How to Tell if a Tree Is Dangerous

Most hazard trees give warning signs long before they fail. The trick is knowing where to look and what actually matters. Walk your tree from the ground up, in that order — most serious defects are visible from a slow lap around the base.

At the base

• Soil heaved, cracked, or lifted on one side of the trunk — this means the root plate is moving.
• Mushrooms or shelf-like conks growing from the roots or trunk — decay fungi already inside.
• Exposed, rotted, or cut roots, especially after construction or a storm.
• A trunk that goes straight into the soil like a telephone pole — the root flare is buried, which shortens tree life significantly.

On the trunk

• A new lean (any lean that wasn't there a year ago) — much more concerning than an old, stable lean.
• Vertical cracks or seams that open when the tree moves in wind.
• Large cavities or hollows, especially combined with a lean or a target below.
• Tight V-shaped forks with included bark — common failure points.

In the canopy

• Dead limbs larger than 2 inches — small deadwood is normal, big deadwood is a hazard.
• Hanging or broken limbs caught in the branches ("widow-makers").
• More than 30–50% of the canopy dead or bare in the growing season.
• Sudden thinning compared to previous years.

What to do if you see two or more of these

Photograph the base, trunk, and canopy from several angles. Note when things started changing. Keep foot traffic and parked vehicles out of the fall zone. Then get an ISA-certified arborist to walk the tree — typically $75–$200 for a written assessment and easily the best money you can spend before hurricane season.