Washington neighbor tree law: boundary trees, overhanging branches, fallen trees

The short answer

Overhanging branches and roots: the self-help rule

Washington settled this question in 1921. In Gostina v. Ryland the Supreme Court held that a tree whose branches or roots cross the boundary is a nuisance only to the extent of the encroachment, and that the adjoining owner’s remedy is to clip the branches or cut the roots at the line. The Court of Appeals restated the rule in Mustoe v. Ma in 2016: a neighbor who dug a ditch on the adjoining lot and severed nearly half the roots of two Douglas firs next door owed no duty of care to the trees, because removing the encroaching portion was lawful self-help. The tree owner, who argued the firs were now a falling hazard, had “no legal cause for complaint.”

The rule has three edges you need to respect. First, you cut at your own expense; there is no statute making the tree owner pay for the pruning. Second, you stay on your side: entering the neighbor’s yard, or cutting past the line, is a trespass. Third, cutting that reaches the trunk or kills the tree stops being self-help and becomes an injury to a tree “on the land of another,” which is where RCW 64.12.030 and its treble damages start.

Practically, that means a heavy pruning job on a big western redcedar or bigleaf maple at the fence line is worth a conversation and a tree trimming crew that prunes to the line cleanly rather than topping or stub-cutting. If the limbs are over a service drop or a primary line, do not touch them; the tree removal near power lines guide explains who may work within 10 feet of a conductor. Keep dated photos of the encroachment before and after, and give written notice to the neighbor even though the law does not require it. A neighbor who was told in writing that a limb was cracked has knowledge, which matters later.

Cutting a neighbor’s tree: RCW 64.12.030 treble damages

The timber trespass statute is older than the state. RCW 64.12.030 says that when a person cuts down, girdles, injures or carries off any tree, timber or shrub on another’s land, or on the street or public grounds in front of it, without lawful authority, the judgment for the plaintiff “shall be for treble the amount of damages claimed or assessed.” The word is “shall”: once liability is found, the court does not have discretion to award single damages unless the defendant proves a mitigating fact.

Those mitigating facts are in RCW 64.12.040. Damages drop to single damages where the trespass was “casual or involuntary,” where the defendant had “probable cause to believe” the land was their own or belonged to the person who directed the work, or where the timber came from unenclosed woodland for a public road or bridge. The burden is on the person who did the cutting. In Happy Bunch the person directing the work for Grandview believed he had a right to clear the trees, but he had survey evidence showing the neighbor’s ownership interest; the Court of Appeals held that a subjective belief in the face of a survey is not probable cause and sent the case back for treble damages.

Damages are measured by the value of the trees or the loss to the land; in Happy Bunch the trial court valued each tree individually before the figure was trebled. A mature Douglas fir or madrone appraised by a consulting arborist can carry a serious value before trebling, which is why a neighbor who “helpfully” removed a tree on your side of the line is facing a real claim and why you should never remove one on theirs, even with a verbal OK. Get consent in writing, with a sketch of which trees, and keep it.

City penalties stack on top. In Seattle, Kirkland, Bellevue and other cities with tree codes, cutting a regulated tree without approval draws municipal fines separate from the civil claim; the tree removal permits in Washington guide lists them city by city.

Boundary trees are common property

Happy Bunch, LLC v. Grandview North, LLC (Division I, December 3, 2007) is the Washington case on trees that straddle the line. Grandview, a developer, cut trees whose trunks stood partly on Happy Bunch’s parcel after Happy Bunch had refused permission. The court adopted the rule that a tree standing directly on the boundary, “so that the line passes through it, is the common property of both parties,” and held Grandview liable under RCW 64.12.030 even though part of each trunk was on its own land.

The damages formula is the useful part. The trial court valued each tree and awarded Happy Bunch the share matching the percentage of the trunk on its side, $32,519.22 in all, and the Court of Appeals then ordered that figure trebled. So if 40 percent of a trunk is on your side, you can claim 40 percent of the tree’s value, times three, if the neighbor removes it over your objection.

What this means in practice:

• Neither owner may remove a line tree without the other’s consent, even if most of the trunk is on their side.
• Either owner may still trim back encroaching branches on their own side under the self-help rule.
• If the tree is a genuine hazard and the neighbor refuses, the path is a written tree risk assessment from a TRAQ-qualified arborist, a written demand, and then court, not a chainsaw.
• A recorded survey settles where the line runs. Fence lines and old stakes often do not match the deed, and “I thought it was mine” only helps under RCW 64.12.040 if you had probable cause to think so.

