Resumo. This study aimed to quantify biomass, the export and nutrient replacement in trees of a first thinning Pinus taeda L. stand, in Cambará do Sul, RS state. To do so, a forest inventory was done in three plots (60 m x 60 m), where three trees were cut in each plot. Live and dead needles, live and dead branches, bark, wood (bole) and wood from tip with bark, were measured. Total biomass was 44,5 Mg ha-1, being 62,8% of bole wood, 10,3% live branches, 8,9% bark, 10,1% live needles, 6,1% dead branches, 3,5% of wood from tip with bark and 0,5% dead needles. Total nutrients in biomass, in kg ha-1, was: 100,5 of N; 51,1 of Ca; 46,8 of K; 18,2 of S; 14,3 of Mg; 11,7 of P; 0,599 of Mn; 0,158 of Fe; 0,435 of Zn; 0,181 of B and 0,177 of Cu. The quantity of the fertilizer to be replaced will depend on the exploration type. If the total biomass occurs, the quantity of the fertilizers to be replaced will be of 391 kg ha-1, and if it is considered just the wood harvest this replacement will be 60% inferior, 169 kg ha-1.