Increased phytotoxic O3 dose accelerates autumn senescence in an O3-sensitive beech forest even under the present-level O3.
Ground-level ozone (O3) concentrations are expected to increase over the 21(st) century, especially in East Asia. However, the impact of O3 has not been directly assessed at the forest level in this region. We performed O3 flux-based risk assessments of carbon sequestration capacity in an old cool temperate deciduous forest, consisting of O3-sensitive Japanese beech (Fagus crenata), and in a warm temperate deciduous and evergreen forest dominated by O3-tolerant Konara oak (Quercus serrata) based on long-term CO2 flux observations. On the basis of a practical approach for a continuous estimation of canopy-level stomatal conductance (Gs), higher phytotoxic ozone dose above a threshold of 0 uptake (POD0) with higher Gs was observed in the beech forest than that in the oak forest. Light-saturated gross primary production, as a measure of carbon sequestration capacity of forest ecosystem, declined earlier in the late growth season with increasing POD0, suggesting an earlier autumn senescence, especially in the O3-sensitive beech forest, but not in the O3-tolerant oak forest.
Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba 305-8687, Japan.
Mitsutoshi
M
Kitao
Tohoku Research Center, Forestry and Forest Products Research Institute, Nabeyashiki 92-25, Morioka 020-0123, Japan.
Yukio
Y
Yasuda
Kansai Research Center, Forestry and Forest Products Research Institute, Nagaikyutaroh 68, Kyoto 612-0855, Japan.
Yuji
Y
Kominami
Hokkaido Research Center, Forestry and Forest Products Research Institute, Hitsujigaoka 7, Sapporo 062-8516, Japan.
Katsumi
K
Yamanoi
Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba 305-8687, Japan.
Masabumi
M
Komatsu
Kansai Research Center, Forestry and Forest Products Research Institute, Nagaikyutaroh 68, Kyoto 612-0855, Japan.
Takafumi
T
Miyama
Hokkaido Research Center, Forestry and Forest Products Research Institute, Hitsujigaoka 7, Sapporo 062-8516, Japan.
Yasuko
Y
Mizoguchi
Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba 305-8687, Japan.
Satoshi
S
Kitaoka
Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba 305-8687, Japan.
Kenichi
K
Yazaki
Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba 305-8687, Japan.
Hiroyuki
H
Tobita
Kansai Research Center, Forestry and Forest Products Research Institute, Nagaikyutaroh 68, Kyoto 612-0855, Japan.
Kenichi
K
Yoshimura
Department of Forest Science, Hokkaido University, Sapporo 060-8589, Japan.
Takayoshi
T
Koike
Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
Takeshi
T
Izuta