In an earlier blog, Old-Growth Forests, we described how an unbroken forest stretched across eastern North America from Canada to Florida and west to the Great Plains before America was settled by Europeans in the 1600s. In that forest, the predominant tree was the American Chestnut, Castanea dentata, dominating vast portions of the eastern U.S. forests. Estimated at four billion, the tree was among the largest, tallest, and fastest-growing in these forests. One in four trees in the old-growth forest was an American chestnut. It was prized for innumerable uses, from furniture to fencing, foundations to telegraph poles. Its nut fed billions, from insects to humans, and was a significant contributor to rural agricultural economies. Hogs and cattle were fattened for market on chestnuts.
Here at Howard Falls, an 1891 visit by the Natural History Society of Erie, PA, describes the forest as “a splendid growth of birch, maple, chestnut, and numerous other forest trees.” Northwestern PA is well within the native range of the American Chestnut, as shown on the following map.
All of this began to change at the turn of the 20th century with the introduction of a deadly blight from Asia. In about 50 years, the pathogen, Cryphonectria parasitica, killed essentially all of the four billion trees. Virtually no mature trees exist today in America, yet the tree persists as stump sprouts from the root systems of the old forest. Nonetheless, as the sprouts become saplings, the blight kills them again, and the cycle of stump sprouts continues.
We are committed to re-establishing the American Chestnut in the forest at Howard Falls. We have obtained back-crossed hybrid Chestnut from the American Chestnut Foundation (ACF) and currently have several seedlings established here. Hopefully, they are blight resistant and will mature to fine specimens.
However, in 2021, we made a startling discovery in our forest along the Falls Run Gorge Natural Heritage Area. One day while walking along the rim trail, we noticed a 6-inch diameter tree, perhaps 30 feet in height, with distinctive chestnut-like leaves. A sample of a twig and leaf was carefully obtained and sent to the ACF field office at Penn State. After genetic analysis of the sample, it was confirmed that this tree was indeed an American Chestnut.
In 2022, we continued our search for other trees and found five additional
American Chestnut growing in the forest along the Gorge. There are probably many others, but the steep ravine makes surveys very difficult. It is estimated that these trees are 20-50 years old. Being in the understory of the forest, it is hard to say how quickly these trees grow. Nonetheless, all of the young trees that we have found are healthy,
with no sign yet of blight. The puzzling question is how these trees propagated here. They do not appear to be stump sprouts from older trees, yet we have not found a mother tree from which nuts could have been spread by squirrels or chipmunks.
Our search to understand why we have young American Chestnut re-establishing themselves in our forest continues. Nonetheless, American Chestnut are fighting back and seeking to return to the native forest here at Howard Falls. We could not be more pleased.