Friday, September 7, 2007
New plant species for hills: Scrub oak
Not much of a name, but there you have it. The scrub oak (Quercus berberidifolia) is found in chaparral from Humboldt Co. into northern Baja Calif., Mexico (like many chaparral plants and animals). In the Los Angeles area, it is generally found in the foothills of the San Gabriel Mtns. and in the Santa Monicas where other chaparral species are present, such as chamise, mountain-mahogany and Ceanothus. It is scarce or absent at lower elevations and along the immediate coast such as Palos Verdes, the Baldwin Hills and the Montebello/Repetto Hills, where coastal sage scrub - dominated by sages, sagebrush and buckwheat - tends to replace the higher, thicker chaparral.
In the Puente Hills, typical chaparral occurs only east of Powder Canyon, from the open space south of Rowland Heights east and north into Diamond Bar. West of here, tall shrubland tends to be dominated by sumacs and toyon, and has been called "sumac scrub". It is possible that the scrub oak and other chaparral species were burned out of the Whittier Hills over the years, or were eliminated by early brush clearance and grazing. Or, there exists a mysterious ecological barrier that has prevented their expansion west.
While conducting fieldwork here in 1997, I noticed a couple scraggly-looking scrub oaks along the Edison powerline right-of-way west of Colima Rd., growing between a steep slope and a chain-link fence, and thus protected from fire and brush-clearance. The plants were still there when I collected a sample this week (photographed), and may be the only ones in the western Puente Hills.
Posted by Dan Cooper at 5:06 PM