This study assessed the amount of carbon stock in the Oyimo forest reserve in Ondo Statewith the view to determine the above ground biomass (AGB) and belowground biomass (BGB), estimate the organic carbon content and evaluate the soil organic carbon sequestered. The SDG 15.3.1 embedded in plugin quantum geographic information system (QGIS) was the method used to carry out the analysis. In this SDG 15.3.1 there are indicator for quantifying carbon stock and sub-indicator to measure forest degradation. The results showed that initial forest area was 59,413 hectares; initial non-forest area was 245 hectares (ha), total biomass was 3,535,543 tonnes of C, loss of carbon was 127,703 tonnes of C and total carbon emission during the years was 468,669 tonnes of CO2e.From land cover of soil organic carbon of sub-indicator the area with no data was 19.01 hectares, degraded area was 18,727.849 hectares, stable area was 29,032.919 hectares and improved area was 11,9780.2184 respectively. The estimation of Carbon stock gives an idea about the quantity and quality of carbon available in the area and also how it behaves in ecosystem, where the carbon is ultimately degraded to carbon emissions to the atmosphere causing global warming and climate change, which affect entire ecosystem significantly. Therefore, Trend. Earth can be used to assess the Carbon stocks of a given forest and also can be found as the best method to calculate soil organic carbon (SOC) due to measurement of carbon and degradation, low cost and less time requirement.

Keywords : Carbon estimation, degradation, biomass, land cover, Trend. Earth and QGIS.