Significance and limitation of scarification treatments on early establishment of Betula maximowicziana, a tree species producing buried seeds: effects of surface soil retention

ABSTRACT

We compared early establishment of B. maximowicziana, a commercially valuable tree species producing buried seeds, among the standard scarification and three alternative treatments in which surface soil was retained (soil replacing, screening, and plowing). We found the efficiencies of the soil retention for the seedling emergence were clearly different among the treatments; the replacing and plowing caused significantly richer seedling emergence, whereas the screening resulted in lower emergence than the standard treatment. In total, the most abundant seedling emergence was estimated to have occurred in the case of higher soil water content with lower soil hardness. These seemed to be attributed to soil properties, induced differently by each treatment, and relatively high water demand characteristics of B. maxomowicziana. On the other hand, plowing showed low seedling density at the end of the second growing season despite its greater emergence, probably because of suppression from understory vegetation recovered from undisturbed root system. We conclude that replacing would be a best alternative for regeneration of B. maxomowicziana. The scarification treatments in which surface soil is retained can be evaluated to be positive or negative according to the site conditions, physiological characteristics of the target tree species, and recovery of other vegetation.

KEYWORDS:

• Site preparation
• birch
• natural regeneration
• soil properties
• soil water content

Acknowledgments

We would like to thank to the editor and two anonymous reviewers for their helpful comments and suggestions. We would sincerely thank N. Hyodo, I. Asada, T. Sato, H. Abe and technical staff of the Teshio experiment forest, for their assistance in the field work, and members of the Nayoro laboratory for their valuable discussion for this study. We also thank T. Watanabe and T. Inoue for their help to conduct soil chemical analyses. Thanks are extended to H. Shibata, K. Fukuzawa and M. Kobayashi for their critical reading of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by JSPS KAKENHI Grant Number JP26450187