Industry News: Bark and Trunk Concerns

Q: What are some thoughts on "yarn bombing" trees?

Wednesday, December 30, 2015   (0 Comments)
Posted by: Shannon Sperati

A: Yarn bombing (also known as yarn storming) is a fairly recent and lately expanding phenomenal form of temporary graffiti that used to be all about invigorating cold and sterile public spaces. Since the late 90s, this temporary form of art has broadened to become more expressive and decorative, with a few exceptions that have focused on socio-political commentary. While other forms of graffiti lend themselves to territorial markings for gangs, vandalism, and even advertisements, yarn bombs tend to be less destructive and convey a softer, gentler and warmer form of expression that requires a great deal of forethought, preparation, and effort. While many people would likely be influenced by public trees being yarn bombed, and the aesthetic impact of yarn bombing trees in our public spaces would certainly and effectively draw attention, I do have a few concerns about the application of knitted yarns to trees from a health standpoint.

1. From a strictly horticultural standpoint, landscapers and other tree planters tend to avoid new plants that have wrappings around the trunk and lower branches. This is because tree wraps are often used to hide damage that has occurred in the nursery. These wrappings do very little to protect trees from mechanical injury, and they can hold water on the trunk, promoting insect infestations from borers and infections of disease/decay-causing fungi and bacteria. The same would also be true of yarn bombs that are wrapped around trees.

2. Another concern I have about yarn bombs is the fact that they obscure tree defects. It is important for municipalities to have an unobstructed view of tree structures that contain defects to be able to determine if the defect can cause tree parts to fail. Obscuring these defects could cause a serious defect to go undetected and could contribute to a tree failure that causes damage or injures someone.

3. Finally, there are concerns with the yarn itself. Depending on the composition of the yarn and its color and longevity, there is the potential for girdling, scalding, toxicity, and other unknown and undesirable physiological changes that could occur as a result of changes to the environment of the living cells just under the bark from the natural open air to an unnatural, confined scheme.

4. While I can see the potential for great social benefits to yarn bombing in certain sterile urban environments, I would have to weigh the potential benefits against the health risks to the tree as a result of yarn treatment. I can see no health benefit to trees as far as it is known from the literature, it can only hurt. Considering that the tree itself already contains a wealth of aesthetics and provides a wealth of benefits to cold and sterile public places, the addition of yarn bombing treatments would seem better served on inanimate, man-made elements in these spaces. I suggest that yarn bomb treatments be directed to things such as light poles, fences, and statuary for greater impact.

I recommend exercising caution before moving ahead with yarn bombing any public objects.

Responder: Marty Shaw, RCA #470, Franklin, TN