Gene editing could revive a nearly lost tree. Not everyone is on board.

^{Photo by Yoksel 🌿 Zok on Unsplash}

SYRACUSE, N.Y. — Kyra LoPiccolo crouched in front of a small, white foam box under the hot summer sun. She opened the cooler and from the ice plucked a tiny vial of pollen — a potential salve for an entire species.

Clasping a branch of a two-story American chestnut, LoPiccolo pulled out a delicate, yellow-dusted glass slide and rubbed the thawed pollen onto some of the tree’s flowers. A few feet away and armed with another set of vials, a pair of colleagues at this field research station were aloft in a crane working on higher limbs.

The team gloved the fingerlike flowers with white bags and zip-ties them — an effort to control the flow of pollen. In a few months, genetically modified chestnuts will be ready for harvest.

“We open them up, and it’s like Christmas every time,” said LoPiccolo, a recent graduate of the State University of New York College of Environmental Science and Forestry (SUNY ESF).

These trees once ruled the canopies of much of Appalachia, with billions of...