Arborist Reports & Tree Risk Assessments in Sammamish, WA

MTS Tree & Landscape provides arborist reports and tree risk assessments in Sammamish for tree-removal permits, unhealthy and hazardous trees, property evaluations, HOA requests, and construction planning.

Sammamish does not use the same documentation for every tree. An unhealthy tree generally requires an arborist report. A hazardous tree requires an ISA Basic Tree Risk Assessment Form prepared by a TRAQ-qualified professional. If a tree is clearly dead, the City allows photo evidence instead of the unhealthy-tree arborist report.

Our arborist consultations in Sammamish can be scoped around the exact decision or City requirement in front of you.

Call (425) 369-8733 or request an arborist-report quote.

Which Sammamish Tree-Removal Documentation Path Applies to Your Tree?

For a healthy significant tree, Sammamish requires a Tree Removal Permit but does not automatically require an arborist report. An unhealthy tree requires an arborist report unless it is clearly dead. A hazardous tree requires a TRAQ-based risk assessment. An imminent-threat removal is documented after the emergency with evidence of the threat.

That distinction matters because ordering the wrong document can add work without solving the permit issue.

The City’s Sammamish tree-removal permit requirements are the best starting point if you are not sure which path applies.

When Does Sammamish Require an Arborist Report or TRAQ Form?

Sammamish currently requires an arborist report for an unhealthy tree and an ISA Basic Tree Risk Assessment Form for a hazardous tree. The hazardous-tree form must be prepared by a professional with the ISA Tree Risk Assessment Qualification.

The City’s February 2026 Tree Removal Permit application separates the two cases clearly.

Unhealthy Trees

For an unhealthy tree, the City requires an arborist report prepared by an ISA professional arborist.

There is one useful exception:

If the tree is clearly dead, the City allows a photograph saved as a PDF to be submitted instead of the arborist report.

That means a dead tree and an unhealthy living tree should not automatically be sent down the same documentation path.

Hazardous Trees

For a hazardous tree, the City requires an ISA Basic Tree Risk Assessment Form prepared by a professional with the ISA Tree Risk Assessment Qualification.

The City can review that assessment and then request a separate arborist report from an ISA Certified Arborist if additional information is needed.

Sammamish also reserves the right to send a submitted risk assessment or arborist report to its on-call contract arborist for peer review. The applicant is responsible for the cost of that peer review.

You can review the City’s current 2026 Tree Removal Permit application before scheduling the assessment.

What Does the Arborist Examine Before Writing the Report?

For a permit or tree-risk report, the arborist documents the tree’s condition, the specific defect or concern, potential failure points, nearby targets, and whether pruning, monitoring, mitigation, or removal is justified.

The inspection may include:

• Species
• Diameter at breast height, or DBH
• Crown condition
• Dead or broken branches
• Trunk structure
• Branch unions
• Cracks and cavities
• Visible decay indicators
• Root flare
• Visible root damage or movement
• Previous branch or trunk failures
• Changes to grade, drainage, or the surrounding site
• Nearby houses, roads, driveways, walkways, and other targets
• The part of the tree that could fail
• Likelihood and potential consequences of failure

A visible defect is not the same thing as a final risk conclusion.

A tree can lean without being unstable. A fungal fruiting body can indicate decay without telling you, by itself, how much structural strength remains. A cavity, dead limb, or crack needs to be considered in the context of the entire tree and what could be affected if failure occurs.

For broader diagnosis that is not primarily driven by a municipal permit, MTS also provides professional tree health assessments.

What Will Be in Your Written Arborist Report?

A professional arborist report should identify the tree, document the condition being evaluated, explain the arborist’s findings, provide supporting evidence, and give a clear recommendation. Permit reports should also include the credentials and information Sammamish needs to review the case.

Depending on the assignment, the report may contain:

• Property or site information
• Tree number or location
• Species
• DBH
• Crown and foliage condition
• Trunk and branch observations
• Visible root conditions
• Structural defects
• Photographs
• Nearby targets
• Assessment methodology
• Risk findings when risk is being formally evaluated
• Mitigation options
• Pruning, monitoring, retention, or removal recommendation
• Arborist credentials
• Report date and signature

A permit report should be written for the actual permit question.

A generic statement that a tree is “unhealthy” is much less useful than documentation that identifies the observed condition, explains its significance, and supports the recommended next step.

