Ailanthus altissima
Due to prolonged periods of natural fire suppression, much of the Pine Bush has evolved into northern or southern hardwood forests. These forests, often dominated by invasive species, occupy roughly of the Albany Pine Bush Preserve. The southern hardwood forests are dominated by black locust ("Robinia pseudoacacia"), which is exotic, and black cherry ("Prunus serotina"); with lesser numbers of native oaks ("Quercus") and maples ("Acer"), and the exotic, invasive tree of heaven ("Ailanthus altissima"). The shrub layer is dominated by black raspberry ("Rubus occidentalis") and other brambles ("Rubus" sp.). In contrast the northern hardwood forests are dominated by aspen ("Populus"), black cherry, red maple ("Acer rubrum"), white pine ("Pinus strobus"), gray birch ("Betula populifolia"), green ash ("Fraxinus pennsylvanica"), and oaks.