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| Titel |
Chemodiversity of a Scots pine stand and implications for terpene air concentrations |
| VerfasserIn |
J. Bäck, J. Aalto, M. Henriksson, H. Hakola, Q. He, M. Boy |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 2 ; Nr. 9, no. 2 (2012-02-06), S.689-702 |
| Datensatznummer |
250006760
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| Publikation (Nr.) |
 copernicus.org/bg-9-689-2012.pdf |
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| Zusammenfassung |
| Atmospheric chemistry in background areas is strongly influenced by natural
vegetation. Coniferous forests are known to produce large quantities of
volatile vapors, especially terpenes. These compounds are reactive in the
atmosphere, and contribute to the formation and growth of atmospheric new
particles.
Our aim was to analyze the variability of mono- and sesquiterpene emissions
between Scots pine trees, in order to clarify the potential errors caused by
using emission data obtained from only a few trees in atmospheric chemistry
models. We also aimed at testing if stand history and seed origin has an
influence on the chemotypic diversity. The inherited, chemotypic variability
in mono- and sesquiterpene emission was studied in a seemingly homogeneous
48 yr-old stand in Southern Finland, where two areas differing in their
stand regeneration history could be distinguished. Sampling was conducted in
August 2009. Terpene concentrations in the air had been measured at the same
site for seven years prior to branch sampling for chemotypes.
Two main compounds, α-pinene and Δ3-carene formed
together 40–97% of the monoterpene proportions in both the branch
emissions and in the air concentrations. The data showed a bimodal
distribution in emission composition, in particular in Δ3-carene emission within the studied population. 10% of the trees
emitted mainly α-pinene and no Δ3-carene at all,
whereas 20% of the trees where characterized as high Δ3-carene emitters (Δ3-carene forming >80% of total
emitted monoterpene spectrum). An intermediate group of trees emitted equal
amounts of both α-pinene and Δ3-carene. The emission
pattern of trees at the area established using seeding as the artificial
regeneration method differed from the naturally regenerated or planted
trees, being mainly high Δ3-carene emitters. Some differences
were also seen in e.g. camphene and limonene emissions between chemotypes,
but sesquiterpene emissions did not differ significantly between trees. The
atmospheric concentrations at the site were found to reflect the species
and/or chemodiversity rather than the emissions measured from any single
tree, and were strongly dominated by α-pinene. We also tested the
effect of chemodiversity on modeled monoterpene concentrations at the site
and found out that since it significantly influences the distributions and
hence the chemical reactions in the atmosphere, it should be taken into
account in atmospheric modeling. |
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