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Characterization of Forest Degradation beyond Canopy Cover Change in Mau Forest, Kenya

Open Journal of Forestry 2022年第4期12卷 393-407页

作者： Merceline Awuor Ojwala Felix Mutua mwangi james kinyanjui Department of Geomatic Engineering and Geospatial Information Systems Jommo Kenyatta University of Agriculture and Technology Nairobi Kenya Directorate of Resource Surveys and Remote Sensing Nairobi Kenya School of Natural Resources and Environmental Studies Karatina University Karatina Kenya

Monitoring Forest degradation is evidence enough to show a country’s commitment to monitor the forest trend both for national and local decision-making and international reporting processes. Unlike deforestation which is easier to point out, monitoring forest degradation is quite a challenge since there is no universal definition and thus no clear monitoring methods apart from the canopy cover change. This research, therefore, sought to look at the degradation trends in the Mau forest complex between 1995-2020 with the aim of finding out whether monitoring canopy density changes over time and quantifying these changes in terms of biomass loss could be a good approach in monitoring forest degradation. Forest Canopy Density (FCD) model was adopted focusing on using vegetation indices describing biophysical conditions of Vegetation, Shadow and Bareness to monitor changes in canopy density as a parameter for describing forest degradation in the forest blocks of Maasai Mau and Olpusimoru in Mau forest complex. Results indicated how different vegetation indices responded to changes in the vegetation density and eventually changes in the canopy density values which were converted in terms of biomass loss. The forest Canopy Density model proved to be a good tool for monitoring forest degradation since it combines different biophysical indices with different characteristics capturing what is happening below the canopy.

关键词： Forest Degradation Canopy Density Vegetation Indices Biomass Loss Monitoring

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Estimation of Above Ground Biomass in Forests Using Alos Palsar Data in Kericho and Aberdare Ranges

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Open Journal of Forestry 2017年第2期7卷 79-96页

作者： Eunice Wamuyu Maina Patroba Achola Odera mwangi james kinyanjui Department of Geomatic Engineering and Geospatial Information Systems Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya Division of Geomatics School of Architecture Planning and Geomatics University of Cape Town Cape Town South Africa Department of Forestry School of Natural Resources and Environmental Studies Karatina University Karatina Kenya

Above Ground Biomass is one of the six pools identified in the inventory of forest resources and estimation of greenhouse gas emissions and sinks from the forestry sector. The pool varies by management practices in different agro-ecological or agro-climatic zones in forests. The quantification of above ground biomass (AGB) hence carbon sequestration in forests has been very difficult due to the immense costs required. This research was done to estimate AGB using ALOS PALSAR L band data (HH, HV polarisation) acquired in 2009 in relation with ground measurements data in Kericho and Aberdares ranges in Kenya. Tree data information was obtained from ground measurement of DBH and tree heights in 100 circular plots of 15 m radius, by use of random sampling technique. ALOS PALSAR image is advantageous for its active microwave sensor using L-band frequency to achieve cloud free imageries, and the ability of long wavelength cross-polarization to estimate AGB accurately for tropical forests. The variations result between Natural and plantation forest for measured and estimated biomass in Kericho HV band regression value was 0.880 and HH band was 0.520. In Aberdare ranges HV regression value of 0.708 and HH band regression value of 0.511 for measured and estimated biomass respectively. The variations can be explained by the influence of different management regimes induced human disturbances, forest stand age, density, species composition, and trees diameter distribution. However, further research is required to investigate how strong these factors affect relationship between AGB and Alos Palsar backscatters.

