If you search for the worst natural disasters in the history of the United States, you will find lots of accounts of devastating events that claimed many lives and destroyed much property. Nowhere, however, will you find what I believe to be this country’s greatest natural disaster. The American Chestnut Blight that started in 1904 and killed 3 to 4 billion American Chestnut trees. It was a silent disaster that unfolded over 40 years and almost completely wiped out a tree species that had existed for 40 million years.
It was almost a perfect tree, the flowers of the American Chestnut appeared in June- July, producing a spectacular display of creamy-yellow blossoms and were strongly scented. The fruits ripened and dropped after the first frost. The nuts of the American Chestnut were large, sweet, and highly desired by people, deer, squirrels, and chipmunks. In the days before the Chestnut blight, the tree reproduced abundantly by seeds and sprouts, had few insect enemies, and competed well with the other trees of the forest.
For the people of the southern Appalachians, the American Chestnut was economically important. The reddish-brown wood was lightweight, soft, easy to split, very resistant to decay; and it did not warp or shrink. Because of this resistance to decay, industries sprang up throughout the region to use wood from the American Chestnut for posts, poles, piling, railroad ties, and split-rail fences. Its straight-grained wood was ideal for building log cabins, furniture, and caskets. Split-rail fences made from the American Chestnut can still be found along country roads throughout the northeast United States and the southern Appalachians. The fruit that fell to the ground was an important cash crop. Families raked up chestnuts by the bushel and took wagon loads to sell in nearby towns. The people even cooked the chestnuts for their own use. The bark and wood were rich in tannic acid which provided tannins for use in the tanning of leather. More than half of the vegetable tannin used by the American leather industry at the turn of the century came from the American Chestnut. In addition, the American Chestnut was a graceful shade tree found in city squares and on the rural homestead.
The “thing” that killed and continues to kill the American Chestnut is a fungus, Cryphonectria parasitica . The fungus came into the country on some Japanese and Chinese chestnut trees that were being imported to the Bronx Zoological Park in New York City. The blight quickly spread to some American chestnut trees in the park through the air and by the 1940’s it had spread throughout the entire range of the species. The American chestnut tree, which evolved without the presence of the blight, was not resistant to the fungus and rapidly began to be killed off. The blight enters the chestnut tree through cracks in the bark, which usually appear once a tree is a few years old. Once under the bark, the fungus then “eats” away the living part (vascular cambium and phloem) of the tree leaving a girdling, sunken canker. This canker prevents the tree from transporting the food it makes in its leaves. Without this food, the tree dies within a decade. Interestingly, the root systems are not affected by the blight and often sprout to form new trees. Once the sprouts are a few years old, they again become infected with the blight and die.
Many of these giant trees are still alive underground, their roots pushing up new shoots which succumb to the fungus after a few years, decade after decade the cycle continues. Simple well-meaning actions can have devastating consequences.
There are several thousand American Chestnut trees that have continued to grow, fungus free, in the northern US and Canada. In 2006 a stand of American chestnut trees, estimated to be between twenty and thirty years old, was discovered in Pine Mountain, Georgia. Composed of six forty-foot-tall trees, the stand is the southernmost representative of the species able to produce flowers and nuts. Pollen from the trees is expected to help scientists produce a breed resistant to the chestnut blight fungus.
To learn more and support the work of restoring this endangered species check out the following organizations:
Forestique is a proud contributor to the American Chestnut Foundation. We are full of hope that we may someday see this species flourishing again in our forests and neighborhoods.
What do you think? What other well-meaning human caused eco-system disruptions are there to know about?