Department of Ecosystems and Conservation

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Variation, association and Inheritance of morphological and wood characters in an improvement programme for eucalyptus dsglupta blume
(Australian National University, 1972-03) Davidson, John
DAVIDSON, J. (1972) Variation, association and Inheritance of morphological and wood characters In an Improvement programme for Eucalyptus dsglupta Blume. Ph.D. Thesis, Australian National University, Canberra, Australia. Up to 93 percent of variation In the wood of 20-year-old Eucalyptus dsglupta Bl. has been explained by four components of a principal components analysis. Fibre cross-sectional characters were the main parameters contributing to this variation. Dens Ity satisfactorily represented the main and one subsidiary component which, together, represented 70 per cent of the total variation. Density was easy to measure and had a phenotypic variation of about 20 per cent of the mean value.. It had a broad sense herltabillty of 0.68 ± 0.17 and a narrow sense herltablllty of 0.44 ± 0.23 In seedling material. Density could be modified Irrespective of growth rate and stem form In trees 14-20 years old. Hence wood density Is a very suitable factor for Including In a tree Improvement programme.
Plant species in the Kilimanjaro agroforestry system
(Martinus Nijhoff/Dr W. Junk, 1984) O'kting'ati, A; Maghembe, J. A; Fernandes, E. C. M; Weaver, G. H
An inventory of plant species was conducted on farms, farm boundaries and homesteads in the Kilimanjaro agroforestry system. The survey covered 30 farms in 6 villages in Hal District on the slopes of Mount Kilimanjaro, Tanzania. Over 100 plant species spread over 40 families were identified and their uses obtained through inter- views with farmers. The species identified include 53 tree species, 29 food crop species, 21 non-woody plants of economic value and 8 weed species. The food crops, trees and other economically useful plants are carefully chosen by the local farmers and intimately intercropped on the same unit of land. In most cases, the plants had two or more uses of which food, fuelwood, medicine, poles, timber and fodder were the most important.
Growth and ectomycorrhizal development of pinus caribaea seedlings inoculated with basidiospores of scleroderma dictyosporum in fertilized nursery soil in Tanzania
(Elsevier, 1984-01) Maghembe, J. A; Redhead, J. F
Seeds of Pinus caribaea were sown in plastic pots containing nursery soil with or without a basidiospore inoculum of Scleroderma dictyosporum. After seedling establishment, five fertilizer treatments involving 0, 250, 500, 750 and 1000 g NPK per m3 of nursery soil were administered. The ratio of N:P:K in NPK was 3:3:1.Basidiospores of S. dictyosporum were an effective inoculum for P. caribaea seedlings. Inoculated seedlings showed superior growth in height, root collar area, length of stem with needles and dry matter production. Inoculation also increased the concentration of P in the plant tissues but had no effect on other nutrients studied.Fertilizer response was evident, but there were generally no benefits of using fertilizer levels above 250 g NPK per m3 soil. In fact, mycorrhizal development was progressively reduced with each increase in the level of NPK fertilizer. Tissue Mg concentrations were also deficient, a reflection of nutrient uptake imbalance due to high concentrations of ammonium sulphate and potassium chloride in the soil. Basidiospores of S. dictyosporum can therefore be used for routine inoculation of P. caribaea seedlings in nursery soils at low levels of NPK. Coincidentally such a reduction in the amount of NPK applied in nursery soil will have both biological as well as economic benefits
Effect of hot water and chemical treatments on the germination of Albizia schimperana seed
(Elsevier Science Publishers B.V, 1986-03) Msanga, H. P; Maghembe, J. A
The effect of water temperature at soaking and various chemical applications following soaking on the germination of Albizia schimperana seed was studied. The aim was to increase the overall germination percentage and to hasten the rate at which germination occurs. The water soaking treatments included: (1) no soaking; (2) soaking at 50°C; (3) soaking at 75°C; and (4) soaking at 99°C. The chemical treatments included; (1) no chemical applied; (2) immersion in KNO3; (3) immersion in H2O2; and (4) combined in a factorial arrangement replicated 4 times. Germination percentages were generally low, ranging from 10.0 to 33.5% at 36 days after sowing. The highest germination percentage (33.5%) was attained by seeds which were soaked in water at 75°C followed by immersion in hydrogen peroxide. Seeds which were soaked in water at this temperature but not treated with chemicals showed a germination of 32.0%. It is preliminary recommended that seeds of A. schimperana be immersed in water at the initial temperature of 75°C and allowed to soak until the water cools to room temperature.
