Increased phytotoxic O 3 dose accelerates autumn senescence in an O 3 -sensitive beech forest even under the present-level O 3

摘要: Ground-level ozone (O3) concentrations are expected to increase over the 21st century, especially in East Asia. However, impact of O3 has not been directly assessed at forest level this region. We performed flux-based risk assessments carbon sequestration capacity an old cool temperate deciduous forest, consisting O3-sensitive Japanese beech (Fagus crenata), and a warm evergreen dominated by O3-tolerant Konara oak (Quercus serrata) based on long-term CO2 flux observations. On basis practical approach for continuous estimation canopy-level stomatal conductance (Gs), higher phytotoxic dose above threshold 0 uptake (POD0) with Gs was observed than that forest. Light-saturated gross primary production, as measure ecosystem, declined earlier late growth season increasing POD0, suggesting autumn senescence, but