People enjoy a wide range of outdoor activities, from recreation, camping, and hiking to simply taking in the beauty of nature in public spaces, campgrounds, and parks. Forests and trees are essential to our natural world, providing significant environmental, social, and economic benefits. However, trees can also present risks, particularly when they develop structural weaknesses or diseases that make them prone to failure. As living organisms, trees are vulnerable to natural threats like insects, diseases, and extreme weather, as well as human-caused damage from construction, soil compaction, and heavy equipment. While trees offer many benefits, they can also become liabilities in public spaces, campgrounds, and recreational parks.
Importance of tree risk hazard assessment
Tree risk hazard assessment is a systematic process designed to identify and evaluate potential risks associated with trees, ensuring public safety while preserving their environmental and social benefits. No tree can be considered entirely “safe” since trees are living organisms, though only a small percentage ever cause damage. Tree failures can lead to property damage, disrupt infrastructure such as utility lines, roads, and underground systems, and, in rare cases, result in personal injuries or fatalities. A thorough risk assessment helps property owners, managers, and municipalities make informed decisions regarding tree maintenance, preservation, and removal. Key reasons for conducting a tree risk hazard assessment include:
Cost efficiency: Preventative measures are more cost-effective than dealing with emergency removals or damage repairs.
Public safety: Identifying hazardous trees in parks, streets, campgrounds, and around public buildings helps prevent accidents.
Liability reduction: Property managers and municipalities can mitigate potential legal and financial liabilities associated with tree-related damage.
Tree health management: Assessments can reveal hidden diseases, infestations, or structural weaknesses that need intervention.
Legal responsibilities
Tree owners and manger must understand and address potential tree risk and failure. Under the Alberta Occupiers’ Liability Act that you as the owner is responsible under the “duty of care of visitors” to provide the safety to visitors. The common duty of care applies in relation to: “ (a) the condition of the premises, (b) activities on the premises, and (c) the conduct of third parties on the premises”
Duty of Care is legal obligation that the owner of trees has some duty to be responsible for the tree(s) and to ensure it is reasonable degree of safety for people or property near tree under his and her care.
Standard of Care is degree of care that a reasonable person should exercise in performing duty of care; a measurement used to assess whether an individual acted in a reasonable manner. For Municipal and other publicly land managers, meeting the Standard of Care is a part of Due Diligence and should be entrenched in their policy and procedures.
There is a significant and important distinction between “tree risk” and “tree hazards”. Under the International Society of Arborist (ISA) – Tree Risk Assessment Manual defines them as follows:
Risk is the combination of the likelihood of an event and severity of the potential consequences. In the context of trees, tree risk is the likelihood of a conflict or tree failure occurring and affecting a target, and the severity of the associated consequences—personal injury, property damage, or disruption of activities.
A hazard is a likely source of harm. In relation to trees, a tree hazard is the tree part or parts identified as a likely source of harm.
Common tree hazards in public places, campgrounds and parks
There are several key tree hazards that increase the likelihood of tree or part of tree failures posing risks to people, properties and infrastructure.
- Dead, dying trees and falling branches – Dead and dying trees are more prone to falling. One of the most common and significant risks is falling branches or entire tree failures. These can occur due to weak or dead limbs breaking off unexpectedly. Structural defects, such as co-dominant stems or included bark. Root decay, making trees unstable and prone to toppling. Storm damage causing delayed failures in weakened trees.
- Diseased and infested trees – Trees suffering from diseases or infestations are more likely to deteriorate and become hazardous. Common threats include fungal infections like root rot and cankers. Insect infestations such as spruce or pine beetles and variety of wood boring insects. Variety of bacterial diseases that weaken structural integrity. Trees with cavities and with large internal decay may appear healthy externally but are structurally weak.
- Weather related risks- Extreme weather conditions can increase tree-related dangers. High winds, heavy snowfall, ice accumulation, and prolonged droughts can cause branches to snap or entire trees to uproot. Weaken trees over time, making them more vulnerable to failure. Increase the risk of wildfires in dry conditions, particularly in forested parks. Cracks and Splits are structural weaknesses in the trunk or major limbs indicate potential failure points.
