Publications: Forest Utilisation, Products and Trade
Fuel-wood energy properties of Prosopis juliflora and Prosopis pallida grown in Baringo District, Kenya Published: 2013 Author: Oduor N. and Githiomi J.
Kenya depends on fuel-wood for cooking and heating in most households. Over 80% of both rural and urban households in the country use fuel wood for cooking. These Prosopis plant species provide excellent fuel wood. These plants were introduced in the arid and semi-arid areas of Kenya in the early 1970s as a source of woodfuel and also for the rehabilitation of degraded lands. Prosopis is a prolific seeder and has invasiveness behaviour that results in a number of social, ecological and economic concerns to the local communities, and challenges to development partners. Now with the Kenyan Forest Policy 2005 which proposes strategies and actions to enhance sustainable and efficient production of wood-fuel, Prosopis species is a suitable candidate. The Kenya Forest Service is now issuing permits allowing charcoal burning of Prosopis species in an effort to manage and curb uncontrolled spread. There is a national ban on charcoal making from unsustainable wood sources which include the woodlands and natural forest reserves. The aim of this project was to determine the energy values from Prosopis fuel-wood. The moisture content, volatile matter, ash content, carbon content and calorific values were determined from Prosopis fuel-wood plants. The calorific values for Prosopis juliflora and Prosopis pallida wood are 4.952 and 4.862 Kcal respectively. The calorific values for P. juliflora and P. pallida charcoal are 7.854 and 7.797 Kcal, respectively.Download: Fuel-wood energy properties of prosopis spp in baringo district Oduor and Githiomi.pdf Post date: 18 Jun 2013 - 09:13 GMT Updated date: 18 Jun 2013 - 09:13 GMT
Dimensional Stability of Particle Board and Radiata Pine Wood (Pinus radiata D. Don) Treated with Different Resins Published: 2013 Author: Oduor N., Vinden P. and Kho P.
Particleboard and solid wood stakes were treated with either an isocyanate or phenol formaldehyde resin and exposed in soil beds comprising three different soil types and two moisture contents. The treatments resulted in a marked improvement in the dimensional stability of particleboard but had no effect on solid wood. Higher moisture uptakes in stakes exposed in sandy soils indicated that the technique used for measuring soil water holding capacity needs to be reviewed.Download: Dimensional Stability of Particle Board and Radiata Pine Wood (Pinus radiata D..pdf Post date: 6 Jun 2013 - 17:00 GMT Updated date: 6 Jun 2013 - 17:02 GMT
Evaluating Mukau wood Published: 2013 Author: Nellie Oduor
Melia volkensii commonly known as Mukau is an well known indigenous tree species in the plant family Meliaceae growing naturally in the semiarid zones of Ethiopia, Somalia, Tanzania and Kenya.Melia volkensii mechanical properties are compared with mahogany (Khaya species), teak (Tectona grandis) and mvule (Milicia excelsa)Download: Evaluating mukau wood.pdf Post date: 6 Jun 2013 - 16:46 GMT Updated date: 6 Jun 2013 - 17:02 GMT
Analysis of Heartwood –Sapwood Demarcation Methods and Variation of Sapwood and Heartwood within and Between 15 Year Old Plantation Grown Eucalyptus Regnans Published: 2012 Author: Githiomi J, K. and Douglas E.
This study was carried out using 15-year old Eucalyptus regnans F. Muell trees from three seedlots in a progeny trial in Norbethong, Victoria in Australia. Colour, stain and light table methods were used to demarcate the boundary between the sapwood and heartwood on the discs cross sectional surface. The main objective of this study was to examine the variation within and between tree in heartwood and sapwood in plantation grown Eucalyptus regnans material and also to compare the three techniques used in demarcating the boundary between sapwood and heartwood. Wood discs were removed from the base, breast height, 20%, 40%, 60% and 80% of the total tree height. Measurements were made on cross sectional surfaces of the discs to determine the sapwood width and heartwood percentage. The results showed that there was no significant difference in heartwood-sapwood demarcation methods using natural colour and stain. However sapwood-heartwood demarcation method using light table method had significant difference with both colour and stain methods with P = 0.000. The mean sapwood and heartwood width varied significantly between trees and along the height. The lowest mean sapwood width of 21.0 mm was found at breast height which increased with height to 33.9mm at 80% tree height it also increased from breast height to 29.9mm at the base of the tree. The largest heart wood percentage of 69.51% was found at breast height and decreased with height to zero at 80% height and it also decreased from breast height to 65.75% at the base. A very high correlation was found between the heartwood diameter and disc diameter.Download: Anaylysis of heart and sapwood Eucalyptus regnans.pdf Post date: 18 May 2013 - 22:14 GMT Updated date: 18 May 2013 - 22:17 GMT
Strategies for Sustainable Wood fuel Production in Kenya Published: 2012 Author: Githiomi J.K and Oduor N.
