Tree Health Assessment Guide: Most homeowners find out a tree was a hazard after it falls — not before. The gap between those two moments is almost always a proper tree health assessment, and most people have never seen one done. They picture someone glancing up at a tree from the driveway. That’s not what we do, and it’s not what actually catches the problems that turn into a 2 a.m. call after a storm.
I’m Alex Wright, owner of 855TREEMAN and a Maryland Licensed Tree Expert (LTE) #2123. This is the walk-through I actually use on a property — the same eight checkpoints, every time, whether it’s a routine health check or someone calling because a tree “just doesn’t look right.”
Why a proper assessment is different from a glance
A homeowner’s visual check catches the obvious stuff: a dead branch, an obvious lean, a trunk that looks off. What it misses is almost everything that actually predicts failure — root plate movement that hasn’t shown up in the canopy yet, included bark at a union that looks fine from the ground, early-stage decay hidden under healthy-looking bark. Tree risk assessment as an industry discipline exists precisely because canopy health and structural soundness are not the same thing, and a tree can look green and full while carrying a structural defect that has nothing to do with its leaves.
The framework the arboriculture industry uses for tree risk assessment evaluates a tree across several independent categories rather than one overall impression. That’s the structure behind what follows — not a checklist for its own sake, but eight places where problems actually hide.
Tree Health Assessment Guide – The eight things we check on every assessment
1. Root flare and root zone
We start at the base, not the top. A healthy root flare gradually widens where trunk meets soil. If it goes straight into the ground like a telephone pole, or if we see exposed girdling roots wrapping the trunk, that’s a structural red flag long before it shows up above ground. We also check for soil heaving near the base — a subtle sign the root plate has already started to shift.
2. Trunk condition
We walk the full circumference, not just the street-facing side. We’re looking for cracks (especially vertical seams that can indicate internal decay), cavities, old wounds that haven’t closed properly, fungal conks (mushroom-like growths that indicate active internal decay), and bark that’s sloughing off in patches rather than shedding naturally.
3. Major limb unions and included bark
Where two large limbs meet the trunk at a tight, V-shaped angle rather than a wide U-shape, bark can get pinched between them instead of forming solid wood — a condition called included bark. It’s one of the most common causes of limb failure in mature shade trees, and it’s almost invisible unless someone is specifically looking for it.
4. Canopy density and dieback pattern
We look at how dieback is distributed. Dieback scattered evenly through the crown often points to a stress factor — drought, root damage, soil compaction. Dieback concentrated on one side can point to root damage on that side, or a vascular disease like oak wilt moving through the tree’s water-conducting tissue. Where the dieback shows up changes what we recommend.
5. Deadwood size and location
Not all deadwood is equal. Small deadwood high in the canopy is often low-priority. Large deadwood over a driveway, roofline, or anywhere people or vehicles regularly sit is a different conversation entirely — that’s a target proximity issue, which we cover next.
6. Lean, and whether it’s old or new
A tree that has always grown at an angle and has compensating root and trunk growth to match is usually stable. A tree that has recently started leaning, especially if the soil around the base is cracked or lifted, is often actively failing. Distinguishing “always been that way” from “just started” is one of the most consequential judgment calls in an assessment.
7. Target proximity
The same defect on the same tree carries very different risk depending on what’s underneath it. A tree with a moderate defect over open field is a monitoring item. The identical defect over a house, driveway, power line, or a spot where kids play is a priority item. Risk assessment isn’t just about the tree — it’s about the tree relative to what it could hit.
8. Pest and disease signs specific to Maryland
We check for the pressures actually active in Southern Maryland right now: D-shaped exit holes and canopy dieback from emerald ash borer on ash trees, wilting and leaf browning consistent with oak wilt on oaks, and general insect and fungal pressure tracked by the Maryland DNR Forest Health Program. A pest issue caught early is often a treatment decision. Caught late, it’s a removal decision.
What happens after the assessment
An assessment isn’t a sales pitch for removal — most of the trees we assess don’t need to come down. After we walk the eight points above, a tree lands in one of four buckets:
- Monitor. No action needed now. We note what to watch and recommend a re-check timeline.
