How to Tell if a Leaning Tree Is Dangerous

The short answer: a leaning tree is dangerous enough to remove when the lean is new, the ground around the base is lifting, or the trunk is cracked or hollow.

A leaning tree is dangerous enough to remove when the lean is new, the ground around the base is lifting, or the trunk is cracked or hollow. A tree that has leaned at the same angle for years, with a full crown and solid wood at the base, is usually stable. The danger comes from change: a lean that appeared after a storm, soil that has begun to mound on one side of the trunk, or a crack you can see. Those are the signs that mean the tree may fail, not just lean.

In Evansville, the calls we get about leaning trees usually follow a wind event, a wet spring, or a summer storm that left the ground soft. The tree may have been leaning for a decade, but the homeowner noticed it only after the storm. That is why the first question is not “how far is it leaning” but “has this lean changed.”

How do I know if the lean is new or old?

Look at the soil at the base of the trunk. If the lean is new, you will often see a mound of soil pushed up on the side opposite the lean, or a crack in the ground radiating out from the trunk. That mound is the root plate lifting. An old lean does not have fresh soil movement; the ground around the base is settled and may be covered with grass or mulch that has not been disturbed.

Check the trunk for reaction wood. A tree that has leaned gradually for years grows what is called reaction wood on the underside of the lean, making that side of the trunk wider. You can see it as a bulge or a difference in bark texture. A new lean does not have that bulge yet.

Look up. A tree that has leaned for a long time will have a crown that has grown back toward vertical, with branches on the lean side reaching up. A tree that just started leaning will have a crown that is still tilted with the trunk.

If you are not sure, take a photo now and compare it in a month. A lean that has moved even a few inches in that time is a change you can measure. That is the kind of lean that needs a removal decision, not a wait-and-see.

Three signs that mean removal, not waiting

Remove the tree if you see any of these three signs. They are the ones that tell you the tree is already failing, not just tilted.

• 1 Soil lifting or cracking at the base. When the root plate is moving, the ground on the tension side of the lean will lift or crack. This is the most reliable sign that the tree is not stable. If you can see a gap between the soil and the trunk, or a crack that was not there before, the tree is a removal candidate.
• 2 A crack, hollow, or split in the trunk. A vertical crack in the trunk, especially one that goes deep into the wood, means the tree has lost strength. A hollow trunk is even worse: the outer shell may be holding up a tree that has no core. You cannot fix a cracked trunk. You remove it.
• 3 Roots exposed or cut on the lean side. If the lean is toward a side where roots have been cut by construction, trenching, or erosion, the tree has lost its anchor. A tree that leans toward a cut root is far more likely to fall than one that leans away from its root mass.

If none of those three are present, the tree may still be a risk if it is large and leaning toward a house, a driveway, or a power line. In that case, the decision is about what the tree would hit, not just whether it is stable.

What the tree would hit matters as much as the lean

A tree that leans 15 degrees toward an open field is not the same as a tree that leans 5 degrees toward a bedroom. The target decides the urgency. If the tree would hit a structure, a vehicle, or a person when it falls, the risk is higher even if the lean looks minor.

Measure the distance from the base of the tree to the target. Then estimate the height of the tree. If the tree is taller than the distance to the target, it can reach it. A tree that is 60 feet tall and 40 feet from a house can hit that house if it falls in that direction.

Look at what is between the tree and the target. A fence or a shed may take the hit instead of the house, but that is still a loss. A power line is a different category: if the tree is leaning toward a line, do not touch it. Call the utility first.

If the tree can reach something you care about, the lean is not the only question; the target is.

What to do before you call

Before you call, do three things: take photos, note the direction of the lean, and check the ground at the base. Photos from two angles help us see what you see. Note whether the lean is toward a structure or away from it. Check for soil movement, cracks, or mushrooms at the base.

Do not try to pull the tree straight or cut it yourself. A leaning tree under tension can kick back when cut. The trunk may be holding stored energy that releases when the wood is cut. That is a job for a crew with the right equipment and the experience to read the load.

When you call, we will ask about the lean, the target, and what you have seen. From there, we can tell you whether the tree needs to come down now or whether it can wait. If it needs to come down, we will explain how we plan to do it: whether we can drop it in place, whether we need to rig it down in sections, or whether a crane is the safer choice.

If you are in Evansville and you have a leaning tree that worries you, call us at (812) 555-0123. We will talk through what you are seeing and help you decide.