Intercropping, weeding and spacing effects on growth and nutrient content in Leucaena leucocephala at Morogoro, Tanzania
(Elsevier, 1986-03) Maghembe, J. A; Kaoneka, A. R. S; Lulandala, L. L. L
The study was conducted to evaluate the suitability of Leucaena leucocephala for fuelwood and pole production using agroforestry in a semiarid environment. The trial site, planted in February 1980 at Mafiga, Morogoro, was a split plot design with four main plots: (1) Leucaena intercropped with maize; (2) Leucaena intercropped with beans; (3) Leucaena monoculture and clean weeded; and (4) Leucaena monoculture and spot weeded. Each main plot included three tree-spacing sub- plots, 3 X 3 m, 4 X 4 m and 5 × 5 m, and replicated four times. Each of the subplots comprised at least 25 trees. Twenty-four trees representing all the diameter classes in the trial were harvested in March 1984 and used to determine mean plot height, volume and biomass by regression analysis. Nutrient content was determined using routine laboratory methods. Mean subplot height varied from 7.0 to 7.8 m, whereas diameter at the stem base varied from 10.2 to 14.9 cm. The volume varied from 10.3 to 32.8 m 3 ha -~ and total biomass values from 13.5 to 31.1 metric t ha -1. Trees under spot weeding showed the poorest growth, whereas those under clean weeding showed the best. Spacing influenced both diameter and height growth, with the widest spacing producing the largest trees. Because of a higher tree population, however, the lowest spacing showed the highest volume and biomass production. Intercropping with maize and beans showed significantly higher volume and biomass production as compared to spot weeding. However, there was no significant difference between trees under clean weeded treatments and those under intercropping. Nutrient concentra- tions were high and comparable to other pasture legumes. The total nutrient accumulation in the aerial biomass in kg ha- 1 was 201, 25.1,267, 106, 34 and 18 for nitrogen, phosphorus, potassium, calcium, magnesium and sodium, respectively.
Growth and yield of maize alley cropped with Leucaena leucocephala and Faidherbia albida in Morogoro, Tanzania
(Kluwer Academic Publishers, 1998) CHAMSHAMA, S. A. O.; MUGASHA, A. G.; KLØVSTAD, A.; HAVERAAEN, O.; MALIONDO, S. M. S.
This study examined the effect of alley cropping of Leucaena leucocephala and Faidherbia albida on wood biomass, maize grain yield and soil nitrogen status. The treatments were: trees planted alone at 1 × 5 m spacing; trees intercropped with maize and a sole maize crop. Mulch biomass averaged 6.18 and 0.97 t ha−1 for L. leucocephala and F. albida, respectively. Corresponding wood production was 1.71 and 1.11 t ha−1. Both total N and inorganic N (NO − 3 –N plus + 4 –N) were higher under F. albida and lowest under L. leucocephala. Similarly, foliar N concentration in maize was higher in plots intercropped with F. albida and least in L. leucocephala intercropping. Maize grain yield was little affected by the tree intercrop as competition for resources was reduced through periodic pruning and clean weeding. There was no gain in maize grain yield due to the presence of L. leucocephala and F. albida. These results suggest that alley cropping in Gario is justified for wood production but not for increasing maize grain yield.
