Spatial Analysis of Tree Cover Loss and Its Drivers in the Guinea-Congolian Forest Zone of South West Nigeria Using Remote Sensing

Tree cover loss in the Guinea-Congolian forest zone of South West Nigeria is accelerating, driven by agricultural expansion, timber extraction, and urban growth, yet the spatial pattern and relative contribution of each driver lack rigorous empirical quantification at a regional scale. This study conducted a spatial analysis of tree cover loss and its drivers in the Guinea-Congolian forest zone of Ogun, Osun, and Ondo States over the period 2005 to 2022, using Hansen Global Forest Change dataset (Landsat-based, 30m resolution) supplemented by Sentinel-2 time-series imagery. Annual tree cover loss maps were produced and overlaid with agricultural expansion layers from FAO land use data, timber concession maps from state forestry departments, and urban growth footprints from Nigeria's National Population Commission data. Random forest classification was used to map and quantify the area attributable to each driver class. Results showed that total tree cover loss in the three states was 218,400 ha over the study period, equivalent to 14.2% of the 2005 forest cover. Agricultural encroachment accounted for 58% of total loss, followed by urbanisation (22%), logging concessions (12%), and other disturbances (8%). Loss was spatially concentrated in buffer zones of forest reserves, particularly around Omo and Oluwa Reserves. Annual loss rate accelerated from 8,400 ha/year (2005 to 2010) to 16,200 ha/year (2018 to 2022). The study fills a critical knowledge gap in spatially explicit forest loss accounting for South West Nigeria and recommends targeted deforestation controls in forest reserve buffer zones.

Keywords: tree cover loss, remote sensing, Guinea-Congolian forest, deforestation drivers, South West Nigeria