Study of the C cycling is important to clarify the characteristics of the ecosystem. Recently, the importance of fungi in the forest C cycling has been also suggested. It suggested 25% of the forest soil respiration may be derived from fungi. It has also attempted to evaluate their role in C cycling by measuring the production of hyphae. However, the characteristics of CO₂ efflux from fungi are still unknown compared to those of the soil and bark respirations. This is mainly because of the small size of hypha, which make difficult to collect their data. In this study, we tried to characterize the temporal changes and a factor controlling the chance of CO₂ efflux from fruiting bodies.

We selected S. granulatus and R. pectinatoides in pine forest in Hyogo. We measured CO₂ efflux from those fruiting bodies 24 times every hour in 2015. At that time, it was taken only those after the separation of the fruiting bodies by plastic sheet.

Mean(±SD) CO₂ efflux from the soft fruiting body was 9.9±2.0 mg gDW^-1 hr^-1 in mature stage, 10.4±6.0 mg gDW^-1 hr^-1 in senile stage. Mature stage showed a pattern of which is being increased gradually in the daytime. But senile stage was unclear pattern. We found positive linear correlation between the temporal changes of CO₂ efflux and air temperature in the mature stage, but not in the senile stage.