Legal Question in Real Estate Law in California

A tree on your property is yours to do with as you wish. So long as you are not negligent in maintaining the tree you have no liability to anyone regarding your tree.

Unfortunately, the previous answer is far too general, and in some locations and under some circumstances will be totally incorrect. There are some counties and cities that have ordinances protecting views, among them Alameda County and I believe there are some in Southern California and elsewhere. You need to check with your city or county. Note also that these ordinances may have exemptions for certain species and/or very large or very old trees, so inquire about exemptions as well.

A certified arborist may be able to give you advice about whether this tree is protected and how you might handle this situation from his profession's standpoint.

Also, I know there are instances where parcels or neighborhoods have enforceable view easements or CC&Rs;. Check your deed and your title insurance, HOA documents if any, and related papers for any reference to a view or sunlight easement.

Finally, you should ask the neighbor what he's relying upon to assert that you have a legal duty to trim. He may have something, or maybe not.