Increased phytotoxic O3 dose accelerates autumn senescence in an O3-sensitive beech forest even under the present-level O3

• Published in: Scientific reports 2016-09, Vol.6 (1), p.32549-32549, Article 32549
• Main Authors: Kitao, Mitsutoshi, Yasuda, Yukio, Kominami, Yuji, Yamanoi, Katsumi, Komatsu, Masabumi, Miyama, Takafumi, Mizoguchi, Yasuko, Kitaoka, Satoshi, Yazaki, Kenichi, Tobita, Hiroyuki, Yoshimura, Kenichi, Koike, Takayoshi, Izuta, Takeshi
• Format: Article
• Language: English
• Subjects: 704/158/2454; 704/172/4081; Carbon dioxide; Carbon sequestration; Conductance; Coniferous forests; Fagus crenata; Forests; Humanities and Social Sciences; multidisciplinary; Ozone; Primary production; Quercus serrata; Science; Senescence; Stomata; Terrestrial ecosystems
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep32549

Ground-level ozone (O 3 ) concentrations are expected to increase over the 21 st century, especially in East Asia. However, the impact of O 3 has not been directly assessed at the forest level in this region. We performed O 3 flux-based risk assessments of carbon sequestration capacity in an old cool temperate deciduous forest, consisting of O 3 -sensitive Japanese beech ( Fagus crenata ), and in a warm temperate deciduous and evergreen forest dominated by O 3 -tolerant Konara oak ( Quercus serrata ) based on long-term CO 2 flux observations. On the basis of a practical approach for a continuous estimation of canopy-level stomatal conductance (G s ), higher phytotoxic ozone dose above a threshold of 0 uptake (POD0) with higher G s 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 O 3 -sensitive beech forest, but not in the O 3 -tolerant oak forest.