A tree worth preserving: UMass students get close-up lesson in the battle against Dutch elm disease

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  • Owen Bryan, left, a student in Kristina Bezanson’s commercial arboriculture class at the University of Massachusetts, and Ryan Mange, center, arborist at Northeast Tree Care in Sunderland, measure the circumference of an elm tree on Sunset Avenue in Amherst while Rob Gorden, right, of Arborjet, a Woburn company that treats diseased trees, gives a demonstration on treating Dutch elm disease to the class on Thursday. STAFF PHOTO/KEVIN GUTTING

  • Ryan Mange, arborist at Northeast Tree Care in Sunderland, prepares a working solution of systemic fungicide during a demonstration on treating Dutch elm disease Thursday in Amherst. STAFF PHOTO/KEVIN GUTTING

  • Rob Gorden, Director of Urban Forestry and Business Development at Arborjet, prepares to apply systemic fungicide to an elm on Sunset Avenue in Amherst during a live demonstration on treating Dutch elm disease on Thursday, Sept. 16, 2021. STAFF PHOTO/KEVIN GUTTING

  • About 30 spectators, including students in Kristina Bezanson’s commercial arboriculture class at the University of Massachusetts and residents of the Alpha Tau Gamma fraternity across the street, attend a live demonstration on treating Dutch elm disease on Sunset Avenue in Amherst, Thursday. STAFF PHOTO/KEVIN GUTTING

  • Rob Gorden, Director of Urban Forestry and Business Development at Arborjet, talks to students in a University of Massachusetts commercial arboriculture class about treating Dutch elm disease during a live demonstration on Sunset Avenue in Amherst on Thursday, Sept. 16, 2021. STAFF PHOTO/KEVIN GUTTING

  • Kristina Bezanson, a lecturer in Arboriculture and Urban Forestry at the University of Massachusetts, brought students from her commercial arboriculture class to watch a live demonstration on Dutch elm disease at an elm on Sunset Avenue in Amherst on Thursday, Sept. 16, 2021. STAFF PHOTO/KEVIN GUTTING

  • Ryan Mange, left, arborist at Northeast Tree Care in Sunderland and a University of Massachusetts alum, helps UMass Stockbridge School of Agriculture student Owen Bryan measure the circumference of an elm tree on Sunset Avenue in Amherst during a live demonstration on treating Dutch Elm disease on Thursday, Sept. 16, 2021. The specimen is over 17 feet in circumference. STAFF PHOTO/KEVIN GUTTING

Staff Writer
Published: 9/19/2021 8:04:42 PM

AMHERST — The patient stood approximately 80 feet high and somewhere over 17 feet in circumference at its base, depending on where you placed a tape measure. Its age? Probably close to 100 years, maybe more.

To the untrained eye, this stately elm tree — known as the Grayson elm — at 111 Sunset Ave. in Amherst, looked reasonably healthy, with a full canopy of branches and leaves, though perhaps its lower bark was a little ragged.

But this elm, just like so many others across the country, is battling Dutch elm disease, a plague that arrived in the U.S. in the late 1920s/early 1930s and within about five decades proceeded to destroy over 80% of the nation’s elm trees, according to some sources.

The disease is caused by a fungus, spread by bark beetles that burrow into the trees; the fungus blocks water movement in a tree, causing its foliage to wilt and eventually die. The whole elm can then follow.

But there are ways to fight the disease and to preserve elms, as an arborist explained last week to a group of University of Massachusetts students who gathered at the Amherst tree for a demonstration of one of the treatment methods.

Rob Gorden, director of urban forestry and business development at Arborjet, a Woburn company that treats diseased trees and other plants, told students from the Stockbridge School of Agriculture that arborists should ideally think of themselves as “tree physicians, not tree morticians.”

“There are way too many trees being taken down unnecessarily,” said Gorden. Even if removing a tree — typically an expensive job — can generate a good amount of income, treating trees regularly to preserve them also generates money for arborists and is a much better outcome from an environmental and aesthetic standpoint, he noted.

