Populus tremuloides - image Populus alba - image Populus alba - image Populus alba - image Populus nigra - image Aspen: Populus tremula - Photographs of this tree, its bark, leaves and Autumn colours. Populus angustifolia - Distribution and occurrence, value and use, characteristics and fire ecology. Populus balsamifera ssp. balsamifera - Distribution and occurrence, value and use, characteristics, and fire ecology. Populus deltoides - Distribution and occurrence, value and use, characteristics, and fire ecology. Populus fremontii - Includes distribution and occurrence, botanical and ecological characteristics, value and use, and fire ecology. Populus grandidentata - Distribution and occurrence, value and use, characteristics, and fire ecology. Populus tremuloides - Distribution and occurrence, value and use, characteristics, and fire ecology. Populus deltoides - Student project on the cottonwood tree including classification, habitat, adaptation, nutrition, reproduction and interactions with other species. Populus alba: European White Poplar - Tree identification fact sheet with photos of the leaf, flower, fruit, twig, bark and form. Populus balsamifera spp. balsamifera: Balsam Poplar - Tree identification fact sheet with photos of the leaf, flower, fruit, twig, bark and form. Populus balsamifera spp. trichocarpa: Black Cottonwood - Tree identification fact sheet with photos of the leaf, flower, fruit, twig, bark and form. Populus deltoides: Eastern Cottonwood - Tree identification fact sheet with photos of the leaf, flower, fruit, twig, bark and form. Populus grandidentata: Bigtooth Aspen - Tree identification fact sheet with photos of the leaf, flower, fruit, twig, bark and form. Populus heterophylla: Swamp Cottonwood - Tree identification fact sheet with photos of the leaf, flower, fruit, twig, bark and form. Populus tremuloides: Quaking Aspen - Tree identification fact sheet with photos of the leaf, flower, fruit, twig, bark and form.