Hmm. That's normally American Willow, Salix discolor, which usually likes it a bit colder, but maybe some areas of Central CA are chilly enough? Plus, like most willows, it likes a lot of water. Willows tend to be weak-wooded, and can split or break, so keep that in consideration. Not sure if some of our more native varieties of willows will produce these soft little buds, so perhaps it's one of our more native willow varieties. Hard to say without seeing more photos of the entire tree and leaves. You could always ask an online source for Salix discolor and see what they think.

Patty S.