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By: Beau Brodbeck, regional agent on Alabama Extension’s Forestry, Wildlife and Natural Resource Management Team and Jack Rowe, Extension community forestry specialist

Immediately after a damaging storm, trees are always a concern. Tree debris is the most common problem blocking roads and foot traffic, and likely have damaged property. Here, we want to talk about tree problems that should be addressed immediately because they present a clear and present danger to people and property. Later, we will discuss rules of thumbs for caring for trees with less risk potential. This discussion is about trees that are damaged by the storm but are still standing. Fallen branches and trunks are a different matter. Please see our article about trees and powerlines.

large branch crack 2

Step 1: Targets:

First, assess the risk a storm damaged tree poses to people or property should it fail in any way. Buildings, power lines, roadways and most importantly people are targets for falling trees. If the damaged tree is over rarely visited or unimproved places, they are not the worry that trees over your home, roads, parking lots, or frequently used patios or playgrounds are.  A tree with a target is a tree that has to be managed. The larger the tree, the more important the problem be dealt with quickly.

Step 2: Locate Any High Risk Storm Damage:

A. Leaning Trees:

Some of the worst storm injuries happen below ground to the root system. High winds combined with rain cause trees to rock in wet loose soil which can break or pull free roots, and in extreme cases cause whole tree to fall. The most prominent sign of this kind of root failure are leaning trees.

If a tree is leaning after a storm, look for a soil mound at the base of the tree on the opposite side of the lean. On the inside of the lean, there may be an indentation in the soil. If the mounded soil has cracks in it, consider the tree a serious problem. Leaning trees with mounding indicates broken and damaged roots, and removal is recommended.

Try and remember if the lean existed before the storm. Naturally leaning trees will often have branches or tree tops that have adjusted to the lean. In such cases, the branches will be growing towards the light even if the tree is leaning away. Call a Certified Arborist if you see any of the following:

Lean

Recommended Maintenance

Likelihood of surviving

Danger

With mounding

Immediately Remove

Low

High

Soil Cracks

Hire Certified Arborist for         further assessment

Low

Moderate

Mounding & Soil Crack

Immediately Remove

Low

High

Lean with no mounds      or Cracks

Hire Certified Arborist for        further assessment

High

Low

heave1 heave2

B. Cracked Trunk or Branches:

During storms, trees are twisted and bent. If the storm is extreme, the wood will crack. The most common cracks are in the crotches where branches or trunks connect. In very high winds, vertical cracks may happen in trunks. All cracks are a major problem and require immediate attention. Trees with cracks may fail at any time and will develop decay compounding the problem. In most cases these trees need to be removed. Contact a Certified arborist if you observe the following:

  • Crack in the trunk (Look carefully because they may be very narrow. You can probe cracks with a knife to check its depth—the deeper the crack the greater the concern.)
  • Cracks in large branches
  • Cracks between two or more trunks or main branches

Crack Recommendations:

Crack

Recommended Maintenance

Likelihood of surviving

Danger

Other

Considerations

Vertical crack on       main trunk

Immediately Remove Tree and Replant

Low

High

These cracks are common and will generally require full tree removal.

Horizontal crack on    main trunk

Immediately Remove Tree and Replant

Low

High

Horizontal cracks are rare but very dangerous and often times hard to spot due to the bark.

On Branch

Prune Branch to ISA standards

High

Moderate

Might consider whole tree removal if the cracked branch is large and the tree species does not respond well to pruning; such as water or laurel oak.

large branch crack 3 large branch crack

 

STEP 3: Moderate Risk Storm Damage

This type of storm damage may not require immediate attention but can wait a few days. However, they will need attention because they predispose your tree to failure in a new storm.

A. Splits:

Start by carefully walking around the tree looking for cracks (see previous section), twisted wood spiraling around the tree, torn or ripped bark, or breaks. Note the severity of the damage to provide the proper management technique. Below is a chart to help quantify damage and receive corresponding management recommendations.

  • Splits occur when large branches break away from the tree. These usually cause large wounds that allow decay to enter the tree, causing structural problems later
  • Smaller splits or broken limbs from them, are easier for the tree to seal. This sort of damage requires checking over years to come. If the tree does not seal over the wound, have an ISA Certified Arborist examine the problem.
  • Broken off trunks require that the tree be removed. Even if lower limbs remain the loss of the top of the tree is a major concern.

 

Broken or Split Trunk Recommendations:

Trunk damage

Recommended      Maintenance

Likelihood of surviving

Broken or stubbed trunk

Remove and Replant

Low

Split or broken limb causes damage to less than 30% of the diameter of the stem

Prune away stubs and Monitor

High

Split or broken limb between 30 to 50% of the trunk diameter

Prune away stubs and Monitor/or Remove

Moderate

Split or broken limbs greater than 30% of the stem diameter

Remove and Replant

Low

Pine trunk broken anywhere

Remove and Replant

Low

Hardwood trunk broken in the top 1/3 of the tree

Prune away damage and Monitor

Moderate

Hardwood trunk broken from the ground to 2/3rds up

Remove and Replant

Low

 

bark rip 4  

 

d. Bark Ripping on the Trunk:

Bark ripping often results from a limb partially breaking and as it falls ripping the bark down the side of the tree. This damage is not initially a structural problem. Rather it can girdle the tree or allow decay and insect problems in the future.

Below are recommendations based on the percentage of the trunk diameter that is affected.

Bark Ripping Recommendations

Amount of Stripped Bark

Recommended Maintenance

Likelihood of surviving

25% or less

Trim the bark

High

25-50%

Trim the bark and    Monitor

Moderate

50% or more

Remove and Replant

Low

 

bark rip 1 bark rip 2

bark rip 3  

The resilience of trees in storms must not be denied. Most of our trees have withstood amazing tests of their strength and remain with us today. Just be aware of the following after any storm event:

  • The trees you examine and make quick decisions about are the trees that might hurt people or property. They have a Target.
  • The bigger and more aged the tree, the more important any damage to it becomes.
  • Any potential for failure must be alleviated.
  • Be willing to remove trees that have suffered irreparable damage.

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