Resource:Tree Hazards for Municipalities

Many municipalities have attractive grounds that include green lawns, landscaped areas and beautiful trees. Evaluating the location and health of trees, coupled with necessary pruning or removal, can help protect buildings, utilities and people who are in close proximity. 

It is not uncommon for municipalities to have multiple incidents from tree damage following storms. High winds, soft ground, freezing rain and heavy snow increase the potential that a tree or branches will fall.  Injury and damage from trees is often associated with the following:

  • Falling onto and injuring people
  • Structural damage to windows, walls and roofs of buildings
  • Ponding on roofs or building leaks caused by roof drains clogged by tree leaves/debris
  • Damage to rooftop equipment
  • Undermining the foundations of buildings
  • Upheaval of streets, driveways and sidewalks resulting in tripping hazards
  • Pulling down of electrical lines, which disrupts power distribution and possible electric contact accidents
  • Landing on vehicles or other outdoor equipment (i.e. fencing, bleachers, playgrounds)
  • Clogging of sewer and water system piping

Bradford Pear Trees

These genetically modified trees were introduced in the 1960’s by the U.S. Department of Agriculture. Because of their aesthetic appeal, towns and cities started placing them all over their land and bordering their streets. However, these trees were never field tested over a period of time or exposed to natural weather occurrences. Since planted, these trees have unfortunately caused many injuries, downed power lines and property damage. They grow in excess of 40 feet tall and they are scientifically proven to have the weakest branch structure in nature.  Though these pear trees were created by the federal government, they are now being removed from federal land. 

Suggested Ways to Reduce Tree Hazards

Carefully selecting tree type and location – Trees within existing developed communities are often exposed to human and natural stresses such as air pollution, elevated temperatures, compacted soils, and restricted growing spaces. Plan carefully so that trees do not outgrow a site, damage roads, foundations and sidewalks or become susceptible to diseases and insect infestations.1

Consider working with a certified arborist to assist in the selection of the appropriate trees and placement. An arborist can perform tree care services, including pruning, removal, spraying, fertilization or planting. Many can also diagnose tree problems, such as how to control insect pests and tree diseases. Arborists often work for tree service companies, but they may also work as independent consultants.2.  Often, the chemicals that treat healthy trees are only available to those with appropriate licenses to apply these chemicals. Other individuals who can serve as resources may work for tree companies or landscape architects.

Prior to planting trees, consider the following:

  • Purpose of the tree (i.e. shade, privacy, property boundary marking, ecology, beauty, etc.) to ensure  the correct species for the chosen location is selected
  • Characteristics of the plant including height, spread, root size, branch, leaf and fruit features
  • The weather conditions that will affect the tree
  • Longevity of the species 

Use professional expertise to assist in the selection of the appropriate species and location to prevent unnecessary problems after planting, such as:

  • Trees attracting bees
  • Tree sap getting on parked vehicles
  • Trees dropping fruit and nuts and causing tripping hazards
  • Trees needing replacement or removal if they are inappropriate for the chosen location including scraping roofs, reducing visibility, causing security issues or becoming too large for courtyards

It is also important not to plant too many trees of a single species, called monoculture, since this practice may result in many trees being susceptible to disease or death at one time.

Plant trees anticipating final size - Most of the damage from trees occurs to people and buildings that are too close to the tree. The initial planting should be far enough from exposed property and activities so that the tree will fit as intended when it reaches its full size.

Keep clear of power lines - If working around power lines contact the local electric utility company prior to starting so they can send a professional to survey the area and work with the municipality on a safe plan of action.

Evaluate tree health –Work with professionals to assist in evaluating and caring for trees. Routine care may include pruning to remove lower tree branches or cutting trees back from driveways, structures or other areas. If the canopy, or crown of the tree, has excessive branches, the tree canopy can be removed. This method of tree thinning allows the wind to blow through the tree canopy, thereby reducing the chance that the tree will be damaged or fall in a storm.3

Encourage staff to learn how to recognize the signs of unhealthy trees. Below are some of the more obvious signs that indicate trees may be distressed, diseased or dying:

  • Dead or dying limbs
  • Missing, smaller or curled up leaves
  • Insect damage
  • Split trees
  • New growth sprouting up from the base of an existing tree
  • Extensive growth of ivy or mold/fungus on the tree
  • Nearby construction that may have damaged the tree roots

Assess trees when performing exterior checks of municipalities’ buildings and grounds. Instruct the buildings and grounds and/or facilities staff to alert supervisors of tree-related problems immediately in order to help mitigate risks before any incidents occur or another storm approaches. Some problems, such as insect damage, can quickly shorten the lifespan of an otherwise healthy tree, quickly increasing the likelihood of problems. Learn about invasive species and the problems facing the specific trees in the region.4

Decaying trees are not only unsightly, they can also be dangerous. During stormy or windy weather, a toppled tree can crash through a structure and cause injury or death. To be safe, carefully inspect all locations for signs of a sick or dying tree. If attempting to control a diseased tree in-house, consider consulting a local arborist to help identify the disease and give advice of the best treatments available.4

Focus on critical areas - Be especially concerned about trees located near heavy use spaces, such as areas with many pedestrians and vehicles or structures and equipment used during emergencies. Completing inspections of trees near playgrounds helps ensure tree branches are cut back from all equipment. This practice may help prevent youths from trying to climb onto trees from the playground and reduce the likelihood of falls. 

Perform a regular tree check up to evaluate the trees, especially before winter arrives. Train staff to report situations such as: tree branches scraping a building, drooping down over parking lots or blocking security lights or cameras, so the situation can be promptly addressed.  

Critical areas to evaluate may include:

  • Parking lots and sidewalks
  • Campus driveways
  • Entrances/exits/fire exits of buildings
  • Student drop off and pick up areas
  • Near overhead electrical lines
  • Buildings, roofs and walls 
  • Near large areas of plate glass or skylights
  • Outdoor recreational areas
  • Near outdoor generators
  • Walking paths/running tracks
  • Playgrounds


Trees are a common feature of municipal grounds and provide many benefits to the community. Trees also can present a risk of injury to individuals and damage to buildings and vehicles located in close proximity. To help reduce the potential for claims from tree hazards, give proper consideration to tree selection and planting location including the anticipated final tree size. Tree care professionals and local utility companies can also be included as partners when caring for the municipal landscaping. Ongoing evaluations of tree health can be beneficial, especially in high public use locations and areas located close to buildings, roads and parking. 


  1. Vermont Division of Forestry Home|Fpr. (n.d.) Retrieved from
  2. National Arborists Home|Fpr. (n.d.) Retrieved from
  3. Invasive Species. (n.d.). Retrieved from
  4. US Forest Service (n.d.). Retrieved from
  5. Bradford Pear Trees: Facts, Pruning, & More (n.d.) Retrieved from
  6. Ashmore, Durant (March 21, 2016). The Curse of the Bradford Pear. Retrieved from