What Is an Arborist? (And Why You Need One)

When most people think about tree work, they picture a person with a chainsaw cutting down a tree. And yes, arborists do that. But an arborist is to a tree what a physician is to a person — someone who understands the biology, diagnoses problems, recommends treatment, and sometimes performs surgery. Cutting a tree down is the last resort, not the starting point.

What "Certified Arborist" Means

The term "arborist" is not legally protected in Alberta, which means anyone with a chainsaw can call themselves one. However, the designation "Certified Arborist" is a professional credential issued by the International Society of Arboriculture (ISA). To earn it, a candidate must pass a comprehensive exam covering tree biology, diagnosis, pruning, soil science, tree risk assessment, and tree protection. They must also maintain the certification through continuing education.

Additional ISA specializations include:

• Board Certified Master Arborist (BCMA): The highest level of ISA certification, requiring extensive experience and a rigorous exam.
• Tree Risk Assessment Qualified (TRAQ): A specialized credential for arborists trained in the ISA's standardized tree risk assessment methodology.
• Utility Specialist: For arborists who work specifically around power lines and utility infrastructure.

When you hire a company with ISA-certified arborists on staff, you are getting professionals who have demonstrated competency in tree care science, not just tree-cutting skill.

What Arborists Actually Do

The scope of an arborist's work extends far beyond cutting and grinding:

Diagnosis and Consultation

Just like a doctor, an arborist examines trees and identifies problems. Is the yellowing on your spruce caused by spider mites, drought stress, or iron chlorosis? Is the crack in your elm's trunk a cosmetic blemish or a structural failure waiting to happen? These questions require knowledge of tree biology, pathology, and local conditions. An arborist answers them and recommends a course of action.

Pruning

Professional pruning is not just cutting branches. It is a deliberate process guided by the tree's biology and the owner's goals. An arborist knows where to make cuts to promote wound closure, how to reduce weight on overextended limbs without damaging the tree, and which branches to leave alone. Improper pruning — topping, lion-tailing, flush cuts — causes more damage than no pruning at all.

Tree Risk Assessment

Arborists evaluate trees to determine whether they pose an unacceptable risk to people or property. This is a formal, standardized process that considers the likelihood of failure, the likelihood that a falling tree or branch would hit something of value, and the consequences of that impact. The result is a documented risk rating and recommended actions.

Tree Preservation

During construction projects, arborists develop and oversee tree preservation plans. They define protection zones, supervise root pruning, monitor construction activity, and provide aftercare recommendations. This service can save trees that are worth tens of thousands of dollars in property value.

Planting and Establishment

Arborists advise on species selection, site conditions, proper planting technique, and post-planting care. Choosing the right tree for the right location is the single most important decision in the life of a tree, and getting it wrong is expensive and disappointing.

Tree Removal

When a tree must come down — due to disease, structural failure, or the needs of the property — an arborist plans and executes the removal safely. Complex removals near structures, power lines, or other trees require an understanding of physics, rigging, and equipment that goes well beyond chainsaw operation.

Arborist vs. Tree Service: What Is the Difference?

A "tree service" is a business that performs tree work. An arborist is a qualified professional. The best tree service companies employ certified arborists. However, not all tree services do. Some operate with skilled labourers who can operate chainsaws and chippers but lack formal training in tree biology and care.

The distinction matters most when the job involves diagnosis, risk assessment, or preservation — anything beyond straightforward cutting. If you need a tree assessed for disease, evaluated for safety, or protected during construction, you need a certified arborist. If you just need a dead tree cut down, a competent tree service crew (properly insured) can do the job, but even then, an arborist on staff ensures the work is done correctly.

When to Call an Arborist

Consider calling a certified arborist when:

• A tree is showing signs of decline — wilting, yellowing, dieback, sparse canopy — and you do not know why.
• You want to know if a tree is safe or needs to come down.
• You are planning construction or landscaping near mature trees.
• You need pruning done on large, valuable, or structurally complex trees.
• You are selecting and planting new trees and want to get it right.
• You need a written report for insurance, legal, or real estate purposes.
• A storm has damaged your trees and you are not sure what can be saved.

The Cost of Not Calling One

Skipping professional advice to save money often costs more in the long run. A tree that is improperly pruned may need corrective work — or removal — within a few years. A tree that could have been saved with proper treatment during construction may die and need to be replaced at significant expense. And a hazardous tree that was never assessed may eventually fail and cause thousands of dollars in property damage, or worse.

An arborist consultation is an investment in the health, safety, and value of your property. For the cost of a single visit, you get expert eyes on the trees that frame your home and define your landscape.