Africana Trees Research Articles

Integrating Cordia Africana Trees on Farms Differentially Improves Soil Properties in Small Holder Farms in Kirinyaga County, Kenya

Integrating Cordia Africana Trees on Farms Differentially Improves Soil Properties in Small Holder Farms in Kirinyaga County, Kenya

A New Proposed Symbiotic Plant-Herbivore Relationship between Burkea africana Trees, Cirina forda Caterpillars and Their Associated Fungi Pleurostomophora richardsiae and Aspergillus nomius.

Burkea africana is a tree found in savannah and woodland in southern Africa, as well as northwards into tropical African regions as far as Nigeria and Ethiopia. It is used as fuel wood, medicinally to treat various conditions, such as toothache, headache, migraine, pain, inflammation, and sexually transmitted diseases, such as gonorrhoea, but also an ornamental tree. The current study investigated the possible symbiotic relationship between B. africana trees and the C. forda caterpillars and the mutual role played in ensuring the survival of B. africana trees/seedlings in harsh natural conditions and low-nutrient soils. Deoxyribonucleic acid isolation and sequencing results revealed that the fungal species Pleurostomophora richardsiae was highly predominant in the leaves of B. africana trees and present in the caterpillars. The second most prominent fungal species in the caterpillars was Aspergillus nomius. The latter is known to be related to a Penicillium sp. which was found to be highly prevalent in the soil where B. africana trees grow and is suggested to play a role in enhancing the effective growth of B. africana trees in their natural habitat. To support this, a phylogenetic analysis was conducted, and a tree was constructed, which shows a high percentage similarity between Aspergillus and Penicillium sp. The findings of the study revealed that B. africana trees not only serve as a source of feed for the C. forda caterpillar but benefit from C. forda caterpillars which, after dropping onto the soil, is proposed to inoculate the soil surrounding the trees with the fungus A. nomius which suggests a symbiotic and/or synergistic relationship between B. africana trees and C. forda caterpillars.

DNA sequencing reveals high arbuscular mycorrhizal fungi diversity in the rhizosphere soil of Prunus africana trees in fragmented Afromontane forests

PurposeArbuscular mycorrhizal fungi (AMF) play a key role in medicinal plant species, besides their ecological role in shaping plant communities. Knowledge about the diversity and structure of AMF communities associated with the endangered Prunus africana is valuable in the conservation and domestication of the species for its medicinal products.MethodsWe investigated the diversity and structure of AMF species communities in the rhizosphere soils of P. africana trees occurring in four fragmented Afromontane forests found in Cameroon (Mount Cameroon and Mount Manengouba) and Kenya (Chuka and Malava) using Illumina Miseq sequencing of 18S rRNA gene amplicons.ResultsA total of 64 virtual taxa (VT) belonging to eight genera were detected, namely Glomus (43 VT), Claroideoglomus (6 VT), Paraglomus (5 VT), Acaulospora (4 VT), Diversispora (3 VT), and Archaeospora, Pacispora, and Scutellospora with 1 VT each. Scutellospora heterogama VTX00286 was the most abundant and common species in all four sites (49.62%). Glomeraceae and Gigasporaceae were the most abundant families found across the sites, while Acaulosporaceae, Pacisporaceae, and Archaeosporaceae were rare, represented by < 1% of all the detected taxa.ConclusionOur data shows a high diversity of AMF species associated with P. africana and variable community structure partially shaped by local edaphic factors.

Soil physicochemical properties and coffee production under canopies of Croton machrostachyus and Cordia Africana tree species in Sayo district, western Ethiopia

Soil physicochemical properties and coffee production under canopies of Croton machrostachyus and Cordia Africana tree species in Sayo district, western Ethiopia

Post Debarking Response of &amp;lt;i&amp;gt;Prunus africana&amp;lt;/i&amp;gt; (Hook. F) Kalkman (&amp;lt;i&amp;gt;Rosaceae&amp;lt;/i&amp;gt;) Trees at Two Exploitation Sites in North Kivu (Eastern Democratic Republic of Congo)

