Dinâmica do estoque de carbono como serviço ambiental prestado por um fragmento de Floresta Ombrófila Mista Montana localizada no sul do Estado do Paraná

Abstract

This research has a main scientific issue the dynamics of forest carbon stocks as an environmental service provided by the Montane Mixed-Araucaria Forest, once studies on this subject are scarce. Hence, the general objective of the study was to quantify the dynamics of the aboveground carbon stocks of the forest, analyzing the changes in floristic diversity, phytossiological indexes, as well as to discuss the role of forests as carbon sinks and the payment for environmental services. Data from continuous forest inventory carried out at four 1.00hecatre permanent plots located in General Carneiro county, Parana State, southern Brazil. The first measurement of the plots was done in 1999 and the last in 2009. Besides that, the so-called REDD (Reduced Emissions from Deforestation and Forest Degradation), using a baseline scenario for 4,000 hectares of Mixed-Araucaria Forest, for a period of 50 years and a deforestation rate of 0.55% for the Atlantic Rain Forest. The results showed the occurrence of 50 tree species at the first inventory in 1999, distributed over 24 botany families, and a slight increase in number after 11 years, reaching 53 species and 25 families in 2009. Shannon diversity index shifted from 2.79 to 2.83, indicating an enrichment in floristic diversity. Absolute density in 1999 was 32.61 m2.ha-1 at the beginning of the study (1999) and 33.94 m2.ha-1 at the end (2009), with a slight periodic annual increment (PAI) of 0.12 m2.ha-1.year-1. The estimated carbon stock for 1999 was 74.07 t.ha-1, increasing in 2009 to 77.53 t.ha-1, with a PAI of 0.31 t.ha-1.year-1, i.e. 1.15 t.ha-1.year-1 CO2eq. Among the species groups, “Araucarias” showed a PAI of 0.76 t.ha-1.year-1 CO2eq., followed by “Canelas”, with 0.45 t.ha-1.year-1 CO2eq. The group “Brancas” (other species) performed a negative CO2eq.PAI of 0.05 t.ha-1.year-1. Araucaria angustifolia shared over 65% of the PAI in carbon stocks. A hypothetical REDD project would provide an environmental compensation to the land owner estimated at over R$ 5 million (US$ 1.00 = R$ 1.72) throughout the project duration period, i.e., over R$ 100 thousands/year. The conservation of the forest stand would mean an avoided emission of 319,745 t CO2eq. It was concluded by this study that the forest studied, even though shows a low annual carbon growth, it represents and important carbon sink. Therefore, by applying it to a REDD project, the carbon stock would be maintained, representing an environmental service provided by the forest. It would give to the land owner the possibility to earn an extra-money to protect the forest and maintain their ecological services.