| Title: | Interannual and Seasonal Dynamics of Volatile Organic Compound Fluxes From the Boreal Forest Floor |
| Author(s): | Maki M; Aalto J; Hellen H; Pihlatie M; Back J; |
| Address: | "Institute for Atmospheric and Earth System Research/Forest Sciences, Helsinki, Finland. Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland. Department of Physics, Faculty of Science, University of Helsinki, Helsinki, Finland. Finnish Meteorological Institute, Helsinki, Finland. Department of Agricultural Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland. Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland" |
| ISSN/ISBN: | 1664-462X (Print) 1664-462X (Electronic) 1664-462X (Linking) |
| Abstract: | "In the northern hemisphere, boreal forests are a major source of biogenic volatile organic compounds (BVOCs), which drive atmospheric processes and lead to cloud formation and changes in the Earth's radiation budget. Although forest vegetation is known to be a significant source of BVOCs, the role of soil and the forest floor, and especially interannual variations in fluxes, remains largely unknown due to a lack of long-term measurements. Our aim was to determine the interannual, seasonal and diurnal dynamics of boreal forest floor volatile organic compound (VOC) fluxes and to estimate how much they contribute to ecosystem VOC fluxes. We present here an 8-year data set of forest floor VOC fluxes, measured with three automated chambers connected to the quadrupole proton transfer reaction mass spectrometer (quadrupole PTR-MS). The exceptionally long data set shows that forest floor fluxes were dominated by monoterpenes and methanol, with relatively comparable emission rates between the years. Weekly mean monoterpene fluxes from the forest floor were highest in spring and in autumn (maximum 59 and 86 mug m(-2) h(-1), respectively), whereas the oxygenated VOC fluxes such as methanol had highest weekly mean fluxes in spring and summer (maximum 24 and 79 mug m(-2) h(-1), respectively). Although the chamber locations differed from each other in emission rates, the inter-annual dynamics were very similar and systematic. Accounting for this chamber location dependent variability, temperature and relative humidity, a mixed effects linear model was able to explain 79-88% of monoterpene, methanol, acetone, and acetaldehyde fluxes from the boreal forest floor. The boreal forest floor was a significant contributor in the forest stand fluxes, but its importance varies between seasons, being most important in autumn. The forest floor emitted 2-93% of monoterpene fluxes in spring and autumn and 1-72% of methanol fluxes in spring and early summer. The forest floor covered only a few percent of the forest stand fluxes in summer" |
| Keywords: | biogenic volatile organic compound decomposition flux forest floor seasonality temperature vegetation; |
| Notes: | "PubMed-not-MEDLINEMaki, Mari Aalto, Juho Hellen, Heidi Pihlatie, Mari Back, Jaana eng Switzerland 2019/03/12 Front Plant Sci. 2019 Feb 22; 10:191. doi: 10.3389/fpls.2019.00191. eCollection 2019" |
