Where would we be without trees? They enrich the environment, boost curbside appeal, clean the soil, dampen noise pollution, and produce oxygen. But even with all of these amazing attributes, it’s easy to overlook the risks related to defective trees.

Whether diseased, infested, or poorly maintained, defective trees have a greater risk of falling branches or uprooting completely, causing damage to property and injury to people. That’s why preventative maintenance is absolutely critical.

Check out how you can identify hazardous trees in your yard.

1. Dead wood

As if the term isn’t ominous in itself, dead wood is usually brittle, soft, and often can’t bend in the wind or under the weight of ice or snow. Dead wood can be unpredictable and afflicted branches can break on a whim —which is why time is of the essence.

Signs of dead wood

  • Foliage discrepancy: If certain branches are leafless while others are thriving with green leaves, you may be dealing with dead wood. Conversely, if some dead leaves are clinging to life (so to speak) during the fall season when they should be, you know, falling, then dead wood may be the culprit. But be careful — some trees, like beech or oak, often hold onto their leaves fairly late into the season.
  • Fallen bark: A healthy tree often sheds old bark and replaces it with new bark —pretty simple. But a warning sign is if the bark falls off and isn’t replaced with new bark, exposing patches of smooth and unprotected wood.
  • Fungi: Large wood conchs, shelf fungus, or sprouting mushrooms indicate that a part of a tree is either dead or death is imminent. And that makes fungus an assuring (or not-so-assuring?) clue that your tree is hazardous.

If there’s any doubt, you can always give a smaller branch a little jostle to gauge its flexibility. And it’s important to remove dead branches as soon as possible to prevent insects and decay organisms from nesting in the tree.

Because removing a branch can be dangerous (especially one high up in the tree or near a power line) and can affect the overall health of the tree, it may be wise to contact your local tree service.

2. Tree cracks and splits

Cracks occur for a variety of reasons, and usually cold temperature is to blame. Otherwise known as frost cracks, these arise when the inner and outer wood of a tree expand and contract at varying rates as the temperature fluctuates.

Cracks to look out for

  • Vertical cracks: Frost cracks on their own have little impact on the sturdiness of a tree. But if a tree has 2 vertical cracks on either side, it may be an indication of root breakage, which is extremely hazardous.
  • Splits into the ground: Wounds that penetrate into the ground require your close attention … and perhaps the eye of a trained arborist. The rotting inner core of a tree trunk, lightning scars, or structural weakness in general are also known to split trees in half.
  • Cracks on leaning trees: If you’ve got cracks on the side of a leaning tree — especially on the side opposite of the lean — then you should take immediate action by calling your local tree expert. And any cracks that are in contact with other tree deficiencies should be addressed sooner than later.

If you notice damage to the tree, you can start by removing all the loose bark. For large, dangerous cracks, contact a certified arborist. Usually professionals can bolt the split shut with a method known as “lip bolting.” But if there’s extensive splitting in the trunk, or more than 2 cracks present, professional tree removal is probably your best bet.

3. Trees with multiple trunks

Some trees are formed by multiple trunks and if the trunks are weakly connected, the tree is more likely to break. Conjoined trunks can sometimes crack or produce layers of bark instead of growing healthy wood — and make for a hazardous tree.

Warning signs in multiple trunks

  • “U” versus “V” shapes: Stronger trunk unions often have a “U” shape at the point of connection, while weaker junctions have a narrow “V” shape. The weak “V” shaped union means the tree is more vulnerable to splitting down the middle since its expanding roots are likely to rub up against each other and create wounds.
  • Deep cracks in the trunk: It goes without saying that the deeper the split in the trunk, the more likely the tree won’t be able to support its own weight.

It’s important that multiple tree trunks are regularly inspected for any frailties or past storm damage to prevent further decay or wounds. Improving weak multiple tree trunks includes moderate pruning and installing bracing rods to help with weight distribution. Of course, be sure to contact your local arborist to determine the best course of action.

4. Tree Borers

Tree borers are insects that nest inside trees, where their larvae feed on living tissues. Such pests include beetles or clearwing moths, but the damage is always devastating. Over time, these fervent miscreants can cripple branches and weaken tree structure to the point of breakage.

Signs of tree borers

  • Tiny holes: The most obvious indication of an infestation is when tree trunks are perforated with tiny holes. The holes can either be perfectly symmetrical or oblong in shape. Sometimes these hole borers produce a substance known as frass, which often resembles sawdust and falls gently on branches below.
  • Girdled trees: Girdling occurs when a strip of bark is removed around the circumference of a tree and is extremely hazardous to its health and safety. Bark provides a protective barrier and spreads nutrients throughout the tree. Without it, the tree is left to a slow, grueling demise.

If the tree has only a few noticeable holes, you should take immediate action. Because tree borers are attracted to damaged trees, start by treating wounds and removing defective branches — both of which are common points of entry. It’s also wise to spread mulch around your tree, feeding it with water and fertilizer to maintain its health or to help it heal from any previous stress or damage.

For girdling, using twigs to bridge graft the exposed woods can be an effective way to replace bark. By mimicking bark, these twigs help to transport nutrients through the tree while providing a protective covering. If this undertaking seems too ambitious, though, you may want to call on a tree expert who’s a little more twig-savvy.

5. Cankers

Cankers are dead areas of bark on a tree’s branch or trunk, leaving trees vulnerable to wood-rotting organisms and wood decay. The more sunken in the canker, the more likely a tree’s structure is compromised.

Types of cankers

  • Wound cankers: Repeated injury caused by lawn mowers and other landscaping equipment can lead to girdling and death.
  • Targetshaped cankers: Gradual fungi growth during fall and winter can lead to a hard formation of tissue around afflicted areas. Deciduous trees in the Northeast are especially vulnerable to various species of fungi.
  • Diffuse cankers: Sometimes fungi grows so quickly that the tree doesn’t even have a chance to react. Cankers like these are usually shallow, with the bark around it off-color. Diffuse cankers are deadly and infected branches should be removed immediately.

Canker treatment and prevention largely depend on tree species and the type of canker involved. But generally, the healthier the tree, the better they can withstand the presence of cankers. Trees shouldn’t be planted in poor site conditions or where root growth is limited by sidewalks or stone walls. And annual fertilization in early spring can also facilitate a tree’s growth and vitality, keeping would-be cankers at bay.

Protect your home

While there’re many preventative measures you can take, sometimes the inevitable comes crashing down in spite of your best efforts. For this reason, protect your abode with homeowners insurance you can trust. Should a tree be felled by a windstorm in your yard or encroaching roots rupture your neighbor’s fence, you’ll be able to get right back on track.

Related links

5 Trees to Avoid Planting in Your Yard

7 Ways to Give Your Home More Curb Appeal

Safe and smart | Home safety


about Evan

From writing content for life coaches to working on indie film press releases, Evan’s motley repertoire has been considerable in the last couple of years. Now he employs his varied aptitude as a content writer for Esurance. He’s also a self-proclaimed polyglot in training with a proclivity for dog-eared books.