Abstract Forest management alters the growing conditions and thus further development of trees. However, quantitative assessment of forest management on tree growth has been demanding as methodologies for capturing changes comprehensively in space and time have been lacking. Terrestrial laser scanning (TLS) has shown to be capable of providing three-dimensional (3D) tree stem reconstructions required for revealing differences between stem shapes and sizes. In this study, we used 3D reconstructions of tree stems from TLS and an unmanned aerial vehicle (UAV) to investigate how varying thinning treatments and the following growth effects affected stem shape and size of Scots pine (Pinus sylvestris L.) trees. The results showed that intensive thinning resulted in more stem volume and therefore total biomass allocation and carbon uptake compared to the moderate thinning. Relationship between tree height and diameter at breast height (i.e. slenderness) varied between both thinning intensity and type (i.e. from below and above) indicating differing response to thinning and allocation of stem growth of Scots pine trees. Furthermore, intensive thinning, especially from below, produced less variation in relative stem attributes characterizing stem shape and size. Thus, it can be concluded that thinning intensity, type, and the following growth effects have an impact on post-thinning stem shape and size of Scots pine trees. Our study presented detailed measurements on post-thinning stem growth of Scots pines that have been laborious or impracticable before the emergence of detailed 3D technologies. Moreover, the stem reconstructions from TLS and UAV provided variety of attributes characterizing stem shape and size that have not traditionally been feasible to obtain. The study demonstrated that detailed 3D technologies, such as TLS and UAV, provide information that can be used to generate new knowledge for supporting forest management and silviculture as well as improving ecological understanding of boreal forests. 1

中文翻译：

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评估间伐对单个苏格兰松树茎生长分配的影响

摘要 森林管理改变了树木的生长条件，从而进一步发展。然而，由于缺乏全面捕捉空间和时间变化的方法，因此需要对森林管理对树木生长的定量评估。地面激光扫描 (TLS) 已显示能够提供揭示茎形状和大小之间差异所需的三维 (3D) 树茎重建。在这项研究中，我们使用来自 TLS 和无人机 (UAV) 的树干的 3D 重建来研究不同的间伐处理和以下生长效应如何影响苏格兰松 (Pinus sylvestris L.) 树的茎形状和大小。结果表明，与适度间伐相比，密集间伐导致更多的茎体积，因此总生物量分配和碳吸收。树高和胸高直径（即细长）之间的关系在间伐强度和类型（即从下方和上方）之间变化，表明对疏伐的不同反应和苏格兰松树的茎生长分配。此外，密集的变薄，特别是从下面，在表征茎形状和大小的相对茎属性方面产生的变化较小。因此，可以得出结论，间伐强度、类型和以下生长效应对苏格兰松树的间伐后茎形状和大小有影响。我们的研究提供了对苏格兰松树细化后茎生长的详细测量，这些测量在详细的 3D 技术出现之前是费力的或不切实际的。此外，来自 TLS 和 UAV 的茎重建提供了表征茎形状和大小的各种属性，这些属性在传统上是无法获得的。该研究表明，详细的 3D 技术（例如 TLS 和无人机）提供的信息可用于生成支持森林管理和造林以及提高对北方森林生态理解的新知识。1 该研究表明，详细的 3D 技术（例如 TLS 和无人机）提供的信息可用于生成支持森林管理和造林以及提高对北方森林生态理解的新知识。1 该研究表明，详细的 3D 技术（例如 TLS 和无人机）提供的信息可用于生成支持森林管理和造林以及提高对北方森林生态理解的新知识。1