These first two videos, from the USDA Forest Service’s Southern Research Station, are on restoration of the American chestnut in the southern Appalachians. The videos feature information on the Southern Research Station’s chestnut research, the National Forest System’s silvicultural program, The University of Tennessee’s Tree Improvement Program, and The American Chestnut Foundation’s backcross breeding program.
The American chestnut was once a common and abundant tree species that occupied 200 million acres in the eastern hardwood forests of North America. The species had a cultural significance and was a keystone species, providing wildlife with food and habitat sources. Two non-native pathogens led to the chestnut's extirpation in the 20th century, but efforts are underway to conserve and restore this iconic tree.
The USDA Forest Service, The University of Tennessee, and other partners showcase their research on the American chestnut (Castanea dentata), a species that was extirpated by a non-native pathogen (Cryphonectria parasitica) that causes chestnut blight disease. Over 4,000 hybrid chestnuts that were bred for blight-resistance were planted on three national forests since 2009, and research is still ongoing.
This next video is by Dr. William A. Powell. Dr. Powell is the Director of the American Chestnut Research & Restoration Project at the SUNY College of Environmental Science and Forestry. His team has focused on enhancing blight tolerance by adding only a couple genes to the approximately 38,000 gene pairs in the chestnut genome using the tools of genetic engineering (GE). This is important because these GE tools retain all of the American chestnut genes required for its adaptation to its forest ecosystem.
The most promising gene tested to date comes from bread wheat (Triticum aestivum) and encodes an oxalate detoxifying enzyme, called oxalate oxidase (OxO). This gene is a common defense gene found in many plants and it can confer enhanced blight tolerance in American chestnut. The original blight tolerant trees have been outcrossed to susceptible American chestnut trees through three generations to date, increasing genetic diversity and local adaptation. Environmental impact experiments have been completed and these trees are currently under federal review before being released to the public and to restoration programs. This video describes the program and its current progress toward restoring this keystone species.
Billions of American Chestnut trees used to grow in America—and then a fungal blight spread throughout its native range. By the 21st century, this population had all but disappeared. Using revolutionary technology, the American Chestnut Research & Restoration Project aims to resuscitate the Castanea dentata. In this Stories of Impact video, William A. Powell (SUNY ESF) and Rex Mann (The American Chestnut Foundation) discuss the American chestnut and their goal of restoring the iconic tree to its former glory. Supported by the Templeton World Charity Foundation, this first-of-its-kind project is engineering a blight-resistant chestnut and reintroducing it to its native habitat.