A quantitative assessment of forest rejuvenation activities by a community on the borders of Hwange National Park using GIS and Remote Sensing

Abstract

Various natural and human activities have led to land degradation in the Hwange National Park and in the surrounding communal areas. The deforestation has in turn upset the natural ecosystem, with the desecrated vegetation leading to reduced soil moisture-holding capacity, reduced carbon sequestration by the forest and the subsequent loss of biodiversity. There has been attempts to rejuvenate the forest through activities that include holistic grazing methods, the use of swales, the mulching of fields, the cultivation of cover crops, the use of gabions, erosional restoration works, and the use of rocket stoves to minimise the reliance of inhabitants on firewood. These have been followed up by the application of scientific methodologies to assess the effectiveness of the various methods used. By applying the Normalized Difference Vegetation Index (NDVI) and assessing the land use / land cover changes (LULC), the impacts of the aforementioned rejuvenation activities were studied over a period of five years (2017-2022). Annual mean NDVI values were computed to reduce the bias in respect of changes in leaf phenology caused by variations in rainfall. The results show an increase of NDVI from a mean of 0.304 in 2020 to a mean of 0.345 in 2021.  More so, there was a 30% increase in 2021 and a 46% increase in 2022 from the previous years for forest cover in the study area. The results show the positive impact of the performed rejuvenation activities.