Pollinating Chestnut Trees

Once a life staple for people and wildlife in the eastern United States, the American chestnut was almost entirely wiped out by an imported fungus known as “chestnut blight.” The fungus destroyed more than four billion chestnut trees — nearly 150 million acres of forest land — in the first half of the 20th century.

The American Chestnut Foundation is working to restore the chestnut to its natural range. Scientists believe that by crossing an American chestnut tree with its blight-resistant cousin, the Chinese chestnut, the tree will retain both its American traits (e.g., tall-growing) and the gene for blight resistance. The Foundation heavily depends on local volunteers to make this breeding process a success. That’s where Ron Kuipers (pictured) and the Izaak Walton League’s Rockville Chapter come in.

Kuipers, a long-time League member and Rockville Chapter board member, attended a presentation on the chestnut’s plight several years ago and asked how the Ikes could help. The Rockville Chapter agreed to plant 90 American chestnut seedlings in a breeding orchard, maintain the orchard, and harvest seeds and pollen. This summer, the chapter’s orchard reached a major milestone: pollination.

Chapter volunteers worked through the painstaking pollination process together. It began with Kuipers placing bags over the female flowers on six trees to prevent uncontrolled natural pollination. Then, with a vial of pollen from a chestnut tree in Seneca State Park, Kuipers and the other volunteers manually pollinated the six trees. They removed the bag from each female flower, dipped the flower into the pollen, and placed another specially marked bag over the pollinated flower to prevent introduction of pollen from a different source.

When pollination is successful, the flower produces a spiny pod — called a “bur” — that contains three chestnuts. Kuipers and other chapter volunteers harvested these nuts in late September. The nuts will be planted in a mother tree orchard in Black Hill Park, where volunteers continuously plant new trees in an effort to keep the genes of the American chestnut alive long enough for the breeding program to (hopefully) be successful.

Kuipers has visited League chapters throughout the state to talk about the American chestnut restoration program. With his encouragement, several other Maryland chapters started their own breeding orchards. For championing American chestnut restoration, Kuipers was honored by Field & Stream magazine as a 2011 Hero of Conservation and was one of six finalists for the national Conservation Hero of the Year.