The influence of planting date on survival and growth of Larix kaempferi containerized seedlings

Abstract

To evaluate the optimum planting date for containerized seedlings of Larix kaempferi, we compared the survival rate and shoot and root growth of seedlings planted monthly from May through November. The planting date affected the growth in both the planting year and the following year. The survival rate one month after planting was at least 97%. However, root elongation remarkably decreased when seedlings were planted in October or later, because of the low ground temperature. In the planting year, shoot elongation was observed only in seedlings planted in June or earlier, and their shoot elongation rate peaked one month after the peak of the root elongation rate. Seedlings with the earlier planting dates yielded the greater root weight at the end of the planting year, which resulted in the greater shoot elongation in the following year. The difference in tree height, which existed at the end of the planting year, was still apparent at the end of the following year. Our results thus indicate that Larix kaempferi containerized seedlings should be planted until August, though seedling survival one month after planting was independent of the planting date.