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Anna Maria Jönsson


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Time shift between net and gross CO2 uptake and growth derived from tree rings in pine and spruce


  • Fredrik Lagergren
  • Anna Maria Jönsson
  • Hans Linderson
  • Anders Lindroth

Summary, in English

Key message: A 6–9 month backward time shift of the carbon uptake gave the highest correlation between annual biomass increment and carbon uptake in this old even aged forest. Abstract: Plants’ carbon uptake and allocation to different biomass compartments is an important process for both wood production and climate mitigation. Measurements of the net ecosystem carbon dioxide exchange between ecosystems and the atmosphere provide insights into the processes of photosynthesis, respiration and accumulation of carbon over time, and the increase in woody biomass can be assessed by allometric functions based on stem diameter measurements. The fraction of carbon allocated to radial stem growth varies over time, and a lag between carbon uptake and growth can be expected. The dynamics of non-structural carbohydrates and autotrophic and heterotrophic respiration are key mechanisms for understanding this lag effect. In this study, a 9-year record of carbon flux and tree-ring data from Norunda, Sweden was used to investigate the relationship between net and gross carbon uptake and carbon allocated to growth. The flux data were aggregated to monthly sums. When full 12-month periods of accumulated carbon exchange were successively shifted backwards in time, the highest correlation was found with a 6–9 month shift, showing that a large part of the previous growing season was important for explaining the biomass increment of the following year.


  • Dept of Physical Geography and Ecosystem Science
  • BECC - Biodiversity and Ecosystem services in a Changing Climate
  • Quaternary Sciences

Publishing year







Trees - Structure and Function





Document type

Journal article




  • Climate Research
  • Physical Geography


  • Boreal forest
  • Carbon balance
  • Dendrochronology
  • Eddy covariance
  • Picea abies
  • Pinus sylvestris




  • ISSN: 0931-1890