What does an arborist look at during an inspection?

Structural condition, signs of decay and disease, lean and root stability, the state of any existing cables or braces, deadwood sitting over things that matter, and how close the tree is to anything a failure would damage. On a wooded property the assessment is weighted toward the trees with something underneath them.

I have just bought a wooded property. Where should I start?

With the trees closest to the house, the driveway and anywhere people park or sit — that is where a failure actually costs you something. What a first visit gives you is not a list of defects but an order of operations, so the work can be spread across several seasons instead of done all at once.

Is a tree that was struck by another tree still dangerous?

It should be assessed. Impact can crack a stem or tear a branch union in ways that are not obvious from the ground, and the second tree is the one people routinely forget after a storm. We have removed trees left standing and structurally compromised after a neighboring tree came down onto them.

When is the right time to have trees looked at?

Before storm season rather than after it, and before any construction, regrading or trenching inside the root zone. Interior decay and root damage are not visible from a driveway, and a tree in full leaf looks healthy right up until it is not.

Tree Inspection & Risk Assessment in Rockville, MD

About Our Tree Inspection & Risk Assessment Services

Most of the trees that come down on a house were showing something first. It is rarely dramatic: a large dead branch high in the crown, a crack running down the trunk, a fork where two stems press together with bark trapped in the union, soft wood and an open cavity at the base. An inspection is an ISA Certified Arborist walking the tree and the ground around it and telling you which of those things matter on your property and which ones do not.

Where the tree stands decides as much as the defect does. A dead top over a back lawn and the same dead top over a bedroom are not the same problem — one drops a limb into grass, the other drops it through a roof. So before recommending anything we look at what is underneath: the house, the driveway, the deck, the play set, the spot where a car sits every night. A defective tree over open lawn can often be left standing and watched. The identical tree over a walkway usually cannot.

Two different things get called an inspection, and it is worth knowing which one you need. A free on-site evaluation is a visit — an arborist looks at the tree, tells you what he sees, and quotes any work it needs. A formal written risk assessment is separate, billable work: a document setting out the tree’s condition, the risk it does or does not present, and the recommended treatment, in a form an insurance adjuster, a permit reviewer or a buyer’s agent will accept. The free visit is not that document. If the document is what you need, say so when you call and we will quote it.

When Homeowners Call Us For Tree Inspection & Risk Assessment

Large dead branches in the crown, or a whole dead top, standing over a house, driveway, deck or parking spot
A crack in the trunk or a main limb — particularly one running vertically, or one that has opened wider since you last looked at it
A fork where two stems press tightly together with bark trapped in the union, on a tree big enough to reach something
Soft or crumbling wood, an open cavity, or mushrooms and shelf fungus at the base or over a root
A lean that has changed — the tree is sitting at an angle it was not sitting at a year ago
Soil cracked, heaving or lifted on one side of the trunk, especially after high wind or a long wet stretch
An insurer, a buyer, an HOA or a neighbor asking for something in writing about a tree

Our Process

01

Free on-site evaluation

An ISA Certified Arborist comes out, walks the tree and the property around it, and tells you plainly what he sees. No charge for the visit, and no obligation to have work done afterward.

02

The tree, crown to root plate

Deadwood and broken limbs in the crown, cracks in the trunk and main limbs, forks with included bark, decay and cavities, and the root plate and the soil over it. From leaf drop through early spring this gets easier: deadwood, cracks and bad unions that summer foliage hides are obvious against a bare sky.

03

What the tree stands over

A defect only matters in relation to what it can hit and how often somebody is under it. We record the targets — roof, driveway, walkway, deck, play area, parked cars — because that is what turns the same crack into "monitor it" on one property and "take it down" on the next.

04

Written risk assessment, on request

If you need it in writing, that is a separate billable piece of work and we quote it up front. The report sets out the tree’s condition, the risk it does or does not present, and the recommended treatment, in a document an insurer, an HOA, a permit reviewer or a buyer will accept. Ask for it when you call.