Wood energy provides 70% of Kenya’s national energy needs and it is expected to continue as the country’s main source of energy for the foreseeable future. Wood is the standard cooking fuel for the majority of Kenyan households and also an important energy source for small-scale rural industries. Past studies on supply demand balance of woodfuel have shown a deficit. To address this deficit there is need for a comprehensive wood energy plan with implementation strategies which ensure its sustainable production. This paper outlines some of the strategies that need to be put in place for a sustainable woodfuel production. The strategies are both supply and demand oriented which are aimed at either increasing the supply or reducing the demand. The supply strategies include; enhancing on-farm tree planting, efficient management of rangelands and woodlands, development of fuelwood plantations by Kenya Forest Service. The demand oriented strategies include ; reducing demand through promotion of more efficient cooking stoves and charcoal conversion kilns, use of alternative sources of energy other than wood. Other strategies include formulation of woodfuel policies that enhances decentralized sustainable wood energy planning at all levels. The later can only be achieved if the wood energy institutional framework is strengthened and facilitated to collect wood energy data to be used in national energy planning alongside the conventional fuels that are currently given more emphasis. The decentralized wood energy planning is important as the strategies to be used for sustainable woodfuel production may vary from one region to the otherDownload: Strategies for sustaibale wood fuel production in Kenya.pdf Post date: 18 May 2013 - 22:06 GMT Updated date: 18 May 2013 - 22:17 GMT
NUTRITIONAL ASSESSMENT OF Sclerocarya birrea (Amarula) FRUIT FROM KENYA Published: 2013 Author: Wairagu, N. W., Kiptoo J. and Githiomi, J. K.
The aim of this study was to carry out nutrient content of Sclerocarya birrea (Amarula) fruits as one of the
Kenyan drylands indigenous fruits with a high potential. Mature fruit samples were collected from the field in
Mbeere in Eastern part of Kenya and then taken to the Forest Products laboratories for analysis. Edible portions
were analysed for the nutritional composition. The analysis carried out included energy, moisture, ascorbic acid,
proximate and minerals (i.e. Ca, Mg, K, Cu, P, Fe and Zn). Flame atomic absorption spectrophotometer (FAAS)
was used for elemental analysis, Ultra Violet-visible spectrophotometer (UV/VIS.) for phosphorous analysis,
Kjedahl method for crude protein, bomb calorimeter for internal energy and soxhlet method of analysis for crude
fat while various classical methods of analysis were employed for the other parameters. The results of analysis
indicated that the kernel was rich in fat (57.36 ± 0.95%), energy (30.36 ± 0.04kj/g), protein (30.34 ± 0.36%),
potassium (486.64 ± 2.6mg/100g), phosphorous (160.74 ± 2.6mg/100g) and calcium (449 ±18.59mg/100g) while
pulp had significantly high values of ascorbic acid (190 ± 0.81mg/100g), Potassium (K) (3220.3 6± 4.32mg/100g),
Phosphorous (P) 145.634 ± mg/100g), Calcium (Ca) (688.488 ± 20.74mg/100g). However iron (Fe) (2.792 ± 0.26
mg/100g), Magnesium (Mg) (155.82±1.044mg/100g), zinc (2.33 ± 0.03mg/100g) and copper (0.32 ±
0.075mg/100g) were present in low quantities.
Optimum Parameters for the Formulation of Charcoal Briquettes Using Bagasse and Clay as Binder Published: 2012 Author: Onchieku J. M, Chikamai B. N. and Rao M. S.
Kenya generates about 1.6 million tones of sugarcane bagasse which has enormous
potential for exploitation in modern commercial applications. Due to rising fossil
fuel prices, availability in large quantity and rapidly growing interest in bio-energy
as well as technological advances and environmental concerns , bagasse could be
utilized for the formulation of charcoal briquettes for household use to
supplement wood charcoal. In this study briquettes were formulated using
carbonized bagasse, clay as a binder and molasses as a filler. Bagasse was obtained
from sugar factories for carbonization. Carbonization was carried out using a
brick-built kiln while blending used a manually operated drum mixer. A piston type
briquetting press fitted onto a universal strength testing machine was used for the
production of briquettes. The most optimum parameters that produced briquettes
which complied to current charcoal specifications for household use were in the
ratio of 1:1:40 for molasses, clay and carbonized bagasse respectively at
0.50N/mm2 pressure. At this formulation, briquettes were produced whose ash
content, volatile matter and calorific energy were 36.4%, 27.2% and 4.390 Kca/g
respectively. The briquettes produced burnt without sparks and were smokeless,
producing no irritating smell. They ignited easily and took relatively long before
they extinguished. They were recommended for household use in Kenya.