“I’m not sure what kinds of careers you guys are looking at, but I can tell you that you can make a decent living this way and feel good about what you’re doing,” said Gorden. (The students were in fact from a commercial arboriculture class taught by Kristina Bezanson, a lecturer in arboriculture and urban forestry.)

The demonstration was arranged by members of the Alpha Tau Gamma (ATG) fraternity at UMass, which is right across the street from the elm and has been a Stockbridge-affiliated frat for a century, according to Nessim Watson, the school’s director of recruitment and communication. He said current members and Stockbridge/ATG alumni have raised money for treating the tree over the last several years.

For his demonstration, Gorden teamed up with Ryan Mange, an arborist with Northeast Tree Care in Sunderland and a UMass alum. Arborjet, according to its website, manufactures treatment systems designed to combat invasive pests and species that are based on the specific physiology of each individual plant that’s serviced.

In this case, Gorden explained, he would be injecting a mix of water and fungicide directly into the elm tree at its base; the mixture would enter the tree’s vascular system, which would draw the solution up from its base and roots to its upper branches and leaves.

Gorden drilled a succession of small holes all around the base of the tree, about 18 inches off the ground, pointing out how he was spacing the holes to make sure that what he called “the chemistry” was delivered evenly to the elm. In each hole, he would then knock in a small boring tool, about the size of a screwdriver, with a mallet to gauge the depth of the hole and to check for any internal decay in the trunk’s bark.

Internal rot and decay is often the cause, Gorden noted, “when you read about all these trees coming down in a bad storm.”

In each hole in the elm, he hammered in a small, plastic plug with a tiny hole; in those holes, he inserted slender needles that were connected to rubber hoses, which in turn were connected to a bottle of the “chemistry.”

That bottle of fungicide solution would go in on one side of the elm’s trunk, but only after Gorden took what seemed an unusual step: He used a bicycle pump to force air into the bottle to pressurize it.

Then he asked students to step closer to watch the air bubbles in the rubber hoses as he opened the valves on the needles; the faster the air bubbles moved through the rubber hoses, the better, as this would show the tree’s vascular system was not blocked, or at least not badly blocked, and that the elm was quickly absorbing the fungicide.

The bubbles marched in a steady stream, pleasing Gorden. “This is a good sign,” he said.

Bezanson, the UMass lecturer, said there are some significant trees on the UMass campus that Stockbridge School students examine as part of their studies, and since this one is located close to campus, “It made sense for us to have a look at it, and to hear from someone who went through some of the same programs.”

She and Gorden also recalled growing up in towns — Gorden in Rhode Island, Bezanson in Massachusetts — where whole stands of elm trees succumbed to disease. Gorden said part of the problem was that elms had once been planted in rows along streets all across many parts of the country for their shade value, making them more vulnerable to Dutch elm disease, as the fungus could easily spread from tree to tree.

The disease got its name because it was first diagnosed in the early 1920s by Dutch tree experts. It’s believed to have originated in Asia; it made its first appearance in Europe around 1910. According to a number of sources, it came to the U.S. around 1930 or the late 1920s in a shipment of infected logs from Europe, either from Holland or France.

Today there are a number of elm species in the U.S. known as cultivars — trees selectively bred — that are more resistant to Dutch elm disease. However, according to the UMass Extension Service, some of these varieties tend to have weaker branches and poor canopy structure compared to the more common American elm species.

Gorden said avoiding monoculture planting of trees can also help protect elms (and other trees), as can keeping a close watch on them and treating them regularly; that can include lopping off any branches with wilting leaves. He noted that some old holes in the trunk of the elm at 111 Sunset Ave. indicated it was likely injected with fungicide about three years ago.

Preserving trees, and working with municipal officials to do that, should be a goal for any arborist working in urban forestry, he added. He said one of his most satisfying jobs was convincing officials in Chicago a few years back to preserve, through injected treatments, extensive numbers of Ash trees that had been slated for removal because another pest, the emerald ash borer, had infected some of the trees.

“There’s an opportunity here to make a difference,” he said to the students.

Steve Pfarrer can be reached at spfarrer@gazettenet.com.


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