The role of fine‐root mass, specific root length and lifespan in tree performance: a whole‐tree exploration

1. The root economics spectrum (RES) hypothesis predicts that fast-growing tree species have short-lived roots with high specific root length (SRL) to allow rapid resource uptake, and opposite trait expressions for slow-growing species. Yet, the mixed support for this hypothesis suggests that trees can adopt alternative strategies to increase resource uptake, besides an increase in SRL.
2. We combined a novel mechanistic whole-tree model and empirical fine-root data of ten tree species to test the effects of one of these alternative strategies, notably increasing fine-root mass, on the tree’s net C gain (used here as a proxy for tree performance), and to assess how fine-root lifespan influences the relative importance of SRL and fine-root mass for the C balance of trees.
3. Our results indicate that accounting for the short lifespan of high-SRL roots has important implications for explaining tree performance and the role of roots herein. Without considering their faster turnover, high-S...

1. 根经济谱（root economics spectrum, RES）假说预测，速生树种拥有比根长（specific root length, SRL）更高、寿命更短的细根，以实现快速的资源获取；而慢生树种则呈现相反的性状表达。然而，针对该假说的支持证据混杂，表明树木除了提升比根长之外，还可采用其他替代策略来增加资源获取能力。
2. 本研究结合了一款新型机理型全树模型与10个树种的实测细根数据，用以检验其中一种替代策略——即提升细根生物量——对树木净碳增益（本研究中将其作为树木性能的替代指标）的影响，并评估细根寿命如何影响比根长与细根生物量在树木碳平衡中的相对重要性。
3. 本研究结果表明，考虑高比根长细根的短寿命特性，对解释树木性能及其根系的作用具有重要意义。若未考虑其更快的周转速率，高比根长……