Ghosts of the Forest: The American Chestnut

What follows is an abridged version of my research paper for my environmental science class. I was particularly struck by the personal stories and pictures that I encountered during my research. I highly recommend visiting the excellent resource links provided to read the first-hand accounts of people who lived through one of the greatest ecological disasters of our time.

***************************************************************************

The virgin forests of the Eastern United States prior to the dawn of the 16th century were markedly different from the oak-dominated forests of today. As the Europeans arrived on the new continent, they beheld towering giants; trees that regularly spanned 150 feet and grew to a massive diameter of 10 feet. Innumerable species of animals, insects, and birds coexisted with, and depended on, the annual bounty of nuts from over 3 billion American chestnut trees which stretched from Maine to Georgia (Lutts par. 1). After the turn of the 20th century, in span of only four decades, almost every single living tree was destroyed.

The American chestnut, Castenea dentata, is a deciduous, nut bearing tree in the beech family. Along with oak trees, they comprised the majority of tree species in the eastern United States. In the Appalachians, American chestnut occurred in one out of every four trees. This species competed well with oaks and beech trees, and became numerically dominant through their range. As a “keystone species”, these giants of the forest provided the foundation for the entire forest ecosystem of the Eastern United States (Freinkel par. 4).

Animal species depended greatly on the unfailing deluge of fruits produced each fall and supported large mammal populations including moose, elk, bears, wolves, white-dear, wild hogs, mountain lions, turkeys, and many species that are now extinct, such as the passenger pigeon who visited the trees in massive flocks each autumn. While a mature oak tree produces around 2,000 acorns per year, a similarly sized Chestnut tree could produce over 6,000 calorie-rich nuts each year (http://www.patacf.org/index.htm).

The chestnut tree has a related species in Europe, Castenea sativa, which had been used for thousands of years as a food source, especially for the poorest classes of people. Similarly, settlers in the chestnut-rich Appalachians owed their continued subsistence to the abundance of free chestnuts each year to trade, sell, or fatten their livestock (Lutts, par. 3). Improvements in transportation into the 19th century allowed the chestnut-gatherers in the blue-ridge communities to grow their chestnut trade substantially (Lutts, par 6). Poor families could support themselves by foraging for Chestnuts and trading them through the local general store for eggs, milk, bread and other food staples. Commercial outfits sprang up to take advantage of the free bounty, and a new industry was born. At the height of the chestnut trade, counties could net over $100,000 dollars per season, which was, according to a 1937 economic study, “a greater source of revenue than cattle.” (Lutts par. 11) The trade of chestnuts linked poor rural families in the Appalachians with residents of the big northeastern cities, who bought them for roasting from street vendors (Lutts par. 12).

Americans also quickly discovered the usefulness of this prolific tree for lumber and for extracts of tannic acid, used for tanning leather. At the turn of the century, more than half of all vegetable tanning extracts were obtained from chestnuts, giving rise to a thriving tannic export industry (Freinkel par. 23). The wood of the chestnut is relatively light for its size so it was cheaper to ship than oak, and was straight-grained, and rot-resistant. This made the ideal wood for housing, furniture, rail ties, siding, and fence posts. “By 1909, about 600 million board feet of chestnut were being cut each year and the tree was contributing more than $10 million annually to the economy of the region – profits that went mainly to the large timber companies.”(Freinkel par. 24) While it commanded less per board than cherry or black walnut, the versatility and sheer abundance of the American Chestnut combined to make this tree one of the most vitally important natural resources of 19th century life and trade in the Appalachians.

Early in the 20th century, the chestnuts in New York began to exhibit symptoms of an unknown but lethal disease. The first native chestnut to have been infected was recorded in 1904 in the New York Zoological Park. In the following year, 98% of the chestnut trees in Bronx had been decimated. In 1905, the American mycologist William Murrill identified the cause of the blight was a bark fungus which he named Diaporthe parasitica (later renamed Cryphonectria parasitica) accidentally introduced on exotic trees imported for either ornamental purposes, or on infected lumber from Japan or China. The next four years saw the loss of the tree throughout New York, New Jersey, Pennsylvania, Connecticut and Massachusetts despite massive efforts to stop the spread of the fungus. Over 220 million acres, from every field, farm and forest, the trees began to disappear, leaving only towering skeletons where vast chestnut groves once stood and by 1940, 99% of all mature American chestnut trees were eliminated across its range, comprising in total over 3 billion trees (Lutts par. 60).

