摘要:Global warming is an important issue in the world which it gives a negative effect on human life. One indicator of global warming is increasing greenhouse gas i.e. carbondioxide from human activities. Deforestation and forest degradation are the second largest contributor of carbon into the atmosphere, after the use of fossil fuels by industry and transportation. As lungs of the world, forest is enable to produce renewable energy sources i.e. biomass. Forest carbon stock in above ground biomass (AGB) is the greatest effect source on deforestation and forest degradation. Therefore, it is necessary to perform a study the potential of carbon in forest. The purpose of this research is to determine carbon stock value in Batang Gadis National Park, Mandailing Natal Regency, North Sumatera Province, Indonesia. The carbon potential stored in this forest vegetation is calculated using AGB allometric equation by using data in diameter at breast height (dbh = 1.3 m), height, and density of the wood for trees. Data obtained from secondary data is Asset Assessment Report which State Controlled Forest Natural Resources Batang Gadis National Park, 2016. Study locations were Pagar Gunung and Sopo Tinjak Villages. Carbon stock values were calculated and analyzed with assumption that a half of biomass part is carbon stock which using Australian carbon price about AUD $ 11.82 Australia (Australian dollars) and EU € 5 (US $ 6). The results showed that the total biomass in Pagar Gunung and Sopo Tinjak Villages amounted to 259.83 tonnes and 160.89 tonnes. From the results of the total biomass, the total carbon stocks (C) and CO2 stocks in both villages are 210.36 tonnes (129.92 tonnes in Pagar Gunung Village and 80.45 tonnes in Sopo Tinjak Village) and 772.03 tonnes (476.79 tonnes in Pagar Gunung Village and 295.24 tonnes in Sopo Tinjak Village). By using the carbon price prevailing in the market place Australia Emission Trading System (ETS) and the EU ETS (AUD $ 11.82/t CO2e and € 5 (US $ 6)/t CO2e), the value of carbon stock that can be produced from Batang Gadis National Park (Pagar Gunung and Sopo Tinjak Villages) is about Rp. 92,499,921.72 (in AUD $) or Rp. 61,654,433.67 (in US $).