A tall, handsome white ash tree shades the east side of our Vermont home. Its golden-brown autumn foliage contrasts with the reds of the sugar maples around it. Its ramrod-straight trunk reminds me of a favorite baseball bat, also ash, that I swung as a boy.
This tree should outlive me by many years, but it probably won’t. Every ash tree in eastern North America — an estimated 7.5 billion trees in all — is in peril. My white ash may well be gone within a decade.
The problem, as usual, is not something vast and amorphous like global climate change. It is something small and specific: an invasive species, in this case the emerald ash borer, introduced to this continent by human carelessness, spread by more human carelessness, and now, many experts fear, impossible to stop.
The ash borer is a metallic green insect, about one-third of an inch long, that is native to mainland northeast Asia and Japan. It was discovered in 2002 in Michigan, where it is believed to have arrived several years earlier as a stowaway in shipping containers from Japan. The ash borer soon migrated to neighboring states and Canada, and was further spread to Virginia and Maryland via illegal shipments of infected Michigan trees.
The insect is very difficult to kill. The ash borer’s larvae carve tunnels through the layers of wood that carry water and nutrients up to the tree’s crown, starving the tree to death within two or three years.
The ash would not be the first iconic American tree to be wiped out by a foreign pest, though it would be the most plentiful and commercially important species lost so far.
In the 1920s the chestnut blight spread across the country, virtually eliminating a tree that gave us fine furniture and sturdy homes as well as a favorite food. A decade later, Dutch elm disease arrived in a shipment of wood from Holland and decimated American elms, a favorite shade tree in small towns and big cities alike.
I encountered Dutch elm disease firsthand when I was in college. The centerpiece of the University of Montana campus is a large oval that was then shaded by a ring of 70-year-old elms. One summer day in 1976, when I was co-editor of the school newspaper, I noticed workmen cutting down several of the trees. I learned about Dutch elm disease by interviewing those workmen. It had taken four decades for the disease to find our small cluster of hand-planted elms tucked deep in the northern Rockies, but it had indeed found us.
Within a few years every one of our elms was gone. To this day, the oval, with its scrawny, immature replacement trees (and not an elm among them), does not look nearly as beautiful as it did when I started school.
The emerald ash borer has not yet been reported in New England, but it is pressing hard. It was detected two years ago outside Montreal, and by last year it was seen in western New York state. Even though the insect does not move rapidly on its own, it is only a matter of time until someone — most likely a camper or homeowner cluelessly hauling firewood — unwittingly allows it to hitch a ride.
The ash borer may be the most serious threat to my trees, but it is hardly the only one. The Asian long-horned beetle, which attacks maple trees among others, has spread from New York City in the past decade. Authorities are fighting a serious infestation in Worcester, Mass., which is perilously close to the prized stands of sugar maple that are big business in northern New England.
There is still time to contain the Asian long-horned beetle, but it is probably too late to stop the emerald ash borer. State and federal foresters lack the money for early detection, rapid destruction of infested trees, and strict enforcement of quarantines and other prophylactic measures. Instead, in a sign of how bad the situation has become, they have established a seed bank to try to preserve the ash genome in order to repopulate American woodlands if the borer wipes out today’s trees.
This carnage makes me wonder: Are we setting the right priorities in our efforts to protect the environment?
We play an expensive and often futile game of catch-up every time an exotic species threatens us with vast damage. The emerald ash borer is just one example. Great Lakes states are alarmed at the prospect of Asian carp that may decimate sport and commercial fisheries. Zebra and quagga mussels cost Great Lakes power companies an estimated $3.1 billion in the 1990s, with damages rising by hundreds of millions of dollars every year since then. A disgusting algae with the descriptive nickname “rock snot” is fouling pristine mountain streams from one end of the continent to another.
Yet, in an era of mushrooming global trade and casual international travel, we have not put much effort into preventing the inadvertent spread of pests. If our invasive-species controls came close to rivaling our drug interdiction efforts (or if critters like the emerald ash borer made a habit of traveling in bales of marijuana), we probably would be much better off.
There is a host of other clear and present dangers to our health and that of our fellow species. While we were fixated on images of crude oil pouring from the now-capped well in the Gulf of Mexico (a serious problem, but one that probably will not have a huge long-term impact), we routinely pay almost no attention to the uncontrolled spewing of pollutants in developing economies like China’s, nor the contamination and misuse of water resources around the world, on which billions of people — mostly poor — depend.
The debate about climate science, and the sloppiness with which the cost/benefit ratios of climate change and its proposed solutions are considered, are literally sucking all the air out of environmental discussion. While we argue about what global warming will or won’t mean for our New England forests 100 years from now, the emerald ash borer is out there today, a little green death warrant for my white ash.