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| Titel |
Factors promoting larch dominance in central Siberia: fire versus growth performance and implications for carbon dynamics at the boundary of evergreen and deciduous conifers |
| VerfasserIn |
E.-D. Schulze, C. Wirth, D. Mollicone, N. Lüpke, W. Ziegler, F. Achard, M. Mund, A. Prokushkin, S. Scherbina |
| 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. 4 ; Nr. 9, no. 4 (2012-04-16), S.1405-1421 |
| Datensatznummer |
250006950
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| Publikation (Nr.) |
 copernicus.org/bg-9-1405-2012.pdf |
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| Zusammenfassung |
The relative role of fire and of climate in determining canopy species
composition and aboveground carbon stocks were investigated. Measurements
were made along a transect extending from the dark taiga zone of central
Siberia, where Picea and Abies dominate the canopy, into the Larix zone of eastern Siberia.
We test the hypotheses that the change in canopy species composition is
based (1) on climate-driven performance only, (2) on fire only, or (3) on
fire-performance interactions. We show that the evergreen conifers Picea obovata and
Abies sibirica are the natural late-successional species both in central and eastern
Siberia, provided there has been no fire for an extended period of time.
There are no changes in performance of the observed species along the
transect. Fire appears to be the main factor explaining the dominance of
Larix and of soil carbon. Of lesser influence were longitude as a proxy for
climate, local hydrology and active-layer thickness. We can only partially
explain fire return frequency, which is not only related to climate and land
cover, but also to human behavior.
Stand-replacing fires decreased from 300 to 50 yrs between the Yenisei
Ridge and the upper Tunguska. Repeated non-stand-replacing surface fires
eliminated the regeneration of Abies and Picea. With every 100 yrs since the last
fire, the percentage of Larix decreased by 20%.
Biomass of stems of single trees did not show signs of age-related decline.
Relative diameter increment was 0.41 ± 0.20% at breast
height and stem volume increased linearly over time with a rate of about
0.36 t C ha−1 yr−1 independent of age class and species. Stand
biomass reached about 130 t C ha−1(equivalent to about 520 m3 ha−1). Individual trees of Larix were older than 600 yrs. The maximum age
and biomass seemed to be limited by fungal rot of heart wood. 60% of old
Larix and Picea and 30% of Pinus sibirica trees were affected by stem rot. Implications for the
future role of fire and of plant diseases are discussed. |
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