The fungus originates in Asia, where the shrubby-form of chestnut species evolved with the pathogen and therefore have a degree of resistance which was absent in North American and European trees. The spores of the chestnut blight fungus are transmitted through animal and insect vectors, primarily wood-boring species which can infect the bark of the tree directly. The fungus creates swollen cankers which shatter the bark and girdle the tree within a few years, killing the tree(Hebard, 1). A witness describes his impression of blight-ravaged central Virginia in 1926:

“I passed through a scene impressive in its aspect of desolation and almost a tribute to the destructive power of the chestnut blight. This section must at one time have been entirely a pure chestnut grove. Now every tree was dead. All the trees had been uprooted and lay on the ground. The rains and the snow had washed away the dead bark and bleached the trunks a grayish white. No underbrush of any sort grew there. The area was as free from tree growth as are some of the western plains. These chestnuts were of tremendous size—a foot or two or three feet in diameter. Now it is a graveyard of giant trees. ... The area was easily two square miles.”
(Lutts par. 37)

For rural Americans whose lives and livelihoods were dependant on the chestnuts for food and trade, the loss of the trees was devastating. Without the chestnuts to feed the hogs, farmers could not afford to buy feed and once lively communities faltered. Eventually, an exodus of Appalachian mountain families and farmers ensued as they searched for new sources of income to feed their families during the increasingly difficult economic times of the emerging great depression (Freinkel par. 30). For its part, the chestnut lumber industry resorted to selling “wormy chestnut”, or the rot-resistant remains of fallen trees, eventually declining into obsolescence.

Despite the overwhelming and thoroughly tragic loss of one quarter of the eastern forests, some trees continue to survive as stump sprouts in the under story of the forests they once dominated. While these trees generally weaken and die before flowering, the roots continue to survive to preserve at least some of the genetic diversity of this majestic tree. The legacy of the American Chestnut may have some hope of preservation through organizations such as the American Chestnut Foundation (http://www.acf.org/) which strives to create blight resistant trees through a process known as the backcross method (Hebard, 1). This process uses blight resistant Asian chestnut genes and crosses them with American Chestnut genes. The hybrid resistant offspring is then bred with American chestnut genes until the result is a tree with predominantly American chestnut genes, but with the blight resistance of Asian species.
Because of the exacting relationship that the chestnut had with the bird, insect and mammal species in North America, it is vital that the blight-resistant trees retain as much of the original characteristics of the American chestnut tree, while providing genetic defenses against the introduced fungus. At least 20 different genetically diverse species have been used for the backcross method to avoid inbreeding (http://www.acf.org/r_r.php).

The ultimate goal is to produce healthy, mature and genetically diverse American chestnut trees which have no genetic characteristics of the Chinese chestnut other than blight resistance. TACF harvested their first blight-resistant chestnuts in 2005 and continue their efforts through educational programs, tree-spotting initiatives, and associations with scientific foundations and research universities worldwide.

The loss of the American chestnut was an environmental disaster of great magnitude, with profound and persistent ecological, social, and economical impacts. Along with the vast changes in industry, economy, and society that occurred in the 1920’s and 30’s, the loss of the Chestnut unpinned the end of an era; a time of abundant, seemingly unending, natural resources exploited by humans without consequence. It was also the end of our direct connection to foraging for food, and the concept of free land and shared resources.

The chestnut’s tragic demise is a testament to the true vulnerability of our environment, and the terrifying destructive power of human beings through environmental ignorance. People who can remember the taste of sweet chestnuts roasting “on an open fire”, the beauty of flowering chestnuts on the hillsides, or the toil of gathering nuts to trade are passing on, and the hope of the future restoration of the chestnut is now squarely in the hands of those who recognize the responsibility we share in restoring these majestic giants to their place as sentinels of the forest.

Works Cited:

Lutts, Ralph H., Like Manna From God: the American Chestnut Trade in Southwestern Virginia. Environmental History 9.3 (2004): 76 pars. 22 Mar. 2009 http://www.historycooperative.org/journals/eh/9.3/lutts.html.

Freinkel, Susan “Whole World Gone: The Loss of the American Chestnut Tree” APF Reporter Vol.22 #2 (2005) http://www.aliciapatterson.org/APF_Stories/Freinkel/Freinkel01/Freinkel.html

Hebard, Fred V., The Backcross Breeding Program of the American Chestnut Foundation
http://chestnut.cas.psu.edu/Meetings/NPS/proceedings/_2_07hebard%20manuscript%20on%20TACF.pdf

Leopold, Donald J.. Native Plants of the Northeast: A Guide for Gardening and Conservation. Portland, OR: Timber Press, Incorporated, 2005.

A Field Guide to Eastern Forests: North America (Peterson Field Guides(R)). Boston: Houghton Mifflin, 1998

Carley, Bruce. "New Hope for the American Chestnut." Saving the American Elm. 22 Mar. 2009 http://www.elmpost.org/chestnut.htm.