Key message

High-density airborne laser scanning can be used to generate metrics that help characterize and differentiate the structure of Douglas-fir across three genetic levels at three different planting spacings.

Abstract

In British Columbia, Canada, Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] selective breeding is used to develop genetically improved regeneration stock. To evaluate realized performance of improved stock, breeders take frequent measurements in genetic gain trials to determine whether yield gains are being met. Currently, variables collected focus on individual tree yield attributes; however, information generated from progeny test trials may not directly reflect plantation performance. Realized yield trials help to bridge the gap between progeny test estimated gain and plantation setting performance. High density airborne laser scanning (ALS) has the potential to identify variables that could improve the selection and validation process. We utilized ALS collected from an unmanned aerial system to assess performance of genetic improvement across three genetic levels and three stand spacings. ALS derived metrics were used to test three hypotheses: (1) tree height is correlated with the level of genetic superiority, (2) tree crown shape varies across genetic level, and (3) tree crown density is associated with genetic level. Random forest algorithms were used to identify candidate ALS metrics. To account for interaction effects, a two-way analysis of variance was conducted for each metric, followed by a post-hoc test to investigate significant differences between genetic level and spacing. The scale and shape parameters of Weibull probability density functions, vertical complexity index, and the fraction of euphotic voxels were found to be important metrics. Results show that genetically superior trees are typically taller, with higher, shorter and denser crowns. In addition, variation across genetic level may be indicative of greater phenotypic plasticity, as superior trees possess the ability to respond to tighter stand spacing.

中文翻译：

---

利用机载激光扫描表征具有不同遗传增益水平的花旗松之间的生长特性变化

关键信息

高密度机载激光扫描可用于生成度量标准，以帮助在三个不同种植间隔的三个遗传水平上表征和区分花旗松的结构。

抽象

在加拿大不列颠哥伦比亚省，花旗松[ Pseudotsuga menziesii（Mirb。）Franco]选择性育种用于开发遗传改良的再生种群。为了评估改良种群的已实现表现，育种者经常在遗传增益试验中进行测量，以确定是否满足了产量增益。当前，收集的变量集中在单个树的产量属性上。但是，后代测试试验产生的信息可能无法直接反映人工林的生长性能。进行的单产试验有助于弥合后代试验估计的收益与人工林整地性能之间的差距。高密度机载激光扫描（ALS）可以识别变量，从而改善选择和验证过程。我们利用从无人机系统中收集到的ALS来评估跨越三个遗传水平和三个机架间距的遗传改良性能。ALS衍生的度量标准用于测试三个假设：（1）树高与遗传优势水平相关；（2）树冠形状在遗传水平上有所不同；（3）树冠密度与遗传水平相关。随机森林算法用于识别候选ALS指标。为了说明相互作用的影响，对每个度量标准进行了方差的双向分析，然后进行事后检验，以研究遗传水平和间隔之间的显着差异。Weibull概率密度函数的尺度和形状参数，垂直复杂度指数以及共晶体素的比例被认为是重要的指标。结果表明，具有遗传优势的树木通常较高，冠高，矮而密。此外，