Black cottonwood has short, fine fibers and is used to produce pulp for high-grade book and magazine paper. Other primary wood products include veneer, plywood, and lumber. Black cottonwood also provides food, cover, and shade for a variety of wildlife species. The crowns of black cottonwood provide nesting sites for bald eagles, ospreys, and blue herons. Woodpeckers, great horned owls, wood ducks, flying squirrels, raccoons, and a variety of songbirds nest in black cottonwood trunk cavities.
Beavers use black cottonwood for food and building materials.
At least 70 fungal species cause decay in cottonwood, but only six fungi cause significant losses. This disease limits photosynthesis and causes leaves to fall prematurely, thus decreasing tree growth and vigor. Black cottonwood is also subject to the condition known as wet wood, which leads to wood collapse during drying. Black cottonwood saplings are often injured and sometimes killed by unseasonably early or late frosts.