What Is a
Danger Tree?

The definition, word for word

“dangerous tree means a tree that is a hazard to a worker due to (a) its location or lean, (b) its physical damage, (c) overhead conditions, (d) deterioration of its limbs, stem or root system, or (e) any combination of the conditions in paragraphs (a) to (d).” WorkSafeBC OHS Regulation s. 26.1

Read the five limbs of that definition again, because they're the whole thing.

(a) Location or lean

A perfectly healthy tree can be a dangerous tree. If it's leaning over the only path to your back door, its health is irrelevant, the location is the hazard. This is the part most people miss.

(b) Physical damage

Split stems, cracks, lightning strike, machine damage at the base, fire scarring, barber-chair from a botched cut. Anything that has structurally compromised the tree.

(c) Overhead conditions

Hung-up limbs, broken tops sitting in the crown, a neighbouring tree leaning into it. The tree itself may be sound while what's above it is not.

(d) Deterioration of limbs, stem or root system

Decay. This is the one you can't see. Butt rot and root rot do their work underground and the tree looks fine from the deck right up until it doesn't. Conks and fruiting bodies at the base, soil heaving on one side of the root plate, and a hollow sound on the stem are the tells, and by the time they're obvious, the tree has usually lost a lot of strength.

(e) Any combination

Which is where most real danger trees live. A moderate lean is manageable. A moderate lean plus a compromised root collar plus a house in the fall path is a different tree entirely.

What the regulation requires

Section 26.11 is the operative provision. Where a worker will be exposed to a dangerous tree, the employer must either fell it, or have a risk assessment conducted by “a person who has completed a training program acceptable to the Board.” The recommendations from that assessment have to be implemented before work starts.

WorkSafeBC names two accepted programs:

• Wildlife/Danger Tree Assessor: for forestry operations. Coordinated by the Wildlife Tree Committee of BC, delivered through UNBC. Three modules: Forest Activities, Parks & Recreation, and Wildland Fire Safety. Certificates are valid four years.
• Tree Risk Assessment Qualification (TRAQ): for arboriculture operations, administered by the International Society of Arboriculture.

Other training may also meet the standard, but those are the two WorkSafeBC names.

Fire-killed trees are their own problem

A burned tree does not fail like a green one. The lean you'd normally read may be gone. The root collar can be burned out underground with the stem looking sound above it. Heat-checked wood loses strength unpredictably. This is why the Wildland Fire Safety module exists as a separate qualification, assessing post-fire timber is a genuinely different skill from assessing a rotten cottonwood.

Across the Cariboo, after the fire seasons this region has had, there is a great deal of standing burned timber on private property that nobody has assessed.

Does any of this bind a homeowner?

Directly, no. The OHS Regulation binds employers and workers, not you on your own land.

Indirectly, it binds you the moment you hire anybody. A roofer, a fencer, a painter, a falling contractor, if they're going to be exposed to that tree, it's now in scope. And a contractor who works under a dangerous tree without an assessment is taking a risk with someone else's life and their own registration.

There's also the insurance dimension. A tree that comes down in a storm is one thing. A tree you knew was dead, that came down in a storm, is a different conversation with an adjuster. A written assessment tells you what's wrong and puts a date on the record.

Signs worth calling about

• A lean that has changed, new lean is much more concerning than old lean
• Soil heaving or cracking on one side of the base
• Conks, mushrooms or fungal fruiting bodies at the base or on the stem
• Vertical cracks or seams in the trunk
• Large dead limbs in the upper crown, or a dead top
• Bark sloughing off in sheets with nothing regrowing
• Standing dead pine anywhere within reach of a structure
• Any hung-up tree, call about this one today