Genetic diversity of Kenyan Prosopis populations based on random amplified polymorphic DNA markers Published: 2012 Author: Muturi M. G et al
Several Prosopis species and provenances were introduced in Kenya, either as a single event or repeatedly. To date, naturally established Prosopis populations are described as pure species depending on site, despite the aforementioned introduction of several species within some sites. To determine whether naturally established stands consist of a single or mixture of species, six populations from Bamburi, Bura, Isiolo, Marigat, Taveta and Turkwel were compared for relatedness with reference to Prosopis chilensis, Prosopis juliflora and Prosopis pallida using random amplified polymorphic DNA markers. Cluster analysis based on Nei’s genetic distance clustered Kenyan populations as follows: Marigat, Bura and Isiolo with P. juliflora, Bamburi with P. pallida and Taveta with P. chilensis, whereas the Turkwel population is likely to be a hybrid between P. chileneis and P. juliflora. Four populations had private markers, revealing germplasm uniqueness. Expected heterozygosity tended to be larger for Kenyan populations (ranging from 0.091 to 0.191) than in the three reference (ranging from 0.065 to 0.144). For the six Kenyan populations and two P. juliflora provenances from the Middle East, molecular variation was larger within populations than between population. Higher molecular variance among populations is attributed to their geographical separation and the low variation within populations is due to gene flow between individuals within a population. Overall, this study shows that (1) the Kenyan Prosopis populations are genetically isolated, (2) multiple introductions enhanced genetic diversity within sites and (3) P. juliflora and its hybrid are the most aggressive invaders.Download: Muturi et al.pdf Post date: 3 May 2013 - 14:41 GMT Updated date: 3 May 2013 - 16:59 GMT
Bending and modulus of elasticity properties of ten Lesser-used timber species in Ghana using structural Dimensions Published: 2012 Author: Appiah-Kubi, E., Kankam, C. K., & Adom-Asamoah, M.
For structural use, the properties of large size specimens are preferred to those of small clear specimens because of unavoidable defects such as knots and shakes found in wood. The objective of this study was to assess the bending strength, modulus of elasticity properties and failure behaviour of ten Lesser-used Species (LUS) by use of structural size dimensions (50mm x 120 mm x 2000 mm). The ten species were Albizia ferruginea, (Gulland Perr) Beuth., Sterculia rhinopetala,(K. Schum), Blighia sapida,(Koenig), Canarium schweinfurthii (Engl.), Petersianthus macrocarpus, (P. Beauv.) Liben, Sterculia oblonga, (Mast.) Cola gigantea, (A.Chev.) Celtis zenkeri, (Engl.) Antiaris toxicaria (Lesch.) and Amphimas pterocarpoides (Harms.). The moisture contents of the 10 timber species used ranged from 16.1% (Antiaris toxicaria) to 51.0% (Albizia ferruginea). It was observed during loading under flexure that the elastic stiffness and rate of increase in the strength capacity of the beams did not change after three cycles of loading and unloading. All the beams failed in a form of tension rupture. The breaks were usually splintering tension failure or brittle (brashness) tension failure or a combination of the two modes
of failure. Sterculia rhinopetala exhibited the highest bending strength with a 5th percentile bending strength of 56.8 ,/mm2 and a mean local modulus of elasticity of 15,973 ,/mm2. Sterculia oblonga was also found to be the 2nd best in terms of material properties with a 5th percentile bending strength of 52.1 ,/mm2 and a mean local modulus of elasticity of 16,408 ,/mm2. Celtis zenkeri which had the highest mean local modulus of elasticity, however, had the 6th best 5th percentile bending strength of 39.9 ,/mm2. A good linear correlation (69.6-91.3%) was established between mechanical strength properties for average density, average bending strength, average local modulus of elasticity and average global modulus of elasticity.
Sanding properties of several lesser-used timber species in Ghana Published: 2012 Author: Owusu, F.W., Ayarkwa, J. K. & Frimpong-Mensah, K.
Sanding qualities of seven lesser-used timber species and two primary species used as control were investigated at 12% and 20% moisture contents using four grit sizes of sandpaper on two machine sanders. The species were extracted from three ecological zones of Ghana. Samples were prepared in accordance with American Society for Testing and Materials Standards (ASTM) D143-94 (2007) and ASTM D1666-87 (2004). The results of the chipping tendencies showed that the belt sanding machine with both grit sizes 60 and 80 performed better than the drum sander for all the species. Sandpaper of grit size 60 recorded higher percentages of defect-free samples, ranging between 74% and 95%, for the species investigated than sandpaper of grit size 80 which ranged between 33% and 68%. The surface quality of the chipped grain samples that were sanded at 20% moisture content to eliminate the chipped/torn defect was better than at 12%. The results of tests on fuzzing and scratching tendencies indicated that the performance of the belt sander was better than the drum sander. Higher percentages of fuzzy-free samples were obtained at 12% moisture content with grit sizes 100 and 120 but lower percentages of scratch-free samples were recorded at 20% moisture content. Also, sandpaper with grit size 100 had more pronounced fuzzy and scratchy defects on the wood species than with grit size 120. Generally, the texture and the density of the species had influence on their sanding qualities. On average, the sanding qualities of the medium and high density species of each of the lesser-used timber species studied were comparable to Milicia excelsa while Rhodognaphalon brevicuspe (low density species) was also comparable to Triplochiton scleroxylon.Download: sanding_properties.pdf Post date: 20 Mar 2013 - 18:09 GMT Updated date: 20 Mar 2013 - 18:11 GMT