Articles containing the keyword 'carbon stock'.

The article considers the relation of shifting cultivation to deforestation and degradation, and hence its impacts in terms of carbon emissions and sequestration potential. There is a need to understand these relationships better in the context of international policy on Reduced Emissions from Deforestation and Forest Degradation (REDD+). The article reviews the way in which shifting cultivation has been incorporated in global and national estimations of carbon emissions, and assembles the available information on shifting cultivation in Tropical Dry Forests (TDF) in Mexico, where it is widely practiced. It then takes the case of two villages, Tonaya and El Temazcal, which lie within the basin of the River Ayuquila in Jalisco, Mexico. Field data for the typical carbon stocks and fluxes associated with shifting cultivation are compared with stocks and fluxes associated with more intensive agricultural production in the same dry tropical forest area to highlight the carbon sequestration dynamics associated with the shortening and potential lengthening of the fallow cycles. The biomass density in the shifting cultivation system observed can reach levels similar to that of old growth forests, with old fallows (>20 years) having higher carbon stocks than old growth forests. Per Mg of maize produced, the biomass-related emissions from shifting cultivation in the traditional 12 year cycle are about three times those from permanent cultivation. We did not, however, take into account the additional emissions from inputs that result from the use of fertilizers and pesticides in the case of permanent agriculture. Shortening of the fallow cycle, which is occurring in the study area as a result of government subsidies, results in higher remaining stocks of carbon and lower emissions at the landscape level.

• Salinas-Melgoza, University of Twente, Drienerlolaan 5, 7522 NB Enschede, the Netherlands ORCID ID: http://orcid.org/0000-0003-3209-1659 E-mail: ma.masm@gmail.com
• Skutsch, Universidad Nacional Autónoma de México (CIGA-UNAM), Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, Campus Morelia, C.P. 58190, Michoacán, Mexico ORCID ID: http://orcid.org/0000-0001-6120-4945 E-mail: mskutsch@ciga.unam.mx
• Lovett, University of Leeds, Leeds, LS2 9JT, UK ORCID ID: – E-mail: j.lovett@leeds.ac.uk
• Borrego, CONACYT-Centro de Investigaciones en Geografía Ambiental, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, Campus Morelia, C.P. 58190, Michoacán, México ORCID ID: – E-mail: aborrego@ciga.unam.mx

The quantification of the contribution of tropical forests to global carbon stocks and climate change mitigation requires availability of data and tools such as allometric equations. This study made available volume and biomass models for eighteen tree species in a semi-deciduous tropical forest in West Africa. Generic models were also developed for the forest ecosystem, and basic wood density determined for the tree species. Non-destructive sampling approach was carried out on five hundred and one sample trees to analyse stem volume and biomass. From the modelling of volume and biomass as functions of diameter at breast height (Dbh) and stem height, logarithmic models had better predictive capabilities. The model validation showed that in absence of data on height, models using Dbh only as variable was an alternative. The comparison of basic wood densities to data published in literature enabled to conclude that the non-destructive sampling was a good approach to determining reliable basic wood density. The comparative analysis of species-specific models in this study with selected generic models for tropical forests indicated low probability to identify effective generic models with good predictive ability for biomass. Given tree species richness of tropical forests, the study demonstrated the hypothesis that species-specific models are preferred to generic models, and concluded that further research should be oriented towards development of specific models to cover the full range of dominant tree species of African forests.

• Goussanou, Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin ORCID ID: – E-mail: cedricgoussanou@gmail.com
• Guendehou, Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin; Benin Centre for Scientific and Technical Research, 03 BP 1665 Cotonou, Benin ORCID ID: – E-mail: sguendehou@yahoo.fr
• Assogbadjo, Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin ORCID ID: – E-mail: assogbadjo@yahoo.fr
• Kaire, Centre Régional AGRHYMET, Département Formation et Recherche, BP 11011 Niamey, Niger ORCID ID: – E-mail: m.kaire@agrhymet.ne
• Sinsin, Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin ORCID ID: – E-mail: bsinsin@gmail.com
• Cuni-Sanchez, University of Copenhagen, Center for Macroecology, Evolution and Climate, Nørregade 10, P.O. Box 2177, 1017 Copenhagen K, Denmark ORCID ID: – E-mail: aidacuni@hotmail.com

