WATERVILLE – There were once hundreds, perhaps thousands, of elm trees here. Hence the nickname “The Elm City.”

The elms reached their pinnacle in Waterville during the 1930s, according to published reports, but their numbers were drastically cut by the 1960s and ’70s. Today, city officials believe there are just a handful of large mature elms remaining.

The primary culprit has been Dutch elm disease, which — combined with urban development and a lack of regular tree maintenance — has wiped out scores of elms in Maine and elsewhere.

In Waterville, there’s a mammoth survivor in the heart of downtown. Looming in Castonguay Square right outside City Hill, at about 75 feet tall and 125 years old, is one of the last of the city’s large American elms.

City officials are taking steps to keep the elm around for another 125 years.

“I grew up in the city and I knew the ‘Elm City’ nickname,” said City Manager Mike Roy. “Of course, it’s a tragic thing what’s happened to all our elms, and I think our nickname has faded in the background. This one, it may not be the last in the city, but I believe it’s by far the biggest.”

Roy said when he became Waterville’s city manager seven years ago, he was struck by the beauty of the large elm in the public park. About two years ago, Roy said he noticed some of the elm’s upper limbs were dying, with their leaves turning a harsh, unhealthy yellow, known as flagging.

“That really worried me and got me to thinking that it would be a shame to watch it being cut down,” Roy said.

Enter Tim Lindsay, an arborist with Bartlett Tree Experts. On Oct. 14, Lindsay arrived with a small crew and spent the day pruning dead branches as the first step in a plan to keep the elm healthy.

Lindsay said the thinning of tree limbs prevents damage from rubbing and enables wind to pass through the tree more easily instead of pushing against it.

He chose to do the work during the fall because the summer is when elm bark beetles are most active and most likely to be attracted to the bleeding sap caused by pruning. Those beetles carry Dutch elm disease, a fungus that attacks the tree’s vascular system and ultimately causes wilting and death.

“Once it gets into the tree, it gets into the vascular system pretty darn quick — probably once you see the tree start flagging, within a year, two at the most, that tree is gone,” Lindsay said. “It’s much like our circulatory system. What happens is the fungus clogs up the vascular system, shuts down branches, and typically in July you’ll see branches turn bright yellow.”

He said when the flagging appears, “you drop everything and remove the flagged limbs.”

Arborists have learned a lot since Dutch elm disease arrived in the United States 60 to 70 years ago, Lindsay said. For instance, the roots of a row of elms along a street will typically graft, and when the disease hits one of them “it just goes right down the line, and that’s the biggest thing (people) didn’t realize.”

“Now, you have this one solitary tree. This is in good shape, because you don’t see many elms around,” he said. “What happens is the beetles get started in one tree, and if it’s weak, it predisposes it to bring the insects in. Then, that’s kind of a launching point for the disease to go from that tree to other ones.”

Aside from branch pruning, the elm is also receiving a prescription soil treatment, supplying it with key nutrients.

“What we did is called prescription fertilizer: We take a soil sample, send it to the lab, they know it’s an American elm, they check in the database and say, ‘This is what you need,”‘ Lindsay said. “We show up and that’s what we give the tree, rather than your typical 10-10-10 fertilizer. Everybody uses that, or maybe something similar. Well, it may not need as much phosphorus. It made need trace elements — magnesium, zinc.”

To deter the disease from taking hold of the elm in Castonguay Square, Lindsay’s crew will return in the spring to inoculate the tree with a fungicide, a process known as a root flare injection. If the disease gets into the tree, the fungicide shuts the disease down, Lindsay said.

That injection lasts two to three years and must be done regularly thereafter in order to be effective.

The pruning, soil treatment and fungicide is costing the city about $1,700.

“It’s an investment,” Lindsay said. “You’re going to hear public outcry if you lose this tree, so as a result you’re kind of forced to take those precautionary actions to treat the tree. This tree’s in really good shape.”

Other massive elms have not been so lucky.

The day after the elm tree work in Waterville, Lindsay and his crew were in Scarborough to cut down a 200-year-old elm nicknamed Elsa along U.S. Route 1.

A 215-year-old, 110-foot elm known as Herbie was cut down in Yarmouth because of Dutch elm disease in January 2010.

Roy concedes the investment is no guarantee that the elm outside City Hall won’t also one day suffer the same fate. But the steps that are being taken are important ones toward preservation, he said.

“It is our heritage,” Roy said. “I think we have a responsibility to do everything we can.”

Kennebec Journal Staff Writer Scott Monroe can be contacted at 861-9239 or at:

[email protected]