Encontro de Energia no Meio Rural
AGRENER

Abstract

VALE, Ailton Teixeira do, BRASIL, Maria Aparecida Mourão and LEAO, Alcides Lopes. Disponibilidade de energia na forma de calor da biomassa lenhosa de um cerrado sensu stricto da região de Brasília.. In: ENCONTRO DE ENERGIA NO MEIO RURAL, 3., 2000, Campinas. Proceedings online... Available from: <http://www.proceedings.scielo.br/scielo.php?script=sci_arttext&pid=MSC0000000022000000100005&lng=en&nrm=abn>. Acess on: 31 Oct. 2024.

The production of energy in the form of heat from dry biomass was studied in a stretch of stricto sensu cerrado scrubland at Água Limpa farm in Brasilia (Federal District, Brazil). In ten plots of land, each measuring 20m x 50m, all the trees with a diameter equal to or larger than 5cm, measured 30cm above ground, were identified. Three trees of each specie were felled at random in seven distinct pre-established diameter categories, data relating to the green mass of the trunk and branches being recorded. In the laboratory, cross-sections were used to separate wood from bark, establishing a mass ratio. The moisture content of the wood and bark were then determined. This made it possible to estimate the dry mass of the wood and bark of the trunk and branches per tree specie and per area. The community was structurally characterised by the Cover Value Index. A total of 47 species and 673 individuals/ha were encountered in the stand consisting of 71% wood and 29% bark. The average production of the stand was 12.38 t/ha and 18.39 kg/tree. After analysing the main components, a group of 17 species were singled out as being responsible for 83% of the production of dry biomass per hectare. The heat combustion and the specific gravity of these species were then determined. The specific gravity varied from 0.38 g/cm³ to 0.78 g/cm³ for wood and 0.41 g/cm³ to 0.67 g/cm³ for bark. The wood presented heat combustion ranging from 19,109.09 kJ/kg to 20,883.95 kJ/kg, whereas the figures for bark ranged from 19,523.50 kJ/kg to 24,019.27 kJ/kg. The average heat combustion of the wood was 20,025.82 kJ/kg compared with 20,754.19 kJ/kg for the bark. The average quantity of heat produced per hectare was 15,207.74 MJ but individual variation among the species was remarkable: 290.59 MJ to 58,870.14 MJ. The best species for the production of energy in the form of heat were: Sclerolobium paniculatum, Dalbergia msicolobium and Pterodon pubescens.

Keywords : Energy production; biomass; wood; bark; cerrado.