When is a City Tree Worth Saving?

By Dan Testa, 8-12-08

	Caption: Brittany Pervais, an urban forestry intern, measures a black locust tree on Third Avenue East in Kalispell. - Lido Vizzutti/Flathead Beacon

At one time, Great Falls had more American elm trees than any other city in Montana, around 14,000. Early urban planners planted the tree due to its majestic size and shape. It grows quickly and is able to thrive in the compacted soil and air pollution of a city environment. But sometime in the 1980s, Dutch elm disease arrived. Jon Thompson, natural resources supervisor for the city of Great Falls, suspects it came in a load of firewood from elsewhere.

“Since the mid-80s, out of those 14,000, we’ve lost almost 10,000 of them,” Thompson said. “Like a lot of communities, the city wasn’t looking for this.”

Dutch elm disease is actually a fungus that attacks the trees’ vascular system, impeding water circulation until leaves, and eventually whole branches of the tree, wither and die. The spores of the fungus are spread by elm bark beetles, which lay their eggs beneath the bark of diseased trees, then the offspring pass the disease spores onto healthy trees. The disease also spreads among interconnecting root structures of American elm trees in close, urban environments. Once Dutch elm disease afflicts a tree, there is no cure except a costly fungicide treatment that doesn’t always work, and must be kept up over the life of the tree.

For about a year now, city officials have been aware of the disease’s existence in Kalispell.

“It’s been verified that we have Dutch elm disease,” Mike Baker, director of Kalispell parks and recreation. “If we don’t do anything it will take every single American elm in the city of Kalispell.”

The city has already removed 32 American elms because of the disease, Baker said, and plans to remove about 30 more in the fall. American elms in Kalispell’s parks and along its boulevards make up a little more than 7 percent of the city’s trees. Of the 608 elm trees, according to a 1991 inventory, 379 of the elms are American, and Baker said Kalispell can expect to eventually lose them all.

Brittany Pervais records tree information, including height and location, onto a PDA (Personal Digital Assistant) that will be copied to a main computer at Parks and Recreation Department.

The budget for Kalispell’s urban forestry unit comes from an assessment paid for by city residents to take care of the trees, which means treating and containing Dutch elm disease is unlikely to be hindered by the serious financial pinch the city finds itself in this year. The same can’t be said for the rest of the parks and recreation department’s budget. But the key for the urban forestry program is to keep the number of American elms requiring removal to a minimum.

“If we get hit with having to remove 160 trees in a year, then that’s going to get fairly expensive,” Baker said.

To assess the health of – not only the elms – but all of Kalispell’s urban canopy, the parks and recreation department has begun a new inventory of the city’s trees, the first of its kind since 1991.

As part of a grant from the state Department of Natural Resources and Conservation to update the city’s tree inventory, Urban Forestry Intern Brittany Pervais has wandered the streets and parks of Kalispell, armed with a caliper and a GPS device which allows her to enter the location and basic characteristics of every city tree into a database. Since June, she has uploaded information on nearly every tree from Center Street to 14th Street on the east side of downtown, and plans to finish the job next year.

“It’s basically just simplifying the information that we would like to have,” she said.

Pervais measures the width of the tree at chest height, then records the overall height, species and relative health of the tree – though assessing the health of the tree can be difficult if the symptoms aren’t obvious.

“You can tell when a tree is sick because the leaves are dying or wilting,” Pervais said. “Some diseases, like Dutch elm, to really make sure that the tree is sick, you would have to strip the bark and look for markings within the tree.”

Pervais isn’t qualified to make those assessments, but she can alert more senior staff to trees in need of a closer examination.

Some residents Pervais has encountered question why the city has trees at all. According to Baker, Kalispell’s urban canopy is a large economic asset that elevates the property values within the city by purifying the air and providing shade. The National Arborist Foundation places a value on urban trees based on their size, location, and health, Baker said, and part of what the current inventory aims to learn is what the current value of Kalispell’s urban canopy is worth. Baker anticipates the value will be well above $3 million.

As for dealing with Dutch elm disease, Kalispell sent some parks and recreation staff members to Great Falls last summer to learn more on mitigating the spread of the disease. In Great Falls, the city has opted to use a fungicide to preserve its oldest, biggest American elms in key locations. The treatments cost between $200 and $300 per tree, and are required every three years.

Kalispell now must decide whether it can afford to treat any of its biggest, oldest American elms accordingly. [End of article]