Date of Award

Spring 2014

Degree Type


Degree Name

Master of Science (MS)


Forestry and Natural Resources

First Advisor

Douglass Jacobs

Committee Member 1

Charles H. Michler

Committee Member 2

Keith E. Woeste

Committee Member 3

Harmony J. Dalgleish


Chestnuts, members of the genus Castanea , family Fagaceae, are valuable worldwide, and all species have noteworthy ecological, economic, and cultural importance in their native ranges. Historically, American chestnut (Castanea dentata (Marshall) Borkh.) was an abundant tree species in eastern North America until its decimation in the early 20 th century by chestnut blight, caused by the fungus Cryphonectria parasitica . To regain the benefits of this prized species in North America, efforts are ongoing to produce and introduce blight-resistant hybrids of C. dentata and the blight-resistant Chinese chestnut ( C. mollissima Blume). It is important that the C. mollissimaportion of hybrids be well adapted to the C. dentata native range and growing conditions, but very little is known about the ecology of C. mollissima . To improve the quality and success of hybrid breeding programs, this knowledge gap is addressed. In Dayville, CT, there exists a 50-yr-old naturalized stand of C. mollissima co-mingled with native forest species adjacent to an 85-year-old C. mollissima orchard. We addressed questions of forest composition, spatial distributions of woody stems, horizontal and vertical distributions of woody roots, past stand dynamics of C. mollissima , health and ecophysiology of C. mollissima , and genetic relationships of C. mollissimain the forest and orchard. On this site the exotic species is adapted and competitive and has assumed an ecological position similar to its extirpated relative, C. dentata . From a competition point of view, the introduced species has been neither overly aggressive nor suppressed relative to sympatric native forest tree species. Genetic composition of the naturalized population compared to its adjacent planted parents indicated little effect of natural selection or inbreeding depression. The seeming ease and persistence with which this exotic species introduced itself begs for an explanation as to why such naturalized stands of C. mollissima scarcely exist elsewhere in eastern North America. Likely explanations are that a rare time window of low seed and seedling depredation allowed seedlings to establish, and the shallow soil depth at this particular site has limited the native forest canopy height to a height that is attainable by the characteristically short-statured C. mollissima . The existence and success of this naturalized stand of C. mollissima supports the notion that hybrids between C. mollissima and C. dentata may be equally successful in future natural and anthropogenic forests in North America. However, the issue of seed/seedling depredation by wildlife needs to be considered as well as the possibility that hybrids may need the genetic potential to grow taller on more productive sites.