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| Titel |
Photosynthesis of boreal ground vegetation after a forest clear-cut |
| VerfasserIn |
L. Kulmala, J. Pumpanen, T. Vesala, P. Hari |
| 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 ; 6, no. 11 ; Nr. 6, no. 11 (2009-11-06), S.2495-2507 |
| Datensatznummer |
250004087
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| Publikation (Nr.) |
 copernicus.org/bg-6-2495-2009.pdf |
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| Zusammenfassung |
| Heather (Calluna vulgaris), rosebay willowherb
(Epilobium angustifolium), wavy hair-grass
(Deschampsia flexuosa) and raspberry (Rubus
idaeus) are typical species at boreal clear-cut sites. In this
study, we measured their photosynthesis separately in the growing
season of 2005 using a manual chamber. All measured species showed
clear and species-specific seasonal cycles of photosynthetic
activity (Pmax). The maxima of C. vulgaris and
E. angustifolium occurred around June and July, while that
of R. idaeus occurred as late as August. A simple model of
photosynthetic activity is presented, addressing the photosynthesis
of C. vulgaris was mainly explained by temperature history
when the soil moisture is high. The activity of deciduous
D. flexuosa also followed the temperature history, unlike
the activities of E. angustifolium and R.
idaeus. During a short drought, some shoots decreased their
Pmax levels but none of the species showed similar reactions
between individuals. We also observed that the comparison of the
whole-plant Pmax or respiration of different-sized individuals
were less scattered than the results based on full-grown leaf mass,
implying that species-specific rates of photosynthesis at ground
level are rather similar regardless of the plant size. Using species
composition and continuous temperature and light measurements, we
upscaled the species-specific process rates and integrated fixed and
respired CO2 of ground vegetation for the entire 2005 growing
season. The photosynthetic production per surface area of soil was
760 g C m−2 y−1 at the fertile site and 300 g C
m−2 y−1 at the infertile site. During the snow-free
period (18 April–21 November), the above ground parts of measured
species released 75 g C m−2 y−1 at the infertile site.
At the fertile site, E. angustifolium and R.
idaeus respired 22 and 12 g C m−2 y−1, respectively. |
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