A 20-foot tree with its wide trunk and long reaching thick branches may appear indestructible, but it is not. Trees are vulnerable to weather conditions, pest or disease or an unfriendly pet. When any part of a tree is damaged, whatever the cause, there are things you can do to restore that tree to almost new.
One part of a tree that is susceptible to damage is the bark. Tree bark is said to be like our skin. It protects the circulatory system or phloem layer of the tree that brings the energy generated by the leaves to the rest of the system. If the bark is scratched or damaged, then the tender phloem layer is also injured.
If the bark’s damage goes less than one-quarter of the way around the trunk of the tree, then the tree should be fine and will survive without any problems. Still, the wound must be treated and should not be left open to allow disease to get in. If the bark’s damage goes from one-quarter to half around the tree, it will sustain some damage, but will most likely survive. This damage will result in lost leaves and maybe some dead branches. Wounds of this size need to be cared for as soon as possible and should be monitored carefully for some period of time.
If the bark’s damage is greater than half way around the tree, the tree’s survival is in jeopardy. You should call a tree expert to determine what can be done to save the tree.
If the tree is experiencing 100 percent damage of the bark, then it is suffering what is called girdling and it will most likely die. Some arborists may attempt to treat and fix the tree or create a condition in which it is kept alive long enough to repair itself.
Girdling can occur when a lawn care tool like a weed eater or a lawn mower accidentally strikes the trunk, when a stake tie becomes too tight, or when a small rodent or pet chews on the tree bark. Spreading mulch around the tree can help to prevent mechanical damage. Perhaps a low structure around the tree may keep rodents and pets away.
Treating a Girdled Tree
Treating a girdled tree must be started immediately.
The first thing to do is to clean the wound and keep the wood from drying. Professional arborists would perform grafting or bridge grafting so that nutrients can be transported across the tree. The graft is considered successful when enough nutrients can be carried over the wound. This would permit the roots of the tree to survive and permit the tree to suck up water and minerals to help the tissues and leaves. Providing time will permit the leaves to make food that helps form new tissues. A new growth will form over the wound and ensure the tree’s survival.
The first step to fixing a girdled tree is to thoroughly clean the wound. The process starts with the removal of any loose bark as well as some healthy branches or twigs that are the size of your thumb in diameter and 3-inches longer than the width of the wound. Use a clean and sharp utility knife to trim each end of the surviving twigs so they lie flat on the tree’s trunk and cut a wedge shape into the other ends. These twigs will serve as the bridge that gets nutrients beyond the wound to the rest of the tree.
Make two parallel cuts starting at the wound and through the bark to form flaps above and below the wound. The cuts should be a bit longer than the wedge shaped cuts of the bridge. Lift the flaps and insert the bridge under it. The bark on the bridge pieces should be placed slightly under the flaps, topside up. If the trunk layers and the bridges join, a flow of nutrients will be re-established and the tree will be restored.
If you need help to treat a girdled tree, then contact the local cooperative extension office.
(Next time – Part II – Repairing Damaged Trees)