Here’s a good summary (have

[njtosd]

Here’s a good summary (have no idea whether it’s accurate, but it’s at least clear) regarding “California Tree Law:”

http://www.legal-news-california.tozerlaw.com/tree_law_california.html

It seems to suggest that you should be careful about trimming the roots. These sort of things vary a lot from state to state so it’s best to try to find California law if possible.