The parts the original inhabitants didn’t get around to burning down yet, you mean. :)
They are the source of trees throughout most of Southern California ~ else that place would have little but sage and scrub.
It's noteworthy that there's a crowd in San Francisco who want to REMOVE all the invasive species from the state and return the Southland to the barren desert it resembled when first discovered.
Uh, it didn't just resemble a desert ~ IT WAS A DESERT and a great deal of it STILL IS A DESERT. I've been there. It's dry. It's sandy. It's got exposed rock. It's got these animals that get up on the highest rock and urinate if you get too near.