Growth comparison between spring- and fall-planting containerized sugi (Cryptomeria japonica) seedlings

Abstract

We compared the growth of one-year-old containerized sugi (Cryptomeria japonica) seedlings outplanted in early September (fall-planting) with those outplanted after nursing continued until early April of the following year (spring-planting). The height-diameter ratio of the fall-planting seedlings decreased from 113 ± 21 cm cm^-1 in early September to 67 ± 12 cm cm^-1 in early April of the following year. Compared to the spring-planting seedlings, the fall-planting seedlings showed vigorous height growth from April, with the annual growth of 56.1 ± 32.5 cm for the fall-planting seedlings being significantly greater than the 20.3 ± 13.2 cm for the spring-planting seedlings. The annual height growth of the seedlings varied greatly depending on the planting location within the planting trial site, but regardless of the planting location, the fall-planting seedlings tended to have a greater annual height growth than the spring-planting seedlings. We could suggest the expectation of vigorous height growth of containerized sugi seedlings whose height-diameter ratio were large from the following spring by fall-planting before growth stopped.