Dominance of interplanted American chestnut ( Castanea dentata) in southwestern Wisconsin, USA

Abstract

American chestnut ( Castanea dentata (Marsh.) Borkh.) once dominated the eastern deciduous forests of the USA before nearly all trees throughout the range were annihilated by the introduced pathogen Cryphonectria parasitica (Murr.) Barr. It is anticipated that a blight-resistant hybrid form of American chestnut will be available for reintroduction in the near future, and many reintroduction programs will likely involve mixed interplantings with other hardwood species. Little is known, however, about plantation performance of American chestnut relative to other species. This study assessed early plantation development (seven or eight growing seasons following direct seeding) of American chestnut relative to black walnut ( Juglans nigra L.) and northern red oak ( Quercus rubra L.) on a site with no evidence of blight in southwestern Wisconsin (43°54′N, 90°53′W). American chestnut exhibited greater height (47 and 77% more) and diameter at breast height (DBH) (50 and 140% more) growth than black walnut and northern red oak, respectively. Mean total height of American chestnut was 6.4 m (0.84 m per year), while mean total DBH was 6.4 cm (0.83 cm per year). American chestnut also had better stem form, measured as deviation in stem straightness for the first 2 m, than the other two species. This data reaffirms historical observations of pre-blight growth rates for American chestnut. The reintroduced hybrid chestnut tree will be predominately American chestnut, and is expected to exhibit similar silvical characteristics to the tree tested here. Thus, on suitable sites, American chestnut reintroduction may provide a valuable new resource for plantation forestry.