Quantificação da produção de biomassa e do teor de carbono fixado por clones de eucalipto, no Pólo Gesseiro do Araripe – PE

Abstract

The subject of the climatic changes is winning prominence and being more discussed by the world scientific community that is more concerned with the increase of the carbon dioxide concentration in the atmosphere. The Conference of Kyoto, 1997,was the of larger importance for summoning countries to a reduction in the emission of the greenhouse effect gases, mainly CO2, with established quotas and reduction periods. As tree species of fast growth are considered efficient in the fixation of carbon, in this research 15 clones of species of Eucalyptus spp were used. Also they have high timber productivities. The objective of this work was to determine the biomass production and the content of carbon, in the different compartments of the total aerial biomass (stem, leaves, branches and bark), of clones of eucalypts. The data set were collected in the Experimental Station of the Pernambuco Company of Agricultural Research - IPA, located in the municipal district of Araripina. 90 trees were cut down, in which were determined the fresh weights, as well as samples of leaves, branches, bark and wood for determination of the average density of the wood, biomass and content of carbon. The basic average density of the wood located between 0.536 and 0.653 g/cm3. The content of total organic carbon was on average 46.97%; 38.95%; 35.64% and 34.74% of the total biomass, respectively for the components: stem, leaves, bark and branches, with variation among the studied treatments. The aerial total biomass of the clones of eucalypts were 62.08; 92.27; 70.27; 95.36; 104.75; 132.13; 119.35; 58.60; 107.06; 92.51; 109.93; 50.87; 61.17;69.90; 93.76 t ha-1, respectively, and the amounts of total carbon were 27.17; 41.51;32.50; 42.36; 48.30; 60.14; 50.36; 22.89; 44.69; 40.98; 44.63; 21.31; 25.86; 29.79;46.35 t ha-1, respectively. In agreement with the analysis of variance and the of Scott-Knott comparison test, there were differences among the treatments of the components leaves, branches and stem, regard to biomass production. For the component bark there was not significant difference among the treatments. Regard to carbon content there were differences among the treatments of the components branches and stem, for the components bark and leaves there were not significant difference among the treatments. There were significant differences for the form factor of the trees. The higher and lesser productive clones in terms of biomass and fixation of carbon were the treatment 6 Hybrid of Eucalyptus urophylla x E. tereticornis x E. pellita (controlled pollination) and the treatment 12-hybrid of E. brassiana (natural crossing), respectively, showing that there is a direct relationship between the biomass production and the content of fixed carbon. The clones of eucalypts are a potential alternative for carbon sequestration.