Fuelwood caters for about 70% of domestic energy use in Northeast Brazil. Consumption is currently gradually declining, but this trend is dependent on unpredictable factors such as gas prices and household income. Firewood also represents a major cash crop, complementing the agriculture and livestock production of smallholders, and there is significant demand from the industrial sector.
Presently, firewood harvesting remains largely extractivist and opportunistic, partly due to inadequate knowledge on how to manage the resource sustainably. The result is over-exploitation of a narrow range of preferred species such as Caesalpinia pyramidalis (catingueira) by those who depend on the forest for their livelihoods. As a consequence the caatinga vegetation has, over the years, suffered decreased forest cover, loss of biodiversity and general ecosystem degradation.
Over the last decade conflicting data have emerged on trends in forest cover in the Northeast of Brazil. Whilst some studies indicate rapid decline (Radambrasil, 1990), others suggest stability within the same-arid region (IBGE, 1996; SUDEMA, 2004). However, pressure for forest clearance for agriculture and cattle ranching, mining and other human activities remains strong in many areas of the caatinga biome.
The Sustainable Management of the Caatinga Vegetation for Firewood Production Project was developed to establish better management for the native caatinga trees preferred by local people for fuel. Specifically, this project aims to determine which of a series of harvesting techniques (cropping, pollarding and crown thinning) is most appropriate for these priority species, providing optimum, 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 region, with a view to selecting sites supporting mature trees with a high proportion of the target species. Two of the areas selected are located within the IPA research station in Pernambuco (Serra Talhada and Sertânia) and the third, conveniently placed to involve the local community and schools, is situated in Caroalina (approximately 30 km from the Sertânia station). These areas are located 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 for study were Caesalpinia pyramidalis (catingueira), Croton sonderianus (marmeleiro), Mimosa tenuiflora (jurema preta) and Mimosa ophthalmocentra (jurema de imbira). A total of 5280 trees were surveyed prior to treatment, which took place in both the wet season (between March and June ) and the dry season (between October and December) of 2002. Monitoring of the re-growth takes place annually, in collaboration with local school children. Data gathered in the field are recorded in a database for statistical analysis, in order to assess the weight variables and weight per product class (i.e. poles; firewood and kindling), to allow statistical comparison between the areas, 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 involve local people by means of environmental education, 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.