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Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 14, 1285-1303, 2017
https://doi.org/10.5194/bg-14-1285-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
15 Mar 2017
Carbon stocks and dynamics at different successional stages in an Afromontane tropical forest
Brigitte Nyirambangutse1,2, Etienne Zibera2, Félicien K. Uwizeye2, Donat Nsabimana2, Elias Bizuru2, Håkan Pleijel1, Johan Uddling1, and Göran Wallin1 1Department of Biological and Environmental Sciences, University of Gothenburg, P.O. Box 461, 405 30, Sweden
2Department of Biology, University of Rwanda, University Avenue, P.O. Box 117, Huye, Rwanda
Abstract. As a result of different types of disturbance, forests are a mixture of stands at different stages of ecological succession. Successional stage is likely to influence forest productivity and carbon storage, linking the degree of forest disturbance to the global carbon cycle and climate. Although tropical montane forests are an important part of tropical forest ecosystems (ca. 8 %, elevation  >  1000 m a.s.l.), there are still significant knowledge gaps regarding the carbon dynamics and stocks of these forests, and how these differ between early (ES) and late successional (LS) stages. This study examines the carbon (C) stock, relative growth rate (RGR) and net primary production (NPP) of ES and LS forest stands in an Afromontane tropical rainforest using data from inventories of quantitatively important ecosystem compartments in fifteen 0.5 ha plots in Nyungwe National Park in Rwanda.

The total C stock was 35 % larger in LS compared to ES plots due to significantly larger above-ground biomass (AGB; 185 and 76 Mg C ha−1 in LS and ES plots), while the soil and root C stock (down to 45 cm depth in the mineral soil) did not significantly differ between the two successional stages (178 and 204 Mg C ha−1 in LS and ES plots). The main reasons for the difference in AGB were that ES trees had significantly lower stature and wood density compared to LS trees. However, ES and LS stands had similar total NPP (canopy, wood and roots of all plots  ∼  9.4 Mg C ha−1) due to counterbalancing effects of differences in AGB (higher in LS stands) and RGR (higher in ES stands). The AGB in the LS plots was considerably higher than the average value reported for old-growth tropical montane forest of south-east Asia and Central and South America at similar elevations and temperatures, and of the same magnitude as in tropical lowland forest of these regions.

The results of this study highlight the importance of accounting for disturbance regimes and differences in wood density and allometry of tree species dominating at different successional stages in an attempt to quantify the C stock and sink strength of tropical montane forests and how they may differ among continents.


Citation: Nyirambangutse, B., Zibera, E., Uwizeye, F. K., Nsabimana, D., Bizuru, E., Pleijel, H., Uddling, J., and Wallin, G.: Carbon stocks and dynamics at different successional stages in an Afromontane tropical forest, Biogeosciences, 14, 1285-1303, https://doi.org/10.5194/bg-14-1285-2017, 2017.
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We investigated the carbon (C) stock and net primary production (NPP) of early (ES) and late successional (LS) forest stands in a tropical montane forest (TMF) in Africa. The total C stock was 35% larger in LS compared to ES stands due to larger tree biomass, while NPP was similar. The results highlight the importance of accounting for disturbance regimes and differences in wood density and allometry between ES and LS tree species when quantifying C stock and sink strength of TMF.
We investigated the carbon (C) stock and net primary production (NPP) of early (ES) and late...
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