Globally, treelines form a transition zone between tree‐dominated forest downslope and treeless alpine vegetation upslope. Treelines represent the highest boundary of “tree” life form in high‐elevation mountains and at high latitudes. Recently, treelines have been shifting upslope in response to climate warming, so it has become important to understand global tree diversity and treeline distributions. However, to the best of our knowledge, no global database on tree flora of treelines exists, which limits our capacity to undertake macroecological analyses. Here, for the first time, we present a global data set on the trees of the treeline ecotone, supported by an online ToTE database. We synthesized the database from 1202 studies published over the last 60 years (1962 to 2022) following the Preferred Reporting Items in Systematic Reviews and Meta‐Analysis (PRISMA) protocol. We classified the tree species in the database into three categories: treeline tree (TL) species, near to treeline (NTL) tree species, and tree species with an upper montane range limit (TUMR). The ToTE Version‐1 presents a total of 208 tree taxa, including 189 species, five subspecies, and 14 varieties, belonging to 54 genera and 26 families distributed across 34 mountain regions worldwide that either grow exactly at the treeline or have a range limit below the treeline. Of the total taxa, 155, 14, and 39 belong to TL, NTL, and TUMR, respectively. Genera such as Abies, Picea, Pinus, Larix, and Juniperus are more represented in the treeline tree category. On the other hand, Acer, Prunus, Populus, and Quercus have more representatives in the near to treeline category, whereas Erica, Nothofagus, and Polylepis contribute more tree species with an upper montane range limit. Furthermore, families such as Rosaceae and Pinaceae include trees that occur both at the treeline and with an upper montane range limit, whereas Sapindaceae includes trees that occur exclusively near to treeline. Our database also includes information on the global distribution patterns of treeline tree species richness across mountains and biomes. The mountains with the highest number of tree species are the Andes (39) followed by the Himalaya (37). Close to 67% of tree species show restricted distributions in different mountains, with the highest endemism in the Andes and the Himalaya. In terms of tree species distribution, Pinus sylvestris was widespread, with a distribution across nine mountain regions, followed by Picea glauca and Fagus sylvatica, both distributed across five mountain regions. In terms of species' distribution across biomes, the temperate biome harbors the highest treeline tree species richness (152 species), which may reflect the fact that the majority of studies are available from the temperate regions of the world. The remaining 56 species are distributed within five other biomes, with the least in dry tropical and subarctic (four species each). Furthermore, currently 40 treeline tree species fall under different International Union for Conservation of Nature threat categories. We anticipate that our database will help advance research on macroecological, biogeographic, evolutionary, climate‐change, and conservation aspects of the treeline on a global scale. The data are released under a Creative Commons Attribution 4.0 international license. Please cite this data paper when the data are reused.

中文翻译：

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ToTE：林线生态交错带树木的全球数据库

在全球范围内，林线形成了下坡以树木为主的森林和上坡无树高山植被之间的过渡带。林线代表了高海拔山区和高纬度地区“树”生命形式的最高边界。最近，由于气候变暖，林线一直在向上移动，因此了解全球树木多样性和林线分布变得非常重要。然而，据我们所知，不存在关于林线树木区系的全球数据库，这限制了我们进行宏观生态分析的能力。在这里，我们首次提供了由在线 ToTE 数据库支持的林线生态交错带树木的全球数据集。我们根据系统评价和荟萃分析 (PRISMA) 协议中的首选报告项目，从过去 60 年（1962 年至 2022 年）发表的 1202 项研究中合成了该数据库。我们将数据库中的树种分为三类：林线树种（TL）、近林线树种（NTL）和山地范围上限树种（TUMR）。 ToTE Version‐1 共展示了 208 个树类群，包括 189 个物种、5 个亚种和 14 个变种，属于 26 个科 54 个属，分布在全球 34 个山区，它们要么恰好生长在林线，要么生长范围限制在以下林线。在总类群中，分别有 155 个、14 个和 39 个属于 TL、NTL 和 TUMR。属如冷杉,云杉属,松属,落叶松， 和杜松属在树线树类别中更多地代表。另一方面，宏碁,李属,胡杨属， 和栎属在靠近林线类别中有更多代表，而艾丽卡,水青冈属， 和波鳞属贡献更多具有山地范围上限的树种。此外，蔷薇科和松科等科包括生长在林线和山地范围上限的树木，而无患子科包括仅生长在林线附近的树木。我们的数据库还包括有关山脉和生物群落林线树种丰富度的全球分布模式的信息。树种最多的山脉是安第斯山脉（39 种），其次是喜马拉雅山脉（37 种）。近 67% 的树种在不同山脉中的分布受到限制，其中安第斯山脉和喜马拉雅山的特有性最高。从树种分布来看，樟子松分布广泛，分布在九个山区，其次是青云杉和水青冈，均分布在五个山区。就物种在生物群落中的分布而言，温带生物群落拥有最高的林线树种丰富度（152种），这可能反映了大多数研究都来自世界温带地区的事实。其余 56 个物种分布在其他 5 个生物群落中，最少分布在干燥的热带和亚北极地区（各 4 个物种）。此外，目前有 40 种林线树种属于国际自然保护联盟不同的威胁类别。我们预计我们的数据库将有助于推进全球范围内林线宏观生态、生物地理学、进化、气候变化和保护方面的研究。这些数据根据 Creative Commons Attribution 4.0 国际许可发布。重复使用数据时请引用本数据论文。