C concentration in tree rings of beech trees living near CO vents in the Hakkoda Cardera, Aomori, Japan

Horiuchi, Kazuho*; Chiba, Takuji*; Hoshino, Yasuharu*; Oyama, Motonari*; Tanaka, Takayuki; Amano, Hikaru*

We investigated how volcanic CO emission affects the C concentrations in tree rings of beech trees in the Hakkoda Caldera in Aomori, which is one of high emission regions of volcanic CO in the world. There was a tendency that the obtained C concentrations were, surprisingly, quite near to the values of the concurrent atmospheric CO and decreased from 1991 to 2001. The C concentrations in caldera are lower than those of the control samples taken from a beech living outside of the caldera. We revealed the possibility that we can solve the local dynamics of fossil CO emission using C in tree rings. However, the maximum difference of C between inside and outside of the caldera was 14 permil. This result showed that the volcanic CO mixed with atmospheric CO by 4.4 ppm or less. As the trunk absorbing CO exist in height that is several meters higher than the volcanic CO vents, the low mixing may occur.