A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

Fine litter fall and standing tree component contribution to the nutrient cycling in anamazonian rain forest, Caxiuanã, Pará, Brazil. Almeida, Samuel Soares & Silva,Rosecélia Moreira. MCT/Museu Paraense Emílio Goeldi, Av. Magalhães Barata 376,Nazaré, Belém-PA (samuel@museu-goeldi.br, celitamoreira@hotmail.com.br).The most important and efficient mechanism of nutrients cycling in tropical forests is relatedto the litter fall. This panel presents the results of litter fall and organic matter decompositionin a dense amazonian rain forest, at the “Ferreira Penna” Scientific Station, Caxiuanã, Pará.The experiments had been carried out in 2 plots (A and B) of 1 hectar each. During 12months litter fall was collected, composed by foliage, reproductive fraction and fine branchs.The total production of litter fall was 9.63 Mg.ha -1 .ano -1 , divided into 5.65 Mg.ha -1 .ano -1 ofleaves; 1.68 Mg.ha -1 .ano -1 of fine branchs and 1.39 Mg.ha -1 .ano -1 of reproductive fraction.These values are among more highly obtained to the amazonian forests, reflecting theelevated biomass of the Caxiuanã forest. Annually this forest can be recycling about 4,820kg.ha -1 of C; 132.6 kg.ha -1 of N; 3.7 kg.ha -1 of P and 23.93 kg.ha -1 of K. The organic matterdecomposition experiment consisted of 360 plastic bags (180 by hectare). The decompositionrate in the first 180 days has been about 50 % of the decomposed material. To relate with theprimary production the floristic inventory in the parcels studied was carried out, recording alltrees and lianas with DAP ≥ 10 cm, its respective species, trunk and total height. The A andB parcels included about 180 and 185 species respectively, with considerable diversity of bigtrees that present an single or few individuals by hectare. The contribution of tree species forthe litter fall and the recycling is changeable during the year, being that plants that lose leavesduring the dry period can contribute massivelly to overall biomass decayed.(Research carried through with support of the MCT/Museu Goeldi, Project Esecaflor/UEdinand Instituto of the Milênio/LBA).