The high afforestation costs and the decline of public functions as a consequence of appearance of unsuccessful plantations in the Japanese Cryptomeria are serious problems in snow districts. Therefore the degree of success of afforestation (DSA) with regard to site factors in man-made Cryptomeria forests was surveyed, and the possibilities to improve afforestation of Cryptomeria were reconsidered. The study site was the region with deepest snow depth of 1.03.0 m in the Gifu Prefecture Hida district, central Japan. A result of analysis using quantification method I proved the deepest snow depth (SD) as a factor affecting the DSA most intensely. The DSA decreased with the deeper SD. A frequency distribution of DSA in each SD showed that afforestation of Cryptomeria was possible in the zone under 1.5 m SD but unsuccessful in the zone over 2.5 m SD. In the zone of 1.52.5 m SD, the DSA was affected mainly by the inclination and the profile form of the slope with SD. Afforestation was difficult on steep or concave slopes in this zone, because of the low DSA.