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Natascha Kljun. Photo.

Natascha Kljun


Natascha Kljun. Photo.

Vertical distribution of sources and sinks of volatile organic compounds within a boreal forest canopy


  • Ross Petersen
  • Thomas Holst
  • Meelis Mölder
  • Natascha Kljun
  • Janne Rinne

Summary, in English

The ecosystem-atmosphere flux of biogenic volatile organic compounds (BVOCs) has important impacts on tropospheric oxidative capacity and the formation of secondary organic aerosols, influencing air quality and climate. Here we present within-canopy measurements of a set of dominant BVOCs in a managed spruce- and pine-dominated boreal forest located at the ICOS (Integrated Carbon Observation System) station Norunda in Sweden, collected using proton-transfer-reaction mass spectrometry (PTR-MS) during 2014-2016 and vertical emission profiles derived from these data. Ozone concentrations were simultaneously measured in conjunction with these PTR-MS measurements. The main BVOCs investigated with the PTR-MS were isoprene, monoterpenes, methanol, acetaldehyde, and acetone. The distribution of BVOC sources and sinks in the forest canopy was explored using Lagrangian dispersion matrix methods, in particular continuous near-field theory. The forest canopy was found to contribute ca. 86% to the total monoterpene emission in summertime, whereas the below-canopy and canopy emissions were comparable (ca. 42% and 58%, respectively) during the fall period. This result indicates that boreal forest litter and other below-canopy emitters are a principal source of total forest monoterpene emissions during the fall months. During night, our results for methanol, acetone, and acetaldehyde seasonally present strong sinks in the forest canopy, especially in the fall, likely due to the nighttime formation of dew on vegetation surfaces.


  • Dept of Physical Geography and Ecosystem Science
  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • LTH Profile Area: Aerosols
  • Centre for Healthy Indoor Environments
  • MERGE: ModElling the Regional and Global Earth system
  • ICOS Sweden
  • LU Profile Area: Nature-based future solutions
  • Centre for Environmental and Climate Science (CEC)

Publishing year







Atmospheric Chemistry and Physics





Document type

Journal article


Copernicus GmbH


  • Climate Research




  • Sesquiterpene emissions from boreal forest, and their interactions with climate and tropospheric chemistry
  • FORMAS: Towards full understanding of managed boreal forests as part of climate system: Role of biogenic volatile organic compounds


  • ISSN: 1680-7324