Holes in Trees: Hazards or Harmless?

Holes in Trees: Hazards or Harmless?

Hazardous trees cause a danger to people and property. When strong winds and storms hit, parts or all of the tree can fall to the ground. However, by paying attention to the warning signs of hazardous trees, homeowners can prevent most accidents and property damage.

Fortunately, homeowners can notice the clues that show a tree is about to have a defect. For instance, if a tree has large branches attached with tight, V-shaped forks, you should consider having those branches removed or lightened. Other warning signs of structural instability include cracks in the trunk or major limbs, hollow or decayed areas, or the presence of extensive dead wood.

Mushrooms growing from the base of the tree or under its canopy may be a sign of root decay. Remember to be thorough in your evaluation; the absence of fungus does not necessarily mean a tree is healthy. When any trees have had construction activities – such as addition or removal of soil, heavy equipment movement or digging, trenching – anywhere under the spread of branches, homeowners also should be suspicious. These activities can cause root decay or death, and it can lead to the structural instability of the tree.

The most recognizable sign is a hollow part in the tree, but even a large hole does not mean that a tree is going to be hazardous or that has to be filled. Filling of hollow trees, a process called “cavity filling,” used to be practiced by arborists for many years. Recent research discovered that cavity filling is not needed to support or improve the health of hollow trees. Cavity filling with cement can actually damage a tree.

Cavity filling with cement actually can damage a tree, because the cement column in the hollow does not move at all. Tree are always moving, swaying with wind, and growing continuously. The friction between the solid cement filling and the tree can damage the tree.

Wood decay fungi that created the hollow in the first place may take advantage of new injuries created by rubbing and invade the remaining healthy tissue of the tree. Professional arborists are using new types of synthetic foam now to fill cavities just for aesthetic reasons. These foams will bend and move with the tree, reducing injuries. However, it does not improve the health of trees or give extra support for the tree. If structural support of a tree is required, a professional arborist will recommend cabling, bracing, propping, tree guying or removing the tree – not cavity filling.

Remember, a professional arborist can assess your landscape and work with you to determine the best course of action to care for and maintain the trees and shrubs in your landscape.

If you have any questions, please feel free to call the Tree Guys at 402- 438-875.

* Source Tree Care Industry Association