The effect of site quality on performance of american chestnut (castanea dentata) seedlings bred for blight (cryphonectria parasitica) resistance

Efforts to produce American chestnuts (Castanea dentata) resistant to chestnut blight fungus (Cryphonectria parasitica) have spurred an interest in reintroducing the species to managed forests. Understanding how site characteristics impact chestnut performance will inform appropriate site selection. This study was designed to evaluate the impact of site quality on survival, growth, competitive ability, and blight resistance durability of American, Chinese, and three families of backcross hybrid chestnuts. Chestnuts were planted in xeric, intermediate, and sub-mesic sites in Pennsylvania. Three years after planting, survival was 86 percent across all treatments. American chestnuts were taller on intermediate than xeric sites, and two backcross hybrid families were taller on intermediate as compared to mesic sites. Intermediate sites may offer enough soil moisture to optimize growth, without the intense competition characteristic of more mesic sites. Incidence of blight infection was too low to assess differences among treatments, though is expected to increase over time.