About a year ago I was exploring the desert east of Joshua Tree National Park, looking for a good spot to hold a desert camping meetup for readers of Coyote Crossing, and I stopped at a little open spot not far from a mature desert ironwood tree.
It had rained a week or so beforehand, catastrophically so in some places. The storm series that came through closed major roads through the park for some months afterward. Where I stopped there was about a ten-foot earthen flood-control berm put in place to protect the (LA) Metropolitan Water District’s buried aqueduct from storm damage, and a flash flood had taken a slice out of that ten-foot berm that was as straight-sided as if it was a cake recently attacked by a knife.
The ground had recently been very wet, in other words. And when the desert soil gets wet in the late summer, interesting things happen. Winter rains are more predictable, and after a wet winter you can predictably get a pretty damn nice bloom across the desert; yellow primroses and pink desert verbena and white ghost flower covering entire bajadas that are usually shades of brown desert varnish.
But summer rains are sporadic, unpredictable, and usually very localized. A given valley in the desert might go fifty years without a good summer rain. When that valley does get a summer rain, annual plants that have been waiting in the soil seed bank for decades can come up within a few days, flower within a couple weeks, set seed and disperse that seed and die back within a month and a half. My desert botanist friends watch the weather carefully in summer, ready to plan trips out into the backcountry with the plant presses within two weeks of the drop of a hat.
The North American deserts are essentially terra incognita for botanists. There are a few things that are quite well known, because they grow and bloom during the more comfortable parts of the year within a few miles of pavement. And then there are the valleys that are a difficult day’s hike from the hearest two-rut 4WD road, and we generally don’t know what blooms there when it’s 115°F during the day because botanists are not that much more insane than the rest of us. That’s true of herpetologists and entomologists as well, and so we don’t really know some of the smaller fauna of the remote parts all that thoroughly either.
Jim André of the Sweeney Granite Mountains Desert Research Center in the Mojave Preserve tells me that if you look out at a typical Mojave Desert landscape, 10% or more of the species in your field of view aren’t known to science. He says that just about every time he goes out in the field he finds either a species or subspecies not formerly known to lie in that area, or even new to science. I’ve been in places relatively easy to get to, the California Black Hills for example, and noted plants that had not been recorded by any botanist whose records are available to the Calflora database: this tiny little cactus being one inconspicuous example:
But you find totally expected things too, like for instance on that day on which I was scouting out possible meetup campsites. A week or so after a drenching rain, in an area in which a mature ironwood tree had been dropping its leguminous seeds for some centuries, it wasn’t at all surprising to find that a couple had sprouted.
I don’t know how long the seeds had lain there before sprouting. Unlike a lot of other hard-coated desert tree seeds, ironwoods will sprout without scarification — without scratching the seed coats to let moisture in. They might have been there for six months or a century, waiting.
Ironwoods are likely my second favorite desert tree, possibly third if you count saguaros as trees. They fix nitrogen, always in short supply in the desert. They grow slowly, When they die, the wood they leave behind is — in the words of Phillips and Comus’ A Natural History of the Sonoran Desert,“rich in toxic chemicals and essentially non-biodegradable.” It’s supposed to be the second densest wood known after lignum vitae, and it’s a gorgeous chocolate color when carved and polished, which trait southwestern gift shops use to their full advantage. (The Seri Indians pioneered the art of ironwood carving using fallen wood, but the art proved so popular that others appropriated it and started cutting live trees to meet demand.)
It was a little hard to imagine that these tiny seedlings, first true leaves just starting to peek out from between the waxy cotyledons, might within a few months become some of the toughest, most enduring organisms the desert knows.
It’s been a year: I’ll have to go back and check on them.