Carbon dynamics in spruce forest ecosystems - modelling pools and trends for Swedish conditions
2006 (English)Doctoral thesis, comprehensive summary (Other scientific)
Carbon (C) pools and fluxes in northern hemisphere forest ecosystems are attracting increasing attention concerning predicted climate change. This thesis studied C fluxes, particularly soil C dynamics, in spruce forest ecosystems in relation to interactions between physical/biological processes using a process-based ecosystem model (CoupModel) with data for Swedish conditions. The model successfully described general patterns of C and N dynamics in managed spruce forest ecosystems with both tree and field layers. Using regional soil and plant data, the change in current soil C pools was -3 g C m-2 yr-1 in northern Sweden and +24 g C m-2 yr-1 in southern Sweden. Simulated climate change scenarios resulted in increased inflows of 16-38 g C m-2 yr-1 to forest ecosystems throughout Sweden, with the highest increase in the south and the lowest in the north. Along a north-south transect, this increased C sequestration mainly related to increased tree growth, as there were only minor decreases in soil C pools. Measurements at one northern site during 2001-2002 indicated large soil C losses (-96 g C m-2 yr-1), which the model successfully described. However, the discrepancy between these large losses and substantially smaller losses obtained in regional simulations was not explained. A simulation based on Bayesian calibration successfully reproduced measured C, water and energy fluxes, with estimated uncertainties for major components of the simulated C budget. Site-specific measurements indicated a large contribution from field layer fine roots to total litter production, particularly in northern Sweden. Mean annual tree litter production was 66% higher at the most southerly site (240 g C m-2 yr-1 compared with 145 g C m-2 yr-1 in the north), but when field and bottom layers were included the difference decreased to 16% (total litter production 276 g C m-2 yr-1 and 239 g C m-2 yr-1 respectively). Regional simulations showed that decomposition rate for the stable soil C fraction was three times higher in northern regions compared with southern, providing a possible explanation why soil C pools in southern Sweden are roughly twice as large as those in the north.
Place, publisher, year, edition, pages
Stockholm: KTH , 2006. , viii, 25 p.
Trita-LWR. PHD, ISSN 1650-8602 ; 1029
boreal, climate, CoupModel, net ecosystem production, nitrogen, process-based model, soil carbon
IdentifiersURN: urn:nbn:se:kth:diva-4240ISBN: 978-91-7178-544-2OAI: oai:DiVA.org:kth-4240DiVA: diva2:11418
2006-12-19, D3, Lindstedtsvägen 5, KTH, Stockholm, 10:00
Paustian, Keith, Professor
Jansson, Per-ErikBerggren Kleja, Dan
QC 201009222006-12-152006-12-152010-09-22Bibliographically approved
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