Plantas usadas como combustível em uma área de caatinga (Nordeste do Brasil): seleção de espécies, padrões de coleta e qualidade do recurso.

Abstract

Woody products in Caatinga correspond to a forest resource with high value to local populations of these regions. From all wood extracted in this biome, about 80% is collected to supply the energetic demand of industrial and domestic sectors of the northeast, but there’s still a great lack of information referent to fuelwood use in the region. So this work aimed to characterize the use of this resource in a rural community in the Caatinga, state of Pernambuco state, seeking to register the known and used species, the collection and consumption patterns, besides registering the locally adopted criteria to plant preference, associating this local knowledge to the wood physical properties. The study was developed in the community of Riachão de Malhada de Pedra, localized in the district of Gonçalves Ferreira, Caruaru (PE). There were visited all the community residences that were inhabited and whose owners agreed participating of the work, totalizing 102 households. There were applied semistructured interviews with the head of family (man or woman), and it was questioned, among other things, the known, used and preferred plants, and collection locals and strategies. The data was enriched using other usual techniques in ethnobotanical study like free listing, walk-in-the-woods and observer participation. To analyze fuelwood quality there were measured density, moisture and Fuel Value Index (FVI) from 38 species which are used and/or preferred by residents. It was verified that half of the households use only Liquefied Petroleum Gas (LPG), while 45.1% use LPG associated to firewood and/or vegetal charcoal and only 4.9% depend uniquely on firewood and charcoal for their domestic needs. In relation to the collection places, 20% report extracting this resource from the forest fragment that is located adjacently to the community, 68.5% report collecting in anthropogenic zones and 11.5% in both regions. Because it’s an inspected area, the forest may have been less cited as a source of collection due to the apprehension generated on the informants. The community knows 67 fuelwood plants, distributed in 46 genera and 20 families. From this group of known plants, firewood and charcoal use isrestricted to only 27 and 10 species, respectively. Among the most used species there are Anadenanthera colubrina var. cebil, Caesalpinia pyramidalis e Schinopsis brasiliensis , also corresponding to the informant’s most popular and preferred species. There were significant differences in knowledge among informant’s genders and ages (p<0.05), and the men and the older are the greatest owners of knowledge about fuelwood, although these factors don’t influence diversity of used plants. From the total group of known plants, 14 species are preferred by the community, and this preference seems to be the main factor acting in plant selection to fuelwood use. There were a significant relation (p<0,05) between the fuelwood species with more quality (High FVI) and its number of citation as preferred species, what shows that wood physical properties can explain these species’ preference. So it becomes necessary to quantify firewood extraction in the region, in order to verify whether this activity is causing pressure over the vegetation of the area, since the most used fuelwood species also have another woody uses associated to them.