The Hazard Tree Evaluation: Safe Vegetation Management for Your Electric Infrastructure

7-minute read

In this article:

• Understand what a hazard tree evaluation is and what factors to consider.
• Learn how to conduct evaluations and the benefits of regularly inspecting trees in your coverage area.
• Discover how electric utilities conduct hazard tree evaluations utilizing remote sensing technology.

At Constellation Clearsight, we understand the importance of evaluating trees for potential hazards. Trees provide tremendous environmental, social, and cost benefits to society such as creating beauty, shade, and habitat for wildlife, but they can also pose a threat to people, property, and electric infrastructure if they become diseased or damaged. 

Related: Here’s How Our Methods Can Help Solve Vegetation Management Problems

In this post, we’ll discuss the hazard tree evaluation process and how it can help you make informed decisions about vegetation management to promote safe and reliable electric service.

What is a Hazard Tree Evaluation?

A hazard tree evaluation is an assessment of a tree’s condition to determine if it poses a risk to a specified target, for example people or property. It considers various factors, such as the tree’s age, size, health, location, and structural integrity, as well as potential hazards, such as falling limbs or branches, root damage to buildings or sidewalks, and disease infestation.

While some hazard trees are easy to spot, many healthy-looking trees may conceal significant issues just a few feet above ground level, making it important to conduct a thorough hazard tree evaluation.

The Benefits of Evaluating Trees

Evaluating trees for potential hazards has several benefits. It helps utilities and electric cooperatives:

•  Make informed decisions about – vegetation and better plan any tree removals.
• Identify any necessary maintenance that should be done on the tree to reduce the potential of failure. 
• Protect assets from damage caused by falling trees or tree limbs, which can impact the safety and reliability of an electric infrastructure.

How to Conduct a Hazard Tree Evaluation

Conducting a hazard tree evaluation requires specialized knowledge of arboriculture and experience in assessing trees for potential hazards. Here are some steps you could take when conducting a detailed evaluation:

• Inspect the tree for signs of disease or damage, such as dead branches, discolored leaves, fungal growths, cavities in the trunk, and more.
• Measure the height and diameter of the trunk at breast height (4 ½ feet) to assess its size and overall condition.
• Check for any structural defects, such as weak branch unions or cracks in the trunk, that could indicate instability.

• Examine the root system for signs of damage, such as girdling roots or root rot, that could affect the tree’s stability.
• Assess the location of the tree in relation to buildings, power lines, sidewalks, and other structures or areas, noting any potential risks posed by its proximity if it were to fail suddenly due to disease or storm damage.
• Go above the ground floor: utilize technologies such as drones and LiDAR to get a more accurate picture of the health and proximity of trees.

Related: Why Drone-Enhanced Solutions are Potential Game Changers for Energy Co-Ops

How do Electric Utilities Conduct Hazard Tree Evaluation

Electric utilities need to manage large populations of trees over extensive electric networks. The typical electric industry hazard tree evaluation technique is visual, or no touch, and rapid (windshield survey). This technique allows for a rapid assessment of a large population of trees, and tends to identify only the obvious (dead, or heavily damaged or severely diseased trees).

How is Remote Sensing Changing Utility Hazard Tree Evaluation

Recent advances in technology and data processing capabilities have made it possible for electric utilities to improve their hazard tree evaluation with the following tools:

• Identification of problem species, as well as the location and number of trees posing a threat to the electric infrastructure.
• Derivation of a relative measure of tree stress or health, enabling the location of problem trees before they self-reveal through death or structural failure.
• Accurate identification of potential off right-of-way fall-in trees using 3-D modeling tools, rather than manual use of measurement tools.

Although remote sensing tools cannot replace qualified and experienced electric utility foresters, they extend their reach and guide them to the areas where problems exist, rather than requiring a full survey of all the lines to find problem areas.

Related: Forest Health Monitoring: Pests and Diseases to be Aware Of

Bottom Line

Conducting a hazard tree evaluation is a crucial step in determining whether a tree should be pruned or removed to promote safe and reliable electric service. What is certain is that remote sensing greatly increases the information available to the electric utility forester about potential threats posed by surrounding vegetation.

At Constellation Clearsight, we are experts in electric infrastructure inspections and vegetation management, including hazard tree evaluations, and provide you with professional guidance and services to ensure the safety and reliability of your electric infrastructure.