How to recognize dangerous trees ?

Trees are very beneficial to the environment, however, sometimes they may be dangerous. Trees or parts of trees may fall and cause injury to people or damage to property.
It is important to assess trees for risk. While every tree has the potential to fall, only a small number actually hit something or someone. There is no such thing as a completely “safe” tree.
It is an owner’s responsibility to provide for the safety of trees on his or her property. Here are some tips to identify the common defects associated with tree risk. Regular tree care will help identify trees with unacceptable levels of risk. Once the risk is identified, steps may be taken to reduce the likelihood of the tree falling and injuring someone.

Trees and Utility Lines. Trees that fall into utility lines have additional serious consequences. Not only can they injure people or property near the line, but hitting a line may cause power outages or surges, fires, and other damage. Downed lines still conducting electricity are especially dangerous.
A tree with the potential to fall into a utility line is a very serious situation.
Tree Risk Checklist
1. Are there large, dead branches in the tree?
2. Are there detached branches hanging in the tree?
3. Does the tree have cavities or rotten wood along the trunk or in major branches?
4. Are mushrooms present at the base of the tree?
5. Are there cracks or splits in the trunk or where branches are attached?
6. Have any branches fallen from the tree?
7. Have adjacent trees fallen over or died?
8. Has the trunk developed a strong lean?
9. Do many of the major branches arise from one point on the trunk?
10. Have the roots been broken off, injured, or damaged by lowering the soil level, installing pavement, repairing sidewalks, or digging trenches?
11. Has the site recently been changed by construction, raising the soil level, or installing lawns?
12. Have the leaves prematurely developed an unusual color or size?
13Have trees in adjacent wooded areas been removed?
14Has the tree been topped or otherwise heavily pruned?

Defects in Urban Trees
The following are defects or signs of possible defects in urban trees:
1. Regrowth from topping, line clearance, or other pruning
2. Electrical line adjacent to the tree
3. Broken or partially attached branches
4. Open cavity in trunk or branch
5. Dead or dying branches
6. Branches arising from a single point on the trunk
7. Decay and rot present in old wounds
8. Recent change in grade or soil level, or other construction


If you detect any of the above, make sure to contact your arborist!