Sunday, February 17, 2013

Chris Clarke on the Old Growth Desert


On Friday night, we attended a lecture on the "Old Growth Desert" by Chris Clarke, an environmental writer, editor, photographer, and long-time desert advocate. His talk turned out to be a revelation. Clarke spoke mainly about the ordinary plants you see everywhere in the desert. It turns out they can be incredibly old...as in, many hundreds to a thousand years or more...older than most Joshua trees, which usually top out at a few hundred years. (Above: a once-tall, fallen Joshua tree in our yard with youngsters beside the broken-off trunk.)


Here are other pictures from our yard of examples he talked about: above, pencil cholla, which Clarke says can live up to 600 years and occasionally even over 1,000 years. Based on the images he showed, I would guess this specimen (which is one plant with multiple trunks) could be a couple hundred years old.


Clarke says that Mormon tea, or Ephedra, can live 700 to 900 years or more. It grows in a "clonal ring" like creosote bushes and Mojave yuccas--which means the original parent plant, at the center of the ring, eventually dies off. I've written about the King Clone before on this blog--the famous creosote ring that has been dated to 11,400 years.


Even the humble buckwheat, with its rust-red, dried-up blooms, is a potential oldster--Clarke says up to 1,100 years! Really?? I admit, I don't understand the science behind how these calculations were made. (Clarke has citations available.)


The kicker is the decidedly unbeautiful blackbrush (also known as blackbush) which can reach 1,400 years or more. Clarke showed a photo of an area of solid blackbrush in the Mojave Preserve and said that an area like that could date back 15,000 years.

Clarke also talked about desert pavement--tamped-down stretches of gravel and rock that serve to trap sand and dust, creating the soil below. He says desert pavement can be thousands of years old, too. The implications are staggering...especially when you consider the current push to tear up the desert for solar farms.

Clarke frequently writes for KCET.org, and he is currently working on a book on Joshua trees based on over a decade of research. He is also co-founder of Solar Done Right. You can read his blog, Coyote Crossing, by clicking here.