The report also does not grant permission to remove the tree. It gives the City professional evidence to review.

How Much Does an Arborist Report Cost in Sammamish?

MTS currently lists $200–$400 for a single-tree written report and $250–$500 for a single-tree TRAQ risk assessment. Full-property written reports are listed at $500–$1,000+, while pre-construction tree assessments run $500–$2,000+ based on scope.

These are MTS regional service prices, not independent Sammamish market averages.

The main cost drivers are:

• Number of trees
• Verbal consultation vs. written report
• Formal TRAQ requirements
• Amount of photography and documentation
• Tree inventory or mapping
• Construction-plan review
• Site access
• Advanced diagnostic work, if needed

A written report for one unhealthy backyard tree is a much smaller assignment than evaluating dozens of retained trees around a proposed construction site.

Request an exact report quote with the number of trees and the reason the assessment is being requested.

What Happens After the Arborist Report Is Finished?

For a Sammamish tree-removal permit, the applicant submits the application, site plan, and required tree documentation through MyBuildingPermit.com. The City currently says it screens submissions for acceptance within two business days and reviews accepted applications within five business days.

That does not mean every permit is finished within seven business days.

Missing documents, City questions, arborist peer review, critical-area issues, or other project complications can extend the process.

For a Tree Removal Permit

The current City process is:

1. Prepare the required permit form.
2. Prepare the site plan.
3. Add the required arborist report, TRAQ form, or photographs for the applicable tree category.
4. Upload the application through MyBuildingPermit.com.
5. Respond if the City requests additional information.
6. Receive the permit or approval letter through the portal once review is complete.

If removal is approved and you need the physical tree work, MTS also provides Sammamish tree removal services.

A Healthy Tree, an Unhealthy Tree, and a Hazardous Tree Are Not the Same Permit Case

Sammamish treats healthy, unhealthy, hazardous, and imminent-threat trees differently. A healthy tree is primarily a removal-limit and permit question. An unhealthy tree requires condition documentation. A hazardous tree requires formal risk documentation. An imminent-threat tree is reviewed as an emergency after the removal.

Healthy Significant Trees

For permit purposes, Sammamish currently defines:

• Significant coniferous tree: 8 inches DBH or larger
• Significant deciduous tree: 12 inches DBH or larger
• Heritage tree: 22 inches DBH or larger
• Landmark tree: 32 inches DBH or larger

A healthy significant tree normally requires a Tree Removal Permit.

It does not automatically require a risk assessment simply because the owner wants it removed.

Unhealthy Trees

An unhealthy tree requires an arborist report under the City’s current application.

If it is clearly dead, a photograph showing the condition may be submitted instead.

That distinction matters. A dead tree does not need a paid report simply to prove that it is obviously dead if the City’s photographic evidence requirement can be satisfied.

Hazardous Trees

A hazardous tree uses a different standard.

The applicant must hire a TRAQ-qualified professional to evaluate the tree and submit the ISA Basic Tree Risk Assessment Form. The City may request an additional arborist report after reviewing that form.

A homeowner’s concern that a tree might fall is therefore the start of the assessment, not the final risk determination.

Imminent-Threat Trees

An imminent threat is reserved for a true emergency where a significant tree may have caused serious or life-threatening injury or death.

The current City form allows the owner to document a removal that has already happened because of that emergency. There is no City fee for an imminent-threat removal, but City staff still review the evidence to determine whether the situation qualified.

If it does not qualify, the owner can be directed into a retroactive significant-tree permit and potentially code enforcement.

For an active tree failure that needs physical response now, use MTS’s Sammamish emergency tree service.

Does an Arborist Report Automatically Let You Remove the Tree?

No. An arborist report documents the tree’s condition or risk, but the City of Sammamish decides whether the proposed removal is allowed. Healthy significant trees are also subject to annual and 10-year removal limits based on lot size.

The City’s current limits are:

The City applies whichever applicable limit is lowest.

So even a professionally prepared report should not be described as a removal authorization.

Its job is to document the facts and professional opinion needed for the decision in front of the City, HOA, insurer, buyer, or other reviewing party.

What Changes for Street Trees, Critical Areas, or Construction?

Street trees, trees in critical areas, and trees affected by development follow additional Sammamish rules. Street trees use a Type B right-of-way permit, critical-area removals can trigger additional protection and mitigation requirements, and development sites cannot remove trees before the construction permit is issued.