关键词： Above Ground Biomass Estimation Green House Gas Carbon Credits Alos Palsar Backscatter Cross-Polarization Regression Analysis

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Effects of Sawdust, Forest Soil and Cow Dung Mixtures on Growth Characteristics of Blue Gum (<i>Eucalyptus saligna</i>) Seedlings in South Kinangop Forest, Nyandarua, Kenya

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Open Journal of Forestry 2017年第4期7卷 373-387页

作者： Fredrick Atanas Ashiono Hellen Kamiri Wangechi mwangi james kinyanjui Kenya Forest Service South Kinangop Forest Station Nairobi Kenya School of Natural Resources and Environmental Studies Department of Natural Resources Karatina University Karatina Kenya School of Agriculture and Biotechnology Department of Crop Science Karatina University Karatina Kenya

Forestation programs, in Kenya have been hindered by, among others, high cost of tree seedling production and longtime seedlings stay in the nursery. This has been attributed to poor quality of forest soil and unavailability of alternative growth media. Study was carried out in South Kinangop forest station to evaluate the potential of mixing sawdust and cow dung with forest soil to form a nutrient rich growth media. Using forest soil;sawdust, cow dung and mixture of these components, this study sought to determine growth characteristics of Eucalyptus saligna seedlings under different conditions available in the nursery. The experiment was laid out in a Completely Randomized Design (CRD) with six treatments comprising of Saw dust alone (Tr 1), Forest soil alone (Tr 2);Sawdust: Cow dung mixture in the ratio of 1:1 (Tr 3);Forest soil to Sawdust-Cow dung mixture (1:1) in ratio of 1:1 by weight (Tr 4);Forest soil to Sawdust-Cow dung mixture (1:1) in ratio of 1:2 by weight (Tr 5) and Forest soil to Sawdust-Cow dung (1:1) in ratio of 1:3 by weight (Tr 6). Treatments were replicated three times and an experimental unit consisted of 110 seedlings of which 15 were tagged for height and root collar diameter measurement. The remaining 95 were used for biomass determination by destructive sampling. The results showed that Sawdust: Cow dung mixtures (Tr 3) had the highest measurements for height, root collar diameter and biomass at week 20 when compared to the rest of growth mixtures. Height measurements were significantly high (13.81 cm) for the Sawdust: Cow dung mixtures while the variation in root collar diameter and biomass were not significantly different among the treatments. Sawdust alone did not favor seedling growth and recorded the lowest measurements in height, root collar diameter and biomass. Nutrient release from the growth media during the experimental period was equally high for the Saw dust: Cow dung mixture (Tr 3) which was ideal media for raising tree seedling

关键词： CowDung Forest Soil Sawdust Tree Seedling

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Estimation of Tree Height and Forest Biomass Using Airborne LiDAR Data: A Case Study of Londiani Forest Block in the Mau Complex, Kenya

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Open Journal of Forestry 2017年第2期7卷 255-269页

作者： Faith Kagwiria Mutwiri Patroba Achola Odera mwangi james kinyanjui Department of Geomatic Engineering and Geospatial Information Systems Jomo Kenyatta University of Science and Technology Nairobi Kenya Division of Geomatics School of Architecture Planning and Geomatics University of Cape Town Cape Town South Africa School of Natural Resources and Environmental Studies Karatina University Karatina Kenya

Tactical decisions on natural resource management require accurate and up to date spatial information for sustainable forest management. Remote sensing devices by the use of multispectral data obtained from satellites or airborne sensors, allow substantial data acquisition that reduce cost of data collection and satisfy demands for continuous precise data. Forest height and Diameter at Breast Height (DBH) are crucial variables to predict volume and biomass. Traditional methods for estimation of tree heights and biomass are time consuming and labour intensive making it difficult for countries to carry out periodic National forest inventories to support forest management and REDD+ activities. This study assessed the applicability of LiDAR data in estimating tree height and biomass in a variety of forest conditions in Londiani Forest Block. The target forests were natural forest, plantation forests and other scattered forests analysed in a variety of topographic conditions. LiDAR data were collected by an aircraft flying at an elevation of 1550 m. The LIDAR pulses hitting the forest were used to estimate the forest height and the density of the vegetation, which implied biomass. LiDAR data were collected in 78 sampling plots of 15 m radius. The LiDAR data were ground truthed to compare its accuracy for above ground biomass (AGB) and height estimation. The correlation coefficients for heights between LiDAR and field data were 0.92 for the pooled data, 0.79 in natural forest, 0.95 in plantation forest and 0.92 in other scattered forest. AGB estimated from LiDAR and ground truthed data had a correlation coefficient of 0.86 for the pooled data, 0.78 in natural forest, 0.84 in plantation forest and 0.51 in other scattered forests. This implied 62%, 84% and 89% accuracy of AGB estimation in natural forests, other scattered forests and plantation forests respectively. The even aged conditions of plantation forests might have resulted to better estimates of height and AGB as c