Seed dynamics and the ecological restoration of hill slopes of Kondoa Irangi, central Tanzania
(Sokoine University of Agriculture, 1998) Lyaruu Herbert Valentine
Improper agricultural practices such as hill slope cultivation, extensive clearing of vegetation using fire over a long period, and to some extent overgrazing have converted the once fertile hill slopes of Kondoa Irangi in central Tanzania into unproductive marginal land. It is 25 years now since reclamation measures were introduced to save the hills from further degradation, but the regeneration process has been rather slow. The present study was initiated with the objective to explore alternative approaches to facilitate vegetation recovery in the hills. It consisted of a description of an Afromontane dry' forest, soil seed hank, seed rain and seed longevity studies, and experiments on the influence of different soil treatments on regeneration. There was significant seasonal variation in the seed bank (p < 0.001), with dry-season samples having higher densities than wet-season samples. Annual species dominated the seed bank samples in most of Kondoa Irangi Hills, but perennial species were dominant in the soil seed bank of the Afromontane dry forest. In the seed rain, both density and species richness were negatively correlated with vegetation cover. This points to the important role of anemochory and active seed rain in disturbed sites. The interminent and extended germination of buried seeds shown by, i.e.. Acacia tortilis, is an adaptation to prevent synchronous germination, in unpredictable, harsh environments, whereas prompt germination after rains of c.g., Acacia scyal, is a strategy to avoid seed predation. Inorganic fertilisation is not an efficient means of improving short-term productivity in poor savanna soils. Nutrient-deficiency should be corrected by moderate grazing and controlled fires. Permanent and speedy vegetation recovery of degraded savannas such as in the Kondoa Irangi Hills, may require (1) enhanced nitrogen mineralization and seed dispersal by grazing livestock, (2) selective soil seed bank enrichment, and (3) transplanting seedlings with desired traits.
Germination studies on seeds of trichilia emetica and vangueria infausta
(Sokoine University of Agriculture, 1998) Msanga, Heriel Petro
The effect of various physical seed coat scarifications and chemical treatments were studied to determine presowing prescriptions that would ensure uniform, fast and high germination in seeds of Trichi Iia emetica and Vangueria infausta. The studies involved eight 3x5 factorial model experiments arranged in a randomized block design with with 4 blocks each. For each of the two species, two different experiments were conducted in the laboratory and repeated in the nursery. The first experiment of Tri chi Iia erne t i ca involved 3 types of physical seed coat scarification and soaking the seeds in gibberellic acid (CA3) at 5 concentrations; i.e. 0, 250, 500, 750, and 1000 ppm. A second experiment involved 3 types of physical seed coat scarification and soaking the seeds in potassiun nitrate (KNO^) at 5 concentrations; i .e. 0.0, 0.2, 0.4,0.6 and 0.8%. The first study involving Vangueria infausta included 3 types of physical seed coat scarification and treatments of the seed with 5 concentration levels of hydrogen peroxide (H202); i .e. 0, 2, 4, 6 and 8%. In the second experiment, 3 types of physical seed coat scarifi- cation and soaking the seeds in 5 concentration levels of indole acetic acid (IAA); i.e. 0, 25, 50, 75 and 100 ppm were studied. Unscarified seeds of Trichi Iia emetica (without chemical treatment) atta ined cumulative germination of 29% and 35%, while seeds with complete removal of both the aril and the seed coat attained cunulative germination of 94s and 93« in the laboratory and nursery experiments respectively.
Perfonnance ,of Provenances of Sesbania macrontha at Gairo, Morogoro,Tanzania
(1999) Mgangamundo, M.A.; Mugasha, A.G.; Chamshama, S.A.O.
Performance evaluation was 'conducted among 21 provenances of Sesbania macrantha from 9 regions of Tanzania and one region of Rwanda. The trial was established in February, 1996 at Gairo, Morogoro, Tanzania. Assessments were carried out at 6, 12 and 15 months for survival, root-collar diameter and height. Biomass production was ass(!ssed during the last assessment occasion. Significant variation among the provenances for survival, root-collar diameter, height and biomass production was observed. The Andago (Arusha) provenance achieved greatest survival (83.3%) followed by the Biharamulo (Kage ra) and Kisabya (Kigoma) provenances (80.0%), while Miabeze (Mbeya) provenance had least survival 0/20.0%. No significant differences were observed in mean root-collar diameter and height from the (jh to 15th monih after planting. Biharamulo(Kagera) provenance was found to be outstanding in respect ofJotal biomass production (12.2 t ha .1), followed by Chala (Rukwa) provenance (10.3 t ha .1). Kangamo (Mbeya) provenance had the least total biomass production of 2. 3 t ha .1. Overall, the Andago, Biharamulo, Chala, Kikomakoma, Kisabya and Banda provenances were the best perfonners while the Lundamoto, Miabeze, Kibondo, Kishoju, Kidiama, Wondo and Kangamo failed to put on promising growth. It is recommended that Sesbania macrantha provenances from Andago, Biharamulo and Chala be used in improvedfallow/relay cropping systems in Gairo and other areas with similar environmental conditions in that order of priority.
