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.
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:
Likelihood of surviving
Hire Certified Arborist for further assessment
Mounding & Soil Crack
Lean with no mounds or Cracks
Hire Certified Arborist for further assessment
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:
Vertical crack on main trunk
Immediately Remove Tree and Replant
These cracks are common and will generally require full tree removal.
Horizontal crack on main trunk
Horizontal cracks are rare but very dangerous and often times hard to spot due to the bark.
Prune Branch to ISA standards
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.
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.
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.
Broken or Split Trunk Recommendations:
Broken or stubbed trunk
Remove and Replant
Split or broken limb causes damage to less than 30% of the diameter of the stem
Prune away stubs and Monitor
Split or broken limb between 30 to 50% of the trunk diameter
Prune away stubs and Monitor/or Remove
Split or broken limbs greater than 30% of the stem diameter
Pine trunk broken anywhere
Hardwood trunk broken in the top 1/3 of the tree
Prune away damage and Monitor
Hardwood trunk broken from the ground to 2/3rds up
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
25% or less
Trim the bark
Trim the bark and Monitor
50% or more
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:
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