Trends and drivers of forest cover change in the Cherangany hills forest ecosystem, western Kenya

Abstract

Detecting and monitoring forest cover change and its drivers has become a vital component of forest management globally as it helps in decision-making and policy development. The objective of this study was to analyze the spatio-temporal trends of forest cover change and its drivers from 1985 to 2020 in the Cherangany hills forest ecosystem, Kenya. Landsat satellite data and Google Earth Engine (GEE) algorithms were used for land cover mapping and change detection. In addition, a literature review was undertaken to establish the drivers of forest cover change over time in the study area. The results show an overall decline in the forest, water features, and built-up areas land cover categories in the study area while croplands, grasslands, and bareland registered gains. The percentage area under forests declined by about 14.1% (13,782 ha) during the 35 years. This loss translates to an annual average forest loss of 0.40% or 394 ha. Conversely, cropland and grassland registered an increase of about 8.1% (7944 ha) and 5.8% (5616 ha) respectively over the 35-year study period. The drivers of forest cover change in the ecosystem comprised the conversion of forests to croplands and grasslands, grazing, encroachment, illegal logging, firewood harvesting, charcoal production, forest fires, excisions, climate change, population growth, policy, and institutional failures. The findings of this study will help the relevant forest managers re-evaluate the past conservation and management strategies and focus the rehabilitation efforts on the forest ecosystem’s degradation hotspots for sustainable forest management.