Nostalgia, coupled with a little curiosity, can lead to important insights.

When Richard KarbanAn ecology researcher at the University of California, Davis, decided to return to the forest he had studied in 1977 — this time accompanied by his daughter Claire, a doctoral student in ecology at the University of Colorado, Boulder — expecting little change. After all, when he first visited Whiteoak Canyon in Virginia Shenandoah National Parkhe had seen almost the same tree composition that Lucy Braun had described in her groundbreaking book Deciduous forests in eastern North Americapublished in 1950. “At the time, I had the impression that the forest hadn’t really changed that much,” Karban said.

Shocking Decline of American Chestnut Trees

In 2021 he experienced a shock. “We were quite surprised that the forest had changed dramatically since 1977,” says Karban. Most of the mature chestnut trees were gone – succumbing to cancer. Cryphonectria parasitica. This fungus is responsible for the widespread loss of American chestnut trees across the country.

Some white oaks, once “codominant” with the chestnut trees, had provided some respite. However, they were still rarer than when he visited the forest in 1977, a fact he describes as “worrying”. The results of his survey were published in a PLUS ONE report.

“We would have thought that such an exchange would happen much faster,” says Karban. Instead, smaller trees such as birch have filled some of the gaps left by the chestnut trees.

They did find traces of chestnut trees – but in bush form. The cancer fungus lives in the inner bark of young trees and surrounds the trunk. But the roots live on.

Read more: We have lost 35 percent of our forests in the last 300 years

Causes of Slowed Growth in Whiteoak Canyon Forest

Karban isn’t sure why the forest is slow to fill with larger trees. “Many other changes have occurred between 1977 and today that could well be the cause of the changes in forest composition that we observed,” says Karban. For example, more deer now live there, and there have been no significant fires in the forest for a long time.

In addition to chestnut blight, other pests have also invaded the forest. The hemlock woolly adelgid, an aphid-like invasive species, has “hammered” the hemlock population there, Karban says. And the emerald ash borer has also made its appearance.

Karban says since neither he nor his daughter have any training as foresters, they aren’t sure what the best strategy is for managing Whiteoak Canyon — let alone the rest of Shenandoah National Park. He hopes foresters will look at their report and consider some strategies to restore the forest to its former state.

Read more: How do we plant more trees when there is a shortage of seeds?

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Before joining Discover Magazine, Paul worked as a science journalist for over 20 years, specializing in U.S. life science policy and global science career issues. He started his career in newspapers but moved to academic journals. His work has appeared in publications such as Science News, Science, Nature and Scientific American.