Scientists have discovered what they believe may be the oldest plant in the world. The scrub oak found in the arid hills of southern California may first have sprouted during the last ice age.
Methuselah had nothing on this bushy oak, more like a shrub than a tree. Noah’s grandfather was reputed to have lived for 969 years but this plant is estimated at more than 13,000 years.
Details of the "Jurupa Oak", named for the rolling hills in which it was discovered, are published this morning on the free access online journal, PLoS ONE(www.plos.org).
The plant, Palmer's Oak ( Quercus palmeri), was found more than a decade ago during a survey of the Jurupa Hills. The University of California Davis researchers were struck by the fact that the plant was in completely the wrong place.
It normally occurs at high elevations in cool, wet climates, said Prof Jeffrey Ross-Ibarra of UC Davis. “In contrast, the Jurupa Oak scrapes by in dry chaparral, wedged between granite boulders and stunted by high winds, atop a small hill in plain sight of suburban backyards.”
Looking more like a cluster of shrubs, genetic analysis showed that this was a single plant, with many stems cloned from a single individual, the researchers said.
As forest fires razed the plant over thousands of years, it threw off fresh sprouts to produce the spread-out bush seen today, which is more than 22 metres across.
It does not produce acorns and so can only have survived this long by throwing up fresh stems from its roots. The research team was therefore able to count growth rings, tracing back along the trail of roots.
“Ring counts show that the Jurupa Oak is growing extremely slowly,” stated UC Davis student Michael May. “At its current rate of about 1/20th of an inch (1.27mm) per year, it would have taken at least 13,000 years for the clone to reach its current size. And it could be much older.”
That means the plant has been standing on that hillside “through massive biotic changes”, says co-author Dr Andrew Sanders.
“This literally appears to be a last living remnant of a vanished woody vegetation that occupied the inland valleys at the height of the Ice Age.”
The authors also believe there may be many more stands of woody plants dotted across southern California.