Hazard Tree Assessment

What is a Hazard Tree?

A tree is considered hazardous when it has a structural defect that predisposes it to failure and the tree is located near a target.

  • A target is an area where personal injury or property damage could occur if the tree, or a portion of the tree fails.
  • Targets include sidewalks, walkways, roads, vehicles, structures, campsites, playgrounds or any other area where people are likely to gather.
  • Structurally sound and healthy trees may also be hazardous if they interfere with utilities, roadways, walkways, raise sidewalks or obstruct motorist vision.
  • Common hazards include dead trees, dead branches, stubs from topping cuts, broken branches (hangers), multiple leaders, tight angled crotches and an unbalanced crown.

Hazardous Situations

  1. When a tree is in poor health and dying, we call it in “decline”.
  2. A dead, dying or diseased tree can be an extreme hazard, no matter where it is located.
  3. Some trees will never recuperate from the combined stresses placed on them, but will take months, even years to become fully dead. There comes a time when, no matter what you do, the tree will die, so being aware of the tell-tale signs of insect damage, diseases and decline will save you the risk of having a hazard tree in a public place.
  4. Catching the signs early may prevent the loss of a valuable specimen.
  5. Healthy trees are flexible and limber in storms, however, sick trees are much more brittle and limbs will snap and break with the wind instead of swaying with it. These limbs will snap, as might the entire tree, causing property damage, personal injury and possibly a cut in service.


Property owners / managers have a legal obligation to (1) periodically inspect trees for unsafe conditions, (2) correct unsafe conditions immediately upon detection or (3) contact the proper authority immediately upon detection.