By Matt Bewley
Fargo, ND (August 10, 2009)- Keeping the emerald ash borer out of the Plains states may be impossible, but forestry officials in four states want to be sure they know what they’re up against when the time comes to remove and replace the felled ash trees. The Great Plains Tree and Forest Invasives Initiative, funded by a U.S. Forest Service grant and matching state funds, is a combined effort of state forestry agencies in North Dakota, South Dakota, Kansas and Nebraska to quantify the amount of damage expected from an emerald ash borer invasion. Begun in the summer of 2008, the initiative is in the second of the two years allotted. The program organizers are applying for funding to continue into a third year.
The initiative is deemed critical to those who will have to deal with millions of dead ash trees. Ash trees are the most populous tall deciduous trees used in shelterbelts, snow fences and other rural plantings throughout North Dakota and the Plains states.
“There was a general consensus among the Plains states that emerald ash borer was going to pose a very serious threat to some of the forest and tree resources throughout the region,” says Mike Kangas, a project team leader for the North Dakota Forest Service. “We have a higher percentage of ash throughout the plains than any other region of the United States.”
That said, he and his counterparts in the other three states lack hard counts of ash trees, information which will be crucial to those who eventually will plan and allot funds for removal and replacement of the dead trees left in the insect’s wake. “When you have good numbers, it allows you to make better decisions,” Kangas says.
Emerald ash borer is an invasive insect that attacks and kills all native ash species, including white, green, black and autumn purple. Emerald ash borer larvae, which are cream colored and about an inch long, feed on the tissues just below the bark, creating serpentine tunnels. This feeding starves the tree by disrupting its ability to transport water and nutrients from the ground to its leaves.
Adult insects, which are metallic green and approximately a half-inch long, emerge in June and July, leaving “D”-shaped exit holes in the tree’s bark. Symptoms of emerald ash borer infestation include canopy dieback in the top third of the canopy, new sprouting near the base of the tree, bark splitting, serpentine galleries below the bark and the exit holes. The borer has wiped out entire populations of ash in cities, forests and on farmland.
Each state’s forestry organization fields crews during the summer to complete sample-based surveys of their ash populations. Each has its own specific sampling requirements, based on the state’s urban and rural areas.
“One or two of the states are concentrating a little more heavily on urban areas than rural areas,” says Coe Foss of South Dakota’s Resource Conservation and Forestry Division. “We’re concentrating on our rural areas because the street tree inventories we did in years past, combined with our urban inventory data we got last summer, gives us good base data.”
Foss has hired a contractor to assemble three survey crews. These crews will survey 200 plots in South Dakota. Kangas’ team consists of two specialists, a forester and a technician, who will inventory 300 North Dakota plots. All inventory sites are randomly chosen within certain general categories so that a reasonable representation of the state’s ash profile can be drawn up. The number, species, trunk diameter and height of trees will be recorded along with the use of land on which they are found. Observations also will be made about tree health.
The survey will be used to determine where removal and replacement efforts should be focused. “The data itself won’t help us fight emerald ash borer off, but what it will do is give us an idea of what percentage of our shelterbelts throughout the states are going to be affected, our riparian areas, along stream courses… things of that nature,” Coe says.
From this, Kangas and Coe hope to be able work to out an estimate of the removal and replacement costs in urban and rural areas. With millions of trees expected to fall, the removal efforts alone are expected to be enormous in terms of cost and effort. No one’s even sure what to do with them all.
“That’s what we’re all trying to cope with now, trying to come up with ideas,” Coe says. “In the states where they’ve had a lot of emerald ash borer activity, they’re still trying to deal with all of that.” He thinks they should at least be able to avoid some of the mistakes other states have made.
An educational and outreach program is another component of the initiative. “We wanted to get a coordinated, focused message across the Plains so that all four states are sending similar messages,” Kangas says. “Mostly, what we focused on is informing people about moving firewood. That’s how this insect has been spread around.”
Finally, the initiative is laying out the strategy for the detection and monitoring of emerald ash borer, including the use of traps, when it arrives. Kangas and Coe both expect to have their surveys completed in August.
Ag Week- Plains states surveying ash populations before emerald ash borer arrives