Ask The Steward
By Dan Ernst

Question: I have large poison ivy vines in some of my trees. Are they damaging and should I cut them out?

Answer: Poison ivy (Toxicodendron radicans) is one of the most common native plants in Indiana woodlands. Most often it is a low growing plant, perhaps 1-2 feet in height. They may occur as solitary plants or in heavier shrublike groupings interconnected by their underground root system. Poison ivy can also grow as a vine and uses trees as scaffolding to grow upward reaching for sunlight. These vines can get quite large- as much as 3-4 inches in diameter and reach high into the tree’s canopy.

Poison ivy can be easily distinguished from grapevines by the way they are attached to their host tree. The vine attaches tight to the tree with small aerial rootlets, giving the vine stem a ‘hairy’ appearance. The native Virginia creeper can be confused with Poison ivy as it too attaches with rootlets, but these vines rarely exceed ¼” in diameter and the rootlets are not near as hairy. Virginia creeper also has 5 leaves, compared to Poison ivy’s three.

So back to your question: are they damaging your trees? Strictly from a timber and tree health standpoint, poison ivy vines are generally of minor concern. Unlike grapevines which can spread throughout a tree’s canopy and even blanket portions of the canopy, poison ivy foliage is much less dense and generally stays closer to the interior portion of the tree. Their impact on healthy trees is relatively insignificant in comparison to grapevines and other problem vines like Oriental bittersweet. Virginia creeper vine is never a problem. That said, I do recommend treating large poison ivy vines to reduce vine weight and photosynthetic (sunlight) competition. Leave the smaller vines for wildlife benefits. My personal threshold is 1.5 inches in diameter. Simply cut out a small section of the vine and move on. I don’t bother treating the stump with herbicide as their regrowth is quite slow and, in my opinion, inconsequential. If you decide to kill the vines, simply spray the cut stump surface with an appropriate herbicide such as glyphosate.

Final note: When handling or cutting vines you will expose and come in contact with the vine’s irritating urushiol oil. Plan accordingly!

Question: What’s ‘forest bathing’?

Answer: The trendy concept started in Japan and centers around immersing oneself in nature to reduce stress and improve well-being. But here’s my answer: It’s what woodland owners do every day, inherently and without thinking. They enjoy their woodlands and soak in all that surrounds them. They do this by walking their woods, hunting, bird watching, working with trees, trails and nature. They do this when taking a break on a log, in a tree stand, or along the stream bank. They do this by noticing and observing how their woodlands change through the seasons and through the years. They rejuvenate their woods and their woods rejuvenate them. They recognize the blessings around them. Woodland owners- the original forest bathers!

Dan Ernst is a professional forester and past Assistant State Forester with the Indiana Division of Forestry.  He has authored ‘Ask the Steward’ since 1992 and can be reached at foresterdan@yahoo.com