Seven warning signs your tree is about to fall — and what to do before it does

If you own a home in Massachusetts or New Hampshire, you’ve got trees. And every one of them, eventually, is going to come down — the only question is whether you control how, or whether nature does.

Here’s what most homeowners don’t know:

The vast majority of trees that fall on houses showed warning signs for months — sometimes years — before they came down. The owners just didn’t know what to look for.

At AA Tree Service, our certified arborists assess hundreds of trees a year across MA and NH. We’ve seen the patterns. We know what a dangerous tree looks like — and we can tell you, in plain language, what to watch for on your own property.

Here are the seven warning signs that mean it’s time to take action.

1. The Tree Is Leaning More Than It Used To

Some trees grow with a natural lean and they’re perfectly stable. The dangerous kind is the new lean — a tree that’s gradually tilting more than it did a year ago.

Watch for:

• Soil heaving or cracking on the side opposite the lean
• Exposed roots being pulled out of the ground
• A lean that increased after a recent storm

A new lean greater than 15 degrees almost always means root failure. That tree is already coming down — the only question is when.

2. Cracks in the Trunk or Major Limbs

Vertical cracks running up the trunk, especially deep ones, mean the tree is splitting. So do horizontal cracks at branch unions — the V-shaped joints where major limbs meet the trunk.

A tree can stand for years with a crack and then fail suddenly under wind, ice, or its own weight. Any visible crack on a tree near your home warrants a professional inspection.

3. Mushrooms or Fungal Growth at the Base

If you see mushrooms, conks (shelf-like fungi), or fungal brackets growing on the trunk or at the root flare, the tree has internal decay. The mushrooms are the visible fruit — the actual fungus is eating the wood inside.

Common culprits in New England:

• Armillaria (honey fungus) — root and butt rot
• Ganoderma — root and lower trunk decay
• Inonotus — heart rot in oaks and maples

By the time fungi are visible, decay is usually advanced. This is one of the strongest indicators that a tree needs professional assessment.

4. Dead Branches in the Upper Canopy

Trees die from the top down. If you see bare branches at the very top of the canopy while the lower branches are still leafing out, the tree is in decline.

A few dead branches can be normal pruning candidates. But more than 25% of the canopy showing dieback is a serious sign — the tree’s vascular system isn’t supporting the upper crown anymore. Our guide to spotting a dying tree covers this in detail.

5. Hollow or Decayed Sections of Trunk

A hollow tree isn’t automatically dangerous — trees can survive with significant hollows. But the rule of thumb is the “one-third rule”: if more than a third of the trunk diameter is hollow or decayed, the tree’s structural integrity is compromised.

Signs of internal decay:

• Soft, spongy wood when probed
• Cavities or hollow sounds when tapped
• Sawdust at the base (carpenter ants thrive in decayed wood)
• Cracks weeping dark fluid

6. Damaged or Exposed Roots

Trees stand up because of their roots. Anything that compromises the root system — construction damage, trenching, soil compaction, root rot — is a structural problem for the entire tree.

Watch for:

• Roots that have been cut or paved over within the last 5 years
• Heaved soil or visible root lifting
• Dead, soft, or peeling roots at the base
• Trees on the downhill side of recent grading work

7. Trees That Survived a Recent Storm — Barely

A tree that lost a major limb, took a lightning strike, or shifted in the soil during a recent storm is a higher-risk tree going forward. The damage is rarely just cosmetic — it usually changes how the tree handles the next storm.

Get any storm-damaged tree professionally assessed before the next major weather event. Our complete warning signs guide covers post-storm evaluation in more depth.

What a Professional Hazard Assessment Includes

When you hire a certified arborist for a tree hazard assessment, you should expect:

• Visual inspection of the entire tree, from root flare to upper canopy
• Sounding (tapping) the trunk to detect hollows
• Probe testing of suspicious areas
• Identification of any pests, diseases, or structural defects
• A written report identifying targets (what the tree could hit)
• A risk rating and clear recommendation: monitor, mitigate, or remove

Our tree hazard assessment service covers all of this, and you can learn more about working with a certified arborist on our resources page.

When Removal Becomes the Right Call

Not every dangerous tree needs to come down — but some absolutely do. Removal becomes the clear choice when:

• The tree is within falling distance of your house, garage, or driveway
• Multiple warning signs are present at the same time
• Decay or root damage exceeds the one-third rule
• The tree has already partially failed in a storm
• Your insurance company has flagged it as a liability

Our hazardous tree removal team handles high-risk removals with cranes, rigging, and the precision needed to get a compromised tree down without it taking your house with it.

Tree Hazard Experts Serving MA & NH

A tree assessment is the cheapest insurance policy you’ll ever buy. AA Tree Service has certified arborists across Massachusetts and New Hampshire who can walk your property, identify the trees that pose real risk, and give you a clear plan — whether that’s monitoring, pruning, cabling, or removal.

Concerned About a Tree on Your Property?

Don’t wait for the next storm to find out. Schedule a free tree hazard assessment today — we’ll inspect the trees you’re worried about, give you a straight answer on the risk, and only recommend removal if it’s truly necessary.

We proudly serve Boston, Concord, Nashua, Manchester, and surrounding areas throughout MA and NH.

FAQs

1. How can I tell if a tree on my property is dangerous?
   Look for visible lean, cracks in the trunk, mushrooms growing at the base, dead branches in the upper canopy, and exposed or damaged roots. Any one of these is a yellow flag — multiple together mean call an arborist now.
2. Do dead trees always need to be removed?
   Not always — a dead tree far from any structure or path can be left as wildlife habitat. But dead trees within falling distance of your house, driveway, neighbor’s property, or power lines should be removed before they come down on their own.
3. What’s a tree hazard assessment and do I need one?
   A formal hazard assessment is an inspection by a certified arborist who evaluates the tree’s structural integrity, root health, decay, and proximity to targets. Insurance companies often require one before a removal claim, and they’re worth getting on any large tree near your home.
4. Can a tree fall without any warning signs?
   Rarely. Even seemingly healthy trees that fall in storms usually had hidden issues — root decay, internal hollowing, or weak branch unions — that an arborist could have spotted. True “out of nowhere” failures are uncommon.
5. How often should I have my trees inspected?
   Mature trees near structures should be inspected every 1–3 years, and after every major storm. Trees showing any warning signs need annual professional assessment.