Street and Right-of-Way Trees

A tree can be in the public right-of-way even when it looks like part of the front yard.

Sammamish requires a Type B Right-of-Way permit to remove and replace a street tree.

The City’s currently linked street-tree removal guidance calls for an arborist report documenting the tree’s condition and recommendation. It also says the arborist assisting with the permit should have ISA and TRAQ credentials unless the tree is visibly dead.

If you are unsure whether the tree is actually in the ROW, confirm the boundary before treating it as an ordinary private-yard tree.

Critical Areas and Buffers

Trees within critical areas and their buffers receive additional protection.

Current Sammamish critical-area code materials require hazard trees in these areas to be identified by a TRAQ ISA Certified Arborist before removal and include mitigation requirements intended to limit damage to the remaining vegetation and habitat.

This is not a good place to rely on a generic tree-removal rule.

If the tree is near a wetland, stream, steep slope, or other mapped critical area, confirm the parcel-specific City requirements before work starts.

Construction and Development

If development is proposed or anticipated, Sammamish states that trees cannot be removed before the associated construction permit has been issued.

Retained trees also need to be addressed in the site-protection plan.

The City’s current site construction protection requirements call for tree-protection fencing five feet beyond the canopy drip line and require the location of that fencing to be shown on the Site Protection Plan.

Construction-related arborist work can therefore include:

• Tree inventory
• Species and DBH documentation
• Condition assessment
• Retention and removal recommendations
• Construction-impact review
• Tree protection planning
• Arborist monitoring where required by the project

The useful time to do this work is before the grading, access, utilities, and building footprint are effectively locked in.

Can the Same Arborist Report Be Used for an HOA, Home Purchase, or Insurance Request?

Yes, but only when the report answers what the receiving party actually needs. An HOA may need justification for removal, a home buyer may need condition and future-work findings, and an insurer may request documentation tied to a particular tree, loss, or risk concern.

Before the inspection, ask the recipient for:

• The question they need the arborist to answer
• Any required form
• Credential requirements
• Whether photographs are needed
• Whether they need a formal risk rating
• Submission deadline

Then send those requirements to MTS before the visit.

HOA Documentation

A useful HOA report might document:

• Species and size
• Tree condition
• Visible defects
• Photographs
• Risk findings where relevant
• Recommended pruning or mitigation
• Professional basis for a removal recommendation

Do not assume an HOA wants the same report that Sammamish wants for a City permit.

Home Purchase

A pre-purchase inspection can help identify visible tree conditions and potentially significant work before closing.

That can be especially useful on a property with:

• Several mature trees
• Large trees within striking distance of the home
• Trees with visible defects
• Steep or wooded areas
• Planned construction or remodeling

The goal is not to guarantee the future of every tree. It is to give the buyer better information about the conditions that can be observed at the time of inspection.

Insurance Documentation

An insurer may ask for a written opinion concerning a particular tree or incident.

The arborist can document observed conditions and professional findings. The insurer still decides what documentation it accepts and what the policy covers.

Who Is Qualified to Prepare Sammamish Tree Documentation?

For an unhealthy-tree report, Sammamish requires an ISA professional arborist. For a hazardous-tree permit case, the City’s current application specifically requires a professional with the ISA Tree Risk Assessment Qualification to prepare the Basic Tree Risk Assessment Form.

ISA Certified Arborist

ISA Certified Arborist is a broad professional credential covering core arboricultural knowledge.

It is relevant for tree-condition reports, consulting, management recommendations, and many municipal documentation needs.

ISA Tree Risk Assessment Qualified

TRAQ is an additional qualification focused on systematic tree-risk assessment.

It is particularly relevant when the assignment needs a formal evaluation of:

• Likelihood of failure
• Likelihood of impact
• Potential consequences
• Overall risk
• Mitigation options

You can verify an ISA arborist credential through ISA’s public directory.

MTS states that its arborist consulting work includes ISA Certified Arborists and that TRAQ-qualified professionals are available for formal risk-assessment work.

Arborist Report & Tree Risk Assessment FAQ

Need an Arborist Report in Sammamish?

Tell MTS what prompted the report, how many trees are involved, and whether the City, HOA, insurer, buyer, or project team has already given you written requirements. That gives the arborist enough information to start scoping the correct assessment.

MTS Tree & Landscape provides written arborist reports, tree risk assessments, property evaluations, and pre-construction tree consulting in Sammamish.