Identifying root types helps understand the diversity of the morphogenetic capacities of root axes. Unfortunately, root types are generally defined arbitrarily. We used an unsupervised clustering method to define root types and examine the ontogeny of the Pinus pinaster root system. K-clustering was first used on four root traits, including three geometric architectural traits: basal cross-sectional area, root tropism, parent root tropism, and branching angle. Based on these groups, we assigned all the root axes to a root type. Clustering yielded the same five groups of lateral roots and explained the same percentage of variance (70%) whatever the tree age. This way, 11,004 root axes from 69 excavated root systems ranging from 3 to 50 years were assigned in 5 types. P. pinaster root axes showed large differences based on root tropism and parent root tropism intensity. The larger horizontal shallow roots represented most of the woody volume throughout the life cycle of the trees. The frame of the central part of the root system was almost completed in 4-year-old trees. In addition to the taproot, five types of lateral roots were identified in P. pinaster based on root geometry and size, and no consistent age effect was reported. This method could improve the connexion between root trait data and root modelling.

中文翻译：

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松树粗根丛生，从幼年到成熟阶段

识别根类型有助于了解根轴形态发生能力的多样性。不幸的是，根类型通常是任意定义的。我们使用无监督聚类方法来定义根类型并检查松树根系的个体发育。K-聚类首先用于四个根特征，包括三个几何结构特征：基部横截面积、根向性、亲根向性和分枝角。基于这些组，我们将所有根轴分配给一个根类型。聚类产生了相同的五组侧根，并解释了相同的方差百分比 (70%)，无论树龄如何。这样，从 3 到 50 年不等的 69 个挖掘根系中的 11,004 个根轴被分配为 5 种类型。P。pinaster 根轴显示出基于根向性和亲本根向性强度的巨大差异。较大的水平浅根代表了树木整个生命周期中的大部分木质体积。根系中央部分的框架在4年生的树上几乎完成。除了主根之外，根据根的几何形状和大小，在 P. pinaster 中还确定了五种类型的侧根，并且没有报告一致的年龄效应。该方法可以改善根性状数据与根建模之间的联系。pinaster 基于根的几何形状和大小，并且没有报告一致的年龄效应。该方法可以改善根性状数据与根建模之间的联系。pinaster 基于根的几何形状和大小，没有报告一致的年龄效应。该方法可以改善根性状数据与根建模之间的联系。