Abstract We studied the occurrence of extreme weather events and their effects on the carbon dioxide and water exchange of two subarctic forest stands. One study site was a Scots pine site in eastern Finnish Lapland (Varrio), and the other was a Norway spruce site in western Finnish Lapland (Kenttarova). We compared short-term meteorological data with long-term data and found that the pine forest had experienced extremely warm, wet and dry years as well as cold spells during the growing season in the studied period of 2012–2018. The spruce forest was studied during the period 2003–2013, during which time it experienced extremely warm and wet summers, and dry periods, although the dry times were not statistically defined as such. The spruce forest was less resilient to warm and dry periods, as its total ecosystem respiration and respiration potential decreased during warm and dry summers, while the same effect was not seen in the pine forest. The decreased respiration values may have occurred due to slowed decomposition of organic matter. The pine forest experienced two cold spells during the studied period. One of these cold periods was more of a continuation of the previous cold spring and late start of the growing season in 2017, while the other one occurred after a warm period in 2014. The ecosystem respiration rates and gross primary production in 2017 remained low for the whole July–August time period likely due to cold-inhibited growth of ground vegetation, while in 2014 no such effect could be seen. We saw no effect of extreme weather events in the water exchange related measurements in either of the forests. Overall, both forests, especially the trees, were resilient to the weather extremes and experienced no long-term damage.

中文翻译：

---

亚北极苏格兰松和挪威云杉林对极端天气事件的恢复能力

摘要 我们研究了极端天气事件的发生及其对两个亚北极林分二氧化碳和水分交换的影响。一个研究地点是芬兰拉普兰东部 (Varrio) 的苏格兰松林，另一个是芬兰拉普兰西部 (Kenttarova) 的挪威云杉。我们将短期气象数据与长期数据进行对比，发现松林在 2012-2018 年研究期间的生长季节经历了极其温暖、潮湿和干燥的年份以及寒冷的天气。云杉林在 2003 年至 2013 年期间进行了研究，在此期间，它经历了极其温暖潮湿的夏季和干旱期，尽管干旱期并未在统计上如此定义。云杉林对温暖和干旱时期的抵抗力较差，在温暖干燥的夏季，其总生态系统呼吸和呼吸潜力下降，而在松林中则没有出现同样的影响。呼吸值降低可能是由于有机物分解缓慢造成的。在研究期间，松林经历了两次寒流。其中一个寒冷期更多是延续了之前的冷春和 2017 年生长季节的延迟，而另一个则发生在 2014 年温暖期之后。 2017 年的生态系统呼吸速率和初级生产总值仍然较低整个 7 月至 8 月时间段可能是由于地面植被的寒冷抑制生长，而在 2014 年没有看到这种影响。我们在任何一个森林的水交换相关测量中都没有看到极端天气事件的影响。全面的，