Short answer: if the tree’s trunk actually straddles the property line, both neighbors own it together as tenants in common, so neither one can cut it down, remove it, or bill the other for removal without the other’s consent, and the cost is split only by agreement. If the trunk stands entirely on one side, it belongs to that owner, even if the branches and roots cross over. The whole question turns on where the trunk sits, not the canopy or the roots.
The rule: a boundary tree is jointly owned
Where a trunk sits on the line, the common-law rule, codified in several states, is joint ownership. California states it directly:
"Trees whose trunks stand partly on the land of two or more coterminous owners, belong to them in common."
California Civil Code §834
"Belong to them in common" is the operative phrase. A tenant-in-common can’t unilaterally destroy the shared property: courts have held a neighbor who removes or seriously damages a boundary tree without the co-owner’s consent can be liable to that co-owner. So the practical rule for a dead boundary tree is simple, get it in writing before anyone touches it, and split the removal cost by agreement.
The test is the trunk, not the roots
People assume that because a tree’s roots or branches reach into their yard, they own part of it (or owe part of the bill). Courts reject that. As Ridge v. Blaha (Ill. App. 1988) put it, looking to the trunk’s location:
"the fact that a tree’s roots alone cross a boundary line is insufficient to create common ownership, even though the tree thereby derives part of its nourishment from both parcels." Ridge v. Blaha, 166 Ill. App. 3d 662 (1988)
So the ownership map is:
- Trunk on the line → common property; joint decision, shared cost.
- Trunk entirely on one side → that owner’s tree and that owner’s bill, even if roots/branches encroach.
What to do with a dead boundary tree
- Establish where the trunk sits. If it’s genuinely on the line, treat it as co-owned from the start, don’t hire a crew unilaterally.
- Get written consent and a cost-split agreement before removal. Removing a co-owned tree without consent exposes you to liability to the neighbor, even if the tree is dead.
- If the trunk is on one side, that owner is responsible, but if that dead tree threatens your property and you’ve put them on notice, the falling-tree negligence rule can also come into play: see who pays when a neighbor’s tree falls on your house.
- Overhanging branches from a tree that isn’t co-owned are a separate question, can I cut my neighbor’s tree branches.
State statutes and case law vary, and §834 is California’s codification of a broader common-law rule, most states reach the same joint-ownership result for a trunk on the line, but confirm your state before acting. This is general information, not legal advice. Browse all guides or look up your city at the city lookup.