Because of similar design values, the combination includes Engelmann and Sitka spruces and Lodgepole pine from the West, along with Balsam fir, Jack pine, Red pine and several species of spruce from the  US Northeast. Spruce-Pine-Fir (south) design values make it appropriate for general framing applications. In the higher, structural light framing grades, dimension products are appropriate for light trusses and other engineered applications.