Human pressures cause biomass losses and indirectly contribute to climate change. The forest reserve of Goungoun and its riparian lands is constantly under human pressure with a deforestation rate of 2.91%. In this perspective, this research will attempt to answer the question of what is the impact of human activities on woody biomass. The hypothesis underlying this research is that land use changes including deforestation and forest degradation decrease the amount of biomass. The objective of this research is to assess the impact of land use changes on woody biomass in the Goungoun Forest Reserve and its Riparian Landin North Benin. The 2005 Landsat ETM + and 2008 OLI/TIRS images downloaded from the earthexplorer.usgs.gov site in GEOTIFF format were interpreted using the supervised classification method. The variation in aboveground woody biomass was estimated using land use maps obtained from the interpretation of Landsat images and forest inventory data all from 2005 and 2018. The allometric equation developed in the Sudanese and Sudano-Guinean savannas from M'Bow (2014) was used for the estimation of woody biomass. Naturalformations have experienced a decline of 27.34%. This regression leads to a loss of 41.66 t.ms/ha and 8.23 t.ms/ha of biomass from forest land converted to savannah and cultivated land. The transformation of savannah lands into cultivated lands causes the loss of 3.56 t.ms/ha of biomass and saves 54.92 t.ms/ha of biomass to forest lands. Biomass losses and gains were also observed at the level of land use categories that remained unchanged, including forest land (-7.65 t.ms/ha and 28.5 t.ms/ha), savannahland ( -4.44 t.ms/ha and 26.91 t.ms/ha) and cultivated land (-4.29 t.ms/ha and 20.43 t.md/ha). This research has contributed to the understanding of the effects of land-use category conversion on biomass. Actions to strengthen the woody potential of thisecosystem are needed to minimize the degradation of biomass in the FCGTR so that it can be a long-term carbon sink.