Legal Question in Real Estate Law in California

Here is some general law in this area. Each case depends upon its own facts, and I would need to know more to give you proper advise. After you read below, if you have more questions feel free to call me at 818 345 0123

Jones v. Deeter (1984) 152 Cal. App. 3d 798, 805: Owners who plant trees or have habitually trimmed or cared for them have the duty to maintain the trees in a safe condition. Where the City has planted and cared for the trees, dangerous conditions caused by the trees are attributable to the City, in particular, City is liable for trip and fall over break in sidewalk caused by roots of a City tree.

Re: Public entities: must show dangerous condition of public property of which public entity had actual or constructive knowledge in time to remedy, per GC 835 and 835.2

Metcalf v. City of San Joaquin (2008) 42 Cal. 4th 1121, 1136-1139: GC 835.4 provides a special affirmative defense to public entities in dangerous condition cases, that in recognition that they have limited budgets and manpower, if they establish it is too costly and impractical to remedy the condition, their failure to remedy the dangerous condition was not unreasonable and therefore they are absolved from liability. "Under this section, a public entity may absolve itself from liability for creating or failing to remedy a dangerous condition by showing that it would have been too costly and impractical for the public entity to have done anything else." (Cal. Law Revision Com.)

Stevens v. Moon (1921) 54 Cal. App. 737, 741; Crance v. Hems (1936) 17 Cal. App. 2d 450, 453: It seems to be settled law overhanging branches are a nuisance, and it must follow that invading roots are. The person intruded on by branches may cut them off; it must be true that one may cut off invading roots; it must be true that he who is injured by encroaching roots from his neighbor's tree can recover the damages sustained from them.

Booska v. Patel (1994) 24 Cal. App. 4th 1786: Whether in nuisance or negligence, while there may be a right to cut off encroaching roots, one must act reasonably so as not to cause unreasonable risk of harm to others.

Agree with the previous answer. As a practical first step, you might want to hire a professional arborist to come out and look at the situation, and advise you on how much trimming could be done without endangering the trees or making them hazardous to people or property. Then you can give your neighbor an informed opinion and a formal request that he do what can safely be done.