Light availability during spring and autumn determines growth and survival of regenerated Korean pine seedlings

ABSTRACT

The regeneration of Korean pine (Pinus koraiensis Sieb. et Zucc.) is a core issue for restoration from secondary to primary forests in northeastern China. However, Korean pine exhibits limited recruitment within its own canopy in primary forests, but demonstrates excellent regeneration in secondary forests. Until now, the mechanisms underlying this phenomenon have not been satisfactorily explained. Hence, we conducted studies in both primary and secondary forests to investigate whether light availability during the non-growing season determines the fate of regeneration. In spring and autumn, understory light availability in the secondary forest was significantly better than that in the primary forest. The biomass and non-structural carbohydrate (NSC) concentrations of natural pine seedlings were considerably greater in the secondary forests compared to primary forests. The carbohydrate concentrations increased during spring and autumn and decreased in summer. In the manipulation experiment, the biomass of seedlings was positively correlated with the organ NSCs in spring, while the survival rates were correlated with NSCs in autumn. The light availability during the spring and autumn seasons may have a crucial role in the regeneration of Korean pine seedlings. This finding may support our practical management approach for the transformation of secondary forests into Korean pine forests.

KEYWORDS:

• Seedlings
• survival
• nonstructural carbohydrate
• leafless period
• light availability

Acknowledgments

The authors thank all colleagues who assisted with field work, data processing, and manuscript composition and Zhenzhao Xu, Wenxian Du, Weize Xu, Zhen Sun, and Zhiyuan Yang, who helped with chemical analysis. The National Research Station of Changbai Mountain Forest Ecosystem provided accommodation and experimental sites.

Author contribution statement

GZ designed the study, performed sampling, and wrote the manuscript, JW and JY analyzed the data, SM revised the introduction and discussion, and SM and GZ oversaw the experiment.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was financially supported by the National Natural Science Foundation of China [grant number 31670436], the Post-Doctoral Initiation Program of Jiangxi Academy of Forestry, the Doctor Initiation Program of Jiangxi Academy of Forestry, and Key Research and Development Program of Jiangxi Province, China [grant number 20212BBF63018].