SPF (Spruce-Pine-Fir)
A species group combining Spruce, Pine, and Fir that's graded and sold interchangeably. The most common framing lumber in North America outside the southeastern U.S.
In Detail
SPF is the dominant framing species in Canada and the northern U.S. The species within the group have similar mechanical properties, so they're graded together under NLGA rules. SPF is lighter, straighter, and easier to work than SYP but has slightly lower strength values. KD-HT (Kiln-Dried Heat-Treated) SPF is standard for retail lumber.