Prunus africana is a species of great economic, medicinal and ecological importance. Due to its multiple uses, unsustainable exploitation methods and low regeneration capacity in tropical rainforests, this species is threatened with extinction. Present and exploited in the eastern part of DR Congo, knowledge of the dynamics of post-bark regeneration of Prunus africana remains fragmentary and poorly known. In North Kivu province, this species thrives in both afromontane forest and lowland tropical rainforest habitats. In order to contribute to the rational and sustainable exploitation of Prunus africana in this province, this paper was carried out with the objective of contributing to the knowledge of the dynamics of the regeneration of post-harvest bark of Prunus africana in two exploitation sites (low and high altitude). To achieve this objective, the inventory was conducted on 16 plots of 25 hectares each, with 8 plots per site. Dendrometric parameters (diameter at breast height (DBH), total tree height) and tree growth and regeneration parameters, i.e., stem bark thickness of the unharvested and harvested portions of the trees (bark reconstitution) were measured. A total of 716 barked stems of Prunus africana in 2016 in 25 hectares constituted the study sample. Results show that sites do not influence diameter at breast height of P. africana trees (p > 0.05) or total tree height. The bark diameter of harvested trees and the bark diameter of unharvested trees varied significantly by site (p 0.05). In contrast, the annual growth rate of bark differed with altitude; the highest rate was observed in trees growing at high altitude (2.97 ± 0.9 mm/yr) compared to 2.23 ± 0.74 mm/yr at low altitude. In view of these results, this study indicates that a half-rotation of 7 years could allow an effective reconstitution of the bark of Prunus africana at the second passage on the remaining side of the same stem.

Utilisation of Woody Plants by the Cape Porcupine in Mesic Savannas in South Africa.

Herbivory plays a fundamental role in determining the structure of savannas. The impacts of small and medium-sized mammalian herbivores on trees in savannas remain poorly understood because most research attention focuses on large herbivores such as elephants whose destructive effects on trees can be pervasive at landscape scales. On the other hand, feeding activities of generalist herbivores such as Cape porcupines on woody plants can lead to tree mortality. This study investigated the utilisation of woody plants by the Cape porcupine in three mesic savanna sites in South Africa. We determined the woody plant diet of the porcupine for the early and late dry seasons at Roodeplaat Farm in Gauteng Province, and at Goss Game Farm and Bisley Valley Nature Reserve in KwaZulu-Natal Province. Thirty and twenty randomly located quadrats (30 m × 30 m) were laid at Roodeplaat and Goss, respectively, while 10 smaller quadrats (10 m × 10 m) were laid at Bisley. We measured stem diameter and the length and width of bark scars made by porcupines on stems of woody plants. We collected ten dung samples from each study site in the wet and dry seasons for quantification of woody material in porcupine diet. Porcupine foraging behaviour impacted different tree species at each site: Vachellia robusta at Roodeplaat, Spirostachys africana at Goss and Vachellia nilotica at Bisley. Each of these trees was dominant at each site. More scarring and tree mortality were recorded at Bisley with almost 70% tree sapling mortality occurring on trees that porcupine fed on. The size of bark scars was greater at Goss (P < 0.01) than at Roodeplaat and Bisley, which were similar. The area of bark damage on S. africana trees differed significantly by stem diameter size class (P = 0.007) and was greater for small stems (size class < 7.1 cm) than the larger stems (size classes 7.1-14 cm and 14.1-21). For all the study sites, dung samples revealed that woody material contributed over 80% of the porcupine diet during the dry season, but was lower at 35% during the wet season for Roodeplaat, although it was consistently high for Bisley at 79%. Porcupine foraging activities substantially contributed to tree mortality at each site. We posit that porcupine induced mortality on dominant tree species at each site may contribute to structural heterogeneity in woody plant vegetation in mesic savannas.

