Chestnuts in The John Bartram Arboretum
Map of the chestnuts in Wildflower Hill, January, 2025.
Red markers: American chestnuts, Castenea dentata planted in June 2022
Olive markers: American chestnut, C. dentata ‘Millennium’ planted in June 2024
Blue markers: Chinese chestnut, C. mollissima, planting date unknown
Black marker: Hybrid chestnut, C. dentata x mollissima, planting date unknown
The John Bartram Arboretum is home to ten trees in the genus Castenea, a part of the beech family Fagaceae. The first American chestnuts (Castenea dentata) were planted in June, 2022. They were a gift from the State University of New York College of Environmental Science and Forestry (ESF) in Syracuse, NY. Kendal at Oberlin is a participant in the ESF Transgenic American Chestnut Educational Partner Program.
Images: Left, planting C. dentata, Wildflower Hill, June, 2022
Right, Millinnium Grove, Go Native Tree Farm, Note: standing figure at base of tree is over six feet tall
The Millinnium saplings were planted in June, 2024. They were procured from the Go Native Tree Farm in Lancaster, Pennsylvania. The nuts were produced by trees in the Millennium Chestnut Grove shown in the image. The purchase was made possible by a grant from the Ohio Chapter of The American Chestnut Foundation. These trees were produced by a process referred to by The American Chestnut Cooperator’s Foundation (ACCF) as “extreme natural selection” in which “old survivors” are pollinated manually. ACCF geneticists estimate that 10% (range 5% - 20%) of the offspring will exhibit blight resistance “at least as favorable” as the parent trees. Parent trees are between 40 and 50 feet tall with a diameter at breast height of approximately one foot (see photo).
The four remaining trees are of uncertain origin but at least some are believed to have been brought by a resident to Kendal at Oberlin fromPennsylvania.
Early chestnuts in Oberlin
In his memoir titled A Minnesota Story: Restoration of the American Chestnut, Charles Burnham wrote that “nuts produced in 1982 [from a backcross experiment] ... were all sent to Dr. David Benzing at Oberlin College, Ohio.” Benzing recalls “that all were planted along the utility path that runs behind Johnson House, an Oberlin College property, located on the west side of Professor Street just north of the old railroad track that’s now a bike path. Every specimen soon became infected by the blight and none managed to produce burrs.”
C. Burnham, A Minnesota Story: Restoration of the American Chestnut, in The Journal of the American Chestnut Foundation, v 6 no 2, p 82.
Chestnut identification
Spring is the best time to identify chestnuts and to see their reproductive parts. The American chestnut (Castenea dentata) is a large monecious deciduous tree that produces burred fruit with edible nuts. Chestnuts do not self pollinate. Two separate trees are required. The trees put on quite a show the spring, when feathery catkins are present. As shown in the figure the catkins may be all male (white arrow) or hermaphroditic (red arrow). The pollen is a mild allergen, The spiny burrs of American chestnuts typically contain three nuts at maturity. The leaves are alternate, elliptical and are usually between 5 and 9 inches long. They have a pointed toothed end. Leaves usually have between 12 and 20 parallel veins that end in a bristle-tipped tooth. The tops of the leaves are a slightly yellow-tinged green and are paler and slightly hairy beneath. The leaves of Chinese chestnuts (C. Mollissima) are typically shorter and rounder than those of the American chestnut. American chestnuts grow rapidly and may reach substantial heights as shown in the photograph of the Millinnium Grove in Pennsylvania. Chinese chestnuts grow more slowly with a squat profile as evidenced by the oldest tree in the collection on the west end of the Wildflower Hill slope.
C. dentata catkins, red arrow female part of hermaphroditic catkin. It becomes a burr. The white arrow is a male catkin.
Chestnut burrs, credit The American Chestnut Foundation
Chestnut leaves, credit American Chestnut Foundation