Evaluation of the efficacy of the crude extracts of Capsicum frutescens, Citrus limon and Opuntia vulgaris against Newcastle disease in domestic fowl in Tanzania
(Elsevier Science Ireland Ltd, 1999-02) Mtambo, M.M.A; Mushi, E. J; Kinabo, L.D.B; Maeda-Machang’u, A; Mwamengele, G.L.M; Yongolo, M.G.S.; Temu, R. P. C
Prophylactic and therapeutic efficacy of a combination of Capsicum frutescens (red pepper), Citrus limon (lemon) and Opuntia 6ulgaris (prickly pear) against Newcastle disease (ND) in domestic fowl were evaluated. Eighty-eight broiler chickens were divided into five groups. Birds from three groups were inoculated with velogenic ND virus strain, whereas birds from two groups were left as controls. Two groups received a mixture of the plant extract three days prior to inoculation and birds from one group were given the plant extract for two days following development of clinical signs. Blood samples were collected for haemaglutination inhibition tests (HI) for detection of ND virus antibodies. Body weights were monitored during the experiment. Three birds died from the group that was inoculated with ND virus and treated with the plant extract; two died from the group that received the plant extract as a prophylaxis and inoculated with ND virus; and one bird died from the group that was inoculated with ND virus but not given the plant extract. No death was observed in any of the birds in the control groups. Antibody titers for ND virus rose four-fold in the inoculated birds but remained low in the un-inoculated groups. Mean body weights of birds in group B declined markedly compared to the other groups. The results indicated that there was no prophylactic or therapeutic value of the plant extract against ND. The plant extract showed a negative effect on body weights in birds with ND. © 1999 Elsevier Science Ireland Ltd. All rights reserved.
The potential of classical biological control against leucaena psylid, heteropsylla cubana crawford in eastern Tanzania
(2000) Madoffe, S. S.; Mhando, L.; Day, R. K.; Nshubemuki, L.
The Leucaena psyllid HeteropsyHa cubana Crawford (Homoptera: Psyl/idae) has ~aused damaging ef fects to Leucaena leucocephala (Lam.) de Wit in Tanzania since its outbreak in 1992. Cultural, genetic and chemical controls havebel!n tried in some localised areas. In 1995, a hymenopterous parasitoids, Tamarixia leucaenae Boucek (Eupelmidae) was imported from Trinidad and Tobago for biological control of this pest in Tanga and Morogoro areas. Mummies of the parasitoid were recordedfrom the sixth week after release. The population declined to the lowest level between November 1995 and January 1996 before building-up again to about 10 and 11 mummies per shoot in July for Tanga and Morogogro respectively. Spread of the parasitoidwas fairly fast, and at about 16 months afterrelease it had covered over 300 Ian from the release sites. The spread and population build up indicates that this species has been established in Eastern Tanzania. In spite of declining shoot damage at about ten months after parasitoid release, it is probably too early to associate it with the parasitoid. Shoot damage was found to be more closely correlated to laboratory nymph count (r = 0.52) than to field nymph shoot numbers (r =\0.35). Several potential indigenous natural enemies were recorded in association with the psy/lid; however, their role as biological control agents needs further quantification.