Beneficiation of Commiphora africana Plant: Extraction and Application of Green Softener on Cotton Fabric

This paper aims at the extraction and application of eco- and user-friendly natural gum obtained from Commiphora Africana tree. The result obtained is also compared with fabric treated with a commercial softener of the same concentration. The gum was extracted by puncturing the stem of the plant and the extracted gum was applied directly to 100% cotton fabric through a padding process with different concentrations of extracted gum (i.e., 20 gram per litre (g/l), 25 g/l, and 30 g/l). Another similar fabric sample was treated with a silicon softener of the same concentration. The fabric samples treated with both natural gum and silicon softener were tested for their stiffness, crease recovery, and drapability. The results show that the change in fabric softness depends on the concentration of softener used in both cases. As the concentration of the softener increased, there was a decrease in bending length and drape coefficient for both fabric samples. The drape coefficient of fabric sample treated with natural gum has a comparable result with fabric treated with silicon/commercial softener. Maximum increases in recovery angle were seen in fabric treated with natural gum at a concentration of 30 g/l.

Spatial distribution patterns of Afzelia africana (Fabaceae – Detarioideae) in a tropical savanna of Benin: implications for management

Background and aims – Understanding the spatial patterns and associations of tree species with their conspecific and heterospecific neighbours is critical for sustainable management of their stands. This study assessed the intra- and interspecific spatial structure of six life stages in Afzelia africana, a keystone multipurpose and endangered tree species in a tropical savanna of Benin.Material and methods – Three plots of 4 ha each were demarcated on three sites along a conservation gradient (hunting zone – core conservation zone). Individuals of A. africana (irrespective of their diameter at breast height) and heterospecific trees (dbh ≥ 5 cm) were mapped. Tree spatial patterns and associations were determined using univariate and bivariate pair correlation functions. The distance to the nearest neighbour was further used to assess tree-to-tree distance.Key results – We found variable spatial patterns across sites. In the core zone where wildlife density is high, most life stages had a random distribution. In contrast, in the hunting zone where wildlife density is low, the species spatial distribution changed from a predominantly aggregative pattern during early stages to a less aggregative or random spatial pattern for very large adults. Most pairs of life stages showed neutral associations, except for small and large adults, which had positive association between themselves on two sites. We also found that A. africana tree spatial distribution was unrelated to heterospecific trees.Conclusion – We suggest that bush fire, seed dispersion, predation, and local environment would have contributed to the observed patterns.

Effects of scattered Faidherbia albida and Cordia africana Tree on Soil Properties under their Canopies in Fedis District, Easte Hararghe Zone, Oromia

The study was conducted to investigate the effect of scattered trees under their canopies on soil fertility status at Fedis district, East Hararghe Zone, oromia, Ethiopia. Accordingly, six isolated and nearly identical Faidherbia albida and Cordia africana trees were selected and the canopy coverage of each tree was divided into four radial transects. Soil samples from three horizontal distances levels: 2.5m, 5m and 25m with two soil depths levels (0–20cm and 20-40cm) were taken for analysis of soil physical and chemical properties and tree species with two levels with factorial arrangement in RCBD replicated six times were employed. The result revealed soil texture was not influenced significantly (P&gt;0.05) by tree species. Soil bulk density was significantly (p&lt;0.05) influenced by both tree species. Soil moisture was significantly (p&lt;0.05) higher under canopy of trees than open field and in surface than in subsurface soils. Soil chemical properties;- electric conductivity, organic carbon, organic matter, soil carbon stock, total nitrogen, available phosphorus and exchangeable cation (Mg, Ca, Na and K) for surface and subsurface soil layers of under F.albida and C. africana trees were significantly (p&lt;0.05) higher in canopy than open field and in surface than subsurface. Soil pH was not significantly (p&gt;0.05) influenced by both tree species. It can be concluded that these tree species have the potential to improve soil fertility beneath its canopy. This may be important for the agricultural landscape health and demonstrated the scattered trees to retain on crop fields to improve soil fertility status under its canopy and on farm biodiversity conservation in agricultural landscapes conditions.

NMR-Based Metabolomic Analysis and Microbial Composition of Soil Supporting Burkea africana Growth.

