The America Chestnut Foundation (TACF) has been working to restore the magnificent American chestnut, Castenea dentata, since 1983. The driving force that moves this effort forward consists of 16 State chapters of dedicated volunteers. The VT/NH Chapter was first organized in 2007. Three restoration approaches are implemented under the TACF “3-BUR” program: “Breeding, Biotechnology and Biocontrol – United for Restoration.” The VT/NH Chapter incorporates all three methods in its restoration efforts.
Breeding: The traditional TACF breeding program is implemented at nine breeding orchards and three seed orchards that are managed by volunteers and partners across VT and NH. These orchards contain trees produced through three generations of back crossing wild American chestnuts (having no blight resistance) with Chinese chestnuts (which do have blight resistance). The resulting offspring are screened for blight resistance and those with acceptable levels are intercrossed over three more generations. At each generation we continue to refine the balance of blight tolerance and American chestnut character in this population of trees. Blight resistance is a complex trait that is not easily transferred to American trees. Stringent selection criteria and genomic assessment tools helps us keep only the best trees in our program.
Biotechnology: The core of the biotechnology program is transgenics. Scientists at the State University of New York, College of Environmental Science and Forestry (SUNY-ESF), discovered that a gene from wheat produces an enzyme, oxalate oxidase (OxO), which enhances blight tolerance significantly. Release of this transgenic tree into Eastern forests requires Federal approval from USDA, EPA and FDA. The transgenic tree is a clone so it must be crossed for multiple generations with wild America chestnuts to assure genetic diversity. The VT/NH Chapter aggressively seeks nuts from wild trees, with emphasis on those having 100% American characteristics. These nuts are planted in Germplasm Conservation Orchards (GCO) in VT and NH. Flowering trees in GCOs may be pollinated with transgenic pollen following Federal approval.
Biocontrol: The primary biological control method being explored by TACF and its partners is hypovirulence. Chestnut blight fungus is infected by a virus, thereby sickening the fungus and reducing the ability of chestnut blight to cause lethal infections. Using this method, the natural defenses of the chestnut, combined with soil microorganisms may enable the tree to halt canker growth and ultimately survive an infection. In addition, the VT/NH Chapter is experimenting with “mud packing” as a method to slow blight canker development on individual trees.
The goal of the VT/NH Chapter is:
Self-sustaining stands of blight-resistant American chestnut trees growing in Vermont and New Hampshire woodlands.
The Board of Directors strives to achieve this Goal through various committees having responsibilities to manage orchards, locate and harvest nut producing wild American chestnuts, oversee Chapter governance, and convey the chestnut restoration story through outreach.