Trees rarely fail without warning. Most of the time the signs are visible months or years ahead, if you know what to look for. A walk around your property twice a year, once with leaves on and once in winter, will catch most problems early.
Here's what to look for.
Dead branches and hangers
Dead limbs have no leaves in season, bark that's peeling or missing, and wood that looks gray and dry. They're usually the first thing to fall in wind. A broken limb still caught in the canopy, called a hanger, can drop at any time. Keep people and pets out from under it until it's taken down.
Cracks and splits
Look for cracks running into the trunk or down from a fork. A crack that goes deep into the wood, or that you can see light through, is serious. So is a crack that appeared after a storm.
Weak forks
When a tree has two or more trunks of similar size growing from the same point, the union between them can be weak, especially if it's a tight V shape with bark pinched inside. Those forks can split apart under the weight of ice or in high wind. Bradford pears are notorious for this, but many species do it.
Decay and fungus
Mushrooms or shelf-shaped conks growing on the trunk or at the base are the visible part of decay inside the tree. Other signs include large cavities, soft or crumbly wood, sap or dark staining oozing from the bark, and carpenter ants moving in and out of the trunk. Decay low on the trunk or in the root flare matters most, because that's where the tree carries the most load.
A lean that changes
A tree that has always leaned is usually fine. A tree whose lean is new, or getting worse, is not. Check the ground on the side away from the lean. Raised, cracked, or mounded soil means the roots on that side may be pulling up.
Root problems
Roots are easy to forget because you can't see most of them. Watch for:
- Roots cut or crushed by trenching, a new driveway, or construction.
- Fill dirt piled over the root zone, which can smother roots.
- Mushrooms growing from the roots or around the base.
- Roots lifting out of the ground on one side.
A thinning or dying canopy
Branches dying back from the top, leaves that are smaller or sparser than they used to be, or fall color showing up in midsummer can all mean a tree is in decline. Decline from construction damage can take several years to show.
Pests common in East Tennessee
A few insects have killed large numbers of trees in this region:
- Emerald ash borer kills ash trees. Look for thinning canopies, small D-shaped exit holes in the bark, bark split open over tunnels, and heavy woodpecker activity. Dead ash becomes brittle quickly.
- Hemlock woolly adelgid kills eastern hemlocks. Look for small white, cottony tufts on the underside of twigs at the base of the needles, especially from late fall through spring.
- Pine bark beetles attack stressed pines. Look for small globs of resin on the trunk, fine sawdust in bark crevices or at the base, and needles turning yellow, then red, from the top down.
What it would hit
A tree with a problem is only a hazard if it can hit something. When you find a warning sign, look at what's in range: the house, a driveway, a play set, a fence, a power line, a road. A declining tree at the back of the woods can often be left alone. The same tree beside the driveway can't.
What to do if you see these signs
- Take photos so you can compare them over time.
- Keep people and vehicles out from under anything that looks ready to fail.
- Don't climb into a tree with cracks, decay, or hangers.
- Get it looked at. We'll give you an honest opinion and a price if something needs to come out. For a formal written risk assessment, look for an ISA Certified Arborist with the Tree Risk Assessment Qualification.
If a tree near your house has any of these signs, send us photos. If it's actively failing or already on something, see emergency tree service.
