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| Titel |
Prescribed burning of logging slash in the boreal forest of Finland: emissions and effects on meteorological quantities and soil properties |
| VerfasserIn |
A. Virkkula, J. Levula, T. Pohja, P. P. Aalto, P. Keronen, S. Schobesberger, C. B. Clements, L. Pirjola, A.-J. Kieloaho, L. Kulmala, H. Aaltonen, J. Patokoski, J. Pumpanen, J. Rinne, T. Ruuskanen, M. Pihlatie, H. E. Manninen, V. Aaltonen, H. Junninen, T. Petäjä, J. Backman, M. Dal Maso, T. Nieminen, T. Olsson, T. Grönholm, J. Aalto, T. H. Virtanen, M. Kajos, V.-M. Kerminen, D. M. Schultz, J. Kukkonen, M. Sofiev, G. de Leeuw, J. Bäck, P. Hari, M. Kulmala  |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 9 ; Nr. 14, no. 9 (2014-05-07), S.4473-4502 |
| Datensatznummer |
250118684
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| Publikation (Nr.) |
 copernicus.org/acp-14-4473-2014.pdf |
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| Zusammenfassung |
| A prescribed fire experiment was conducted on 26 June 2009 in
Hyytiälä, Finland, to study aerosol and trace gas emissions from
prescribed fires of slash fuels and the effects of fire on soil properties in
a controlled environment. A 0.8 ha forest near the SMEAR II measurement station (Station for
Measuring Ecosystem-Atmosphere Relations) was cut clear; some tree
trunks, all tree tops and branches were left on the ground and
burned. The amount of burned organic material was ~46.8 tons (i.e.,
~60 tons ha−1). The flaming phase lasted 2 h 15 min, the
smoldering phase 3 h. Measurements were conducted on the ground with both
fixed and mobile instrumentation, and in the air from a research aircraft. In
the middle of the burning area, CO2 concentration peaked around
2000–3000 ppm above the baseline, and peak vertical flow velocities were
~9 m s−1, as measured with a 10 Hz 3-D sonic anemometer placed
within the burn area. In the mobile measurements the peak particle number
concentrations were approximately 1–2 × 106 cm−3 in the
plume at a distance of 100–200 m from the burn area. On the ground at the
SMEAR II station the geometric mean diameter of the mode with the highest
concentration was 80 ± 1 nm during the flaming phase and in the
middle of the smoldering phase, but, at the end of the smoldering phase,
the largest mode was 122 nm. In the volume size distributions, geometric
mean diameter of the largest volume mode was 153 nm during the flaming phase
and 300 nm during the smoldering phase. The lowest single-scattering albedo
of the ground-level measurements was 0.7 in the flaming-phase plume and
~0.9 in the smoldering phase. Elevated concentrations of several volatile
organic compounds (VOC) (including acetonitrile, a biomass burning
marker) were observed in the smoke plume at ground level.
Measurements at the forest floor (i.e., a richly organic
layer of soil and debris, characteristic of forested land) showed that VOC
fluxes were generally low and consisted mainly of monoterpenes, and VOC flux
peaked after the burning. After one year, the fluxes had nearly stabilized
close to the level before the burning. The clear-cutting and burning of slash
increased the total long-term CO2 release from the soil, and altered the
physical, chemical and biological properties of the soil, such as increased
the available nitrogen contents of the soil, which in turn, affected the
long-term fluxes of greenhouse gases. |
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