- Human and wildlife related risks- Visitors in public places, campgrounds and parks can unintentionally contribute to tree damage, leading to increased risks. Human-related stressors include soil compaction from foot traffic and vehicle parking, reducing root oxygen. Soil excavations and construction affecting root zone. Damage to tree trunk and roots from lawnmowers, vehicles, knifes, axing, cutting and improper pruning. Root damages and trees with compromised root systems may become unstable, increasing the likelihood of uprooting. Damage from animals such as beavers and woodpeckers. Unintentional introduction of invasive species that affect tree health.
Managing tree risk- mitigation strategies
Developing mitigation strategies is crucial when it comes to tree risk hazards. Variety of mitigation treatments and action reduces risk of tree failure and damage. In most of cases mitigation strategies involved more than action or treatment.
- Tree removal when necessary -When a tree poses an imminent threat and cannot be mitigated through pruning or support systems, removal may be required. Professional arborists should handle removals to ensure safety. In
- Regular tree inspections – Implementing systematic tree assessments can help identify and address hazards before they become dangerous. Inspections should look for visible signs of decay, cracks, or deadwood. Assess tree stability, especially near campsites, trails, and playgrounds. Be conducted seasonally and after extreme weather events.
- Pruning, Care and Maintenance -Proper pruning can reduce risks by removing dead or weak branches before they fall. Improving tree structure to withstand wind and storms. Encouraging healthy growth patterns through early interventions. Installing structural supports (cables, braces rods, guys, and props) can also mitigate risks of tree failure. Proper care including watering, adding mulch, and supplying adequate nutrients can help mitigate the risk. Improving site conditions such as reducing soil compaction, improving drainage in wet soils, creating wind buffers, modifying irrigation system , removal of soil and turf around trunk may also reduce risk of tree failure.
- Target management (movable targets) in some cases can be temporarily employed to immediately reduce the risk and, in some cases, can be permanent solution.
What can you do?
Before the start of the season, campgrounds and parks should be thoroughly inspected for trees with defects that could pose a risk of property damage or injury. Trees should also be assessed after significant weather events such as windstorms, hail, heavy snowfall, or tornadoes. It is advisable to hire a professional, independent, and ISA-certified Tree Risk Assessment Qualified (TRAQ) assessor to conduct a comprehensive inspection and survey. Ensure that a detailed written report is provided after the assessment.
Follow the recommendations outlined in the report and continuously monitor trees throughout the season, especially after strong winds, heavy rain, or snow. To prevent conflicts of interest, choose an independent TRAQ assessor who is not affiliated with a tree removal company.
How can we help?
ATTS Group Inc professional and experienced Tree Expert and ISA Certified TRAQ Arborist offer Limited Visual Assessment (Level 1) and Basic Assessment(Level 2). We can help you manage the trees on your property and can provide treatments to reduce the risks associated with certain trees.
Resources
Tree Risk Assessment Manual, Second Edition By Julian A. Dunster (principal author) and contributing authors: E. Thomas Smiley, Nelda Matheny, and Sharon Lilly ISBN: 978-1-8819956-99-0 @ 2017 International Society of Arboriculture
OCCUPIERS’ LIABILITY ACT Revised Statutes of Alberta 2000 Chapter O-4 Current as of December 5, 2019 Published by Alberta King’s Printer
Dunster, J.A. 2018. Trees and the Law in Canada. Victoria: Dunster & Associates Environmental Consultants Ltd. pp 262. ISBN 978-0-9937133-2-3 Hard cover https://treelaw.info/
Disclaimer
This article is not a substitute for any professional legal advice nor is it a solicitation to offer legal advice. The information on this information sheet and website is provided to public for information purposes only, it is not legal advice and should not be relied upon in such a manner. You should consult a legal adviser to address the specific circumstances of your tree and property lines matters.