Dinâmica e potencial de créditos de carbono na floresta manejada da flona do Tapajós, estado do Pará

Abstract

Biomass studies in tropical forests have been used for ecological evaluation of vegetation and currently play a very important role in the assimilation process of atmospheric carbon, mainly due to the change in land use in the Amazon. It is therefore necessary to know the amount of carbon absorbed in the forest after logging. The objective of this study was to study the effect of forest management on vegetation dynamics and to estimate the carbon credits potential of tree species after logging in the Tapajós National Forest (FNT). The research was carried out at the FNT, along the Cuiabá-Santarém highway (BR-163), located in the state of Pará, in the central portion of the Amazon forest. For vegetation analysis, sampling was carried out in conglomerates randomly assigned to 37 sample units with 4 subunits (plots) of 5 m x 50 m, representing a sample area of 3.7 ha. In each conglomerate subunit, before and after the exploration, all trees with a diameter of 1,30 m (DAP) ≥ 5 cm and total height in meters were measured with the Truepulse 360 apparatus. For the control site, 9 plots, measuring 50 mx 50 m, totaling an area of 2.25 ha. The analysis of variance (ANOVA) for the carbon increment obtained a difference for the study areas (F = 707.6, p = 1.86E-07) and was significant according to the Tukey test (p = 3E-07) . In a temporal analysis of the management area, the carbon stock was reestablished after seven years of forestry activity, evidencing the superior environmental service (annual increase 2.13 ± 0.10 MgC.ha -1 ) to that of a forest without timber intervention (increment 0.85 MgC.ha -1 ). In the analysis of the potential carbon credits, the scenario with management and burning, the forest had a loss of 46.73 MgCO 2 eq.ha -1 in the management and after 5 years recovered 31.99 MgCO 2 eq.ha -1 from the lost stock during the activity. With the burning, it emitted 156.01 MgCO 2 eq.ha -1 . When the growth projection was performed in the second scenario, the forest recovered the stock in seven years and during the cutting cycle, could store 218.65 MgCO 2 eq.ha -1 . This shows the resilience of the vegetation before the management system, which can be the differential to add greater value to the Amazon forest, considering the environmental service carbon.