By Larry Hodgson
One of the damages professional arborists see the most frequently on trees is strangulation (girdling). Someone long ago staked the tree and simply never removed the guy-wire. Or installed a hammock or a clothesline between two trees using a rope and now the rope is eating into the bark. There are dozens of other reasons why someone might think wrapping a restricting device around a tree might be a good idea, but the fact remains: this is never good for woody plants and could eventually kill the tree.
Trunks Expand, Wire Doesn’t
It is important to understand that tree trunks increase in diameter as they grow. So do branches. So, if a cord, a wire or even a supposedly safe tree tie is attached around a trunk or branch and stays in place too long, it will cause damage. The bark will start to grow around it, leaving a permanent mark. Worse, if left too long, the restriction will keep sap from flowing through the tree, eventually killing all growth above the constricted part. This is especially annoying in that it can take years to finally kill the tree and losing a long-established tree is not something anyone wants to see happen.
What to Do?
First, never leave a tree staked very long: normally one year is the most you’ll ever need. So, when the time is up, just unwind the cord or wire or cut it free. The faster you remove the stake (and the wire), the better.
If you have a good reason to leave the stake on longer, at least move the wire or cord to another spot each spring. Also, there is never a need to excessively tighten a wire, cord, or strap around a trunk or branch. Even a staked tree should be able to move at least a bit in the wind.
So much for staking, but what if you want to fix something permanently to a trunk (hammock, clothesline, signage, etc.)? Wrapping a cord or wire around the trunk is never a good idea unless the installation is to be temporary. Even inserting the wire into a section of old garden hose, supposedly to keep it from digging into the bark, will only protect the trunk for a few years: it will cut into the bark if left on permanently.
Instead, don’t hesitate to screw a hook or an eyelet into the trunk. No, it will not cause major damage to the tree: inserting a metal stem into a trunk is no more harmful to the tree than having an ear or nose pierced is to humans.
That sounds suspicious? Visit a botanical garden or arboretum and take a look. They don’t hesitate to screw identification plates into the trunk of a living tree. If botanists do it, you can too.
Whatever your need, the important thing to remember is simply to not strangle the trunk or branch of any tree with a permanent wire or cord.
Article originally published on August 14, 2016.
I had a 3/8 in. steel rope in a rubber sheath around the trunk of a 70 ft. oak, as an anchor for our bird feeder line, for 12 years. Did not realize that it might strangle the tree and I may have left it too long as this year it is leafless and I noticed that the bark had totally surrounded it.. This is the first time that has happened. With no leaves, and the bark surrounding much of the rope, I though it might be good to remove the constraint. So, I dug the road out of the tree which left a 1/2″+ trench around the total circumference of the tree. Is there anything I can plug the trench with to protect the tree from any further challenge? Or, with the loss of leaves, am I too late. PleAse advise.
My mountain Laurel split at the trunk from the freeze…yet it still bloomed above the injury. Today we were able to get it back but had to use circumferential metal cabling (like used w/ pipe fitting) to fix it. I realize this could kill it but the potential is there already. Figured I would set a date to remove the cables in time to see if it can heal. Thoughts?
If I were you, I’d use screws or nuts and bolts in your case, although what you suggest would be acceptable for a year or possibly 2. This article would be more appropriate to your situation: https://laidbackgardener.blog/2018/12/26/how-to-fix-a-broken-branch/
I encounter this less that other arborists did before my time. There are several oaks and a few other trees at the farm that had barbed wire wrapped around them prior to 1974. The wire is still in there somewhere.
My dogwood tree has a greenish-white fungus all over the trunk. It looks terrible but it blooms every year and seems to be okay other than that. What causes that fungus?
It’s probably just lichens: https://laidbackgardener.blog/2015/10/17/lichens-harmless-to-trees/
In a related issue, do you recommend that people do or do not pile mulch clippings around bit trees? Thanks.
Mulch around trees is good… to a point. Too much is harmful, cutting off air circulation to tree roots. The usual recommendation is no more than 4 inches (10 cm).
Father told us to never drive anything into trees, I think it was so they could be used as firewood without damaging tools.
The lesson was learned, I think one should use rubber hose as collars around trees, so it will not hurt the tree.
Rubber hose will still damage tree bark, just not a rapidly as, say, wire. As the trunk expands, the hose will eventually become so stretched it can no longer expand, then if it doesn’t snap, it will start to dig in.