Signs Your Tree May Be a Hazard

Signs Your Tree May Be a Hazard

Introduction

A hazardous tree can cause property damage, personal injury, or even death. Yet most failing trees show warning signs long before they collapse. Knowing what to look for helps protect your home and family while giving you time to contact professionals for a proper evaluation.

Major Warning Signs

1. Dead or Hanging Branches

Deadwood becomes brittle, heavy, and unpredictable. Even a small broken limb can cause significant damage if it falls from height.

2. A Sudden Lean

A lean greater than 15 degrees, especially one that appears suddenly, often indicates root failure. This is one of the most dangerous conditions a tree can develop.

3. Cracks or Splits in the Trunk

Vertical cracks, shear splits, and bark separation expose internal weakness. Deep cracking often precedes structural failure.

4. Fungal Growth

Mushrooms near the base of a tree often indicate internal decay. Common decay fungi in Oregon include:

• Ganoderma
  
  

• Armillaria
  
  

• Artist’s conk
  
  

Fungal fruiting bodies are usually signs of advanced rot.

5. Cavities or Hollows

Hollow trunks or open cavities reduce load-bearing capacity. Even if the tree appears healthy from the outside, it may be structurally compromised.

6. Soil Heaving Around the Base

Raised or cracked soil on the windward side of the tree may indicate that the root plate is lifting—this is a critical emergency sign.

7. Sparse or Discolored Leaves

A thinning canopy often signals disease, root stress, or declining vitality.

Environmental Factors That Increase Risk

• Recent construction
  
  

• Heavy storms
  
  

• Poor pruning techniques
  
  

• Soil compaction
  
  

• Drought or overwatering
  
  

These stresses make a tree more likely to fail.

What to Do if You Suspect a Hazard

Never attempt to diagnose or remove a hazardous tree yourself. Contact a licensed arborist who can perform a full risk assessment using the ISA risk rating system.