关键词： LiDAR Height Biomass Relationship Correlation

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Biomass Energy Resource of the Highland Bamboo (<i>Yushania alpina</i>) and Its Potential for Sustainable Exploitation in Southern Aberdares Forest

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Journal of Sustainable Bioenergy Systems 2017年第3期7卷 85-97页

作者： Ndirangu Monicah Katumbi mwangi james kinyanjui Kimondo JM Mugo Joseph Mware Kenya Forest Service Nairobi Kenya Department of Natural Resources School of Natural Resources and Environmental Studies Karatina University Karatina Kenya Kenya Forest Research Institute Nairobi Kenya

Yushania 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 susta

关键词： Bamboo Biomass Altitude Calorific Value

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An Inventory of the Above Ground Biomass in the Mau Forest Ecosystem,Kenya

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Open Journal of Ecology 2014年第10期4卷 619-627页

作者： mwangi james kinyanjui Petri Latva-Kayra Prasad Sah Bhuwneshwar Patrick Kariuki Alfred Gichu Kepha Wamichwe Department of Resource Surveys and Remote Sensing NairobiKenya Arbonaut Oy Ltd. HelsinkiFinland PASCO Corporation TokyoJapan Kenya Forest Service NairobiKenya Natural Resource Information&Technology Ltd. NairobiKenya

Biomass assessment of the Mau Forest Ecosystem (MFE) was done as part of Kenya’s greenhouse gas inventory. Trans Mara and Mount Londiani forest blocks representing extremes of vegetation types in the MFE were selected for ground data. Based on canopy closure, four forest strata were identified as very dense, moderately dense, open and bamboo. In each stratum, 5 clusters each with 4 plots measuring 30 m × 30 m were located. Big trees (D1.3 ≥ 10 cm) were measured per species for diameter at breast height (D1.3) in the whole plot while height was measured for every 5th tree. Poles (10 cm > D1.3 ≤ 5) were measured for D1.3 in a 10 × 10 m concentric sub plot. Saplings (5 cm > D1.3;ht ≥ 1.5 m) and seedlings (ht < 1.5 m) were enumerated per species within 5 × 5 m and 2 × 2 m concentric sub plots, respectively. Data were recorded in a Personal Digital Assistant (PDA) and quality checked with Open Foris Collect software. Allometric equations that have been used for similar vegetation in Kenya were used to relate D1.3 and height with biomass. The tree data were uploaded to ArboWebForest (AWF) cloud-service and using the AWF-SIMO calculation tool, average values of diameter, height, and biomass were calculated for each plot. The data were generalised to cover all areas for each block using the Sparse Bayesian linear regression process on the vegetation characteristics with 10 m resolution ALOS-AVNIR-2 images of the MFE. ANOVA was used to compare biomass generated from several allometric equations. Results show that the average biomass of the MFE was 236 Mg·ha1. Degradation that converts dense forests into open and moderately dense forests contributed to a biomass loss of 228 Mg·ha1 and 194 Mg·ha1 respectively. Four allometric equations gave no significant difference (P < 0.05) in biomass for the 80 plots implying that costly processes of developing new equations may not improve accuracy. The study offers a learning lesson in Kenya’s forest inventory processes and the biomass v

关键词： Forest Biomass Inventory

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Assessing Tree Species Dominance along an Agro Ecological Gradient in the Mau Forest Complex, Kenya

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Open Journal of Ecology 2014年第11期4卷 662-670页