Burkea africana is a leguminous tree used for medicinal purposes, growing in clusters, on soils impoverished from most nutrients. The study aimed to determine the factors responsible for successful reproduction and establishment of the B. africana trees in nature, as all efforts for commercial production has been proven unsuccessful. An investigation was carried out to determine the metabolomic profile, chemical composition, and microbial composition of the soils where B. africana grows (Burkea soil) versus the soil where it does not grow (non-Burkea soil). 1H-NMR metabolomic analysis showed different metabolites in the respective soils. Trehalose and betaine, as well as a choline-like and carnitine-like compound, were found to be in higher concentration in Burkea soils, whereas, acetate, lactate, and formate were concentrated in non-Burkea soils. Liquid Chromatography-Mass Spectrometry analysis revealed the presence of numerous amino acids such as aspartic acid and glutamine to be higher in Burkea soils. Since it was previously suggested that the soil microbial diversity is the major driver for establishment and survival of seedlings in nature, Deoxyribonucleic acid (DNA) was extracted and a BLAST analysis conducted for species identification. Penicillium species was found to be highly prevalent and discriminant between the two soils, associated with the Burkea soils. No differences in the bacterial composition of Burkea and non-Burkea soils were observed. The variances in fungal composition suggests that species supremacy play a role in development of B. africana trees and is responsible for creating a supporting environment for natural establishment and survival of seedlings.

Farmers Local Knowledge on Niche Selection, Management Strategies and Uses of &amp;lt;i&amp;gt;Cordia africana&amp;lt;/i&amp;gt; Tree in Agroforestry Practices of Sidama Zone, Southern Ethiopia

In Ethiopia Cordia africana is one of the indigenous multipurpose tree species which is being endangered and suffering a lot from overexploitation. Agroforestry is taken as potential ecosystem for counteracting indigenous multipurpose trees species extinction through providing complementary habitat for such species. In Sidama zone of south Ethiopia, farmers deliberately integrate and manage C. africana tree by using their own indigenous knowledge for both its productive and protective functions. However, comprehensive study has not been undertaken to assess and document the local knowledge associated with C. africana tree. Thus, study was designed to assess local knowledge of farmers on niche selection, management practices and uses of C. africana tree in agroforestry practices of Sidama zone. To do so household survey, key informants’ interview and focus group discussions were undertaken to generate the necessary data. A total of 126 sample respondents were randomly selected based on wealth category. In addition to this, about 72 sample households were considered for tree inventory purpose. The inventory was done in the niches of Coffee-Enset tree based, Coffee tree based and Enset-tree based homegarden agroforestry practice. Data were analyzed by using Statistical Package for Social Science (SPSS). Results obtained from the study show that, mean number of stems of tree is found to be significantly higher (p<0.05) in Enset- tree based niche of homegarden agroforestry followed by Coffee-tree based niche. The finding also shows that mean basal area of tree in Enset-tree based niche was significantly (p<0.05) higher of the remaining niches of agroforestry practices over both the midland and lowland agroecological zones. The commonly management practices employed for C. africana by the local farmers were branch pruning (80.6% and 73.2%), coppicing (32.2% and 42.8%) and pollarding (33.8% and 19.6%) in midland and lowland agroecology, respectively. Farmers also have profound knowledge on uses of C. africana tree. From the reported uses; timber production, soil improvement, household utensils, shade and cash generation are the major ones as these could be also vary over age, size and parts of the species to be used. Finally, the study has suggested that, for a conclusive recommendation the effect of C. africana tree on coffee-Enset yield and yield component needs to be further investigated.

