Final answer:
Loggers and timber companies did not contribute significantly to building national parks in the United States after 1870. Conservationists, environmentalists, and the Civilian Conservation Corps played essential roles in the establishment and development of national parks.
Step-by-step explanation:
In the westward migration after 1870, one group that did not contribute significantly to building national parks in the United States was the loggers and timber companies. While they played a role in the development of the West, their focus was primarily on extracting natural resources such as timber, rather than preserving and conserving the natural environment.
On the other hand, groups like conservationists and environmentalists played a crucial role in the establishment of national parks. Figures such as John Muir and President Theodore Roosevelt advocated for the preservation of natural landscapes and played a major part in creating national parks like Yosemite and Yellowstone.
To support the development of national parks, the Civilian Conservation Corps (CCC) was also instrumental. The CCC was a federal program established during the Great Depression that provided employment to young men and focused on conservation, including the construction of trails, infrastructure, and fire prevention efforts in national parks.