Scaling-up from tree to stand transpiration for a warm-temperate multi-specific broadleaved forest with a wide variation in stem diameter

Abstract

Previous studies have demonstrated a clear relationship between diameter at breast height (DBH) and tree transpiration (Q_T) in multi-specific broadleaved forests. However, these studies were conducted with a limited range of tree sizes and species, and thus many multi-specific broadleaved forests fall outside these conditions. Therefore, this study examined the relationship between DBH and Q_T in a warm-temperate multi-specific broadleaved forest (n = 12 species) with a wide range of tree sizes (5.0–70.0 cm DBH) using the Granier-type heat dissipation method. The results showed that, although sap flow density varied between individual trees and species, there was a significant relationship between log Q_T and log DBH (r² = 0.66, P < 0.001) because of the strong dependence of sapwood area on DBH. This study confirmed the applicability of the relationship for the stand transpiration (E_C) estimates even in a multi-specific broadleaved forest with a wide variation in DBH. Our results also revealed that selecting the sample trees in descending order of DBH effectively reduced potential errors in E_C estimates for a specific sample size, as larger trees contribute more to E_C. This information should be useful for future studies investigating the transpiration of multi-specific broadleaved forests, reducing errors during the scaling-up procedure.

Keywords:

• Multi-specific broadleaved forest
• Sampling methods
• Sap flow
• Scaling-up
• Stand transpiration

Acknowledgments

We would like to thank Mr. Haotien Sun, Ms. Yang Xiang and Dr. Yoshiyuki Miyazawa (Lab of Forest Ecosystem Management of the Kyushu University, Japan) for their field works. This study was partly supported by CREST (Core Research for Evolutional Science and Technology) of the Japan Science and Technology Agency, and the Global COE Program (Center of Excellence for Asian Conservation Ecology as a Basis of Human-Nature Mutualism, representative: T. Yahara), MEXT, Japan, and JSPS KAKENHI Grant (Adjustment of stand density control diagram for water resource conservation) Number 26292088.

Notes

Electronic supplementary material The online version of this article (doi:10.1007/s10310-016-0532-7) contains supplementary material, which is available to authorized users.