Impact of &amp;lt;i&amp;gt;Parkland&amp;lt;/i&amp;gt; Trees (&amp;lt;i&amp;gt;Faidherbia albida&amp;lt;/i&amp;gt; Delile and Cordia Africana &amp;lt;i&amp;gt;Lam&amp;lt;/i&amp;gt;) on Selected Soil Properties and Sorghum Yield in Eastern Oromia, Ethiopia

The study was conducted to investigate the impact of Parkland trees in farmland on selected soil physicochemical properties and sorghum grain yields in Fedis District, Oromia, Ethiopia. For the experiment of soil physicochemical properties, three factors: distance from tree trunk with three levels (at 2.5m of crown, edge of crown radius and open field), soil depth with two levels (0-20cm and 20–40cm depth) and tree species with two levels with factorial arrangement in RCBD replicated six times were employed. For sorghum grain yield only two factors; distance from tree trunk with three levels (at at 2.5m of crown, edge of crown radius and open field) and tree species (F. albida and C. africana) with two levels in RCBD replicated six times were used. The result revealed soil texture was not influenced significantly (P>0.05) by tree species. Soil bulk density was significantly (p 0.05) influenced by both tree species. The grain yield of sorghum (sorghum bicolor) were significantly (P<0.05) higher under canopy of both trees species as compared to the open field. In general, the nutrients contents increased by 84.3% and 71.5% for OC, 84.2% and 70.8% for OM, 66% and 59% for SOC Stocks, 82% and 84% for TN, 96% and 79% for AP, 15.6% and 34.2% for CEC, 30% and 10% for EC, 82% and 27.2% for Na, 41% and 30.4% for K, 33.8% and 28.2% for Ca and 58% and 87% for Mg and 13.22% and 13.15% for MC and by 43% and 41% for Sorghum yield were detected under the canopies of F. albida and C. africana tree species respectively. It can be concluded that these tree species have the potential to improve soil fertility and moisture beneath its canopy. Thus, retaining these tree species and in particular F. albida on crop field in the study area is of paramount importance for soil fertility enhancement so as to improve food security of small farming households.

Savanna tree-grass interactions: A phenological investigation of green-up in relation to water availability over three seasons

Phenology of African savannas is considered to have high temporal variability, yet few studies have quantified this variation between seasons. This study assessed the weekly green-up phenology of trees, as well as below- and between-canopy grasses in a broad-leaved savanna woodland in the Nylsvley Nature Reserve (NNR), South Africa over three growing seasons (2012–2014). Tree green-up start dates were highly variable in comparison to the grasses, whose green-up showed close ties to the availability of water, particularly rainfall. Early green-up of Burkea africana trees occurred if rainfall onset was after mid-October, thus long-term rainfall records indicate that trees would benefit from early-greening approximately 46% of the time in the NNR. The effects of tree canopies on the growth and biomass accumulation of below-canopy grasses showed that during periods of irrigation when water was not limited, light availability became the limiting factor for grass growth, with grasses below the higher shading of B. africana producing significantly lower biomass than those below the less shaded Terminalia sericea canopies. Access to higher light conditions at the start of the growing season potentially drives the 2–5days faster green-up of below-canopy grasses compared to the between-canopy grasses. A comparison of the above phenological data to the remotely sensed normalized difference vegetation index (NDVI) was made, to determine if it was possible to detect an early-greening signal from the trees, which the sensor was able to effectively distinguish. This study highlights the variability in temporal separation between tree and grass phenology in an African savanna. Trees take advantage of periods of low competition from herbaceous neighbours at the end of the dry season prior to the onset of seasonal rainfall, and potentially at the end of the growing season when seasonal rainfall concludes through the uncoupling of their green-up cue from seasonal water availability.

Morphological Variability of &amp;lt;i&amp;gt;Prosopis africana&amp;lt;/i&amp;gt; (Guill., Perrott. Et Rich.) Taub in Benin, West Africa

The morphological variability of Prosopis africana in its natural range (which includes three climate zones: Guinean zone, Sudano-Guinean zone and Sudanese zone) of Benin was studied on the basis of forest inventory carried out in three different vegetation types (savannah, fallow and field). The data recorded in 139 plots of 1000 m2 each related to the diameter at breast height (1.3 m over the ground level), the bole height, the height to the first branch, crown height, the crown diameter, number of branches on each individual tree. In these plots, 143 sheets were used to determine the length of leaf, the pinna length, leaflets’ length, numbers of pinna, the number of leaflets, and the stalk diameter. In addition, 735 cloves were measured to determine the fruit pods’ diameter, pod length, the total fruit weight and number of seeds per fruit, the seed length, the weight of a seed, and pulp weight. Analysis of variance components shows that the variability of Prosopis is generally greater among individuals than within vegetation types and climatic zones. Discriminant analysis showed that of the 19 morphometric characters seven (7) in the vegetation types and twelve (12) in climate zones revealed a statistically significant discriminating pattern r (prob. <0.0001). From ascending cluster of 481 P. africana trees measured, 10 morphogroups were depicted on the basis of 19 morphometric characteristics (R2 = 52.6%).

