Research explains larger-than-life perceptions of American chestnut

The American chestnut is often remembered as a giant, towering over forests along the East Coast over a hundred years ago. A study by researchers from Virginia Tech's College of Natural Resources and Environment and Roanoke College published in the Journal of Forestry, however, suggests that those memories may not be entirely accurate.

American chestnuts were once found in forests from Ontario to Alabama. This "redwood of the East" was often described as a towering giant, dominating forests throughout the East Coast. That all changed, however, with the introduction of chestnut blight.  

The blight, a fungus that blisters around the tree's stems and prevents it from transporting water and nutrients, was first identified on the East Coast in the early 1900s. It spread quickly, at a rate of roughly 19 miles per year, and soon killed almost all of the adult American chestnuts in the region.  

"You won't see many mature American chestnuts today. They sprout, because the roots aren't impacted by the blight, but once the stems reach a certain diameter, the blight latches on and they die," explained Carolyn Copenheaver, associate professor of forest ecology in Virginia Tech's Department of Forest Resources and Environmental Conservation.  

In recent years, organizations like the American Chestnut Foundation have worked to restore the species to its former position within the forest by creating a hybrid tree that is resistant to the blight. They hope that the hybrids will retain some characteristics of the Native American chestnut and can help restore eastern forests to their preblight state.  

But what exactly did that preblight state look like?  

"I found records and photographs of an exceptionally large American chestnut," Copenheaver said. "They had been reprinted in many articles and books, but as I looked at them, I couldn't help but think that we just don't have trees like this in the Eastern United States. I really wanted to know where it was coming from."  

To find out, Copenheaver teamed up with several colleagues, including Rachel Collins, associate professor of biology at Roanoke College; Kyrille Goldbeck DeBose, head of the Veterinary Medicine Library at Virginia Tech and liaison to Animal Sciences; and Virginia Tech graduate students Mary Kester and Ethan Barker, who completed his master's in forestry in 2017.

"Carolyn came to me with this project idea, so I started pulling resources that were published prior to 1904, when the blight was first identified," explained DeBose, who was the librarian for the College of Natural Resources and Environment at the time. "We looked at magazines, newspapers, field books, and guidebooks to find everything we could about this species preblight."

The researchers gathered publications by well-known historical foresters as well as personal accounts from landowners, examining each source for quantitative descriptions, including height, diameter, and growth rate.  

Once the raw data were compiled, the team began to search for patterns between the historical documents. They soon realized that there was a significant increase in the reported size of American chestnuts in sources published after the blight decimated the majority of the adult trees.  

According to their study, several factors played a part in creating this shift. Many sources recorded both the average size of a tree and the maximum size. In some sources, the maximum size was recorded as the average, making the species appear to be much larger than it would have normally been. Copenheaver also noted that descriptions collected from landowners who remembered the trees preblight may have been exaggerated owing to nostalgia.  

"It's human nature to romanticize the past," she said. "I think the loss of this species really brought out a lot of emotions in people. They were able to see the impact on the forest, and that may have elevated the species in people's minds."   One tree of particular interest to the researchers was a 17-foot-diameter American chestnut in Francis Cove, North Carolina. According to Collins, the tree was mentioned in multiple sources, but none of the authors had measured it themselves.  

"This would have been a monster tree," Collins said. "We realized that in the 1800s when people were writing about trees, they measured circumference. But in the late 1800s to early 1900s, diameter became the more common measurement, so we think that maybe it was really 17 feet in circumference. That means the tree would have been about 5 feet in diameter. It's still large, but not vastly larger than other tree species."  

DeBose added, "It speaks to how careful researchers have to be in making sure information is correct. As a librarian, I tell people all the time to go back and check the original source. Just because something is cited in a source, you shouldn't take it at face value. Always go back to the original source."  

According to Copenheaver, "These chestnut trees were very large, but they were similar in size to the white oaks and yellow poplars we see in forests today. There was nothing super-powered about these trees that made them grow so much bigger than other trees in the area." 

The study's results also have important implications for restoration efforts.  

"A lot of work has been done to try to restore the American chestnut," Collins said. "Our current culture's description of these trees is so much larger than they actually were, so it could cause the public to have unrealistic expectations for those restoration efforts. It's important to recognize that so we will have realistic expectations of what the results should look like."