Is That Tree a Storm Risk? How to Tell

How do I know if a tree is at risk of falling during a storm?

You know a tree is at risk when you can see a structural defect, a root problem, or a change in how it leans, and those signs matter more than the species or the size of the tree. A big tree with none of those signs is usually a smaller concern than a medium tree with a cracked trunk or a heaving root plate.

Stand where you can see the whole tree, not just the part hanging over the roof. The ground around the base tells you as much as the canopy does. A storm does not create weakness in a tree; it loads the weakness that is already there. Your job before the wind arrives is to find what is already compromised.

• Look for cracks, seams, or hollow spots on the trunk.
• Check the root zone for mushrooms, soft ground, or a raised mound.
• Compare the lean now to what you remember from last year.
• Note dead limbs that are still attached, especially high ones.

Which defects mean the tree is likely to fail?

A trunk crack, a hollow, a conk or mushroom at the base, and a root plate that has lifted are the defects most likely to lead to failure in a storm. Any one of those on a tree within reach of a house, a driveway, or a power line is worth an on-site look.

A crack that runs vertically and opens when the wind blows is a trunk that is already splitting. A hollow is harder to judge from the ground because the tree can look solid while the inside is gone. Conks and mushrooms at the base usually mean decay inside the root or lower trunk, and that is the part that holds the tree up.

A root plate that has lifted shows as a mound of soil on one side of the trunk and a depression or crack in the ground on the other. That tree has already started to move. It does not need a big storm to finish the job.

What does the root zone tell me?

The root zone tells you whether the tree still has the anchorage to stand up to wind. Roots spread wider than the canopy in most species, and the fine roots that hold the soil are in the top foot or so. Anything that damages that layer cuts the tree's grip.

Construction, paving, trenching for a utility, and repeated traffic over the root zone all compact the soil and sever roots. A tree that was fine for decades can become a risk two or three years after a driveway is poured over its roots. The decline is slow, and the failure is sudden.

Look for soil that stays wet long after rain, a side of the tree where the grass has died, or a new hump near the base. Those are signs the root system is changing.

How do I check a tree from the ground without climbing it?

You check from the ground by walking a full circle around the tree and looking up through the canopy from several angles. Binoculars help with the upper limbs. You are looking for dead wood, cracks, and anything that has changed since the last time you looked.

Start at the base and work up. Look for splits in the trunk, seams where bark has pushed out, and holes that could be decay. Then step back and look at the whole crown. A crown that is thinner on one side, or that has dieback at the tips, can point to a root or trunk problem on that side.

Check the lean against a fixed reference, like a fence post or the corner of the house. If the lean has increased, even a little, that is a change worth acting on. Take a photo now so you have something to compare next season.

When is a leaning tree an emergency?

A leaning tree is an emergency when the lean is new, when the ground at the base has lifted, or when the tree is leaning toward a structure that people use. A tree that has leaned for years without moving is a different case from one that changed after the last storm.

• Watch: a slight lean that has not changed, dead limbs in the upper canopy, or a small crack that does not open in wind.
• Soon: a lean that has increased, mushrooms at the base, a hollow you can see, or large dead limbs over a roof or driveway.
• Now: a new lean, a lifted root plate, a crack that opens in the wind, or a tree resting against another tree or a structure.

If the tree is already touching a structure or a wire, keep people away from it and call for help. Do not try to cut it yourself. A tree under tension can move in ways that are hard to predict, and the loads are much higher than they look.

What should I do before the storm arrives?

Before the storm, move anything you can out from under the tree, note which trees have defects, and decide which ones you will not park under or sleep under. You cannot make a risky tree safe by watching it, but you can reduce what it can hit.

Park vehicles away from trees with dead limbs or cracks. Keep the area under a suspect tree clear of people and pets. If you have a tree that has already dropped limbs, treat the rest of that tree as suspect too, because the same defect often shows up in more than one place.

Take photos of the tree and the ground around it. If you call for an assessment, those photos help show what has changed and when.

What does removal of a risky tree involve?

Removal of a risky tree involves taking the tree down in sections rather than felling it whole, because a tree with a defect cannot be trusted to fall where it is aimed. The work is slower and more controlled than a straightforward fell.

A climber or a lift is used to reach the upper limbs, and each section is lowered with rigging rather than dropped. The trunk is cut in pieces from the top down. The ground crew controls the rope so the pieces do not swing into the house, the fence, or the wires.

The stump is usually cut close to the ground. Grinding the stump is a separate step, and whether it is needed depends on what you plan to do with the space. The debris is hauled away, and the site is left clear.

The cost depends on the height, the lean, how close the tree is to a structure, whether power lines are involved, and how much of the tree has to be rigged rather than dropped. Those are the things to ask about when you request an estimate, because the number itself needs an on-site look.

What should I ask before anyone starts work?

Ask how the tree will be taken down, where the pieces will land, and who is responsible for the wires if the tree is near them. Ask what happens to the stump and the debris. Ask for the scope in writing, including what is not included.

Ask what the plan is if the tree is more compromised than it looked from the ground. A tree with a hidden hollow can behave differently once the first cuts are made. Ask how that changes the work and the price.

Ask about the root zone and the lawn. Heavy equipment can damage the ground, and a plan for mats or a different approach may be needed. These are the details that separate a smooth job from a repair bill.