Turgor – a limiting factor for radial growth in mature conifers along an elevational gradient

Richard L. Peters, Kathy Steppe, Henri E. Cuny, Dirk J.W. De Pauw, David C. Frank, Marcus Schaub, Cyrille B.K. Rathgeber, Antoine Cabon, Patrick Fonti

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

A valid representation of intra-annual wood formation processes in global vegetation models is vital for assessing climate change impacts on the forest carbon stock. Yet, wood formation is generally modelled with photosynthesis, despite mounting evidence that cambial activity is rather directly constrained by limiting environmental factors. Here, we apply a state-of-the-art turgor-driven growth model to simulate 4 yr of hourly stem radial increment from Picea abies (L.) Karst. and Larix decidua Mill. growing along an elevational gradient. For the first time, wood formation observations were used to validate weekly to annual stem radial increment simulations, while environmental measurements were used to assess the climatic constraints on turgor-driven growth. Model simulations matched the observed timing and dynamics of wood formation. Using the detailed model outputs, we identified a strict environmental regulation on stem growth (air temperature > 2°C and soil water potential > −0.6 MPa). Warmer and drier summers reduced the growth rate as a result of turgor limitation despite warmer temperatures being favourable for cambial activity. These findings suggest that turgor is a central driver of the forest carbon sink and should be considered in next-generation vegetation models, particularly in the context of global warming and increasing frequency of droughts.

Original languageEnglish (US)
Pages (from-to)213-229
Number of pages17
JournalNew Phytologist
Volume229
Issue number1
DOIs
StatePublished - Jan 2021
Externally publishedYes

Keywords

  • climate change
  • process-based model
  • radial stem growth
  • tree hydraulics
  • tree rings
  • wood formation

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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