A series of abrupt climate events linked to circum-North Atlantic meltwater forcing have been recognised in Holocene paleoclimate data. To address the paucity of proxy records able to characterise robustly the regional impacts of these events, we retrieved a sub-centennial resolution, well-dated core sequence from Lake Kuutsjärvi, northeast Finland. By analysing a range of paleo-environmental proxies (pollen, plant sedimentary ancient DNA, plant macrofossils, conifer stomata, and non-pollen palynomorphs), and supported with proxy-based paleotemperature and moisture reconstructions, we unravel a well-defined sequence of vegetation and climate dynamics over the early-to-middle Holocene. The birch-dominated pioneer vegetation stage was intersected by two transient tree-cover decrease events at 10.4 and 10.1 thousand years ago (ka), likely representing a two-pronged signal of the 10.3 ka climate event. Our data also show a clear signal of the 8.2 ka climate event, previously not well recorded in the European Arctic, with a collapse of the pine-birch forest and replacement by juniper developing in tight synchrony with Greenland isotopic proxies over 8.4–8.0 ka. Supported by climate modelling, severe winter cooling rather than summer might have been driving vegetation disruptions in the early Holocene. The Kuutsjärvi data indicate an early arrival of Norway spruce () by 9.2 ka (pollen, DNA, and stoma finds), as well as the first evidence for Holocene presence of larch () in Finland, with pollen finds dating to 9.6–5.9 ka.

中文翻译：

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揭示全新世气候波动和古代针叶树种群：芬兰北部高分辨率多代理记录的见解


全新世古气候数据已经认识到一系列与环北大西洋融水强迫有关的突发气候事件。为了解决能够有力地表征这些事件的区域影响的代理记录的缺乏问题，我们从芬兰东北部的库茨耶尔维湖检索了一个亚百年分辨率、日期明确的核心序列。通过分析一系列古环境代理（花粉、植物沉积古 DNA、植物大化石、针叶树气孔和非花粉孢子形态），并在基于代理的古温度和湿度重建的支持下，我们揭示了明确的植被序列以及全新世早中期的气候动态。以桦树为主的先锋植被阶段在 10.4 年前和 10.1 千年前 (ka) 发生了两次短暂的树木覆盖减少事件，这可能代表了 10.3 ka 气候事件的双管齐下的信号。我们的数据还显示了 8.2 ka 气候事件的明确信号，此前在欧洲北极没有得到很好的记录，松桦林倒塌，取而代之的是杜松林，与 8.4-8.0 ka 的格陵兰同位素代理紧密同步发展。根据气候模型的支持，严酷的冬季而不是夏季可能是全新世早期植被破坏的原因。 Kuutsjärvi 数据表明，挪威云杉 () 早在 9.2 ka 之前抵达（花粉、DNA 和气孔发现），以及芬兰落叶松 () 全新世存在的第一个证据，花粉发现可追溯到 9.6–5.9 ka 。