Vertical fine-root distribution determines the potential for acquisition of resources throughout soil profiles; yet, variation among forest types and changes in vertical distribution with environments are poorly understood. We examined vertical root distributions of different forest communities to determine how belowground strategies shift across different forest types and along edaphic gradients. Specific root length and diameter of fine roots as well as fine-root biomass, length and area densities were measured in sequential soil layers at 10 cm depth increments across 118 forest plots representing five subalpine forest types. Evergreen forest types, including evergreen oaks, were more deeply rooted than birch forests. Differences in rooting depth were due to the dominant tree species identity, not to variations in shrub or herbaceous components. Within forest types, soil nutrients and physical properties contributed to shifts rooting depth but not root morphology. Vertical distributions of fine roots represent critical inputs of plant carbon into soils as well as different capacities for the acquisition of soil resources. Our findings identify consistent patterns of rooting distributions among forest types that may be predictable based on more easily measured root and soil properties and can improve efforts to model rooting depth profiles in forest communities.

中文翻译：

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五种亚高山森林类型的垂直细根分布随环境梯度的土壤特性而变化

垂直细根分布决定了整个土壤剖面获取资源的潜力；然而，人们对森林类型之间的变化以及垂直分布随环境的变化知之甚少。我们检查了不同森林群落的垂直根系分布，以确定地下策略如何在不同的森林类型和沿土壤梯度变化。在代表五种亚高山森林类型的 118 个森林样地中以 10 厘米深度增量在连续土壤层中测量细根的比根长度和直径以及细根生物量、长度和面积密度。常绿森林类型，包括常绿橡树，比白桦林根深蒂固。生根深度的差异是由于优势树种的特性，而不是灌木或草本成分的变化。在森林类型中，土壤养分和物理特性有助于改变生根深度而不是根系形态。细根的垂直分布代表植物碳进入土壤的关键输入以及获取土壤资源的不同能力。我们的研究结果确定了森林类型之间生根分布的一致模式，这些模式可以根据更容易测量的根和土壤特性进行预测，并且可以改进对森林群落生根深度剖面建模的努力。