Is My Tree Leaning Dangerously? How to Tell

How can I tell if my tree is leaning dangerously and might fall?

You can tell a leaning tree is dangerous when the lean is recent, the soil around the base is cracked or lifted, the trunk has a visible bulge or split near the ground, or the tree is a species with weak wood, and you can confirm these signs with a simple inspection you can do yourself.

Imagine you step outside and notice your maple now angles toward the house. It did not lean that way last spring. You wonder if it has always been that way or if the ground shifted. You want to know before a storm does the deciding for you. The answer is not to guess. You can learn to read the signs, and then you will know when to call for a professional opinion.

Here is the short version of what matters most:

• Check the soil at the base for cracks, heaving, or a visible root plate lifting.
• Look for a fresh lean: a tree that leaned for years may be fine, but a new lean is a red flag.
• Inspect the trunk for cracks, bulges, or fungal growth near the ground.
• If you see any of these, call a certified arborist or tree removal service for an on-site assessment.

What does a dangerous lean look like?

A dangerous lean is one that appears suddenly, worsens over time, or is accompanied by other structural defects. It is not the same as a tree that has grown at an angle for decades and shows no stress.

Some trees naturally grow toward the light, and their trunks curve or tilt. That is a normal shape, not a warning. A tree that has always leaned, with a trunk that has thickened to support the angle, can stand for many years. The problem is a lean that is new or getting worse. A lean that appears after a storm, after excavation near the roots, or after a period of heavy rain is more concerning because it suggests the root system has shifted or failed.

Look at the angle. A vertical tree is 0 degrees. A lean of 15 degrees or more is a reason for caution, especially if the tree is large. But the angle alone is not the whole story. A 10-degree lean with cracked soil is more dangerous than a 20-degree lean on solid ground. You judge the lean together with the condition of the roots and trunk.

What should I check at the base of the tree?

The most reliable warning signs are at the ground line, where the trunk meets the soil. Check for cracks in the soil on the side opposite the lean, a raised mound of soil on the leaning side, or roots that are visibly lifting out of the ground.

When a tree starts to tip, the root plate on the leaning side pulls upward, and the soil on the opposite side compresses and cracks. You may see a crescent-shaped crack that runs around part of the trunk. The crack can be narrow or several inches wide. If you can push a finger into it, the soil has already moved. A raised area of soil, sometimes with roots exposed, means the tree has begun to tilt. This is a serious sign, and you should not wait for a storm to act.

Another sign is a hollow sound when you knock on the trunk near the base. A healthy trunk sounds solid. A hollow sound can mean internal decay, which weakens the tree's ability to stay upright. You can also look for fungal growth, such as mushrooms or conks, on the trunk or at the root flare. Fungi often indicate decay inside the wood, and decayed wood is less able to hold the tree in place.

What should I look for on the trunk and branches?

On the trunk, look for cracks, splits, bulges, and areas where bark is missing. On the branches, look for dead wood, hanging limbs, or V-shaped forks that are prone to splitting.

A vertical crack that runs down the trunk is a structural weakness. It can open and close with the wind, and over time it can cause the trunk to fail. A bulge or swelling on one side of the trunk may indicate that the tree is trying to compensate for stress, but it can also hide internal decay. If you see a crack that extends into the ground or through the root flare, that is a serious warning.

Also check the canopy. Dead branches or a thinning crown can mean the tree is stressed, and a stressed tree is more likely to fail. Look for branches that cross or rub against each other, and for forks where two branches grow upward in a narrow V shape. These forks are weaker than wide U-shaped forks and are more likely to split under wind or ice. If you see any of these signs on a leaning tree, the risk increases.

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

Compare the tree to old photographs or your memory, and look at the soil and trunk for clues. A tree that has leaned for years will usually have a curved trunk or a thickened base that shows it has grown in that position. A new lean often has a straight trunk that angles abruptly, and the soil may be disturbed.

Look at the ground around the base. If the lean is new, you may see a gap between the soil and the trunk on the leaning side, or a crack on the opposite side. If the lean is old, the soil is usually settled and moss or grass may have grown right up to the trunk. The trunk itself may be curved, with the bend at the lower part of the tree, which indicates it has been growing that way for a long time.

If you have photos of the yard from previous years, compare them. If the tree appears to have shifted since the last photo, that is a new lean. If you cannot tell, err on the side of caution and have a professional look.

What about the soil and the weather?

Wet soil, recent excavation, and construction near the roots all increase the chance that a lean becomes dangerous.

Heavy rain can saturate the soil, making it softer and less able to hold the roots. If your area has had a wet spring or a series of storms, the ground may be looser than usual. A tree that leaned slightly after a storm may recover, but if the soil is still soft and the lean worsens, the risk is high.

Excavation, trenching, or paving within the root zone can cut the roots that anchor the tree. If you have done any digging near the tree, or if a neighbor has, that may have disturbed the root system. Even minor soil compaction from heavy equipment can reduce the tree's stability. If the lean appeared after any of these events, take it seriously.

When should I call a professional, and what should I ask?

Call a professional if you see any of the warning signs described above: a fresh lean, cracked or lifted soil, a crack or bulge on the trunk, or a hollow sound. Do not wait for a storm to decide for you.

When you call, ask specific questions. Ask whether the lean is a sign of root failure or just a natural growth pattern. Ask what the professional sees at the base of the tree and what the soil conditions are. Ask what the options are, from monitoring to cabling to removal. Ask for the assessment to be done on site, because a phone call or a photo cannot tell you the whole story.

If the tree is near your house, a driveway, or a power line, the risk is higher. A tree that falls in an open yard may be a nuisance, but a tree that falls on a roof can be dangerous and expensive. The decision to remove a tree is not one to make lightly, but it is also not one to delay when the signs are present.

What is the final step I can take today?

Walk around your tree and do the inspection described in this article. Write down what you see, and if you find any of the warning signs, call a tree removal service for an on-site evaluation.

You do not need to be an expert to notice a cracked soil line or a new lean. You just need to look. If you are unsure, a professional can tell you whether the tree is safe or needs to come down. The cost of an assessment is small compared to the cost of a tree falling on your house. And if the tree is healthy, you will have the peace of knowing it is safe. If it is not, you will have the chance to act before the weather does.

To reach a tree removal service in Des Moines, IA, call 515-555-1234. We will come out, look at the tree, and give you a straight answer about what it needs.