The spatial variability of stemflow on the bole of trees has rarely been the focal point of stemflow studies, despite its potential importance for stemflow-induced changes to soils. This study helps close this data gap by supplying quantitative data on possible drivers of circumferential variation of stemflow on the boles of two Pinus sylvestris L. (Scots pine). Hence, the objectives of the present study were to quantify the circumferential spatial variability of stemflow on tree stems and to assess how some biotic and abiotic factors affect this variability. Continuous stemflow data observed for two trees within a mature stand of Scots pine during a 20-month period (May 2018 to December 2019) showed the existence of preferential flowpaths around the stem, with patterns of stemflow distribution differing between the two trees. Data suggest that biotic factors (trunk lean, bark morphology and tree neighbourhood) have a greater influence on stemflow distribution on tree stems than abiotic factors (rainfall intensity peaks). Our comprehensive spatio-temporal fine-scale measurements strongly support prior observations of non-uniform stemflow. Further studies of stemflow distribution across tree species and aboveground vegetative surfaces are needed to improve our mechanistic understanding of stemflow dynamics vis-à-vis rainfall interception processes and to gain further insight as to how the circumferential variation of stemflow on tree boles alters stemflow–soil interactions.

中文翻译：

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Pinus sylvestris L.（苏格兰松）茎流输入周向变化的驱动因素

尽管茎流引起的土壤变化具有潜在重要性，但树干上茎流的空间变异性很少成为茎流研究的焦点。这项研究通过提供关于两种樟子松树干上茎流周向变化的可能驱动因素的定量数据，有助于缩小这一数据差距L.（苏格兰松）。因此，本研究的目的是量化树茎上茎流的周向空间变异性，并评估一些生物和非生物因素如何影响这种变异性。在 20 个月期间（2018 年 5 月至 2019 年 12 月）对苏格兰松成熟林分内两棵树的连续茎流数据显示，茎周围存在优先流动路径，两棵树之间的茎流分布模式不同。数据表明，与非生物因素（降雨强度峰值）相比，生物因素（树干瘦弱、树皮形态和树邻域）对树干上的茎流分布的影响更大。我们全面的时空精细尺度测量强烈支持先前对非均匀茎流的观察。