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| Titel: |
Photosynthesis of boreal ground vegetation after a forest clear-cut |
| Auteur: |
L. Kulmala J. Pumpanen T. Vesala P. Hari |
| Verschenen in: |
Biogeosciences |
| Paginering: | Jaargang 6 (2009) nr. 11 pagina's 2495-2507 |
| Jaar: |
2009 |
| Inhoud: |
Heather (<I>Calluna vulgaris</I>), rosebay willowherb (<I>Epilobium angustifolium</I>), wavy hair-grass (<I>Deschampsia flexuosa</I>) and raspberry (<I>Rubus idaeus</I>) 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 (<I>P</I>max). The maxima of <I>C. vulgaris</I> and <I>E. angustifolium</I> occurred around June and July, while that of <I>R. idaeus</I> occurred as late as August. A simple model of photosynthetic activity is presented, addressing the photosynthesis of <I>C. vulgaris</I> was mainly explained by temperature history when the soil moisture is high. The activity of deciduous <I>D. flexuosa</I> also followed the temperature history, unlike the activities of <I>E. angustifolium</I> and <I>R. idaeus</I>. During a short drought, some shoots decreased their <I>P</I>max levels but none of the species showed similar reactions between individuals. We also observed that the comparison of the whole-plant <I>P</I>max 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<sup>−2 y<sup>−1 at the fertile site and 300 g C m<sup>−2 y<sup>−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<sup>−2 y<sup>−1 at the infertile site. At the fertile site, <I>E. angustifolium</I> and <I>R. idaeus</I> respired 22 and 12 g C m<sup>−2 y<sup>−1, respectively. |
| Uitgever: |
Copernicus GmbH (provided by DOAJ) |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 18 van 27 gevonden artikelen
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