Oak Woodland

When I picture a oak woodland in my mind it is one with coast live oaks that stand closely together so that their canopies overlap. Low bushes cover the ground along with a layer of debris.

Coast live oak (Quercus agrifolia) is the most abundant species of oak along the California coast, ranging from Sonoma County into Baja California. Of course, in other parts of the state different oaks will predominate; but coast live oak is the one I grew up  and continue to see almost daily.

It is well adapted to to our Mediterranean climate of hot, dry summers and cool, hopefully rainy winters. Coast live oaks are evergreen, with a tough little leaf. 

The oak woodland is one of my favorite habitats. More than coincidently, I guess, in it are found some of my favorite animals as well: Acorn Woodpecker, Western Scrub Jay, and Western Gray Squirrel to recite just three. Plants in this habit could include California Bay and Toyon.

I have read that many early settlers wrote about the mystical beauty of these trees. I certainly get an inspirational feeling when ever I get the opportunity to spend some quiet moments of reflection in a such a grove.

Black Mustard

Black Mustard 2
Originally uploaded by The Marmot

Black Mustard

Last week, Holly and I began seeing patches of Black Mustard (Brassica nigra) on the far side of Thompson Creek, west of Higginbotham Park, while walking on the paved path. This is another one of those plants that is so commonplace most people assume that is a native. But, it is not.

Popular lore has it that the early Spanish explorers, such as Juan Bautista de Anza, spread the seeds of this plant along the routes that they forged ala Hansel and Gretel. Presumedly, the plant would be in bloom during the return trip and they could easily find their way home. I would like to think that this story is true. But, table mustard is made from black mustard so no doubt many people planted for that purpose

Whatever the reason, it is now common through out California and dominates the hillsides in our area at this time of year. Each Spring finds the hills covered in bright yellow flowers. The bloom begins in April and can extend through July.

Some sources say that black mustard, though widespread, is not considered to be as big a problem as some other invasive species. It prefers disturbed habitats, such as roadsides, and is not as likely to extend in to truly natural areas. However, fire counts as a disturbance and other studies have shown that mustard has totally displaced many of our endemic fire annuals. It has decidedly naturalized and as people further encroach in the sage scrub and chaparral environments it and other broad-leaved herbs are sure to follow.

Mustard and the majority of the native plant species in Southern California have their roots in the Mediterranean Basin. The climates are pretty much the same which allows these plants to adapt, settle in, and then take over when conditions are ripe.

These conditions are decidedly in force along Thompson Creek. The landscape surrounded on all sides by homes, parks, a flood control channel, and the effects of the Grand Prix Fire of 2003 still in evidence it is the very definition of a disturbed environment. Still it is a welcome oasis from the urban surroundings.