Balsam Poplar, Bam Tree, Black Cottonwood, Hackmatack, Heart-leaved Balsam Poplar, Tacamahaca: Populus balsamifera (Synonyms: Populus balsamifera var. subcordata, Populus candicans, Populus tacamahacca) - Leaves pale green and brownish below. A tree of interior alaskan forests.
Quaking Aspen, Trembling Aspen: Populus tremuloides (Synonyms: Populus aurea, Populus x polygonifolia, Populus tremula ssp. tremuloides, Populus tremuloides var. aurea, Populus tremuloides var. magnifica, Populus tremuloides var. vancouveriana) - Leaf blades round, less than 5 cm long with flattened petioles.
Black Cottonwood: Populus trichocarpa (Synonyms: Populus balsamifera ssp. trichocarpa, Populus trichocarpa var. ingrata) - Leaves whitish or glaucous below. Generally a species of coastal areas of Alaska. This species is evidently found near the Park Entrance.