Department of Environmental Studies
Permanent URI for this collectionhttp://localhost:4000/handle/20.500.12092/1935
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Item Carbon Sequestration by the Above Ground Biomass Pool in the South West Mau Forest of Kenya, 1985 - 2015(Journal of Environment and Earth Science, 2020) Kinyanjui, Mwangi James; Kigomo, Mathew Kiura; Mburu, David Mwehia; Thuo, Aggrey Daniel Maina; Mundia, Charles NdegwaForests are important for regulation of the global carbon balance. Increase in forest biomass enhances atmospheric carbon sequestration while decrease in forest biomass contributes to carbon dioxide emissions. World over, forest biomass has been declining due to forest loss and degradation. The South West Mau has experienced significant forest loss since 1964. The decline is posited to have significant impacts on carbon sequestration, carbon storage, carbon dioxide emissions and status of atmospheric carbon dioxide. This study assessed interannual trend and variability as well as change point detection in carbon sequestration in South West Mau Forest, Kenya between 1985 and 2015. Above ground biomass carbon sequestration was quantified based on the Carnegie-Ames-Stanford Approach (CASA) and carbon fraction for tropical climate domain. Carbon sequestration dynamics were characterized by increase-decrease cycles of approximately 3 years and low interannual variability (CV= 9.13). It emerged that South West Mau Forest was a net carbon emitter with a carbon sequestration balance of -588.40 Kg/ha between 1985 and 2015Item Impact of human activities on land degradation IN Lugari subcounty, Kakamega county, Kenya(E3 Journals, 2016-10) Kinyanjui, Mwangi James; Wanjala, Wanyonyi RaphaelThis study investigated the impact of human activities on land degradation in Lugari Sub-County, Kakamega County in Kenya. The study sought to analyze the extent of land degradation; identify the causative factors for land degradation and analyze the effect of implemented land conservation measures and propose sustainable land use options in Lugari Sub-County. The study used four Landsat satellite images; A Multi Spectral Scanner (MSS) of 1973, Landsat Thematic Mapper, TM of 1988, Enhanced Thematic Mapper, ETM of 2003 and Enhanced Thematic Mapper Plus, ETM+ of 2010 to develop time series land use and land use change maps of Lugari SubCounty. Data was confirmed by historical data and ongoing human activities from a socio economic survey and secondary sources. Soil erosion, soil fertility loss and pollution of the environment were associated with land use change. Correlations and regression were used to identify the human activities that have significant contribution to land cover change. Findings revealed that poor cultivation methods and traditional livestock grazing methods are the major factors contributing to land degradation. The study proposes the adoption of modern agricultural technologies to meet the nutritional, developmental and energy demands of the rural communities and ensures sustainable productivity of the land.Item Biomass Energy Resource of the Highland Bamboo (Yushania alpina) and Its Potential for Sustainable Exploitation in Southern Aberdares Forest(Scientific Research Publishing, 2017-08) Katumbi, Ndirangu Monicah; Kinyanjui, Mwangi James; JM, Kimondo; Mugo, Joseph MwareYushania alpina is the only bamboo species native to Kenya and covers about 150,000 ha growing in pure or mixed stands in the montane forests. The Aberdare forest is one of the natural habitats for Y. alpine occupying an area of 6419 ha mainly in the water catchment areas. The growing human population and depletion of other forest resources have necessitated the exploration of Y. alpine as a source of energy. This paper assessed the quantity of Y. alpine available for biomass energy and its potential for sustainable exploitation. Plots were laid on area maps to cater for altitude and distance from farms. The study area was stratified into three altitudinal zones: A (2220 - 2330 m), B (2331 - 2440 m) and C (2441 - 2550 m). The initial sampling plot of 10 m × 10 m was located randomly 500 m from the edge of the forest while the subsequent plots were laid out systematically at intervals of 500 m. In each plot, a total enumeration and biomass estimation of bamboo clumps were done using Muchiri and Muga (2013) [1] method. Bamboo samples and those of commonly used biomass energy sources were analysed for calorific value using bomb calorimeter. In addition, data for quantities of biomass energy used by some local industries were used to estimate the amount of bamboo required. The mean stocking was 19,981 (20,000) culms ha−1, and varied significantly among altitude strata and distance from adjacent farms. The mean biomass density and energy content were 86 tons/ha and 380,893 Kca/ha respectively with the higher altitudinal stratum (zone C) having the highest means (114 tons/ha) while the lower stratum (zone A) had the lowest (65 tons/ha). The energy needed by sampled local industries was 416,276,266 Kcal per year against 2.4 billion Kcal available in the bamboo forest. This implies that the bamboo forest in its present stocking can provide biomass energy for these local industries for more than five years. With bamboo maturing with less than five years, the forest can sustainably provide the required energy while still providing its environmental services.