American Chestnut Restoration
The American chestnut [Castanea dentata (Marsh.) Borkh] is a tree species of unique ecological and economic value in the nation’s forests. It was virtually eliminated when a fungus, Cryphonectria parasitica (Murr.) Barr, was accidentally introduced in the early 1900s. Scientists have evaluated many approaches to decreasing the strength of the fungus or increasing the resistance of the tree in an effort to restore the chestnut. However, only one technique – cross-breeding American and Chinese chestnuts with backcrosses to American chestnut – has so far shown promise for near-term restoration. The American Chestnut Foundation (TACF) is a leader in this breeding effort and we are collaborating with TACF to extend this work to forests of the northern United States.
To date, most research and breeding efforts to restore American chestnut have occurred in the central portions of the species’ historic range. However, restoration at the northern range limits may be especially important for population recovery. Under various climate change scenarios, oak-hickory cover types (that once included chestnut) are expected to shift north across much of the continental United States. Restoration of chestnut in northern forests will therefore provide ecosystem services (such as wood products and food for wildlife) that will be important during a time of shifting climate and environmental conditions.
We have identified three issues that, once addressed, will help American chestnut restoration efforts in northern U.S. forests:
- We need more seeds and other genetic materials from surviving, cold-adapted American chestnut trees for the current restoration breeding program.
- We need to know more about the role that cold tolerance plays in the success of the species at the northern limit of its natural range; and
- We need to study different forest management techniques to see if they improve the survival and growth of American chestnuts in northern forests.
Although our work is still evolving, significant progress has been made toward addressing these research areas. We have located and verified mature American chestnut trees for controlled pollination experiments in Vermont. Nuts collected from these trees will be grown in The American Chestnut Foundation (TACF) plantations, tested for disease resistance, and included in later breeding efforts. We have assessed the cold tolerance of chestnut seeds and shoots. We are growing American chestnut plantings from different genetic sources on the Green Mountain National Forest. We are testing whether limitations in cold tolerance can be overcome through either: 1) genetic selection (use of nuts and seedlings from cold-tolerant parent trees), or 2) forest management strategies that improve seedling growth, increase sugar storage or improve cold tolerance.
In collaboration with TACF scientists and managers on the Green Mountain National Forest, we hope to restore American chestnut in Vermont and elsewhere in northern U.S. forests.
Schaberg, Paul; Murakami, Paula; Hawley, Gary J.; Collins, Kendra. 2017. American chestnut restoration in New England - cold damage as an added challenge. New England Society of American Foresters News Quarterly. 78(3): 8-11.
Clark, Stacy L.; Schlarbaum, Scott E.; Pinchot, Cornelia C.; Anagnostakis, Sandra L.; Saunders, Michael R.; Thomas-Van Gundy, Melissa; Schaberg, Paul; McKenna, James; Bard, Jane F.; Berrang, Paul C.; Casey, David M.; Casey, Chris E.; Crane, Barbara; Jackson, Brian D.; Kochenderfer, Jeff D.; MacFarlane, Russ; Makowske, Robert; Miller, Mark D.; Rodrigue, Jason A.; Stelick, Jim; Thornton, Christopher D.; Williamson, Tyler S. 2014. Reintroduction of American Chestnut in the National Forest System. Journal of Forestry. 112: 502-512.
Saielli, Thomas M.; Schaberg, Paul G.; Hawley, Gary J.; Halman, Joshua M.; Gurney, Kendra M. 2014. Genetics and silvicultural treatments influence the growth and shoot winter injury of American chestnut in Vermont. Forest Science. 60(6): 1068-1076.
Schaberg, Paul G.; Saielli, Thomas M.; Hawley, Gary J.; Halman, Joshua M.; Gurney, Kendra M. 2013. Winter injury of American chestnut seedlings grown in a common garden at the species' northern range limit. In: Miller, Gary W.; Schuler, Thomas M.; Gottschalk, Kurt W.; Brooks, John R.; Grushecky, Shawn T.; Spong, Ben D.; Rentch, James S., eds. Proceedings, 18th Central Hardwood Forest Conference; 2012 March 26-28; Morgantown, WV; Gen. Tech. Rep. NRS-P-117. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 72-79.
Saielli, Thomas M.; Schaberg, Paul G.; Hawley, Gary J.; Halman, Joshua M.; Gurney, Kendra M. 2012. Nut cold hardiness as a factor influencing the restoration of American chestnut in northern latitudes and high elevations. Canadian Journal of Forest Research. 42: 849-857.
Gurney, Kendra M.; Schaberg, Paul G.; Hawley, Gary, J.; Shane, John B. 2011. Inadequate cold tolerance as a possible limitation to American chestnut restoration in the northeastern United States. Restoration Ecology. 19: 55-63. https://doi.org/10.1111/j.1526-100X.2009.00544.x.
Schaberg, Paul G.; Gurney, Kendra M.; Janes, Benjamin R.; Halman, Joshua M.; Hawley, Gary J; 2009. Is nut cold tolerance a limitation to the restoration of American chestnut in the northeastern United States? Ecological Restoration 27:266-268.
- Paul Schaberg, US Forest Service Northern Research Station, Research Plant Physiologist
- Last modified: March 4, 2019