Synonyms for Black Cottonwood (same or very similar meaning)
WordNet sense 1 (North American poplar with large rounded scalloped leaves and brownish bark and wood):
swamp cottonwood, downy poplar, Populus heterophylla, swamp poplarWordNet sense 2 (cottonwood of western North America with dark green leaves shining above and rusty or silvery beneath):
Populus trichocarpa, Western balsam poplarFrom the ODE community, based on WordNetadd/edit