John Colson

Sopris Sun Correspondent

Is Carbondale’s “urban forest” in danger of a precipitous decline?

David Coon, the town’s urban forester (among numerous other duties) believes it might be, and has cautioned other town officials that something needs to be done about it.

Coon, who took over the position last May, recently issued a round of blast e-mails to members of Carbondale’s Tree Board, warning of a looming infestation of something called the emerald ash borer, which he said could quickly mow down nearly a tenth of the town’s “urban canopy” of trees.

The Tree Board is made up of volunteers who advise the town’s public works department on matters relating to trees and the urban canopy.

Town Manager Jay Harrington and Public Works Director Larry Ballinger, in turn, advise the board of trustees on any issues they believe warrant official attention.

The Tree Board’s current makeup, according to the town’s website, includes chair Kim Bock, Ken Belinski, Dan Bullock, Connor Coleman, Dieter Martini and Shaun Rourke, with Trustee Katrina Byars serving as the trustee liaison.

According to Coon, officials from the U.S. Forest Service conducted a survey of Carbondale’s urban forest in 2010, and counted “about 1,900” trees of various types on town property.

In an e-mail on Sept. 29, Coon noted that he believes that roughly 20 trees were “removed” (cut down) in the past year, which amounts to “a rate of loss of about 1 percent per year” if that level of removal carries through from year to year.

“That doesn’t sound like a lot, but if we go for 10 years without replacing trees that are removed, we will end up with a loss of 10 percent of our urban forest if the removed trees are not replaced,” he wrote.

He added that the species that mainly are being cut down are ash, aspens and Siberian elm, which he said “are three of the top-four most numerous trees in Carbondale’s inventory, and they are also the most in decline.”

The Siberian elm, he told the Sopris Sun, comprises nearly 17 percent of the town’s tree population, which he said is higher than the accepted diversity standard of 10 percent per species.

At an average age of about 50-70 years, he said of the Siberian elm, they are “reaching the end of their lifespan” and already are beginning to lose branches and show signs of inadequate pruning over the years.

“They’re manageable,” he said of the Siberian elms, “it’s just mainly unsightly,” and the town is debating whether to begin thinning the trees and replacing them with other species.

But, he wrote in one of the e-mails, “We also are going to see a complete decimation of our ash trees when the Emerald Ash Borer (sic) arrives, which almost instantaneously decreases our urban forest by about 8 percent.”

Coon told The Sopris Sun that the borer has reached the Front Range of the Colorado Rockies, but has yet to be detected west of the Continental Divide. But, he pointed out, that could change at any time if, say, some campers from Boulder or Denver travel to the Western Slope carrying ash logs for firewood.

“All they have to do is lay the wood on the ground, and for the ash borer to emerge,” he said.

In a second e-mail to the Tree Board, dated Oct. 6, Coon more cheerfully reported on tree planting that is taking place this fall.

Along Eighth Street and the Rio Grande Bike Path, and in Hendrick Park, he reported, the town is planning to plant a mixture of honeylocust, Amur chokecherry, hackberry, Greenspire linden and swamp white oak.

In addition, he wrote, the town will plant some “semi-dwarf apple trees at the (Carbondale) Nature Park,” which will be supported by a new irrigation system he said is now being installed.

The new trees, he reported, are to be from the Haralred apple family, which are “supposed to be very cold hardy and very resistant to fire blight.”

All in all, Coon told The Sopris Sun on Oct. 7, the town’s urban forest is “in pretty good shape, as far as what we have. In an urban forest, it’s really important to have diversity,” so that if one tree species gets in trouble, the town does not suddenly find itself bereft of shade and bird habitat.

“We’re doing a good job of keeping up with the management of the trees,” he concluded, adding that while his e-mails were intended to serve as cautionary notes, “there’s not a note of alarm.”

The town planted ash trees in Fourth Street plaza more than 10 years ago. Since then, the emerald ash borer arrived in Colorado but has yet to travel west of the Continental Divide. Photo by Lynn Burton