Trees are the subject of many disputes in California. Following, are the general rules that apply:

1. Trees with trunks completely upon the land of an owner belong exclusively to that owner even if their roots grow into the land of a neighboring property. Most courts will allow the neighbor to cut the offending roots and encroaching limbs provided the tree is not seriously damaged or destroyed. Some courts will require the neighbor to prove that the nuisance caused to his or her property outweighs the damage caused by any cutting of roots or limbs.
2. Trees with trunks on the land of two owners belong to both owners and both have the right to deal with the tree on their side of the boundary line.
3. If an owner of a tree is threatened with a violation of the rules set forth above, he or she can obtain a temporary restraining order until the court can hear arguments.
4. When a tree is wrongfully cut, the owner of the tree may be able to recover the cost to replace the tree or the diminution in the value of his or her property.

Before cutting a tree, make certain it is fully on your property. If in doubt, obtain a boundary survey.