作者： mwangi james kinyanjui Chris A. Shisanya Ondimu Ken Nyabuti Wargute Patrick Waqo Merceline Awuor Ojwala Department of Geography Egerton University Njoro Kenya Department of Geography Kenyatta University Nairobi Kenya Department of Resource Surveys and Remote Sensing Nairobi Kenya

Species relative dominance by basal area was assessed along an agro ecological gradient in the Mau Forest Complex (MFC). Trees were recorded per species and diameter at breast height (D1.3) for size class D1.3 ≥ 10 cm in 60 quarter hectare plots distributed in 7 agro ecological zones (AEZ) namely LH1, LH2, LH3, LH4, UH0, UH1 and UH2. Basal area per species was used to calculate species relative dominance i.e. the proportion of basal area by a species to the total basal area of the AEZ. Species associations were analysed as the group of highly ranked species in each AEZ. Sorensons similarity index was used to calculate the proportion of similar species among AEZ. Analysis of variance compared basal area among AEZ and Tukey’s multiple comparison test used to identify specific AEZ with differences. Tabernaemontana stapfiana (Britten) was ranked first in LH1, UH1 and UH0 with relative dominance values of 22.66%, 22.89% and 30.73% respectively. It was however not recorded in any other AEZs. Dombeya goetzenii (K. Schum) occurred in 6 of the 7 AEZs but had moderate dominance values in each of the 6 AEZs. The sum of dominance values per species in all AEZs indicated no species mono-dominance and different species dominated at different AEZs. Co-dominance resulted in species associations like Tabernaemontana-Allophylus-Eke-bergia-Albizia in LH1, Juniperus-Dombeya-Casearia-Prunus in LH2, Acokanthera-Cussonia-Olea-Teclea in LH4 and Tabernaemontana-Syzygium-Podocarpus-Neoboutonia in UH1. Species richness was highest in UH1 and had the highest similarity indices with those of other AEZs. The UH1 had a species similarity of 67% with LH1, 63% with LH2 and 56% with LH4. However, species in the very humid zone UH0 differed with those of the drier lower highland zones (UH0 vs LH3 and vs LH4 = 31% and 37% respectively). Basal area differed significantly among AEZ ( = 3.76) showing that they differ in stocking levels. Tukeys test showed that high potential zones of LH1, LH2, UH0, UH1 d

关键词： Species Dominance Basal Area Agro Ecological Zoning

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Developing a Forest Management Plan (DFMP) for Gatsibo District in the Eastern Province of Rwanda

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Open Journal of Forestry 2018年第2期8卷 247-265页

作者： Felix Rurangwa mwangi james kinyanjui Frederick Bazimaziki Jacques Peeters Anicet Munyehirwe Francis Musoke Gaspard Nelson Habiyaremye Dismas Bakundukize Prime Ngabonziza Jost Uwase Rwanda Water and Forestry Authority (RWFA) Kigali Rwanda Department of Natural Resources Karatina University Karatina Kenya Belgian Technical Cooperation Kigali Rwanda Inclusive Business and Consultancy (IB & C Ltd.) Kigali Rwanda The International Union for Conservation of Nature (Forest Landscape Restoration Kigali Office) Kigali Rwanda Rwanda Land Management and Use Authority Kigali Rwanda

In support of conservation of its fragile land resource, the government of Rwanda has proposed the management of all forests in the country under a specific management plan. This assignment sought to develop a management plan for the public productive forests of Gatsibo District in Eastern province of Rwanda. Data was collected from 1468 plots, proportionally allocated by size to the 375 forest stands. Information about the forest (qualitative data) was recorded and then forest measurements (inventory) done in a concentric cycle of 9.77 m and 3.99 m radius and all data recorded in a digital format using the survey CTO platform. The data was summarized and analyzed in a harmonized forest management tool for Rwanda comprising of six interlinked excel files based on Rwanda’s silvicultural regimes and treatments. This analysis resulted to planning for silvicultural activities in each forest up to the year 2070. Results show that the public plantation forests of Gatsibo are poorly stocked mainly due to poor management and the best stocked forest had a basal area of only 13.3 m2/ha. This implied low forest volumes for each of the wood requirements;timber wood, service wood and energy wood. Eucalyptus forests are the most common but are poorly stocked compared to the Pinus patula forests which are even aged by plantation. A projection of stocks shows that the forests can be sustained with an average wood volume of 73 m3/ha, to provide harvests yearly and reduce the wood supply and demand gap in the district. A viability analysis indicates that some forests are viable for leasing with good profits in the short term (10 years) and full term planning (40 years). However, some forests may not be commercially viable due to their current stocks and agro bioclimatic conditions, and these would be rehabilitated for ecosystem services. This plan supports the restoration of the forests of Gatsibo district through provision of specific guidelines for the management of the forests.

