I recently noticed a tree on my campus which appeared to be near death. At its top bare branches stretched skyward, with just a few putting forth immature and sickly-looking leaves. Around its trunk a thicker cluster of leaves had formed, which I first assumed were from an opportunistic vine, but were in fact new branches coming up at its base. When I asked the director of the University physical plant about the tree, he told me that it was one of ten Ash trees on campus that have fallen victim to the Emerald Ash Borer, an Asian beetle which arrived in North America a little more than a decade ago, and has been wreaking havoc on indigenous Ash Trees across the Midwest. The thick knot of foliage around its trunk was this Ash tree’s desperate attempt at survival, pushing out new life from any part of its body not yet fully comprised by the shiny green beetle.
Upon closer inspection of this tree and two others I found, I could see the signs of the beetle’s presence: tiny D-shaped holes the beetle made as it entered and exited the tree, and in places where the bark had been removed, the squiggly lines left behind as the larvae ate through the tree.
The Emerald Ash Borer arrived in a cargo container from Asia at the port of Detroit in 2002, and has begun rapidly transforming the American canopy, first attacking Red and Green Ash, then, once those are no longer available, moving on to the White Ash. The arrival in North America of this attractively iridescent green beetle is just the latest chapter in the long story of the Columbian Exchange, a term scholars use to describe the consequences of the arrival of animals, plants, and pathogens carried intentionally or accidentally from one place to another as a result of human migration and global capitalism. Columbus gets the credit, or the blame,
because it was in the wake of his 1492 crossing from Europe to the Americas that human contact between once isolated regions became steady, and the environmental consequences of that reality began to play out in rather dramatic ways. The expansion of global capitalism in the late 20th and early 21st century has only accelerated ecological exchanges which have been going on for over 500 years. Any plant, animal or pathogen which has the potential to thrive in an eco-region different from its native one is already thriving there, or eventually will. We cannot reverse the consequences of this new ecological reality, only seek to manage them.
The demise of native tree species perhaps receives more notice and provokes more regret and nostalgia than other Columbian-exchange induced extinctions. Just southeast of the village of New Concord is a sharp rise that some of the oldest residents of the village call Chestnut Hill, once a popular romantic and isolated picnic site where students seeking to escape the social strictures of a Presbyterian campus retreated with their dates. Today it contains no majestic Chestnut trees, which all succumbed to an imported fungus in the first half of the twentieth century. Late nineteenth century photos of the town of New Concord reveal a Main Street cooled by the shade of American Elms arcing gracefully over the road. These, too, have vanished, the victim of another invader: Dutch Elm disease.
If indigenous Ash trees disappears from our lawns, our forests, and our landscapes, will their absence be noticed? The Ash tree does not have the majesty of the mighty oak, and I suspect if you were to ask someone to name the types of trees in their local forest, it might get left off their list. For much of the year the Ash goes unnoticed, late to leaf out, and not a prodigious producer of mast. But in the fall the bronze and mauve leaves of the White Ash are among the most striking of the season. Mostly, however, American Ash trees have been simply useful trees. George Washington called the Black Ash the Hoop Tree, as its strong but pliant wood made very good barrel hoops. Many 18th and 19th century rail fences were made from the Red Ash, and Green Ash was often converted to canoe paddles. The White Ash remains prized most of all, for a wood that is both strong and relatively light. It continues to play a central role in the American pastime, as the Louisville Slugger and virtually all high quality baseball bats are made from the White Ash tree. All of these trees are now threatened by the invasion of the Emerald Ash Borer.
Whenever I want to learn about a local tree, I pull Donald Culross Peattie’s A Natural History of Trees of Eastern and Central North America off my shelf first. First published in 1948, I am sure it has been scientifically superseded by many other volumes. I am nonetheless drawn to its lyrical prose. The author was no mere scientist, but clearly a tree lover. Peattie declared the American White Ash to be “Nature’s last word,” and fittingly placed his description of it at the very end of the volume. Written more than half a century before anyone in North America was thinking about the Emerald Ash Borer, his last words on the tree are a fitting tribute, but hopefully not an epitaph:
How many thousand-thousand of untold Ash trees are the respected companions of our doorways, kindliest trees in the clearing beyond the cabin? No one can say. But this is a tree whose grave and lofty character makes it a lifetime friend. White Ash has no easy, pretty charms like Dogwod and Redbud; it makes no over-dramatic gestures like Weeping Willow and Lombardy Poplar. It has never been seen through sentimental eyes, like the Elm and the White Birch. Strong, tall, cleanly benignant, the Ash tree with self-respecting surety waits, until you have sufficiently admired all the more obvious beauties of the forest, for you to discover at last its unadorned greatness.
William Kerrigan is the Cole Professor of American History at Muskingum University, and the author of Johnny Appleseed and the American Orchard, which tells the story of the old world apple in America, from its arrival half a millenium ago to the present.