Do You Have A Tree At Risk?

Trees require periodic checkups and preventative maintenance to stay in top health. 

If you are the owner or caretaker of large shade trees, you benefi t from their shade and beauty. You may

benefi t from your trees in other ways, too. Their shade or protection may lower your heating or cooling

costs substantially, they may buffer noise from a nearby street, and they may contribute signifi cantly to

the appraised value of your home.

But tree ownership has a cost, too. Trees require periodic checkups and preventative maintenance to

stay in top health. Trees sometimes fail, and sometimes that failure can be predicted. If your tree causes

damage, and its failure could have reasonably been prevented, you can be held liable.

It is generally accepted that there are two levels of defects, moderate risk and high risk. Moderate risk

defects are ones that may worsen over time or fail under signifi cant strain, like an unusually strong

wind. Combinations of moderate defects may cause more immediate tree failure. High-risk defects are

indicators that the tree has failed or is in imminent danger of failing.

There are seven categories of defect.

1. Dead wood – can fail at any time. Branches that have broken off and lodged are especially

dangerous.

2. Rib cracks – longitudinal splits that have opened or closed, where the wood rose along the crack,

indicating that the tree has tried to close over the wound. These are often associated with internal

decay or root damage and can be moderate to high-risk defects.

3. Shear cracks – longitudinal splits that form in the center of leaning trees, and tend to be high-risk

defects.

4. Tension cracks – horizontal or tangential cracks, and indicators that the tree above is moving.

They are catastrophic.

5. Seams – indicate a past rib crack or internal decay that the tree has repaired.

6. Weak unions – these are generally V-shaped tree forks where there isn’t a strong union of wood

fi ber holding the branches together.

7. Decay – this category includes wood that is deteriorated or missing (hollow.) A general rule

is that a tree requires one inch of sound wood for every six inches diameter to be moderate risk.

Heavy branches with decay are high risk. A tree with an open cavity that is one-third or more of its

circumference is high risk.

Other factors, such as canker, poor tree architecture, root problems, or dieback, may be predictors of

tree failure. If you suspect that your tree might contain defects, call a professional arborist who can more

fully evaluate your tree and recommend ways to reduce your risk. Contact the licensed tree professionals

at Pardoe’s Lawn and Tree Service at 800-427-4890.

519 Washington Avenue

Chestertown, MD 21620

1-800-427-4890

www.pardoes.us