February 22, 2013

Aging gracefully: Desert plants live long past century mark

Joshua tree.
By Jimmy Biggerstaff
Hi-Desert Star

A saber-toothed tiger might have stepped on it. A mastodon shaking its behemoth body might have splashed water onto its leaves. And it still grows today.

The creosote clonal ring in Johnson Valley known as King Clone was one of the stars of the show when natural-history writer Chris Clark showed a slideshow of trees and plants that range from very old to ancient.

A full hall of desert aficionados assembled at the Black Rock Visitor Center Feb. 16 to hear Clark’s lecture on old growth.

Clark described the creosote’s clonal ring as “A single, living thing that has fallen into pieces.” Estimating the plant grows outward from the original plant’s germination point at one foot per 300 years, experts say King Clone sprouted 11,400 years ago.

This creosote may be the monarch of ancient life, but the desert is bursting with aged marvels, Clark told the audience.

He showed slides of buckwheat clumps that can live for 700 years. Iodine brush — more than 1,000 years. Clarke projected a photo of a particularly large and robust pencil cholla estimated to have sprouted up to 1,500 years ago.

Clark discussed some of the ways scientists determine a plant’s age and how slowly it grows. During a study in the Mojave Preserve’s Clark Mountain, botanists meticulously cataloged every plant in a plot of land, then returned 15 years later to observe changes.

By this method, they estimated life spans, but in some cases they could set no outward parameter because none of the plants of a specific species died, including buckhorn cholla and ephedra, or Mormon tea.

Not all ancients are plants. Clarke explained the centuries-long process that produces the varnish on desert pavement.

“In some aquifers,” Clarke said, “when you turn on the tap, that water hasn’t seen light since ground sloths roamed.”

Clarke’s first slide was from a favorite camping spot of his east of Cima Dome, a panorama of nearby granite, distant mountains and a Joshua tree forest. Clarke said Joshua trees generally have twice the lifespan of humans.

His next two slides showed the same tree photographed about 60 years apart. In the black and white version, Twentynine Palms pioneer photographer Burton Frasher had captured a particularly distinct-looking Joshua tree (aren’t they all?) growing in the desert northeast of Los Angeles.

The modern-day image of the same plant was the album cover for the band U2’s 1987 album “The Joshua Tree.” As Clarke flipped back and forth between the two images, it was apparent the plant hadn’t grown much in six decades.

Alas, that tree has since fallen over after a long and well-photographed life. Clarke said 300-year-old Joshua trees exist but are a rarity. They are relatively short-lived compared to other plants he mentioned in the lecture.

As the slide show continued, a Google Earth image showed a small, blurry blob Clarke identified as a 13-foot-wide clump of yucca northeast of the Mojave National Preserve. That ancient is no longer there, replaced by an array of solar panels.