Trees Maintenance and Cleanup Question

[Ramsey Rimkeit]

A legal / tree-related question:

What is the correct/common practice (in California) with regards to maintaining and cleaning up debris from trees?

Context: I am the property manager of a mobile home community. There is a line of redwood trees on the adjacent property (owned by the same family) that regularly drops branches, needles, etc. onto the homes, spaces, and the street, especially during storms.

My colleague in charge of maintenance cleans the streets within the park regularly and after storms.

Some of the residents believe the owner is responsible for paying for the cleanup of their sites and their roofs. Is there any precedence for whether this is the owner's responsibility or not?

The websites I've read state that the owner is only responsible for cleanup if the trees are not properly maintained.

Also: there is a dispute about whether or not one resident whose roof leaves fall off of should clean up her neighbor's space.
Side note:

One of the owners has agreed to trim the trees again, but this will not eliminate the problem. Also, he told me this last fall and I've already reminded him once (I plan to remind him again.)

He also told me that the city of Hayward requires him to plant 2 trees for each tree he removes, and the trees listed require much more maintenance (watering in summer, leaf cleanup, etc.). I believe it is even illegal in California to cut down redwood trees.

(I also posted this in the official BP Facebook Group.)