Tree root development and interactions in drylands: focusing on melia volkensii with socio economic evaluations
(University of Dundee, 2000) Mulatya, Jackson M
Tree-crop competition is an important concern in agroforestry systems, and has been the subject of much attention by researchers in recent years. Farmers on the other hand, often seem to either ignore or accept competition and do little to manage it. In this thesis, I make the first attempt to reconcile farmers’ practices and beliefs with experimental data, focusing on the economically important tree: Melia volkensii in drylands of Kenya. This tree is of particular interest because farmers’ perceptions of its competivity appear at odds with researchers perceptions: farmers believe it does not compete with crops while researchers have found it competes. After conducting a survey on farmers’ fields in which it was confirmed Melia volkensii does not compete with crops, an experimental programme was conducted to investigate the causes of this discrepancy in perceptions. The study covered; Kilui, Embu, Kibwezi and Machakos sites. Melia volkensii provenances from these sites and Melia plant types used in tree establishment (seedlings and cuttings) were evaluated to examine whether the reported yield differences were as result of differences in root architecture between provenances or between plant types used by farmers. The rainfall confounded the problem of tree-crop interactions; because extreme rainfall conditions were experienced during the study period. Excessive soil moisture occurred in the first season while rainfall failed in the second season. Competition was therefore evaluated when competition was occurring. Results highlights are as follows; competition index (CI) method was unable to predict tree competitiveness with crops in conditions where trees are planted closely. The CI values were highly variable within individuals of a particular Melia provenance or species and therefore found inconsistent and unreliable to predict tree competition with crops. Surprisingly, it was able to predict tree-crop competition where trees occurred in isolation. There were neither differences in root architecture between the Melia volkensii provenances nor were there difference in soil water or crop yields between provenances’ plots. However, when root architecture of seedlings and cuttings were compared, cuttings tended to develop shallow roots than seedling plants and that roots which descended into the soil at deeper angles developed some secondary root branches which grew to the surface, thus making them competitive with crops. Overall, the results support the view that Melia volkensii is competitive with crops in normal seasons. Isolated Melia trees on farmers’ fields reduced crop yields beyond 15 m radius from trees. However, the value of the timber outweighs the value of the lost crop and farmers may chose to have Melia trees on the cropland whose value will compensate the lost yields and still benefit from other tree products e.g. fuelwood and fodder, or plant trees in separate plots e.g. fallow lands and maximize productivity of both components. Melia timber fetched >45% more cash than timber products of other species such as cypress and pines. Results suggest that when promoting the planting of Melia, seedlings should be used instead of cuttings as they have a less competitive root architecture, as seed germination is a problem this should be a priority research area for Kenya seed specialists.
Improvement of soil fertility by improved fallows of Cajanus cajan, Sesbania sesban and Tephrosia vogelii at Gairo in Morogoro, Tanzania
(2001) Mgangamundo, M.A.; Mugasha, A.G.; Chamsham, S.A.O.
This study was carried out at Gairo in Morogoro Tanzania to evaluate the effects, of fallow periods and fallow types on soil fertility improvement. A split-plot experimental design with three replications was adopted. Three fallow periods (i.e. 1, 2 and 3 years) were involved in this study. Soil pH, EC, OC, total N available P and total P were significantly (P < 0.05) affected by fallow periods and fallow types. Greater improvement in soil fertility was achieved by the improved fallows of S. sesban, T. vogelii and C cajan than the natural fallow. Soil fertility was found to increase with increasing fallow period from 1 to 3 years. Continuous cropping for 3 years resulted in greater decline in soil fertility. It is therefore concluded that improved fallows of S.sesban, T. vogelii, and C. cajan have the potential of improving soil fortility and so reduce the problems associated with a decline in soil fertility Based on the findings of this study, it is recommended that the species be tested on farm and further investigations be carried to examine nutrient dynamics and sustainability of maize crop yield after fallow .
Dry-season sesbania fallows and their influence on nitrogen availability and maize yields in Malawi
(Kluwer Academic Publishers., 2001) Ikerra, S. T; Maghembe, J. A; Smithson, P. C; Buresh, R. J
Nitrogen deficiency is widespread in southern Africa, but inorganic fertilizers are often unaffordable for smallholder farmers. Short-duration leguminous fallows are one possible means of soil fertility restora- tion. We monitored preseason topsoil (0 to 20 cm) ammonium and nitrate, fallow biomass production and grain yields for three years in a relay cropping trial with sesbania [Sesbania sesban (L.) Merr.] and maize (Zea mays L.). Sesbania seedlings were interplanted with maize during maize sowing at 0, 7400 or 14,800 trees ha –1 , in factorial combination with inorganic N fertilizer at 0 or 48 kg N ha –1 (half the recommended rate). After maize harvest, fallows were allowed to grow during the seven-month dry season, and were cleared before sowing the next maize crop. Both sesbania fallows and inorganic N fertilizer resulted in significantly greater (P < 0.01 to 0.05) preseason topsoil nitrate-N than following unfertilized sole maize. In plots receiving no fertilizer N, preseason topsoil inorganic N correlated with maize yield over all three seasons (r 2 = 0.62, P < 0.001). Sesbania fallows gave significantly higher maize yields than unfertilized sole maize in two of three years (P < 0.01 to 0.05). Sesbania biomass yields were extremely variable, were not significantly related to sesbania planting density, and were inconsistently related to soil N fractions and maize yields. Short-duration fallows may offer modest yield increases under conditions where longer duration fallows are not possible. This gain must be considered against the loss of pigeonpea (Cajanus cajan L. Millsp) harvest in the similarly structured maize-pigeonpea intercrop common in the region.
