How to Know If Your Tree Is Dangerous: 10 Warning Signs for Property Owners

By Dan Just, ISA Certified Arborist & TRAQ Qualified

Trees are one of the biggest assets on your property, but like any living organism, they can develop issues over time. A tree that looks fine from a distance can still have structural defects, root problems, or hidden decay that creates a serious risk during storms or high-wind events.

As an ISA Certified Arborist and Tree Risk Assessment Qualified (TRAQ) professional, I’m often asked the same question:

“How do I know if my tree is dangerous?”

While nothing replaces an on-site assessment, there are key warning signs every homeowner should watch for.

1. A Sudden Lean

A lean that has developed recently—especially after storms—is a major warning sign. Look for soil lifting or cracking on one side, exposed roots, or a rapid change in posture. This often indicates root failure, which can lead to the entire tree uprooting.

2. Cracks, Splits, or Seams in the Trunk

Deep cracks, long vertical splits, or seams can weaken the tree’s structure. These are commonly associated with internal decay, weak unions, or storm stress. If you see a crack that goes into the wood, the tree needs professional assessment.

3. Dead or Hanging Branches

Large dead limbs—especially over homes, driveways, streets, or play areas—can break unexpectedly. Signs include no leaves during the growing season, branches breaking during calm weather, or bark peeling off the limb entirely.

4. Mushrooms or Fungi at the Base

Fungal growth at the base of the tree often indicates root rot or internal decay. Mushrooms, conks, soft or spongy wood, or cavities near the base are major signs the tree needs evaluation. Root issues are some of the most dangerous defects and often invisible at first glance.

5. Bark Falling Off in Large Sheets

While some species shed bark naturally, large sections of missing bark, deep cracks beneath the bark, or smooth, exposed wood can signal significant decline or decay.

6. Recent Storm Damage

Iowa storms can cause split or twisted branches, crack formation, hanging limbs, or hidden structural issues. Even if the tree looks okay, internal damage might not show until months later.

7. Soil Heaving or Exposed Roots

If soil appears lifted or cracked around the base, or if new roots are suddenly exposed, this may indicate root instability, shifting root plate, or previous partial failure. This is a common precursor to full uprooting.

8. Large Cavities or Hollow Areas

While some trees can tolerate small cavities, a large hollow area—especially near the trunk base—weakens the tree’s structural integrity. Cavities caused by decay fungi or past injuries often increase failure risk.

9. Poor Structure or Multiple Stems

Included bark or co-dominant stems (two trunks fused together) create weak unions that can split apart. Warning signs include a deep “V” shape between stems, cracks forming where two trunks meet, or bulging at a union. This is a common structural defect in many landscape trees.

10. Changes After Construction or Soil Disturbance

Construction within the root zone (even 10–20 feet away) can severely stress trees. Trenching, digging, installing patios, driveway work, soil compaction, or grade changes all damage roots. Symptoms may not appear immediately but can show up years later through decline or sudden failure.

Why Regular Tree Assessments Matter

Trees change as they age. Weather, soil conditions, pruning, drought, and pests all affect their structure and health. Having your trees assessed every 2–3 years helps you catch problems early, prevent costly failures, protect your home and property, document care for insurance, improve long-term tree health, and make informed decisions about pruning or removals. A Tree Risk Assessment (TRAQ) combines an industry-standard framework with the arborist’s professional experience to help you understand your tree’s condition and level of risk.

Need a Tree Risk Assessment?

If you’re in Des Moines or the surrounding area, I’d be happy to help.

📧 dannyjust78@yahoo.com📞 (515) 330-5168

I provide tree risk assessments (TRAQ), written reports for insurance or documentation, tree health evaluations, and guidance for pruning, removals, or long-term care. Your trees are living assets—make sure they stay safe, healthy, and strong.