A Tough Nut to Crack
Emily Dobry ‘20 and Bryan Hed
Scientists at Penn State research facility contribute to effort to revive the American chestnut If you were to design the perfect tree, it would be the American chestnut. It was known to grow tall and straight and be rot-resistant, making it prized at one time for lumber, furniture, and musical instruments. Despite its tremendous size, once felled, it could be easily split. It was also prolific, sending up new shoots that grew fast. The average mature American chestnut tree could be up to 100 feet tall and 4 to 7 feet thick at the trunk. A healthy specimen might be expected to live for 400 to 600 years and produce several bushels of nuts each year, literally raining down food for humans and animals. In the early 1900s, this majestic species made up a substantial portion of the eastern hardwood forests. There were almost 4 billion American chestnut trees in the United States until a fungal pathogen transported on chestnut trees imported from Japan and China wiped the species out in less than forty years. It is considered to be the greatest ecological disaster to ever strike the world’s forests.
SMALLPOX FOR TREES “The pathogen is native to Chinese and Japanese chestnuts, so the two co-evolved, but the American chestnut had never been exposed to it before and had little natural resistance to it,” 18
said Emily Dobry ’20, a student in Penn State’s Plant Sciences Horticulture master’s program who is doing research work at the University’s Lake Erie Regional Grape Research and Extension Center (LERGREC) in North East, Pa. “Think smallpox for trees.” Today, there are fewer than 1,000 American chestnut trees, largely in isolated areas outside of the tree’s historical range in the eastern half of the United States, along the Appalachian mountain ridge and through New England. A few of them can be found at LERGREC, where researchers have been conducting a trial since 2013 with fifteen chestnut trees—five each of the American, Chinese, and AmericanChinese hybrid species developed by scientists, all planted in one long row. “The idea was to plant American and Chinese chestnuts side by side with some of the hybrids that have been developed and allow them to be challenged with chestnut blight over the years,” said LERGREC’s Bryan Hed, a plant pathologist. “Over the years, most of the trees have suffered dieback from disease, insects, or weather, and have had to be cut back and renewed from sucker growth from the original rootstock,” Hed said. “Interestingly, the Chinese trees have fared the worst. The hybrid trees are notable exceptions; three of them are currently 17 to 21 feet in height.”
