Department of Biological and Environmental Sciences, University of Helsinki, Finland.
Ambio. 2009 Dec;38(8):406-12. doi: 10.1579/0044-7447-38.8.406.
Forests in northern Fennoscandia are mainly composed of the O3-sensitive species--Scots pine and downy, mountain, and silver birches. Seminatural vegetation also contributes to biodiversity, carbon cycling, and ecosystem services as a part of forests, mires, meadows, and road verges. Fumigation experiments show that current O3 concentrations of 30-50 ppb reduce plant biomass production and reproduction. Visible foliar injury is attributable to peak O3 concentrations and relates to fast phenological development and high growth rate. Trees can acclimate to O3-induced water stress by producing more xeromorphic leaves or needles. The direct effects of O3 on grassland vegetation also translate to changes in the structure and size of the soil microbial community, and ecosystem N cycling. It is necessary to reduce the emission of O3 precursors and maintain high biodiversity to protect northern ecosystems. Regular, systematic, countrywide monitoring and validation as well as quantification of the effects of O3 on plants in the Nordic countries are also necessary.
北欧的森林主要由 O3 敏感物种——欧洲赤松、绒毛山杨、银桦组成。半自然植被作为森林、沼泽、草地和路边的一部分，也有助于生物多样性、碳循环和生态系统服务。熏蒸实验表明，目前 30-50ppb 的 O3 浓度会降低植物生物量的产生和繁殖。可见的叶片损伤归因于 O3 浓度峰值，并与快速物候发育和高生长速率有关。树木可以通过产生更多的旱生叶或针叶来适应 O3 引起的水分胁迫。O3 对草原植被的直接影响也会导致土壤微生物群落的结构和大小发生变化，以及生态系统 N 循环的变化。有必要减少 O3 前体物的排放，保持高生物多样性，以保护北欧生态系统。还需要在北欧国家定期、系统、全国范围内监测和验证以及量化 O3 对植物的影响。
