Florística e estoque de carbono em áreas em processo de restauração florestal no noroeste do Rio Grande do Sul.

Abstract

Deforestation and forest degradation are critical threats to biodiversity and the provision of ecosystem services, with the Atlantic Forest being one of the most threatened forest formations in the world. Forest restoration emerges as a crucial tool for recovering the ecological functions of degraded ecosystems. Thus, planting tree species is highly beneficial in forest restoration, as it increases the viability of secondary succession or accelerates this process. Among the benefits of forest restoration, it should be emphasized that it is a crucial tool for neutralizing carbon and combating climate change. The potential for carbon sequestration in altered areas undergoing recovery on the planet is estimated at 4.4 Pg C year-1. Therefore, the present study aimed to analyze the richness, biomass input and carbon stock of above-ground biomass and litter in areas undergoing forest restoration in the south of the Atlantic Forest Biome. The study was carried out in three areas in the process of forest restoration, being an area in the process of active restoration with native species (APRA1); area in the process of active restoration with native and exotic species (APRA2) and area in the process of passive restoration (APRP). A phytosociological inventory was carried out, and the richness and above-ground biomass (AGB) were subsequently determined. The quantification of biomass in the litter was quantified using 0.0625m² frames. From the biomass values, carbon stocks were determined for the two compartments in the three areas studied. Among the study areas, a greater number of species was found in APRA1, with the presence of 40 species. Among the species sampled in APRA1, those with the highest IVC were Sebastiania commersoniana, Prunus myrtifolia, Cupania vernalis, Eugenia uniflora and Jacaranda puberula. Regarding biomass and carbon stock in above-ground biomass, there was a significant difference (p<0.05) between the study areas. APRA1 showed the highest averages of AGB and carbon in aboveground biomass (CAGB). APRP, 13 years after anthropogenic activities, presented a lower result than APRA1. In contrast, APRA2, after 3 years of planting native and exotic species, presented the lowest values of above-ground biomass and carbon stock. While biomass and carbon stocks in the litter were higher in APRP, the lowest values were obtained in APRP2. Active restoration allows for greater carbon stock in above-ground biomass compared to passive restoration, considering that the use of mixed plantings of native species optimizes the use of nutrients in less fertile soils. In this way, restoration plays a crucial role in mitigating climate change, as it enables rapid growth and coverage and increases the number of species present in the area, facilitating the process of forest succession.