Good branch angles versus bad branch angles

Homeowners tend to take the health of trees for granted until the tree fails and causes damage. Trees with both defects and the ability to hit people, homes, fences, power lines or other improved values are considered hazard trees. Professional arborists are trained to evaluate trees for the potential to fail, and the evaluation process can be highly technical.

However, homeowners should look at their trees for cavities and fungal growths because these are obvious to see. Other defects are more subtle and required a trained eye for careful examination.

One place that a homeowner can check their trees easily is at the branch angles. The basic question to ask is, “Is the branch angle U-shaped or V-shaped?” A strong branch angle is U-shaped because there is solid wood attaching the branch to the trunk.

If a homeowner observes a V-shaped branch angle, then that branch has a high probability of failing because there is included bark between the branch and the tree trunk.

In Figure 2, a section from a pecan tree has deep included bark causing a poor attachment with the truck. As both the branch and trunk grow diametrically, there is pressure on this attachment and splitting will result.

If a small tree has a V-shaped angle, the homeowner can prune out the branch with this poor attachment, and the tree’s structure will be improved. If the tree is large with this weak branch union, a professional arborist should be consulted about practical solutions, especially if a home or other improvement is a target of tree failure.

To find a state licensed arborist, visit the Louisiana Horticulture Commission’s page at From there, choose “Arborist” in the “Licensed Horticulture Professionals” list to see a recently updated list of arborists by parish.

Photo of two cross sections of wood displaying branch angles.

Figure 1. Both specimens have U-shaped branches with good wood attachment. The specimen on the left is from a pecan tree, and the specimen on the right is from a black cherry tree. Note the small bark inclusion at the red arrow in the black cherry. Photo by Keith Hawkins.

Photo of a cross section of wood displaying branch angles.

Figure 2. This section from a pecan tree shows a deep V-shaped angle with a major bark inclusion at the red arrow. Photo by Keith Hawkins.

6/1/2023 3:56:33 PM
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