Dispatches

Dispatches

Effects of forest modification on bird community composition and seed removal in a heterogeneous landscape in South Africa

Human disturbance threatens and modifies forest ecosystems worldwide. Previous studies have investigated the effects of human impact on local bird communities in disturbed forests, but we still lack information on how bird species richness and ecological processes respond to different forest modifications present at a landscape scale. In a heterogeneous South African landscape, we chose six types of indigenous scarp forest, differing in the intensity of human disturbance: continuous natural forests and natural forest fragments in nature reserves, forest fragments in eucalyptus plantations, fragments in the agricultural matrix, forest gardens and secondary forests in game reserves. In 36 study sites, we investigated the bird community using point counts and observed the seed removal of birds at the native tree species Celtis africana. Species richness did not differ among the forest types, but abundance varied significantly with most birds observed in fragments in the agricultural matrix, forest gardens, and secondary forests. The higher bird abundance in these forests was mainly due to forest generalists, shrubland and open country species whereas forest specialists were rarely present. Changes in species composition were also confirmed by multivariate analysis which clearly separated bird communities by forest type. Frugivore abundance in C. africana was highest in natural forest fragments, fragments in the agricultural matrix, forest gardens and secondary forests. The same trend was found for the estimated total number of fruits removed per C. africana tree, though the differences among forest types were not significant. Consequently, modified forests seem to maintain important ecological functions as they provide food sources for generalist species which may, due to their mobility, enhance natural plant regeneration. However, we could show that protected forest habitats are important refugees for specialist species sensitive to human disturbance.

Structure and properties of Treculia africana, (Decne) seed starch

Starch isolated from seed flours of four Treculia africana (African breadfruit) trees ranged from 36.0 to 41.7% (w/w, flour). Digital microscopy and image particle size analysis showed smooth, small to medium elliptical granules of sizes 3.56–13.60μm with over 80% of the granules in the size range of 5.50–9.49μm. T. africana starch displayed an A-type X-ray diffraction pattern with crystallinities in the range of 40.21–43.14%. The apparent amylose content ranged from 21.2 to 23.1% while the absolute amylose content was 13.7–21.7%. The gelatinization characteristics, swelling power and amylose leaching, paste clarity, freeze thaw stability and rheological properties were studied. The gelatinization onset temperatures ranged from 71.5 to 75.1°C, and the peak gelatinization temperatures and endothermic enthalpies were 74.5–78.8°C and 12.22–13.99J/g, respectively. Rheological examination of 5% starch paste over the range of shear rate 0.1–1000/s gave shear viscosities of 3.357–8.285Pas and rate indices of 0.44–0.53 and the mechanical spectra indicated that the gels were formed with G′>G′′ over the frequency range studied. T. africana starch exhibited low level of syneresis after six freeze thaw cycles (32–38%); however, it would require modification to enhance its application in processed foods.

Abstract A175: Isolation and identification of compounds from the fruits of Kigelia pinnata with anti-proliferative activity towards human cancer cells

