As afternoon storms become a regular occurrence, thoughts turn to the trees around our home.  You may be wondering if they are safe, or if they can hold up against the wind of a thunderstorm, tropical storm, or even a hurricane. While there is no “risk free” tree, a tree can provide signals, or clues to any defects it may have. A tree does not have to be dead to have structural problems. An observant homeowner with a little knowledge can detect problems in their trees and have them taken care of before damage occurs.

Most property damage from trees during storms occurs because of some sort of failure in the structure of the tree.

Tree failure can be lumped into three categories: branch failure, trunk failure, and root failure. A periodic tree inspection of the branches, trunk, and root area can reveal problems before they become major ones. To find an ISA Certified Arborist to help with

the tree inspection, go to https://www.treesaregood.org/findanarborist/arboristsearch.

The most common type of tree failure is a branch failure

This is also the easiest type of failure to prevent. When you are out in your yard, look up. Take note of any large dead branches. Observe how the major branches are attached to the trunk. If the attachment of the branch looks like a “V” rather than a “U”, it is a weaker branch attachment. The reason V-shaped branch attachments are a problem is because bark gets imbedded in the joint as the branches grow together and weakens the attachment. This condition can be even more of a risk when the tree has more than one trunk. Multi-trunked trees are especially prone to splitting apart because of poor branch attachment.

I often hear that trees should be thinned out so that wind blows through them

This assumption was proven wrong by research from the University of Florida. The research showed properly pruned trees had considerably less damage than unpruned and improperly pruned trees. Improper pruning by over lifting the crown through the removal of large lower limbs and thinning out interior branches resulted in more damage to the tree during windstorms. Properly pruning trees by using reduction cuts and structural pruning resulted in trees that resisted wind and therefore received less damage.

Trunk defects are a little harder to detect than branch defects

The most obvious type of trunk defect is a cavity. Large cavities with decay should be inspected. Any vertical crack in the trunk of the tree that goes into the wood of the tree is a warning sign of structural problems. A horizontal crack is a sign of imminent trunk failure. Any mushroom or mushroom like fruiting structure coming out of the trunk of the tree is a sign that the tree has internal decay. If you have cavities, mushrooms, or cracks in the trunk of your tree, the tree should be inspected by a tree professional.

There is no way of knowing how much of the tree structure has been lost to decay without further testing

Some arborists are very good at using a low-tech rubber mallet to determine the extent of internal defects while other arborists in our area have specialized equipment such as resistographs, and shigometers that can help determine the extent of decay. The arborist inspecting the tree may recommend pruning or cabling to relieve stress on the trunk, however if the defect in the trunk is serious, removal of the tree may be the only means to solve the problem.

Even though most roots are underground, many root defects can be detected with a little inspection.

The part of the root system that bears most of the load in holding the tree up is the root flare. If you picture the tree as a wine glass, the root flare is the base of the wine glass. Many trees have had their root flares covered by soil during construction or landscape activities. Mulch volcanoes are formed when mulch is piled over the root flare and against the trunk of the tree. Both situations are bad for the tree because it buries the roots and promotes disease and makes inspection of the root flare difficult.

Any damage to the root flare by construction, or other means, is a cause for alarm

Recall the wine glass analogy and imagine how unstable the wine glass would be if part of the base were gone. Finally, the last step in inspecting the roots is to step back away from the tree and look at the uppermost branches of the tree. If they are bare, or not as full as the rest of the tree crown, it may indicate root problems. A Certified Arborist should be called in to inspect the tree if any problems with the root system are suspected.

There is no way to fully eliminate the risk of a tree falling and causing damage in a storm

Nevertheless, homeowners can significantly reduce the risk with regular inspection of their landscape, by identifying defects in their trees and taking care of them before they become a problem. More information of trees and storms can be found on the University of Florida “Ask IFAS” website at https://edis.ifas.ufl.edu/entity/topic/trees_and_hurricanes.

Article Written by Larry Figart, Urban Forestry Agent,  August 2023

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