Boreal forest soil contains significant amounts of organic carbon. Soil disturbance, caused for example by site preparation or stump extraction, may increase decomposition and thus lead to higher CO₂ emissions, contributing to global warming. The aim of this study was to quantify responses of soil-surface CO₂ fluxes (R_s) and litter (needle and root) decomposition rates following various kinds of soil disturbance commonly caused by mechanical site preparation and stump harvest. For this purpose four treatments were applied in a clear-cut site in central Sweden: i) removal of the humus layer and top 2 cm of mineral soil, ii) placement of a humus layer and 2 cm of mineral soil upside down on top of undisturbed soil, forming a double humus layer buried under mineral soil, iii) heavy mixing of the humus layer and mineral soil, and iv) no disturbance (control). R_s measurements were acquired with a portable respiration system during two growing seasons. To assess the treatments’ effects on litter decomposition rates, needles or coarse roots (Ø = 6 mm) were incubated in litterbags at positions they would be located after the treatments (buried, or on top of the soil). The results indicate that site preparation-simulating treatments have no effect or may significantly reduce, rather than increase, CO₂ emissions during the following two years. They also show that buried litter decomposes more rapidly than litter on the surface, but in other respects the treatments have little effect on litter decomposition rates.

• Mjöfors, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden ORCID ID: – E-mail: kristina.mjofors@slu.se
• Strömgren, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden ORCID ID: – E-mail: Monika.stromgren@slu.se
• Nohrstedt, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden ORCID ID: – E-mail: Hans-orjan.nohrstedt@slu.se
• Gärdenäs, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden ORCID ID: – E-mail: Annemieke.gardenas@slu.se

• Omoro, Viikki Tropical Resources Institute, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: loice.omoro@helsinki.fi
• Starr, Department of Forest Sciences, P. O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: mike.starr@helsinki.fi
• Pellikka, Department of Geosciences and Geography, P. O. Box 64 (Gustaf Hällströminkatu 2), FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: petri.pellikka@helsinki.fi

• Wutzler, Max Planck Institute for Biogeochemistry, Hans-Knöll-Strasse 10, 07745 Jena, Germany ORCID ID: – E-mail: twutz@bgc-jena.mpg.de
• Profft, Max Planck Institute for Biogeochemistry, Hans-Knöll-Stra§e 10, 07745 Jena, Germany ORCID ID: – E-mail: –
• Mund, Max Planck Institute for Biogeochemistry, Hans-Knöll-Stra§e 10, 07745 Jena, Germany ORCID ID: – E-mail: –

• Hunt, University of Guelph, School of Environmental Sciences, 50 Stone Road East, Guelph, Ontario, Canada N1G 2W1 ORCID ID: – E-mail: shunt@uoguelph.ca
• Gordon, University of Guelph, School of Environmental Sciences, 50 Stone Road East, Guelph, Ontario, Canada N1G 2W1 ORCID ID: – E-mail: –
• Morris, Ontario Ministry of Natural Resources, Centre for Northern Forest Ecosystem Research, 955 Oliver Rd., Thunder Bay, Ontario, Canada P7B 5E1 ORCID ID: – E-mail: –

• Pingoud, VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo, Finland ORCID ID: – E-mail: kim.pingoud@vtt.fi
• Pohjola, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: –
• Valsta, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: – E-mail: –

• Eriksson, SLU, Dept of Bioenergy, P.O. Box 7061, SE-750 07 Uppsala, Sweden ORCID ID: – E-mail: –
• Johansson, SLU, Dept of Bioenergy, P.O. Box 7061, SE-750 07 Uppsala, Sweden ORCID ID: – E-mail: –

• Kauppi, International Institute for Applied Systems Analysis (IIASA), A-2361 Laxenburg, Austria. Present address: Environmental Science and Policy, Department of Limnology and Environmental Protection, PO Box 27, FIN-00014 University of Helsinki, Finland ORCID ID: – E-mail: pekka.kauppi@helsinki.fi

• Mäkipää, The Finnish Forest Research Institute, Vantaa, Finland ORCID ID: – E-mail: raisa.makipaa@metla.fi
• Linkosalo, The Finnish Forest Research Institute, Vantaa, Finland ORCID ID: – E-mail: –