Abstract Kigelia pinnata DC. (Bignoniaceae also referred to as K. Africana or sausage tree), is a tree which is found widely in Africa and the tropics in general. Traditionally hot aqueous extracts of fruit pods from Kigelia pinnata have been claimed to have widespread ethnomedicinal importance. A preliminary study of the components of the aqueous extracts from the fruits of Kigelia pinnata was undertaken to identify fractions with potential anti-cancer activity. A bioactivity guided fractionation process of extracts from fruits of the tree was carried out yielding a number of crude fractions, which demonstrated cytotoxicity in vitro against human melanoma cells. A number of compounds were isolated and identified within purified fractions of several fruit extracts including the dihydroisocoumarins, demethylkigelin and kigelin, a number of fatty acids, and a furonaphthoquinone, as compounds at least in part responsible for the anti-proliferative activity observed in extracted material from the fruits. We tested a number of structurally related dihydroisocoumarins for their anti-proliferative activity in order to conduct a preliminary structure-activity relationship (SAR) study. The preliminary medicinal chemistry programme clearly identified structures with enhanced anti-proliferative activity relative to the isolated compounds. In conclusion, using a bioassay fractionation approach, we have isolated and characterized several classes of compounds that exhibit biological activity against human cancer cell lines. Structurally-related derivatives of these compounds have been synthesized to develop knowledge of the structure-activity relationship for these classes of compounds. Our data to date suggest that this class of molecule has structural features that appear to be of importance in determining its activity against human cancer cells. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A175.

Characterisation of Afzelia africana Sm. habitat in the Lama forest reserve of Benin

A study was carried out in the Lama forest reserve of Benin to characterize the habitat of Afzelia africana Sm., an endangered multipurpose tree species (found in African humid, dry forests and woodlands), in order to define a sustainable management strategy for its conservation. An estimation of species density was done on 100 square plots of 1 ha each, while tree height and dbh of all the species were measured on subplots of 50 m × 30 m within the 1 ha plots. The regenerations of A. africana (dbh < 10 cm) were counted in the diagonal quadrats of the principal plots. Presence–absence data of the species was subjected to multidimensional scaling and results showed four vegetation communities including: young fallow, old fallow, typical dense forest and degraded dense forest. Significant differences were noted between the four communities with respect to dendrometric parameters of the species. High values of these parameters were noted for the species in typical dense forest (5.2 stems/ha, 66.7 cm, 17.9 m, 7.9 m 2/ha and 38.8% for the tree-density, the mean diameter, the mean height, basal area and basal area contribution of the species, respectively) whereas the lowest values were obtained for the old preforest fallow as far as the mean diameter (59.7 cm), the mean height (15.7 m) and the basal area contribution (27.7%) of the species were concerned. In general, the basal area of A. africana in the over vegetation types was less than 3 m 2/ha. No A. africana tree was found in the young preforest fallow while more than 80% of A. africana trees were found in the typical dense forest community. Stem diameter and height structures of the species in all the four communities showed a left dissymmetric Gaussian shape and were well adjusted to Weibull distribution.

Development and evaluation of a threshing machine for &lt;I&gt;Prosopis africana seed&lt;/i&gt;

A decorticating machine for Prosopis Africana was developed, tested and evaluated. Prosopis Africana is popular in the Sub-Saharan Africa, with all the parts of the tree useful for medicinal purposes. This study focuses on the threshing of the pod to obtain the seed, which is the most widely used of the parts of the Prosopis Africana tree. Results from preliminary investigations carried out of on some physical and engineering properties of the pod and seed were used in the design of a threshing machine. The machine was tested with pods at a moisture content of 8% w.b. using speeds of 300, 350, 400 and 450rpm at four feed rates of 1, 2, 3 and 4kg/min. The threshing efficiency (TE), cleaning efficiency (CE) and seed loss (SL) increased as the drum speed increased. There was however no significant difference in the variations of the values of TE, CE and SL at different feed rates but the TE and CE decreased with increase in feed rate. The maximum threshing and cleaning efficiencies were obtained at a speed of 450 rpm as 95.8% and 96.0% respectively at a feed rate of 1 and 4 Kg/min. The highest seed loss (19.1%) was obtained at a drum speed of 450rpm and feed rate of 4Kg/min. The high threshing and cleaning efficiencies obtained in the threshing of Prosopis Africana and minimal loss have shown that there is a prospect in the mechanization of the processing and handling operation hence commercialization and promotion of mechanized threshing at a large scale. Keywords : threshing, Prosopis Africana , development, evaluation, seed Journal of Applied Science, Engineering and Technology Vol. 5(1&2) 2005: 56-62