Forest cover monitoring in Southwestern Ghana with remote sensing and GIS

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial TechnologiesObuasi is one of the major municipalities in southwestern Ghana, Forest resources play a major significant role in the day-to-day activities of the locals due to their high dependency on it. Despite this contribution, the annual rate of current deforestation in Obuasi is about 50 hectares. At this rate the municipality may lose its substantial forest cover completely in the next 25 years. GIS and remote sensing techniques have proven to be efficient ways to monitor forest cover, especially on a large-scale using satellite imagery. In this study, a post-classification comparison change detection algorithm was used to determine the change in forest cover in the 1991-2021 period. The methodology includes a statistical analysis of rainfall and temperature variability for a period of 30years as well as the analysis of perceptions and knowledge of locals on forest modifications. MOLUSCE plugin in QGIS was used to model and generate maps of forest cover and predict future changes in land use/land cover. The land-use/landcover maps showed that between 1991 to 2000 forest areas decline at the rate of 17.1% while another class such as agricultural, built-up, and mining sites has a significant increase of 14%, 4%, and 2% respectively. Between 2000 to 2021, forest areas and agricultural lands decrease from 67% to 60% and 26% to 20% respectively while built-up and mining areas increase from 4% to 12% and 3% to 7% through forest areas remain the dominant landcover class in the area. During the same study period, there was a fluctuation in climatic conditions. Rainfall between 1991 to 2021 has reduced by an amount of 24 mm while temperature has increased to 0.037°C per annum. The majority of the locals believe that cultivated land expansion and mining are the driving forces of forest cover change in the area and the only solutions to these issues are through enrichment planting, and strengthening forest protection laws and mining regulations. Future prediction on forest cover in the area for 2030 map shows that forest areas will be the major contributor of land to other land use/landcover class, henceforth causing it to decline if no intervention is made. These findings can be used to inform conservation and management strategies to mitigate the impact of forest cover change and protect the ecological integrity of forests in the municipality