关键词： Forest Management Planning

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Comparing Tree Heights among Montane Forest Blocks of Kenya Using LiDAR Data from GLAS

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Open Journal of Forestry 2015年第1期5卷 80-89页

作者： mwangi james kinyanjui Ngugi John Kigomo Kamau Miriam Wambui Nderitu Joel Kariuki Nyanjui Charles Nganga John Macharia Ojijo William Odidi Ashiono Fredrick Owate Augustine Omamo Ndirangu Monicah Katumbi Department of Forestry School of Natural Resources and Environmental Studies Karatina University Karatina Kenya Department of Resource Surveys and Remote Sensing Nairobi Kenya Kenya Forest Research Institute Nairobi Kenya Kenya Forest Service Nairobi Kenya

This study was designed to use LiDAR data to research tree heights in montane forest blocks of Kenya. It uses a completely randomised block design to asses if differences exist in forest heights: 1) among montane forest blocks, 2) among Agro ecological zones (AEZ) within each forest block and 3) between similar AEZ in different forest blocks. Forest height data from the Geoscience Laser Altimeter System (GLAS) on the Ice Cloud and Land Elevation Satellite (ICE-SAT) for the period 2003-2009 was used for 2146 circular plots, of 0.2 - 0.25 ha in size. Results indicate that, tree height is largely influenced by Agro ecological conditions and the wetter zones have taller trees in the upper, middle and lower highlands. In the upper highland zones of limited human activity, tree heights did not vary among forest blocks. Variations in height among forest blocks and within forest blocks were exaggerated in regions of active human intervention.

关键词： Montane Forests Tree Height Agro Ecological Zones

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Characterization and Modeling of Mechanical Properties of Additively Manufactured Coconut Fiber-Reinforced Polypropylene Composites

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Advances in Materials Physics and Chemistry 2024年第6期14卷 95-112页

作者： George Mosi Bernard W. Ikua Samuel K. Kabini james W. mwangi Department of Mechatronic Engineering Jomo Kenyatta University of Agriculture and Technology Juja Kenya

In the face of the increased global campaign to minimize the emission of greenhouse gases and the need for sustainability in manufacturing, there is a great deal of research focusing on environmentally benign and renewable materials as a substitute for synthetic and petroleum-based products. Natural fiber-reinforced polymeric composites have recently been proposed as a viable alternative to synthetic materials. The current work investigates the suitability of coconut fiber-reinforced polypropylene as a structural material. The coconut fiber-reinforced polypropylene composites were developed. Samples of coconut fiber/polypropylene (PP) composites were prepared using Fused Filament Fabrication (FFF). Tests were then conducted on the mechanical properties of the composites for different proportions of coconut fibers. The results obtained indicate that the composites loaded with 2 wt% exhibited the highest tensile and flexural strength, while the ones loaded with 3 wt% had the highest compression strength. The ultimate tensile and flexural strength at 2 wt% were determined to be 34.13 MPa and 70.47 MPa respectively. The compression strength at 3 wt% was found to be 37.88 MPa. Compared to pure polypropylene, the addition of coconut fibers increased the tensile, flexural, and compression strength of the composite. In the study, an artificial neural network model was proposed to predict the mechanical properties of polymeric composites based on the proportion of fibers. The model was found to predict data with high accuracy.

关键词： Additive Manufacturing Artificial Neural Network Mechanical Properties Natural Fibers Polypropylene

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