Assessment of the impacts of community participation on the conservation of mangrove resources: A case study of Lindi district, Tanzania.
(Sokoine University of Agriculture, 2001) Machumu,Milali Ernest
The word mangrove refers either to the plants of tropical intertidal forest communities or to the community itself (Semesi, 1991). Mangroves are trees and bushes growing below the high - water level of spring tides (FAO, 1982). "Mangrove" is a general term applied to an association of physiologically specialised plants inhabiting muddy swamps, creeks, deltas and sheltered sea coasts periodically inundated by tides (Banyikwa and Semesi, 1986). The trees are only one component of the complex mangrove ecosystem, which includes associated bodies of water, substrates as well as a variety of other plants, animals and micro-organisms (Semesi, 1986).
Tree and crop productivity in gliricidia/maize/pigeonpea cropping systems in southern Malawi
(Kluwer Academic Publishers, 2003) Chirwa, P.W; Black, C.R; Ong, C.K; Maghembe, J.A
This study examined the hypothesis that incorporation of Gliricidia sepium (Jacq.) Walp.) (gliricidia), a fast- growing, nitrogen-fixing tree, into agroforestry systems in southern Malawi may be used to increase the input of organic fertilizer and reduce the need for expensive inorganic fertilizers. The productivity of maize (Zea mays L.), pigeonpea (Cajanus cajan L.) and gliricidia grown as sole stands or in mixed cropping systems was examined at Makoka Research Station (latitude 15 ◦ 30 ′ S, longitude 35 ◦ 15 ′ E) and a nearby farm site at Nazombe between 1996 and 2000. Treatments included gliricidia intercropped with maize, with or without pigeonpea, and sole stands of gliricidia, maize and pigeonpea. Trees in the agroforestry systems were pruned before and during the cropping season to provide green leaf manure. Maize yields and biomass production by each component were determined and fractional light interception was measured during the reproductive stage of maize. Substantial quantities of green leaf manure (2.4 to 9.0 Mg ha −1 year −1 ) were produced from the second or third year after tree establishment. Green leaf manure and fuelwood production were greatest when gliricidia was grown as unpruned sole woodlots (c. 8.0 and 22 Mg ha −1 year −1 respectively). Improvements in maize yield in the tree-based systems also became significant in the third year, when c. 3.0 Mg ha −1 of grain was obtained. Tree-based cropping systems were most productive and exhibited greater fractional light interception (c. 0.6 to 0.7) than cropping systems without trees (0.1 to 0.4). No beneficial influence of pigeonpea on maize performance was apparent either in the presence or absence of gliricidia at either site in most seasons. However, as unpruned gliricidia provided the greatest interception of incident solar radiation (>0.9), coppicing may be required to reduce shading when gliricidia is grown together with maize. As pigeonpea production was unaffected by the presence of gliricidia, agroforestry systems containing gliricidia might be used to replace traditional maize + pigeonpea systems in southern Malawi.
The Selous-Niassa Wildlife Corridor
(Tanzania Wildlife, 2003) Mpanduji, D. G.; Hahn, R.; Siege, L.
This paper describes how a number of governmental and nongovernmental actors under the leadership of the Tanzanian Wildlife Division have worked towards the creation of „Wildlife Management Areas“ on village land in Southern Tanzania, which would serve as a string of protected areas to form a corridor connecting two elephant ranges of high importance, the Selous Game Reserve and ecosystem and the Niassa Game Reserve in Mozambique.
Rainfall interception and partitioning in afromontane rain forests of the Eastern arc mountains, Tanzania: implications for water conservation.
(Forest Research Institute Malaysia, 2003-05) Munishi, P. K. T.; Shear, T. H.
