Northeast Brazil fuelwood
This project was established to facilitate better management of the native caatinga (dry forest) trees preferred by local people for fuel in Northeast Brazil. It aims to determine which of a series of harvesting techniques (coppicing, pollarding and crown thinning) is most appropriate for these species, providing sustainable returns of wood suitable for fuel and charcoal production.
The project began in April 2001 with a botanical survey of several areas of caatinga, and selection of sites supporting mature trees with a high proportion of the target species. The two selected areas are located within the Institute for Agronomic Research (IPA) research stations in Pernambuco (Serra Talhada and Sertânia). They are in the Depressão Sertaneja Meridional transition, close to priority areas for biodiversity conservation established by the Brazilian Ministry of the Environment.
The four species selected were Poincianella pyramidalis (catingueira), Croton sonderianus (marmeleiro), Mimosa tenuiflora (jurema preta) and Mimosa ophthalmocentra (jurema de imbira). 5280 trees were surveyed and marked before treatment in either the wet season (between March and June) or the dry season (between October and December) of 2002. Monitoring of the re-growth was continued annually until 2008. Data gathered in the field were recorded for statistical analysis, to assess the weight variables and weight per product class (i.e. poles; firewood and kindling), to allow statistical comparison between the areas, to assess the impact of the different types of dry and wet interventions per species, and to observe the success and mortality rate of the species after successive years of regeneration.
All these activities have involved local people by means of training, participative research, extension and field days. Other activities developed in the area include soil assessment, comparison of symbiotic micro-organisms in native caatinga, and botanical inventory.
Half of the trees were harvested following three years of re-growth, and the rest were cut in 2008. Interesting results are already emerging. Mimosa trees (especially M. tenuiflora) cut in the wet season, for example, do not survive as well as those cut in the dry season, whereas Poincianella and Croton trees can be cut in either season. These findings have implications for when trees should be cut, depending on whether the land is to be cleared (by cutting in the wet season to remove Mimosa) or used for tree management (by cutting in the dry season).
Wood samples from each of the four species, taken during harvesting/monitoring, have been subjected to anatomical studies at the Jodrell Laboratory (Kew). This work was undertaken by a visiting Brazilian researcher for his PhD thesis and subsequently a KLARF and Bentham-Moxon grant holder from Salvador in Brazil. Further work will concentrate on measuring re-growth volume and studying the anatomical variation in its wood in relation to that of the original trees.
The large data sets generated by this project are being analysed and interpreted by the Kew and Brazilian teams, and the findings published in scientific journals and disseminated in accessible formats to local stakeholders to enable them to incorporate recommendations into land management practices. To facilitate this process, a workshop was held in the area in March 2011 bringing together local smallholders, governmental and non-governmental organisations and scientists. Outcomes of the project were presented and discussed, and broader implications and requirements for sustainable management of the caatinga were identified.
Key papers published since 2006
- Figueirôa, J.M., Pareyn, F.G.C., Lima Araújo, E., Silva, C.E., Santos, V.F., Cutler, D.F., Baracat, A. & Gasson, P. (2006). Effects of cutting regimes in the dry and wet season on survival and sprouting of woody species from the semi-arid caatinga of northeast Brazil. Forest Ecology & Management 229: 294 – 303.
- Figueirôa, J.M., Pareyn, F.G.C., Araújo, E. de Lima, Cutler, D.F., Gasson, P., Lima, K. Costa de & dos Santos, V.F. (2008). Variações sazonais na sobrevivência, rebrota e produção de biomassa de Caesalpinia pyramidalis Tul. após corte raso e implicações para o manejo da espécie (Seasonal variations in the survival, regrowth and biomass production of Caesalpinia pyramidalis Tul. after coppicing and implications for management of the species). Revista Arvore (Journal of Brazilian Forest Science) 32(6): 1041 – 9.
- Silva, L.B., Santos, F.A.R., Gasson, P. & Cutler, D. (2009). Anatomia e densidade básica da madeira de Caesalpinia pyramidalis Tul. (Fabaceae), espécie endêmica da caatinga do Nordeste do Brasil. Acta Bot. Bras. 23(2): 436 – 445.
- Sampaio, E., Gasson, P., Baracat, A., Cutler, D., Pareyn, F. & Lima, K.C. (2010). Tree biomass estimation in regenerating areas of tropical dry vegetation in northeast Brazil. Forest Ecology & Management 259: 1135 – 1140. doi: 10.1016/j.foreco.2009.12.028
- Dias Leme, C.L., Cartwright, C. & Gasson, P. (2010). Anatomical changes to the wood of Mimosa ophthalmocentra and Mimosa tenuiflora when charred at different temperatures. IAWA J. 31: 335 – 51.
Project partners and collaborators
Associação Plantas do Nordeste (APNE), Pernambuco
Instituto de Pesquisas Agronomicas (IPA), Pernambuco
Universidade Federal da Bahia (UFBA), Salvador, Bahia
Clothworkers’ Foundation, UK