Institute of Forestry, Lithuanian Research Centre for Agriculture and Forestry, Girionys, Kaunas District, Lithuania.
ARGANS, Sophia-antipolis, France.
Sci Total Environ. 2019 Mar 25;658:1265-1277. doi: 10.1016/j.scitotenv.2018.12.092. Epub 2018 Dec 10.
Lithuania is representative of maritime to continental climate, no water limitation, and moderate ground-level ozone (O) pollution. We investigated the trends of meteorological variables and O and how these environmental conditions associate with tree health from 2001 onward. Ozone metrics for forest protection, based on Accumulated O exposure Over a Threshold of X ppb (AOTX) or on Phytotoxic O Dose over a Y threshold (PODY), were modeled at nine ICP-Forests plots over the time period 2001-2014. Tree-response indicators, i.e. crown defoliation and visible foliar O injury, were assessed during annual field surveys carried out at each ICP-Forests plot over the time period 2007-2017. Mann-Kendall and Sen statistical tests were applied to estimate changes over time of meteorological variables, response indicators and O metrics. Finally, the O metrics were correlated (Spearman test) to the response indicators over the common period 2007-2014. Over this time period, trend analyses revealed an increasingly hotter (+0.27 °C decade, on average) and drier climate (rainfall, -48 mm decade). A reduction was found for O annual mean (-0.28 ppb decade, on average) and AOT40 (-2540 ppb·h decade, on average) whereas an increase was found for POD0 (+0.40 mmol m decade, on average). Visible foliar O injury increased (+0.17% decade), while an improvement of the crown conditions (-5.0% decade) was observed. AOT40 was significantly associated with crown defoliation while PODY and soil water content were correlated with visible foliar O injury. As visible foliar O injury was negligible in all the studied species, the results suggest that moderate O pollution (approximately 30 ppb as annual average) does not induce biologically significant effects on this forest vegetation under the current conditions, however the overall O risk (POD0) is expected to increase in the future under a hotter and drier climate.
立陶宛具有海洋到大陆的气候特征，不存在水资源限制，且地面臭氧（O）污染处于中等水平。自 2001 年以来，我们一直研究气象变量和 O 的趋势，以及这些环境条件与树木健康的关系。基于超过 X 个 ppb 阈值的臭氧累积暴露（AOTX）或超过 Y 个阈值的臭氧毒害剂量（PODY），我们对 2001 年至 2014 年期间在 9 个国际森林监测计划（ICP）森林样地建立了森林保护臭氧指标模型。在 2007 年至 2017 年期间，对每个 ICP 森林样地进行了年度实地调查，评估了树冠凋落和可见叶片 O 伤害等树木响应指标。应用 Mann-Kendall 和 Sen 统计检验来估算气象变量、响应指标和 O 指标随时间的变化。最后，在 2007 年至 2014 年期间，对 O 指标与响应指标进行了相关性（Spearman 检验）。在此期间，趋势分析显示气候变得越来越热（平均每十年上升 0.27°C）和干燥（降雨量减少 48mm 每十年）。O 的年平均值（平均每年减少 0.28ppb）和 AOT40（平均每十年减少 2540ppb·h）呈下降趋势，而 POD0（平均每年增加 0.40mmol·m）呈上升趋势。可见叶片 O 伤害增加（每十年增加 0.17%），而树冠状况得到改善（每十年减少 5.0%）。AOT40 与树冠凋落显著相关，而 PODY 和土壤含水量与可见叶片 O 伤害相关。由于所有研究物种的可见叶片 O 伤害都微不足道，因此结果表明，在当前条件下，中等水平的 O 污染（年平均约 30ppb）不会对森林植被造成有生物学意义的影响，然而，在更热和更干燥的气候条件下，整体 O 风险（POD0）预计会增加。