- Prune. Deadwood removal, crown thinning, or a structural reduction addresses the issue without removing the tree. This is where professional tree trimming and the seasonal timing in our pruning calendar guide come in.
- Support. Cabling or bracing at a weak union can extend a tree’s safe life significantly, particularly for trees with sentimental or landscape value that a homeowner wants to preserve if reasonably possible.
- Remove. Reserved for trees where the combination of defect severity and target proximity puts the risk past what pruning or support can fix. If it comes to this, we walk through the realistic cost range before any work is scheduled.
We put the findings in writing either way. If a tree is a genuine hazard, that written assessment is also the document county permitting offices and, in some cases, insurance adjusters want to see — particularly after storm damage, where a written pre- or post-storm assessment can support a storm damage claim.
How often should a healthy tree be assessed?
For mature shade trees with no known defects, we generally recommend a full assessment every 3 to 5 years. That interval shortens if any of the following apply:
- The tree is over a house, driveway, or frequently used outdoor space
- The property has had recent construction, grading, or trenching near the root zone
- The tree is a species currently under regional pest pressure (ash, oak)
- The area has recently had a significant storm with high wind
- The tree has any history of shedding large limbs without obvious cause
Young trees in their first 3 to 5 years benefit from more frequent, lighter check-ins focused on structural training rather than risk — catching a poor branch angle early is far easier than correcting it once the limb is load-bearing.
What you can check yourself between assessments
You don’t need to wait for a professional visit to notice a change. Between assessments, it’s worth glancing at:
- New cracks in the soil near the base, especially after wind
- Any new lean, or a lean that seems to have increased
- Mushroom-like growth at the base or on the trunk
- A sudden change in how much of the canopy has leaves compared to neighboring trees
- Large branches that have dropped without a storm to explain it
Any one of those is a reason to call for a look, not a reason to assume the worst on your own. Plenty of trees have a cosmetic issue that looks alarming and isn’t. The point of an assessment is separating those from the ones that actually are.
Get an assessment scheduled
If a tree on your property has you wondering — a new lean, deadwood you weren’t sure about, or it’s just been a while since anyone looked at it — call 855-873-3626 for a free on-site estimate. We’ll walk the eight points above on your tree specifically, tell you honestly which of the four buckets it falls into, and put it in writing.
FAQ
What does a licensed tree expert actually check during a tree health assessment?
A proper assessment covers eight areas: the root flare and root zone, trunk condition, major limb unions for included bark, canopy density and dieback pattern, deadwood size and location, whether any lean is old or new, target proximity (what’s underneath the tree), and pest or disease signs specific to the region. Each area can hide a problem the others wouldn’t catch.
How is a professional tree assessment different from just looking at my tree?
A homeowner’s visual check usually catches obvious issues like an obvious dead branch or a dramatic lean. It typically misses root plate movement, included bark at limb unions, and early-stage internal decay — all of which can exist on a tree that still looks green and healthy from a distance.
How often should I have my trees professionally assessed?
For mature, healthy shade trees with no known issues, every 3 to 5 years is a reasonable interval. That should shorten to yearly or after major events if the tree overhangs a structure, has had recent nearby construction, is a species under active regional pest pressure, or has any history of unexplained limb drop.
What happens if an assessment finds a problem with my tree?
Findings fall into one of four categories: monitor (no action needed now), prune (deadwood removal or structural reduction), support (cabling or bracing at a weak point), or remove (when defect severity and target proximity outweigh what pruning or support can address). We provide written findings either way.
Can a tree health assessment help with an insurance claim?
Yes, in many cases. A written assessment documenting a tree’s condition before or after storm damage can support a homeowner’s insurance claim by providing a professional, dated record of the tree’s structural state.
Do young trees need assessments too?
Yes, but for a different reason. Young trees in their first 3 to 5 years benefit from lighter, more frequent check-ins focused on structural training — correcting a poor branch angle while the limb is small is far easier and cheaper than addressing it once the branch is large and load-bearing.