MIYAMA Takafumi, KOMINAMI Yuji, TAMAI Koji, GOTO Yoshiaki, Teruhiko Kawahara, JOMURA Mayuko, DANNOURA Masako
Components and seasonal variation of nighttime total ecosystem respiration in a Japanese broadleaved secondary forest
The Yamashiro Experimental Forest is a broad-leaved secondary forest in Kyoto, Japan. On its complex terrain, low wind speed, high air stability, and local advection are common at night. To reduce the uncertainty in measuring woody-tissue respiration at night, we used automated stem chambers to measure stem respiration continuously (for 5 min at 30 min intervals) on stems of Quercus serrata Murr. (deciduous) and Ilex pedunculosa
Miq. (evergreen) throughout 2003. Using these data, we estimated night-time respiration for the total ecosystem and its various components, and we report foliar and soil respiration rates for 2003. Annual average night-time respiration of soil, evergreen leaf, deciduous leaf, evergreen woody tissue and deciduous woody tissue were estimated as 0.0794 (63.2%), 0.0101 (8.0%), 0.0160 (12.7%), 0.0064 (5.1%) and 0.0137 (10.9%) mg CO2
, respectively. The contribution of soil respiration to the total ecosystem respiration rate reached its minimum (49.1%) on 12 June (DOY 163) and its maximum (82.4%) on 29 November (DOY 333). Seasonal change of growth respiration was marked, indicating that the seasonal variation of growth respiration must be evaluated carefully to estimate total ecosystem respiration. Therefore, long-term continuous measurement using automated chambers and averaging provides an effective means of evaluating the annual night-time ecosystem respiration.