TY - JOUR
T1 - Spatial variations in xylem sap flux density in evergreen oak trees with radial-porous wood
T2 - Comparisons with anatomical observations
AU - Tateishi, Makiko
AU - Kumagai, Tomo'omi
AU - Utsumi, Yasuhiro
AU - Umebayashi, Toshihiro
AU - Shiiba, Yasuki
AU - Inoue, Kazunobu
AU - Kaji, Kiyohiro
AU - Cho, Keiichiro
AU - Otsuki, Kyoichi
N1 - Funding Information:
Acknowledgments This work was supported by Grants-in-Aid for Scientific Research (nos. 17380096 and 17510011) from the Ministry of Education, Science and Culture, Japan. We thank A. Kume and K. Yoda for providing the opportunity to conduct this study. We are also grateful to M. Chiwa, I. Murata, Y. Shinohara, and T. Inoue for their able assistance in the field.
PY - 2008/2
Y1 - 2008/2
N2 - To estimate whole-tree water use when employing sap flow measurements, integration of the sap flux density (Fd) over the sapwood area is needed. Accordingly, it is necessary to obtain information on the characteristics of stem water transportation such as spatial variations in Fd and the active xylem area in the stem cross-section. Although evergreen oak trees with radial-porous wood represent a major component of secondary forests in western Japan, detailed information on their stem water transportation characteristics remains unclear. In the present study, we used the heat dissipation method (Granier method) to conduct measurements of azimuthal and radial variations in the Fd of Quercus glauca Thunb. ex Murray, a representative evergreen broad-leaved tree in western Japan. Further, by analyzing the anatomy of the xylem structure, we examined why Fd varies spatially in the stem cross-section. By using a dye solution injected into a radial hole bored into the tree trunk, we confirmed that the entire stem is hydroactive. We also compared the spatial variations in Fd and water conductivity per xylem area (Ks) which were estimated by using the observed vessel diameters and their density over the stem cross-section and Hagen-Poiseuille's law. Azimuthal and radial variations in Fd reached about 60 and 50% of the maximum values, respectively, and could be explained by spatial variation in Ks. As a result, we obtained statistical parameters describing the spatial variation in Fd in Q. glauca and determined that whole-tree water use estimated from measurements in one direction had at most ±20% potential errors for studied trees.
AB - To estimate whole-tree water use when employing sap flow measurements, integration of the sap flux density (Fd) over the sapwood area is needed. Accordingly, it is necessary to obtain information on the characteristics of stem water transportation such as spatial variations in Fd and the active xylem area in the stem cross-section. Although evergreen oak trees with radial-porous wood represent a major component of secondary forests in western Japan, detailed information on their stem water transportation characteristics remains unclear. In the present study, we used the heat dissipation method (Granier method) to conduct measurements of azimuthal and radial variations in the Fd of Quercus glauca Thunb. ex Murray, a representative evergreen broad-leaved tree in western Japan. Further, by analyzing the anatomy of the xylem structure, we examined why Fd varies spatially in the stem cross-section. By using a dye solution injected into a radial hole bored into the tree trunk, we confirmed that the entire stem is hydroactive. We also compared the spatial variations in Fd and water conductivity per xylem area (Ks) which were estimated by using the observed vessel diameters and their density over the stem cross-section and Hagen-Poiseuille's law. Azimuthal and radial variations in Fd reached about 60 and 50% of the maximum values, respectively, and could be explained by spatial variation in Ks. As a result, we obtained statistical parameters describing the spatial variation in Fd in Q. glauca and determined that whole-tree water use estimated from measurements in one direction had at most ±20% potential errors for studied trees.
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U2 - 10.1007/s00468-007-0165-8
DO - 10.1007/s00468-007-0165-8
M3 - Article
AN - SCOPUS:38849147813
SN - 0931-1890
VL - 22
SP - 23
EP - 30
JO - Trees - Structure and Function
JF - Trees - Structure and Function
IS - 1
ER -