosts.
When we weren’t wondering where the end of the trail was because we had run out of water, we were wondering how these formations had come to into being. Wikipedia has since informed me they were formed by the cooling of magma beneath the surface into a form of granite with roughly rectangular joints. Groundwater then filtered through the joints to erode away the corners and edges to create rounded stones. In a final step, flash floods washed away the covering leaving these piles of boulders.
All this was in the higher-altitude Mojave desert. After finally getting a badly-needed drink of water, we started down for the lower-altitude Colorado desert. As we wound our way down, we quite suddenly entered a belt of Cholla cactuses.
These cactuses are gleaming white at their crown
but go coal black at their base
and eventually collapse in an untidy, dirty black pile
leaving behind this strange trunk, empty at the core and with regularly spaced diamond-shaped holes in the remaining husk.
It looks for all the world like a thick mesh fabric which has been rolled into a tube.
Just past the belt of cholla cactuses, we began to spy another strange plant, the Ocotillo.
From a distance, it appeared to be a cactus with long thin branches. But when we got close, we saw that actually the plant closely covers its branches with leaves rather than have them all clustered at the crown like most other trees do.
We were visiting the park at that short moment in the year when the apparently barren desert bursts into flower. The flowers race to create seeds for the next generation before the summer heat builds up and withers away everything on the desert floor.
And with that, we cruised back up to the upper Mojave desert and took the road back to LA.
Minerva Hoyt: https://www.nps.gov/jotr/learn/historyculture/mhoyt.htm
Joshua Tree: https://www.nps.gov/jotr/learn/nature/jtrees.htm
Joshua praying to stop the sun: http://pasemonmaspram.blogspot.it/2017/04/
Joshua Tree cluster: http://www.wolfsvisionphotography.com/JoshuaTreeNationalPark.html
Shasta ground sloth: http://freethoughtblogs.com/pharyngula/2013/03/10/bring-back-the-shasta-ground-sloth/
Rock formations: http://charlesgurche.com/photography/landscape/national-park/joshua-tree/
Cholla cactus gardens: https://www.123rf.com/photo_9396795_beautiful-cholla-cactus-garden-in-joshua-treer-national-park-in-afternoon-sun.html
Cholla cactus close-ups: my pictures
Ocotillo: my pictures
Wildflower close-ups: my pictures