The forests of eastern North America were very different 100 years ago. What we see today is a forest that has experienced the extinction of its keystone species, the American Chestnut Tree. For approximately 40 million years, the American Chestnut made up roughly 25% of the trees from Maine to Florida, and Mississippi to southern Michigan, with a population totaling around 4 billion.
Most Chestnut trees would grow to a height of 100ft, with some growing as tall as 150ft, and they had massive trunks, some 16ft in diameter. They grew straight wood, excellent for lumber. Most were nearly barren of branches for about 50ft, giving them the nickname, “the redwood of the East.”
Fairmount Park in Philadelphia. This engraving appeared in the Art Journal, 1878
photo credit: American Chestnut Foundation
The forest floor was mostly clear underneath the canopies of the giant trees. A person could have easily ridden a horse at full gallop through some of the deepest parts of the woods without cause for concern. The trees produced a massive amount of food in the form of Chestnut seeds which fell to the ground so numerously that one could use a shovel to gather them. Ground plants such as mushrooms thrived in tall forest environments. With Chestnut trees as the backbone of the ecosystem, the woods were populated by many large animals, not only deer, but bear, wolves, and large cats such as cougars and bobcats. A popular school mascot in America is the cougar, giving insight into what the land was like over 100 years ago when many high schools were founded.
It is easy to imagine a land that could have supported huge numbers of Native Americans and eventually European settlers with minimal effort on their part. Animal husbandry would have been prohibitively expensive in terms of feed without chestnuts. Farm animals could be allowed to roam through the forest grazing on chestnuts as opposed to fenced in open fields, and chestnuts were better at fattening animals than grass could ever be.
The chestnuts these trees produce in huge quantities aren’t affected by frosts, and are one of the most reliable food items in the world. They would drop nutritious food on the forest floor during the cooling Fall months when other crops had long since been harvested. Chestnuts didn’t spoil quickly either. They could be stockpiled for the Winter months or left on the forest floor for animals to eat. Settlers could then hunt the animals for food.
Chestnuts were such a staple of American life that they are part of our Christmas songs even though we rarely see or eat them anymore. “Chestnuts roasting on an open fire” would have been a hallmark of the American Christmas season for hundreds of years. They were exported to parts of the country that were unfortunate enough not to have them, making them a cash crop for the Eastern United States.
The American Chestnut was the backbone of the ecosystems of the entire east coast. It grew where most other plants won’t, in acidic, stony soils with little nutrient concentration. Its presence improved those soils and allowed for them to become richly diverse ecosystems. The leaves are full of nutrients like nitrogen, potassium, phosphorus and magnesium, which means that they can turn poor soils into rich ones relatively quickly.
20th Century Blight
The killing fungus — Cryphonectria parasitica — was first discovered in 1904 on a chestnut growing in New York’s Botanical Garden.
The fungus originated in Asia, and had little effect on Asiatic chestnuts that evolved with it, but American chestnuts were defenseless. The fungus entered the tree through any small crack in the bark, creating sunken, orange-black scars. Threadlike filaments encircled the trunk, choking off water and nutrients, killing the tree within 10 years.
Once affected, a single tree began producing millions of fungus spores, infecting its neighbors. Spores were carried on the wind. Insects and birds picked up blight spores on their wings and legs, and carried the disease to distant forests. The blight raced across the Appalachian range at an average rate of 50 miles a year.
Severe worry began to set in by 1910, as fears that the mighty Chestnuts could actually become extinct slowly became reality. Farmers were implored to chop down the trees at the first sign of blight. The American Boy Scouts scoured the forests looking for signs of blight stricken trees to chop down and burn. Pennsylvania tried in vain to create a quarantine zone in the western half of the state.
The full effort of government, universities, and the public was ultimately not enough to save the trees. By 1920, efforts to save them were abandoned.
Current State of the Forest
The trees are so hardy that the remaining ancient stumps still produce sprouts to this day. While they appear to be a sapling on its way to becoming a mature tree, it is a short life. The new sprouts live long enough to produce a few flowers and seed burs before blight fungus infects and kills the young chestnuts before they are more than a few inches in diameter.
The land now grows short scrub and brush full of invasive species underneath what remains of the forest. While still beautiful, it is easy to look at our current forests as a post-apacalyptic scene still transitioning from the loss of the mighty chestnuts.
The loss of this keystone species is one of the greatest ecological disasters ever, and certainly the largest of the 20th century. In total, 188 million acres of forestland were affected by the death of roughly 4 billion American Chestnut trees.
Small chestnut forests exist today in the western United States, the offspring of chestnut seeds transported by European settlers. Blight is a much smaller threat in these regions as the fungus has difficulty growing in the dry air. But when blight does begin to grow an infected tree is immediately chopped down and burned.
Revival
Decades of painstaking work crossbreeding American Chestnut trees with their Asian counterparts have currently resulted in a genetic hybrid with 97% American Chestnut genes. Genes from Asian chestnuts as well as wheat give the hybrid the natural ability to resist the fungus blight and grow to maturity.
Whereas most genetic hybrids are made sure not to be released into the wild, these hybrid Chestnuts have been planted in test forests with the hope that they will propogate on their own and once again restore the ecosystem to what it once was over 100 years ago.
Originally published April 16, 2019
Researched and Written by: Thomas Acreman
Sources:
USDA
The American Chestnut Foundation
Chestnut blight in Asia and north America by Flippo Gravatt
American Chestnut: The Life, Death, and Rebirth of a Perfect Tree by Susan Freinkel