The aim of this study was to quantify the aboveground biomass and organic carbon of Araucaria angustifolia (Bertol.) Kuntze in a Mixed Ombrophilous Montane Forest in the state of Paraná. The aboveground biomass determination was carried out according to the direct method, using 29 trees with Diameter at Breast Height (DBH) ≥ 40 cm. The trees were felled, cubed and weighed by compartments, which were sampled for determining moisture and carbon content. The average aerial biomass and carbon were 2,126.5 kg ind-1 and 935.8 kg ind-1, respectively. The moisture content resulted in a mean individual accumulation of 2,376.6 liters ind-1 of water. Age did not necessarily result in higher volume production but resulted in higher stem biomass production. Organic carbon accumulation by native A. angustifolia trees should support carbon credits as an incentive for the conservation of araucaria and Mixed Ombrophilous Forest fragments.
