Site Factors that Affect Successful Reintroduction of American Chestnut

Research Issue

Daniel Delatte, a seasonal forestry technician, measuring the height of a hybrid American chestnut sapling planted in one of the study sites.Until the early 1900s, American chestnut [Castanea dentata (Marsh.) Borkh] was a dominant forest tree throughout much of the eastern United States. Chestnut was an important source of food for wildlife and was economically valuable for its rot-resistant lumber, high tannin content and edible nuts.

Two non-native pathogens contributed to the near elimination of American chestnut. Ink disease, caused by the fungus Phytophthora cinnamomi Rands, killed chestnut trees in poorly drained sites of the southeastern U.S. starting in the mid-1800s. The chestnut blight fungus Cryphonectria parasitica Murrill, first identified in 1904 at the New York Botanical Garden, was probably imported on Japanese chestnut trees in the late 1800s.

By 1950, most large chestnut trees in the U.S. were dead or dying. Occasional large survivors and sprouts are located throughout the chestnut’s former range, although most die of blight before bearing fruit. Currently, The American Chestnut Foundation and the Connecticut Agricultural Experiment Station are both using backcross breeding to try to develop an American chestnut hybrid that is highly resistant to both ink disease and the blight fungus.

Our Research

2 Hybrid American chestnut seedlings (marked with red flagging) planted at forest sites with different soil moisture levels from dry (xerix) to moderately wet (mesic).  Notice the increase of regenerating vegetation from xeric to mesic conditions.

Understanding how to choose the best forest sites for hybrid American chestnut plantings will be critical to successful large-scale re-establishment of this species. Site quality, including the availability of light, soil nutrients and moisture, is one important characteristic. To address this issue, we are studying how site quality affects the long-term survival, growth, competitive ability and blight resistance in planted hybrid American chestnut seedlings.

In 2015, we planted 960 hybrid American chestnuts at fifteen forest sites in central and western Pennsylvania. Study sites were categorized as mesic, xeric, or intermediate using the integrated moisture index. We are evaluating how different factors across the sites affect the chestnut seedlings’ ability to establish, survive, resist infection by blight, and (eventually) reproduce. We are also looking for evidence of metabolic stress (with a special focus on drought stress) and examining levels of cellular nutrients in the leaves of the trees.

Expected Outcomes

Our research will help us better understand how site characteristics affect successful establishment of hybrid chestnut seedlings. The results will help us select the best sites for chestnut reintroduction in the future.

Research Results

Pinchot, Cornelia C.; Schlarbaum, Scott E.; Clark, Stacy L.; Saxton, Arnold M.; Sharp, Ami M.; Schweitzer, Callie J.; Hebard, Frederick V. 2017. Growth, survival, and competitive ability of chestnut (Castanea Mill.) seedlings planted across a gradient of light levels. New Forests. 48: 491-512.

Pinchot, C.C.; Royo, A.A.; Peters, M.P.; Schlarbaum, S.E.; Anagnostakis, S.L. 2017. The importance of site quality to backcross chestnut establishment success. In: Sniezko, Richard A.; Man, Gary; Hipkins, Valerie; Woeste, Keith; Gwaze, David; Kliejunas, John T.; McTeague, Brianna A., tech. cords. 2017. Gene conservation of tree species—banking on the future. Proceedings of a workshop. Gen. Tech. Rep. PNW-GTR-963. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. p. 198.

Pinchot, Cornelia; Clark, Stacy; Schlarbaum, Scott; Saxton, Arnold; Sung, Shi-Jean; Hebard, Frederick. 2015. Effects of temporal dynamics, nut weight and nut size on growth of American chestnut, Chinese chestnut and backcross generations in a commercial nursery. Forests. 6(5): 1537-1556.

Pinchot, C.C.; Schlarbaum, S.E.; Clark, S.L.; Schweitzer, C.J.; Saxton, A.M.; Hebard, F. V. 2014. Impact of silvicultural treatment on chestnut seedling growth and survival. In: Proceeding of the fifth international chestnut symposium, Double, M.L.; MacDonald W. L. eds.ISHS. Acta Horticulturae 1019: 191-198.

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.

Research Participants

Principal Investigators

  • Leila Pinchot - US Forest Service, Northern Research Station, Research Ecologist
  • Alex Royo - US Forest Service, Northern Research Station, Research Ecologist
  • Scott Schlarbaum, The University of Tennessee Institute of Agriculture, Professor of genetics
  • Matt Peters - US Forest Service, Northern Research Station, Ecologist
  • Arnold Saxton, The University of Tennessee, Knoxville
  • Sandy Anagnostakis, The Connecticut Agricultural Experiment Station, Emeritus Scientist
  • Rakesh Minocha - US Forest Service, Northern Research Station, Plant Physiologist
  • Charlie Flower - US Forest Service, Northern Research Station, Research Ecologist

Research Partners

  • Last modified: March 4, 2019