Composição florística e estoque de carbono em áreas de recuperação da Mata Atlântica na bacia do rio Guapiaçu, Cachoeiras de Macacu, RJ

Abstract

The Atlantic Rainforest is currently considered as biome conservation priority, given its history of devastation, closely related to the history of Brazil's development since its discovery. The small forest fragments remaining, totaling around 7% of the original forest cover resulted in actions that prioritize the conservation of these forests and the enforcement of laws governing man's actions regarding the appropriate alternate use of the soil and natural resources in a general way. Among the numerous environmental services that forests can generate, carbon accumulation in the forest biomass has significant importance for the ability to sequester carbon from the atmosphere, resulting in minimizing the high concentration of Greenhouse Effect Gases. The emergence of global policies, discussing the issue of mitigating the causes of climatic change, has resulted in the design of easing measures, which the main is Clean Development Mechanism (CDM) provided in Kyoto Protocol. The planting of forest trees for fixing CO2 from the atmosphere may propose models for generating carbon credits and be an alternate recovering of degraded areas, conservationist use of the soil and reconnect forest fragments. The aim of this study was to characterize the floristic composition, quantify the carbon stock in biomass above the ground and the carbon stored in the soil, as well as other compartments of the terrestrial ecosystem as litter and root systems in areas of reforestation of different ages in Guapiaçu River in the city of Cachoeiras de Macacu, RJ, Brazil. Three areas of reforestation plantations were evaluated with different ages: 3 years, 5 years and 7 years. In Chapters I and II, mature forest remaining of the city where the study was conducted were used as a control area for comparisons of floristic parameters, phytosociological, quantification of biomass above the ground, root and leaf litter and estimates of the carbon stored in these biomasses. The non-destructive method to evaluate the biomass above the ground was effective both in natural forest areas, and reforestation area. However, it is adviseable to use the destructive method to evaluate the reliability of the data obtained for reforestation. In Chapter III, the pasture was used as a control area for comparison purposes between the carbon stocks in the soil biomass and to evaluate the origin of carbon and nitrogen in the organic matter of the soil through the natural abundance of the isotopes 13C and 15N. The use of an alternate method allowed to evaluate the consistency of the results of carbon stock, which allowed suggesting the inclusion of this compartment of the terrestrial ecosystem in the forest projects of CDM. It is concluded that reforestation aiming at ecological restoration are important sources of atmospheric carbon capture and may present significant results, where the studies quantifying the biomass and carbon stocks estimates in the soil and air compartments of the reforested areas can be used as reference for drafting of Carbon Offsets in the sphere of Clean Development Mechanism (CDM).