© 1991 Heron Publishing—Victoria, Canada
Long-term measurement of CO2 release from the aboveground parts of a hinoki forest tree in relation to air temperature
Samuel Arung Paembonan (1, 2), Akio Hagihara (1, 3) and Kazuo Hozumi (1)
1. Department of Forestry, Faculty of Agriculture, Nagoya University, Chikusa, Nagoya 464-01, Japan / 2. Department of Forestry, Faculty of Agriculture, Hasanuddin University, Ujung Pandang, Indonesia / 3. Author to whom reprint requests should be addressed / Received August 1, 1990
Summary
Nighttime respiration of the aboveground parts of a 12-year-old (as of 1986) hinoki (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) tree growing in the field was continuously measured over a three-year period, using an open gas exchange
system which tracked ambient air temperature. The respiration rate in any month was described as an exponential function of
air temperature. Daily respiration rate was lower in winter when the tree was dormant than in the summer. The daily respiration
rate rose rapidly in spring to a maximum in June–July, decreased abruptly in autumn, and then decreased gradually to a minimum
in January–February. The Q10 for nighttime respiration was inversely related to air temperature. The highest Q10 (≥ 3.0) was observed in January when the monthly mean nighttime air temperature was around 4.0 °C. The lowest Q10 (≈1.5) was observed in August when the monthly mean nighttime air temperature was about 23 °C. A Q10 value of about 2.0 was observed in May and June when monthly mean nighttime air temperature ranged from 15 to 20 °C.