When a tree falls on the neighbor’s property

Washington uses a knowledge standard. In Lewis v. Krussel two healthy hemlocks on the Krussels’ land fell in a December 1995 windstorm and damaged the house next door. The neighbors had complained that the trees swayed in the wind and other trees nearby had fallen before. The Court of Appeals affirmed judgment for the tree owners: a landowner in an urban or residential area has a duty only with “actual or constructive knowledge of defects affecting his trees,” and “absent such knowledge, an owner/possessor does not have a duty to remove healthy trees merely because the wind might knock them down.” A forester found no rot in the fallen tree, and swaying is not a defect.

The same case tells you what does create liability: a defect that is readily observable and a patent danger, or one the owner has been told about. A dead top, a fungal conk at the base, a lean that developed after root damage, or an arborist’s report naming the tree as high risk all put the owner on notice. Once on notice, the owner who does nothing can be liable for the damage the tree later causes.

Money usually comes from insurance before it comes from the neighbor. The Office of the Insurance Commissioner says your own homeowner policy can often be the one that pays for damage from a neighbor’s tree, with you paying the deductible, and that your insurer can pursue the neighbor’s insurer only if the fall was the neighbor’s fault, which “can be hard to prove.” The storm-damaged trees and homeowners insurance in Washington guide covers the claim process and the 5 percent debris-removal extension. For getting the tree off the roof, see fallen tree removal.

If you are the one worried about a neighbor’s tree, send a dated letter with photos describing the defect and asking them to have it assessed. That letter is the “knowledge” Lewis v. Krussel requires. Keep a copy.

Views and sunlight

There is no right to a view in Washington absent an express easement or a recorded covenant. In Collinson v. John L. Scott, Inc., Capitol Hill homeowners sued when two condominium buildings went up below their western view; the Court of Appeals held that a structure “cannot be complained of as a nuisance merely because it obstructs the view from neighboring property” and that an easement of light and air arises in this country only by grant. No statute or case extending a view right to a neighbor’s trees was found on the official sources checked, so the practical answer is the same: a neighbor’s tree that blocks your view of Puget Sound is not, by itself, a legal wrong.

Seattle’s tree code (SMC 25.11) does not list view improvement as a reason to remove a regulated tree, and the city’s illegal-cutting page says removal for views is not permitted on park property. The one place view rights commonly exist is a homeowners association: many Puget Sound and Spokane-area CC&Rs include view-protection or height covenants that let the association require topping or removal. Read the recorded covenants before assuming either way, and remember that a covenant between you and the HOA does not override a city tree permit requirement.

Spite fences and spite hedges

RCW 7.40.030 allows an injunction to restrain the “malicious erection” of any structure “intended to spite, injure or annoy an adjoining proprietor,” and a mandatory injunction to compel its removal once built. The statute speaks of structures; whether a row of fast-growing Leyland cypress planted purely to blind a neighbor’s windows counts was not settled on any official source checked. The elements a court can look at are the intent, the lack of any benefit to the owner, and the harm to the neighbor, so a planting with a real screening purpose is unlikely to qualify.

Small claims and where to sue

Small claims court is the district court department for money claims only. Under RCW 12.40.010 the limit is $10,000 when the claim is brought by a natural person and $5,000 in all other cases, including claims by an LLC or a business. It is cheap and fast, but it cannot order a neighbor to remove a tree or stop cutting; injunctions and claims above the cap go to superior court, where treble-damage suits under RCW 64.12.030 are usually filed. Before either, counties and cities may fund dispute resolution centers under chapter 7.75 RCW, which offer voluntary mediation in an informal setting; most tree disputes that end in mediation end with a shared pruning bill.

Steps to take

1. Find the line. Pull the plat and any survey from the county recorder; if the tree is within a few feet of where you think the line is, order a survey before anyone cuts.
2. Document the tree. Dated photos of the trunk, the encroachment, and any defect; keep any letters from the neighbor.
3. Get a written risk assessment from an ISA TRAQ-qualified arborist if hazard is the issue. In Seattle, Shoreline and Redmond it is also the document the city wants for a hazard-tree exemption.
4. Check the permit rules. In Kirkland, topping that takes more than a quarter of the live crown counts as removal, and in Seattle, paid work that removes a tree 6 inches or more in trunk diameter or cuts live branches 4 inches and up must be done by a registered Tree Service Provider.
5. Write to the neighbor. State what you plan to do, or what you are asking them to do, and by when. Offer to split an arborist’s visit.
6. Trim to the line, nothing more. If the work needs to go past the line to save the tree, get written consent that names the tree and the cut.
7. Mediate, then sue. A dispute resolution center first; small claims up to $10,000 for money; superior court for an injunction or treble damages.

If a tree has already come down across the fence, the order is safety, insurer, photos, then the neighbor. The Washington tree services hub covers the next step for each situation.