Why Hire Rock Creek for Tree Inspection & Risk Assessment

ISA Certified Arborist on site — John Ritz Miller, Jr.
Maryland Licensed Tree Expert #1944
Fully insured — workers comp + liability + auto
We will tell you when a tree is sound and needs nothing done to it
Written risk assessments for insurers, buyers, HOAs and permit applications, available on request
If work is needed, our own crews do it — no handoff to a subcontractor

Service Area

We provide tree inspection & risk assessment services throughout Montgomery County, Maryland and into Northern Virginia — including Arlington, VA, Aspen Hill, MD, Bethesda, MD, Brookeville, MD, Cabin John, MD, Chevy Chase, MD, Columbia, MD, Damascus, MD and more.

How we decide the approach

Two trees the same height can need completely different methods. This is what the arborist is weighing when they walk your property.

Consequence before probability

A hazardous tree is one where failure is both plausible and would matter. Both halves count. A decayed tree at the back of a wooded lot with nothing under it is a monitoring job; the same tree over a bedroom is urgent. So the assessment starts with what sits underneath — the house, the drive, the deck, where people park and sit — and works back to the tree.

What gets looked at

Structural condition and architecture, signs of decay and disease, lean and root stability, soil heaving or cracking at the base, the state of any existing cables or braces, deadwood over targets, and species-specific problems. On a wooded property the assessment is weighted toward the trees with something beneath them rather than spread evenly across the lot.

What an inspection can and cannot see

A great deal is readable from outside: fruiting bodies, cavities, bark condition, canopy dieback, how the trunk sounds. What is not readable is the exact extent of internal decay, and extent matters more than presence — many trees live for decades with substantial hollowing. Where the picture is unclear and the consequences of failure are high, further investigation may be warranted.

The tree that was hit is the one people forget

After a storm, attention goes to the tree that came down. The tree it struck on the way is routinely left standing and routinely compromised — impact can crack a stem or tear a union invisibly. On a Bethesda job this September half a white oak went into a house because a red oak hit it; the standing half had to be dismantled too.

What happens with the findings

Where risk can be reduced without removal we say so — crown reduction to cut sail area and leverage, cabling to support a weak union, targeted removal of the one problem limb. Removal is the recommendation when the risk cannot be brought down any other way. On a wooded property you get an order of operations rather than a list, so work can be spread across seasons.

What your estimate includes

A free on-site visit from an ISA Certified Arborist
A walk of the property with you, weighted toward trees near the house and drive
What we see on each tree, in plain terms, and what it means
A priority order — what is urgent, what can be budgeted, what is worth monitoring
Where risk can be reduced without removal, the alternative explained
A quote for any work that is recommended
A formal written risk assessment is separate, billable work, quoted on request

Request a free estimate

Tree Inspection & Risk Assessment on real properties

Tree Inspection & Risk Assessment guides from our team

Tree Inspection & Risk Assessment Services — common questions

What does an arborist look at during an inspection?: Structural condition, signs of decay and disease, lean and root stability, the state of any existing cables or braces, deadwood sitting over things that matter, and how close the tree is to anything a failure would damage. On a wooded property the assessment is weighted toward the trees with something underneath them.
I have just bought a wooded property. Where should I start?: With the trees closest to the house, the driveway and anywhere people park or sit — that is where a failure actually costs you something. What a first visit gives you is not a list of defects but an order of operations, so the work can be spread across several seasons instead of done all at once.
Can you tell if a tree is hollow or decayed inside?: Often, from external indicators: fungal fruiting bodies, cavities, sounding the trunk, bark condition and canopy dieback. Extent matters more than presence — many trees live for decades with substantial internal decay. Where the picture is unclear or the consequences of failure are high, further investigation may be warranted.
Is a tree that was struck by another tree still dangerous?: It should be assessed. Impact can crack a stem or tear a branch union in ways that are not obvious from the ground, and the second tree is the one people routinely forget after a storm. We have removed trees left standing and structurally compromised after a neighboring tree came down onto them.
When is the right time to have trees looked at?: Before storm season rather than after it, and before any construction, regrading or trenching inside the root zone. Interior decay and root damage are not visible from a driveway, and a tree in full leaf looks healthy right up until it is not.

Tree Inspection & Risk Assessment in Montgomery County, MD