Seedling survival and growth during the 2 years following seed germination of Magnolia stellata, a threatened subcanopy tree, after clearcutting

Abstract

The two-year survival and growth of seedlings of Magnolia stellata were monitored at a site following clearcutting. The mortality rate during the growing season of the first year was 3.4 %, much lower than reported in previous studies, possibly because of the high light levels due to clearcutting. In contrast, the mortality rate during the winter season of the first year was 7.7 %, and 10 of 13 individuals were killed by uprooting due to frost heave in wet locations. Individuals that grew in wet sites and germinated early exhibited good height growth in the first year. However, in the second year, no effects of the moisture conditions or germination timing on the relative growth rate were detected, although there was a correlation between initial height and height growth. This result suggests that the soil moisture conditions and the length of the growing period have strong effects during the early period of life but gradually reduce in influence as the plants grow. We found that soil moisture conditions had positive and negative effects on seedling growth and survival in the growing and winter seasons, respectively, of the first year, but not in the second year. This suggests that effects of the particular environment can vary greatly depending on life stage.

Keywords:

• Frost heave
• Magnoliaceae
• Satoyama
• Soil moisture

Acknowledgments

We are grateful to members of the Forestry and Park and the Environment sections of the Tajimi City Government and the Tajimi City Cultural Properties Preservation Center for help with the field experiment. We thank N. Yanagisawa, M. Matsushita, and S. Matsuhisa for helpful discussions and comments on an early version of this manuscript. We also thank the journal editor and two anonymous referees for their helpful comments.

Notes

Electronic supplementary material The online version of this article (doi:10.1007/s10310-015-0490-5) contains supplementary material, which is available to authorized users.