The partitioning of gross primary production for young Eucalyptus tereticornis trees under experimental warming and altered water availability

John E. Drake, Mark G. Tjoelker, Michael J. Aspinwall, Peter B. Reich, Sebastian Pfautsch, Craig V.M. Barton

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

The allocation of carbon (C) is an important component of tree physiology that influences growth and ecosystem C storage. Allocation is challenging to measure, and its sensitivity to environmental changes such as warming and altered water availability is uncertain. We exposed young Eucalyptus tereticornis trees to +3°C warming and elimination of summer precipitation in the field using whole-tree chambers. We calculated C allocation terms using detailed measurements of growth and continuous whole-crown CO 2 and water exchange measurements. Trees grew from small saplings to nearly 9 m height during this 15-month experiment. Warming accelerated growth and leaf area development, and it increased the partitioning of gross primary production (GPP) to aboveground respiration and growth while decreasing partitioning below ground. Eliminating summer precipitation reduced C gain and growth but did not impact GPP partitioning. Trees utilized deep soil water and avoided strongly negative water potentials. Warming increased growth respiration, but maintenance respiration acclimated homeostatically. The increasing growth in the warmed treatment resulted in higher rates of respiration, even with complete acclimation of maintenance respiration. Warming-induced stimulations of tree growth likely involve increased C allocation above ground, particularly to leaf area development, whereas reduced water availability may not stimulate allocation to roots.

Original languageEnglish (US)
Pages (from-to)1298-1312
Number of pages15
JournalNew Phytologist
Volume222
Issue number3
DOIs
StatePublished - May 2019

Bibliographical note

Funding Information:
We thank Burhan Amiji (Western Sydney University) for maintaining the site, for collecting much of the growth and harvest data, and for his excellent research support. This experiment was made possible through a collaboration with Sune Linder and the Swedish University of Agricultural Sciences, who designed, built, and generously provided the WTCs. We also gratefully acknowledge Courtney Campany (Colgate University) for his measurements of fine root biomass, as well as Renee Smith and Carrie Drake (Western Sydney University) for their help with the whole-tree harvests. This research was supported by the Australian Research Council (Discovery, DP140103415), a New South Wales government Climate Action Grant (NSW T07/CAG/016), the Hawkesbury Institute for the Environment, and Western Sydney University.

Funding Information:
We thank Burhan Amiji (Western Sydney University) for maintaining the site, for collecting much of the growth and harvest data, and for his excellent research support. This experiment was made possible through a collaboration with Sune Linder and the Swedish University of Agricultural Sciences, who designed, built, and generously provided the WTCs. We also gratefully acknowledge Courtney Campany (Colgate University) for his measurements of fine root biomass, as well as Renee Smith and Carrie Drake (Western Sydney University) for their help with the whole-tree harvests. This research was supported by the Australian Research Council (Discovery, DP140103415), a New South Wales government Climate Action Grant (NSW T07/ CAG/016), the Hawkesbury Institute for the Environment, and Western Sydney University.

Publisher Copyright:
© 2018 The Authors. New Phytologist © 2018 New Phytologist Trust

Keywords

  • allocation
  • climate change
  • drought
  • partitioning
  • respiration
  • warming

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