Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Poster

A (Atmospheric and Hydrospheric Sciences) » A-CG Complex & General

[A-CG40] Material Circulations in Land Ecosystems

Thu. May 24, 2018 3:30 PM - 5:00 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Tomomichi Kato(Research Faculty of Agriculture, Hokkaido University), Takashi Hirano(Research Faculty of Agriculture, Hokkaido University), Hisashi Sato(海洋研究開発機構 地球表層物質循環研究分野, 共同), Ryuichi Hirata(National Institute for Environmental Studies)

[ACG40-P02] Stem respiration of trees in a subtropical evergreen broadleaf forest in Okinawa, Japan

*Mimori Shiogaki1, Kazuho Matsumoto1, Shingo Taniguchi1, Mayo Hayamizu2, Atsushi Takashima1 (1.Faculty of Agriculture, University of the Ryukyus, 2.Graduate School of Agriculture, University of the Ryukyus)

Keywords:stem respiration, subtropical forest

We measured the stem respiration of five tree species in a subtropical mature evergreen broadleaf forest in northern Okinawa Island. In August and September 2017, we measured stem respiration at 50 points on 23 trees and examined the differences along the circumference, among individuals, and among species. No significant circumferential variation in stem respiration was found in the two major species: Castanopsis sieboldii and Schima wallichii. In these species, although no significant difference was found among individuals within the same species, there was a positive correlation between stem respiration and individual radial stem growth in Castanopsis sieboldii. The inter-species difference in stem respiration was not significant. The average stem respiration at all measurement points in the summer was 1.5 µmol m-2 s-1. We estimated the total stem and branch respiration on a whole-tree scale by multiplying the average stem respiration per unit stem surface area by the total surface area of the stem and branches, estimated from forest inventory data assessed in 2016. The stand-scale stem and branch respiration per unit ground area calculated by integrating the individual whole-tree values was 3.7 µmol m-2 s-1. After the summer measurements, we continued to make monthly measurements for fewer trees. The stem respiration decreased toward winter depending on the air temperature and was 18% of the summer value in January.