Editorial: Obituary for ash trees is premature
The headlines shout doom and gloom for a glorious species that includes the black ash Native Americans used to make baskets and the white ash that formed the bats of many baseball greats.
“Will we kiss our ash goodbye?” asked the headline in American Forests magazine.
And Tuesday, the headline in the New York Times science section was not a query but a declarative statement: “After the Trees Disappear.”
For the scientists whose study formed the basis of the article, the fate of North America’s ash trees is a foregone conclusion. All but a small percentage will fall victim to the gnawing jaws of the white, worm-like larvae of the emerald ash borer, a metallic green beetle native to Asia.
Their questions now are: What will fill the void left when the ash trees are gone, and how will the web of life change?
The pessimism expressed in the Times article is premature.
Though the hordes of invasive species changing the American landscape may seem unstoppable, there’s a chance the beetles, like other invasive pests, can be contained or defeated.
Emerald ash borers have been found in southern New Hampshire, Canterbury and on Hall Street in Concord. Once infested, trees must be felled and burned. But insecticides have improved, and hope is on the wing in the form of a tiny wasp native to Idaho and Washington.
Some four centuries ago, Jonathan Swift noted in a poem that,
So naturalists observe, a flea
Hath smaller fleas that on him prey;
And these have smaller fleas to bite em.
And so proceeds Ad Infinitum.
The emerald ash borer has as its nemesis several species of parasitic wasps that lay their eggs on the eggs of the beetle. The wasp larva develops within the borer egg and consumes it.
New Hampshire scientists have imported the West Coast species and are breeding it in two small insectaries.
The wasps have been released at the site of several borer infestations to test their effectiveness.
Urban trees are especially valuable.
A mature shade tree on a lawn can be worth thousands of dollars in real estate value and even more in reduced cooling costs in summer and, because trees block wind, heating costs in winter. Meanwhile, trees filter the air, pump out tons of oxygen and recycle huge quantities of water.
Cities in the Midwest, where the beetle’s infestation is at its worst, are finding that it’s cheaper to protect the ash trees that shade streets and yards with insecticides than to cut them down and replace them.
Ash trees form a tiny percentage of Concord’s trees but are the dominant species in towns like Danbury, Bristol and Alexandria. Protecting an ash tree with an insecticide easily applied by a homeowner costs tens of dollars per year.
When the ash borer population is high, use of an insecticide pumped into the tree by a licensed professional costs about $100 per year, and is highly effective. Some treatments even employ an organic insecticide. Please protect your ash trees and those of your neighbors by spending a bit to combat the beetle. And don’t give up hope.
A wasp has been found that attacks the woolly adelgid, a scale insect that destroys the hemlock trees that shade trout streams and shelter deer in winter. Their loss truly would change the landscape. At New Hampshire test sites, the wasp has reduced the adelgid population by 50 to 90 percent.
The battle against invasive species will be ad infinitum, but, with help, the good guys may be able to hold their own or win.