Data from: Carbon allocation to root exudates is maintained in mature temperate tree species under drought

  • Melanie Brunn (Creator)
  • Benjamin D. Hafner (Creator)
  • Marie Zwetsloot (Creator)
  • Fabian Weikl (Creator)
  • Karin Pritsch (Creator)
  • Kyohsuke Hikino (Creator)
  • Nadine K. Ruehr (Creator)
  • Emma J. Sayer (Creator)
  • Taryn L. Bauerle (Creator)



Data in support of the following research: Carbon (C) exuded via roots is proposed to increase under drought and facilitate important ecosystem functions. However, it is unknown how exudate quantities relate to the total C budget of a drought-stressed tree, i.e. how much of net-C assimilation is allocated to exudation at the tree level. We calculated the proportion of daily C assimilation allocated to root exudation during early summer by collecting root exudates from mature Fagus sylvatica L. and Picea abies (L.) Karst. exposed to experimental drought, and combining above- and belowground C fluxes with leaf, stem, and fine-root surface area. Exudation from individual roots increased exponentially with decreasing soil moisture, with the highest increase at the wilting point. Despite ~50 % reduced C assimilation under drought, exudation from fine-root systems was maintained and trees exuded 1.0 % (F. sylvatica) to 2.5 % (P. abies) of net C into the rhizosphere, increasing the proportion of C allocation to exudates two- to threefold. Water-limited P. abies released two-thirds of its exudate-C into the surface soil, whereas it was only one-third in droughted F. sylvatica. Across the entire root system, droughted trees maintained exudation similar to controls, suggesting drought-imposed belowground C investment, which could be beneficial for ecosystem resilience.
Date made available8 Apr 2022
PublisherCornell University


  • Belowground carbon allocation
  • carbon partitioning
  • experimental drought
  • fine-root exudation
  • European beech
  • Norway spruce
  • rhizosphere
  • temperate-forest C budget

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