Marked difference of rainfall partitioning in an unmanaged coniferous plantation with high stand density

ABSTRACT

Many coniferous plantations in Japan have not been managed because of the impact of economic recession on forestry. Few studies have examined rainfall partitioning (RP) in these unmanaged plantations with a stand density ≥ 2500 stems ha⁻¹, which is a typical planting density in Japan. The aims of this study were to examine RP in an unmanaged coniferous plantation and to clarify the differences in RP with other coniferous plantations in Japan. We recorded gross rainfall (GR), throughfall (TF) and stemflow (SF) for one year in an unmanaged 32-year-old Japanese cypress (Chamaecyparis obtusa Endl.) plantation with a high stand density (2500 trees ha⁻¹) in Fukuoka, Japan. The GR, TF and SF were 2248.6 mm, 1068.4 mm (47.5% of GR) and 425.3 mm (18.9% of GR), respectively, which resulted in interception loss (IL) of 754.9 mm (33.6% of GR). The present data were compared with the published data for all components of RP from 36 previous studies of coniferous plantations in Japan. Compared with these plantations, the present ratio of TF/GR was the lowest and the SF/GR was the highest, resulting in the highest IL/GR. This study highlights that not only TF and IL, but also SF account for a high proportion of RP in unmanaged coniferous plantations.

KEYWORDS:

• Rainfall partitioning
• Chamaecyparis obtusa
• throughfall
• stemflow
• interception loss

Acknowledgments

The authors acknowledge staff of Kasuya Research Forest of Kyushu University for their help of the set-up of a meteorological station. We also thank Drs. Ayumi Katayama, Tamao Kasahara, and Masaaki Chiwa of the Kyushu University Forests for their contribution to in situ investigation, and Dr. Kume Tomonori of the Kyushu University Forests for revising our manuscript. Thanks are also due to two anonymous reviewers for helpful comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was partly supported by Fukuoka Prefecture Foundation for Headwater Forests; JSPS KAKENHI [#26292088]; and JSPS KAKENHI [#18H04152].