From Glossary of Meteorology
(Also called subarctic climate.) In general, a climate that produces taiga vegetation; that is, one that is too cold for prolific tree growth but milder than the tundra climate and moist enough to promote appreciable vegetation.
This climate type appears as a subdivision of Köppen's 1936 snow forest climate and Thornthwaite's 1931 microthermal climate.
Köppen, W. P., and R. Geiger 1930–1939. Handbuch der Klimatologie. Berlin: Gebruder Borntraeger, 6 vols.
Thornthwaite, C. W. 1931. The climates of North America according to a new classification. Geogr. Rev.. 21. 633–655.