7 Signs a Tree Is Dangerous

Most trees that fail gave warning signs long before they came down - people just did not know what they were looking at. A hazardous tree does not usually fall out of a clear sky; it declines, cracks, leans, or dies in ways you can learn to spot. Knowing the seven big warning signs lets you tell the difference between a tree that needs watching and one that needs a professional now, before it lands on your house or your family. When in doubt, a qualified local pro should take a look, because some of these signs are far more urgent than they appear.

1. A sudden or worsening lean

Many trees lean a little and always have - that is usually fine. What is dangerous is a new lean, or one that is getting worse, especially if the soil on one side is cracking or lifting. That combination often means the roots are letting go. A tree that has recently tilted toward your house should be treated as urgent.

2. Cracks in the trunk or major limbs

A deep crack running down the trunk, or through the union where two big stems meet, is a structural red flag. Trees carry enormous loads, and a significant crack means the tree may split under wind or its own weight. Vertical cracks and open seams are the ones to worry about most.

3. Large dead limbs

Big dead branches - sometimes called "widowmakers" for good reason - can drop with no warning at all, in no wind. If you see large bare limbs with no leaves during the growing season, or branches with peeling bark and no buds, that deadwood is a falling hazard, especially over a driveway, deck, or play area.

4. A dead or dying tree

An entirely dead tree is one of the clearest hazards there is. Dead wood grows brittle and unpredictable, and the whole tree becomes a question of when, not if.

• Across the Midwest and Northeast, the emerald ash borer has killed millions of ash trees, and dead ash is notorious for failing fast - it becomes brittle and drops limbs or snaps sooner than most species.
• In Texas, oak wilt can kill a large live oak within a season, leaving a big dead tree close to homes.
• In the West, drought has left standing dead trees across many regions that pose serious risk near houses.

A dead tree over a target should be assessed promptly.

5. Root problems and soil heave

The roots you cannot see hold the whole tree up. Warning signs at the base include:

• Soil lifting or mounding on one side of the trunk
• Severed or damaged roots from recent digging, trenching, or construction
• Ground cracking in an arc around the base

Root failure is especially dangerous because it can bring down an otherwise healthy-looking tree all at once.

6. Fungus at the base

Mushrooms or shelf-like fungal growth on the trunk or around the roots often signal internal decay. The tree may look full and green on top while the wood inside or below is rotting. Fungus at the base of a large tree is worth a professional look, because it can mean the structural core is compromised in ways you cannot see from outside.

7. Storm damage and hanging limbs

After a storm, a tree can look upright and still be badly compromised - split branches caught in the canopy, cracked unions, or partially uprooted with a slight new lean.

• In the Southeast, hurricanes leave tall southern pines and palms with hidden cracks and hangers.
• In the Mountain West, heavy wet spring snow splits cottonwoods and leaves branches lodged overhead.

Anything hanging in the canopy is a serious drop hazard and should not be left.

Which signs mean call now

Some signs mean watch and plan; others mean act. Treat these as urgent:

• A new lean with soil heaving
• A major trunk crack
• Large dead limbs or a dead tree over a house or where people gather
• Hanging limbs after a storm

The rest still deserve a professional assessment, just perhaps not the same day.

The trouble is that the most dangerous defects - internal decay, root failure, a compromised union - are exactly the ones hardest to judge from the ground. If your tree shows any of these signs, the safe move is to get expert eyes on it. Compare free quotes from vetted local tree services and have a licensed local pro assess the risk and tell you honestly what your tree needs.