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.
