Most arborists agree that you shouldn’t attach objects to trees with screws, nails, screws or anything else that will penetrate the outer bark. It can harm the cambium, the area under the bark where cells quick divide and enhance tree girth. Also, it can damage the phloem, the cells that transport nutrients from the canopy to the roots, as well as the xylem, the cells that carry nutrients and water to the canopy.
Nail holes provide easy access for diseases and insects. Vascular plants are short of immune systems. When a tree is wounded, a chemical reaction occurs. The tree creates boundaries around the wound that limit or stop the spread of decay and disease. This process is referred to as compartmentalization. If a tree is wounded again, the compartmentalization breaks down, as a newly damaged area retriggers the procedure.
Based on the tree’s health, species, size, and the spacing of the nail holes, ten puncture wounds can create ample health and structural issues to kill the tree. Some tree types are better at compartmentalization than others. For example, live oak is good at it. Water oak isn’t. Another possible issue: A tree will ultimately grow around screws or nails, making them veiled hazards for arborists who prune using chainsaws.
Tips for Tree Attachment
If you need to connect an object to a tree, use a strap at least a half-inch wide. Check every year to ensure it’s not girdling your tree. Sometimes the size of a nail put into a tree won’t harm it. The nail would probably be put in around an inch to an inch and a half into the bark. The tree will compartmentalize and heal the cut around it.
Where there might be a problem is with trees that are small, young, or show signs of bug issues or decay. With these trees, the nail could harm the tissues that transport nutrients and water through the tree’s system. The tree might take longer to heal and have a tremendous amount of stress. Stressed trees are more susceptible to diseases and pests.
Be mindful that something substantial, like a piece of garden art or a hammock with someone it, nailed to a diseased or young tree, puts more weight on the tree. Ultimately, this leads to the bark tearing or a wound opening, creating an invitation for bugs.
Before adding nails or structures to your trees, contact an Orchard Park Arborist who can help you create your project with the lease damage to your trees, in the moment and for the rest of the tree’s lifespan.