A recent Washington Court of Appeals opinion addressed the rights of a neighbor to destroy roots and branches on her property that belonged to trees located on an adjoining landowner’s property.
Mustoe had two large Douglas-fir trees located entirely on her property, about two and one-half feet from the property line with her neighbor Ma. Ma caused a ditch to be dug on her property along the border with Mustoe’s lot. The ditch was 18-20 inches deep. In the process, Ma exposed and removed the trees’ roots, leaving them to extend only three-four feet from the trunks of the trees. This resulted in a loss of nearly half of the trees’ roots, all from the south side, exposing them to southerly winds with no support. The damaged trees posed a high risk of falling on Mustoe’s home. The landscape value of the trees was estimated to be $16,418. The cost of their removal was estimated to be $3,913.
Mustoe filed suit against Ma asserting that Ma had negligently, recklessly, and intentionally excavated and damaged her trees, along with other property, and also sought emotional distress damages. The trial court dismissed Mustoe’s suit. The Court of Appeals affirmed.
The Court of Appeals acknowledged that the law in Washington is that an adjoining landowner can engage in self-help and trim the branches and roots of a neighbor’s tree that encroach onto his or her property. Mustoe contended, however, that earlier Washington law acknowledged that the right to self-help does not extend to removing the tree itself. She contended that the law did not immunize the neighboring landowner against liability for damage to the trimmed trees, and argued that the Court should hold that in exercising self-help, the landowner owed a duty of care to prevent damage to the trees themselves. The Court of Appeals disagreed, and declined to extend Washington law.
Comment: The law in Washington is clear that an adjoining landowner can engage in self-help, and trim the branches and roots of a neighbor’s tree that encroach onto his or her property, even when such trimming and root destruction essentially destroys the tree. The message to tree owners, whose trees are adjacent to the boundary line with their neighbor, is that their neighbor can damage their trees so long as the damage takes place on the neighbor’s property.
 Mustoe v. Ma, 193 Wn. App. 161, 371 P.3d 544 (Div. 1, April 4, 2016).