WordNet sense 1 (common forest tree of the eastern United States and Canada; used especially for pulpwood):

eastern hemlock, Canadian hemlock, Tsuga canadensis

WordNet sense 2 (small spruce of boggy areas of northeastern North America having spreading branches with dense foliage; inferior wood):

black spruce, Picea mariana

WordNet sense 3 (shrubby two-needled pine of coastal northwestern United States; red to yellow-brown bark fissured into small squares):

lodgepole, shore pine, lodgepole pine, Pinus contorta

WordNet sense 4 (large two-needled pine of southeastern United States with light soft wood):

Pinus glabra