Name: Koala Tree
Price range: $$$

You don’t need to climb a tree to spot many of the signs that something is wrong. A slow walk around it, looking from the top down, tells you a lot.

What “risk” means for a tree

Tree risk is about two things together: how likely part of the tree is to fail, and what it would hit if it did. A tree with a dead limb over an empty field is a low concern. The same limb over a driveway, a roof or a play area is a different matter. When you look at a tree, look at what’s underneath it too.

In the crown

Dead branches, often without leaves in summer or with bark falling off.
Hangers, broken branches caught in the crown.
Thinning or early leaf drop across the crown, or dieback at the tips.

On the trunk

Cracks and splits, especially ones that are new or getting longer.
Cavities and hollows, and areas where the bark is missing.
Tight V-shaped unions between large stems, with bark trapped between them.
Bulges, seams or oozing on the trunk.

At the base and roots

Mushrooms or shelf fungi on the trunk or at the base. They can be a sign of decay inside.
Soil lifting or cracking on one side of the tree.
Roots cut or damaged by digging, trenching, paving or construction.
A new lean. A tree that has always leaned is often stable; a tree that has started leaning is not.

Look at what’s under the tree, not just the tree.

Jason checking a cavity in a tree trunk — A cavity isn’t always a reason to remove a tree. How much sound wood is left matters.

When to call an arborist

If you see any of these signs on a tree that could hit something, have it looked at. The same goes after a major storm, after construction near the tree, or if a tree simply doesn’t look the way it used to. Don’t climb a tree you’re worried about, keep people and cars out from under it, and call your electricity utility if a tree is touching a line.

What an assessment involves

Jason is TRAQ qualified, the ISA’s Tree Risk Assessment Qualification. An assessment starts with a careful look at the whole tree and its surroundings. The trunk may be sounded with a mallet to listen for hollow areas. You get the options in plain language: prune, add support, monitor, or remove. Most trees with a defect can be kept with the right work.

Key takeaways

Tree risk, in five lines

Risk is the chance of failure plus what it would hit.
Look up: dead branches, hangers and thinning.
Look at the trunk: cracks, cavities and tight unions.
Look at the base: fungi, lifting soil, cut roots and a new lean.
Have a tree assessed if it shows signs and could hit something.

This is general information. Every tree and site is different. For advice on a specific tree, get a free quote or book a Certified Arborist Assessment.

About the author

Jason Korkidakis

Jason is Koala Tree’s Owner and Lead Arborist in London, ON. He leads an 8-person crew and assesses trees for homeowners, condo boards and property managers.

ISA Certified Arborist ON-3263ATRAQ qualifiedPPQ qualified

About Jason More Field Notes