Doctoral thesis, 2017
Carbon stocks and dynamics in miombo, pinus and eucalyptus forests in MozambiqueGuedes, Benard
AbstractIn Mozambique and neighbouring countries, deforestation and degradation of miombo forests are counteracted by new plantations of fast growing species and conservation of natural woodlands, activities supported by the REDD+ mechanism. The aim of this thesis was to examine the impacts of plantations of Pinus and Eucalyptus compared with mountain miombo forest on carbon stocks and dynamics in soil and tree biomass. The thesis also aimed to develop allometric biomass equations for lowland miombo forest to estimate aboveground tree biomass at the landscape scale. The entire study area was located within the Beira development corridor region, central Mozambique. Study plots of mountain miombo and 34-year-old first rotation plantations of Pinus taeda and Eucalyptus grandis were selected on three study sites in the Western highland of the Manica province to investigate total ecosystem carbon and nitrogen stocks in soil, litter and biomass. Tree biomass was estimated using allometric equations found in the literature. Total ecosystem carbon stocks in soils, litter layer and biomass, and net ecosystem production were all significantly higher in P. taeda and E. grandis plantations than in adjacent mountain miombo forest. Net primary production were higher in P. taeda and E. cloeziana plantations than in adjacent mountain miombo forest. Total soil nitrogen stocks in the topsoil layers were also significantly higher in plantation stands. The higher soil stocks of carbon and nitrogen could be explained to some extent with higher leaf litterfall, from Q-model predictions. However, higher root litter production in plantation stands was probably an additional important contribution to the measured higher soil organic carbon stocks. Two biomass functions were developed for estimating aboveground tree biomass of mixed-species lowland miombo forest. One equation was developed for estimating biomass based on stem diameter at breast height (1.3 m). The other equation was developed for estimating biomass based on stem diameter at stump height, to make it possible to also estimate losses of biomass in high exploitation areas of miombo woodlands.
KeywordsBiomass equation, Brachystegia spiciformis, Eucalyptus grandis, Eucalyptus cloeziana, Pinus taeda, Fine root production, Litterfall, Net primary production, Soil carbon
Published inActa Universitatis Agriculturae Sueciae
2017, number: 2017:104
ISBN: 978-91-7760-098-5, eISBN: 978-91-7760-099-2
Publisher: Department of Ecology, Swedish University of Agricultural Sciences.
Swedish University of Agricultural Sciences, Department of Ecology
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