Hazard Trees

What is hazard tree management?

Tree hazard is the likelihood of property damage or personal injury from tree failure. It is important primarily in developed areas with trees:

  • landscaping around homes, other buildings
  • street trees
  • urban parks
  • campgrounds and other developed recreation sites
  • railroad and highway rights of way
  • utility rights of way

Hazard incorporates not just the condition of the tree, but also the potential target. So hazard is:

  • potential for tree failure, plus
  • potential for serious loss should the tree fail, which includes:
    • potential for hitting and damaging target
    • value of target

Hazard tree management is reduction of hazard through inspection and mitigation, balancing level of hazard against the desire to maintain large, beautiful trees on the site.

Legal issues

Hi! I’m not a lawyer, though I’ve talked to a few of them. This information is provided for general education but has not been checked by a lawyer and should not be considered legal advice, nor should it be relied upon in making management decisions.

Traditionally, you have three levels of responsibility to people who visit your property:

  1. Trespasser: enters without special consent or privilege, without payment or license. Not necessarily illegal. We owe them lowest duty of care, essentially just to not set traps.
  2. Licensee: Has permission or consent, express or implied, to go on land for own purpose. Applies in general to visitors to public land.
  3. Invitee: Someone who pays a fee or is otherwise specifically invited for recreation or business purposes. Highest duty of care, must assure reasonable care has been used to prepare premises and make them safe for user. Must inspect and then remove or warn of known hazards, generally exercising reasonable care to protect user.

Now the standard for invitee pretty much applies to all visitors. Now most states are using a “prudent-man” test for the duty of reasonable care owed to people who enter. What would a prudent person do?

Property owners have a general duty to visitors to use reasonable care to keep the premises safe and to guard or warn the visitor from any hidden danger or defect that is discoverable using due care (such as inspection by qualified hazard tree inspectors) and presents a reasonably foreseeable risk of harm.


If owners do not comply with their duty, they may be liable for resulting damages. Lawsuits up to $60,000,000 for serious injury or death are not uncommon. A property owner is negligent and liable if a claimant can prove that:

  1. The owner had a legal duty to the claimant; and
  2. The owner breached his duty; and
  3. The owner’s breach was the legal cause of the claimant’s injury or property damage.

The Federal government has no sovereign immunity that exempts it from such lawsuits. The Federal Tort Claims Act (28 U.S.C 1346(b), 2671 et seq.) waives sovereign immunity. Federal employees are not individually liable except when acting outside the scope of their employment according to the Federal Employees Liability Reform and Tort Compensation Act of 1988 (the Westfall Act).

In a court case involving tree failure, two fundamental questions come up:

  1. Was the manager negligent? Was there an inspection system? Was it prudent and performed to customary standards? Was it documented?
  2. Was this particular tree inspected? Documented? Could the cause for failure have been detected in a reasonable and prudent inspection?

“Act of God” is not as good a defense as you might think. The same questions will be asked, and if there was detectable defect and no/poor inspection, the manager may still be held liable.

More about hazard trees on forestpathology.org