The role of future forests in global biogeochemical cycles will depend on how different tree species respond to climate. Interpreting the response of forest growth to climate change requires an understanding of the temporal and spatial patterns of seasonal climatic influences on the growth of common tree species. We constructed a new network of 310 tree-ring width chronologies from three common tree species (Quercus robur, Pinus sylvestris and Fagus sylvatica) collected for different ecological, management and climate purposes in the south Baltic Sea region at the border of three bioclimatic zones (temperate continental, oceanic, southern boreal). The major climate factors (temperature, precipitation, drought) affecting tree growth at monthly and seasonal scales were identified. Our analysis documents that 20th century Scots pine and deciduous species growth is generally controlled by different climate parameters, and that summer moisture availability is increasingly important for the growth of deciduous species examined. We report changes in the influence of winter climate variables over the last decades, where a decreasing influence of late winter temperature on deciduous tree growth and an increasing influence of winter temperature on Scots pine growth was found. By comparing climate-growth responses for the 1943-1972 and 1973-2002 periods and characterizing site-level growth response stability, a descriptive application of spatial segregation analysis distinguished sites with stable responses to dominant climate parameters (northeast of the study region), and sites that collectively showed unstable responses to winter climate (southeast of the study region). The findings presented here highlight the temporally unstable and nonuniform responses of tree growth to climate variability, and that there are geographical coherent regions where these changes are similar. Considering continued climate change in the future, our results provide important regional perspectives on recent broad-scale climate-growth relationships for trees across the temperate to boreal forest transition around the south Baltic Sea.

中文翻译：

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北温带森林冬季气候变暖和夏季水分供应对树木生长的影响。

未来森林在全球生物地球化学循环中的作用将取决于不同树种对气候的反应。解释森林生长对气候变化的响应需要了解季节性气候影响常见树种生长的时间和空间模式。我们构建了一个由三种常见树种（栎树、樟子松和山毛榉）组成的 310 树轮宽度年表的新网络，这些树种是在南波罗的海地区三个生物气候带边界处为不同的生态、管理和气候目的收集的（温带大陆性、海洋性、南北方）。确定了每月和季节性影响树木生长的主要气候因素（温度、降水、干旱）。我们的分析表明，20 世纪的欧洲赤松和落叶树种的生长通常受不同气候参数的控制，夏季水分供应对于所研究的落叶树种的生长越来越重要。我们报告了过去几十年冬季气候变量影响的变化，其中发现晚冬温度对落叶树生长的影响减少，而冬季温度对苏格兰松生长的影响增加。通过比较 1943-1972 年和 1973-2002 年期间的气候增长响应并表征站点级增长响应稳定性，空间分离分析的描述性应用区分了对主要气候参数（研究区域的东北部）具有稳定响应的站点，以及共同表现出对冬季气候不稳定反应的地点（研究区域的东南部）。这里介绍的研究结果强调了树木生长对气候变化的时间不稳定和不均匀的反应，并且存在这些变化相似的地理连贯区域。考虑到未来持续的气候变化，我们的研究结果提供了重要的区域视角，以了解近期波罗的海南部从温带到北方森林过渡的树木的大范围气候生长关系。