The aboveground components of the hydrologie cycle of rain forest are important processes that determine the hydrologie behaviour and dynamics of these ecosystems. Precipitation, throughfall, stem flow, canopy interception and streamflow were measured and modelled in two afromontane rain forests of the Eastern Arc Mountains of Tanzania. Measurements were made daily for 50 months in the Ulugurus and 56 months in the Usambaras. Throughfall was 76% of the gross rainfall in the Usambaras and 79% in the Ulugurus. Stemflow was less than 2% of rainfall. Both parameters were correlated with gross rainfall (r2 = 0.97, 0.99, 0.86 and 0.94). Canopy interception was 22% of rainfall for the Usambaras and 20% for the Ulugurus. Streamflow was best modelled using five months running mean rainfall in the Ulugurus (r = 0.67) and three to four months in the Usambaras (r = 0.72). A high proportion of the gross rainfall is delivered as net precipitation. There is effective partitioning of rainfall on the forest canopy providing reasonable dumping effect of rainstorms. The slow response in streamflow to rainfall events shows the efficiency of the forests to mitigate storm water impacts and thus ensuring continuous water supply. Further studies in effects of forest harvesting on water yield are pertinent to enable adequate planning of forest utilization.
Preliminary investigation on accessibility and ultilisation of water in selected villages in Dodoma rural and Bagamoyo districts, Tanzania
(2003-10) Kusiluka, L. J. M; Mlozi, M. R. S; Munishi, P. K. T; Luoga, E. J; Mdegela, R. H; Kambarage, D. M; Karimuribo, E. D
Gum Arabic studies in Tanzania : production, utilization and economic potentials
(University of Wales, Bangor, 2003-11) Makonda, Fortunatus B. S
Studies on gum arabic in Tanzania were conducted in eleven districts aiming at estimating the country’s potential and current production, assessing its utilization and contribution to the local and national economies and its marketing channels. For the gum yield studies, 1,106 trees represented in four diameter classes were sampled and tapped by de-barking a portion of the stem at breast height. The tree parameters assessed were dbh, height and number of branches. Gum from the trees was collected four times at an interval of three weeks, and weighed using a sensitive electronic weight scale. A total number of 518 circular 0.1 ha plots each were selected using a systematic random sampling method for the inventory of Acacia Senegal and other associated woody species. The plot characteristics assessed were elevation, climate, soils, terrain type and disturbance by bush fires whose intensity levels were recognised as 1, 2 and 3. For the studies on actual gum arabic production, economic potentials and marketing data were collected using social survey methods from 630 gum collectors as well as 630 non collectors living in gum producing areas, in 64 villages, eight gum middlemen and three final gum buyers and exporters. The quality of gum was assessed using 90 samples from each district. Secondary data were collected from district and regional forest and natural resources offices in which gum arabic is collected and several other public offices. Data analyses were carried out using the Microsoft Excel package of Microsoft Office 98 and 2000 and SPSS employing descriptive statistics, one-way statistical analysis of variance and regression analyses. Results indicated that the overall mean gum arabic yield per tree is 246±333 g, greatly influenced positively by tree size particularly diameter, up to an optimum size, temperature, fire intensity and stem crowdedness. The overall mean population density of Acacia Senegal was estimated as 225 stems ha'1, marginally influenced negatively by altitude and positively by temperature. The actual mean annual gum arabic production was 4,030 ± 15 metric tonnes composed mainly of gum from A. drepanolobium (65 %), therefore not qualifying for the name gum arabic rather than gum talha. There is a serious lack of a clear definition of gum arabic from the exporters to the collectors, leading to its haphazard collection and trading without processing and grading. All gum is collected from trees in natural stands and not by tapping, by mainly women (44 %), children (30.5 %) and male livestock herders (25.5 %). The gum is important to the subsistence economy of many rural people, using it for food, medicine and glue. The gum is also economically important to the collectors, the middlemen, the final buyers and exporters and local and central governments. The business is however, purely a private enterprise, highly disorganised and controlled by the final buyers and exporters in which the bulk of the gum (75 %) is traded unrecorded. The gum collectors are therefore, the most disadvantaged group receiving the minimum payment in the whole chain. Managing Acacia Senegal plantations for gum is economically viable with LEV of TShs 814,529, NPV of TShs 469,089 and IRR of 63 % at rotation age of 9 years and interest rate of 10 %. Among the recommendations given by these studies include tapping Acacia Senegal trees, gum processing and grading, improvement of the existing A. Senegal resources and closer monitoring of the trade by the local and central governments.

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