Trees fail without warning every year — or at least that's how it seems to the homeowners affected. The reality is that most tree failures are preceded by visible warning signs that, if caught early, give you time to act before a branch or trunk comes down on a car, fence, or worse.
As qualified arborists serving Simcoe County, we inspect hundreds of trees annually and have seen every hazard scenario imaginable. Here are the eight warning signs we look for — and what to do if you spot them on your property.
1. Large Dead Branches in the Crown
Dead branches don't have the flexibility of living wood. They become brittle over time and can snap off with minimal provocation — even on calm days when there's no wind. Look for branches that have lost their bark, turned grey, and have no buds or leaves in season. Any dead branch over two inches in diameter hanging over a structure or walkway should be removed.
2. A Sudden or Increasing Lean
Some trees naturally grow at an angle — that's not necessarily a problem. But a lean that has developed recently, or that appears to be increasing, is a serious red flag. Check the root zone for soil heaving on one side, which indicates the root plate is beginning to lift. This is a near-emergency situation.
3. Fungal Fruiting Bodies at the Base or Trunk
Mushrooms, conks, or shelf fungi growing from the trunk or at the base of a tree are almost always a sign of internal decay. Some wood-decay fungi are highly aggressive and can hollow out the structural core of a tree far faster than the exterior damage would suggest. Don't ignore them.
4. Cracks or Splits in the Trunk
Vertical cracks, horizontal cracks, and splits at branch unions all indicate structural weakness. Co-dominant stems — where two trunks of roughly equal diameter grow together — often have a narrow V-shaped union that is prone to splitting. These are often the failures we're called to clean up after windstorms.
5. Hollow Cavities
A hollow tree is not automatically a hazard — the shell can retain surprising structural integrity depending on species and size — but it does require professional assessment. The rule of thumb is that if the hollow exceeds one-third of the trunk diameter, the risk of failure is significantly elevated.
6. Damaged or Disturbed Roots
Construction activity, trenching for utilities, soil compaction, and grade changes can all damage the root system in ways that aren't immediately visible above ground. Trees with compromised root systems may look fine for years before suddenly failing. If significant work has been done near a tree in the past five years, it warrants inspection.
7. Previous Branch Failures
A tree that has already lost major branches — especially ones that left large wounds that haven't closed — is more likely to fail again. The wounds are potential entry points for decay, and the stress of the failure often accelerates decline elsewhere in the tree.
8. Proximity to Power Lines
A tree doesn't have to be diseased or dying to be a hazard if it's growing into power lines. Contact with live electrical lines is a life-safety issue that should never be approached by untrained individuals. Call your utility company or a qualified arborist immediately.
If you recognize any of these signs in a tree on your property, the safest course of action is to have it assessed by a qualified arborist. At Axe & Wedge Tree Works, we include a complimentary hazard assessment as part of our free quote process. Call us at 705-540-0760 or request a quote online.