Department of Forest Technology and Wood Sciences

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Browsing Department of Forest Technology and Wood Sciences by Subject "Biodiversity"

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    The Eastern arc mountain forests of Tanzania: Their role in biodiversity, wateresource conservation, and net contribution to atmospheric carbon.
    (North Carolina State University, 2001) Pantaleo, Munishi K. T.
    Mountain forests play major ecological and environmental roles. This study evaluated the roles of the Eastern Arc Mountain forests of Tanzania in conservation of biodiversity, water resources, and net contribution to atmospheric carbon. The major objectives were three-fold: (1) the classification and description of plant community composition, diversity patterns, and their environmental correlates, (2) assessment of biomass and carbon pool in the phytomass and soils, (3) assessment of rainfall interception throughfall, stemflow, streamflow, and their correlation with rainfall. Data on vegetation, topography, soils, and hydrology were collected from the Usambara and Uluguru ranges. Using cluster analyses, Non-metric Multidimensional Scaling (NMS) ordination, and indicator species analyses, five different plant communities were identified on each range. These communities were associated with two topographic and fourteen edaphic factors. Elevation was the strongest correlate of community composition in individual ranges, followed by several edaphic factors. Landform index and soil sodium concentration [Na] play major roles in separating plant communities between different mountain ranges. The proportions of rare species were high raising a conservation concern as to whether this is evidence of species’ declines or a biological characteristic. The forests have tremendous capacity for C storage both in the phytomass (517 ± 17 t ha’1 in the Usambaras and 384 ± 10 t ha’1 in the Ulugurus), and in the soil (420 ± 100 t ha’1 in the Usambaras and 290 ± 53 t ha’1 in the Ulugurus). Phytomass C was higher in mid elevation communities while high elevation communities had higher soil carbon, and total carbon. Rainfall interception was 23% in the Usambaras and 20% in the Ulugurus. Throughfall was more than 76% in both forests and stemflow was less than 2%. Streamflow was best modeled using three or more months running mean rainfall. The results suggest that plant community patterns in the Eastern Arc are associated with a complex of topographic and edaphic factors. This complex of factors is an important consideration in restoration and conservation programs. Attention to rare species is especially important. The forests havesubstantial capacity for carbon emission mitigation. The slow response in streamflow to rainfall events shows the efficiency of the forests to store water, mitigate storm water impacts by reducing runoff, delaying onset of peak flows, and ensuring constant water supplies.
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    Modelling and predicting measures of tree species diversity using airborne laser scanning data in miombo woodlands of Tanzania
    (Tanzania Journal of Forestry and Nature Conservation, 2021) Mauya, Ernest William
    In the recent decade, remote sensing techniques had emerged as one among the best options for quantification of measures of tree species diversity. In this study, potential of using remotely sensed data derived from airborne laser scanning (ALS) for predicting tree species richness and Shannon diversity index was evaluated. Two modelling approaches were tested: linear mixed effects modelling (LMM), by which each of the measures was modelled separately, and the k-nearest neighbour technique (k-NN), by which both measures were jointly modelled (multivariate approach). For both methods, the effect of vegetation type on the prediction accuracies of tree species richness and Shannon diversity index was tested. Separate predictions for richness and Shannon diversity index using LMM resulted in relative root mean square errors (RMSEcv) of 40.7%, and 39.1%, while for the k-NN they were 41.4% and 39.1%, respectively. Inclusion of dummy variables representing vegetation types to the LMM improved the prediction accuracies of tree species richness (RMSEcv = 40.2%) and Shannon diversity index (RMSEcv = 38.0%). The study concluded that ALS data has a potential for modelling and predicting measures of tree species diversity in the miombo woodlands of Tanzania.
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    Tropical rainforest deforestation, biodiversity benefits and sustainable landuse: analysis of economic and ecological aspects related to the Nguru mountains, Tanzania.
    (Agricultural University of Norway, 1995) Monela, Gerald C.
    The purpose of this report is to identify the main landuse and landuse problems with reference to agriculture and forestry in the Nguru mountains, and the main factors causing these problems, and analyze ways to reduce them in order to prevent forest degradation and deforestation. Based on data collected in villages in the Nguru mountains using interviews, field observations, and secondary sources it seems that ecological and socio-economic factors have played an important role in shaping the existing landuse practices, landuse problems and factors causing landuse problems in the Nguru mountains. The major landuses are agriculture and forestry. The agriculture is dependent on rainfall, growing mainly subsistence food crops using traditional farming practices. Forestry is for water conservation but also supplies local communities with both timber and nontimber forest products. Relative to other landuses such as settlements and grazing, agriculture and forestry have contributed most to the prevailing landuse conflicts in the Nguru mountains. The main landuse problems in the Nguru mountains are: deforestation pressure through encroachment for agriculture and settlements, forest degradation through excessive forest product exploitation, frequent and uncontrolled bush fires, land degradation and soil erosion, declining crop harvests, squatters inside the Forest Reserve, farming in the buffer zone around the rainforest and non-adherence to forest control measures. The impact of these landuse problems on the rainforest have been more severe on lowland rainforests where high rates of rainforest conversion to agriculture and other landuses were observed. These landuse problems are a consequence of many interrelated factors acting as local agents or beyond local boundaries. These factors are caused by complex processes resulting from human social dynamics. From survey results in the area these factors range from social, economic, cultural and political forces which are related to each other in multilineal causal chains. The main ones are: growing population, land scarcity, search for market goods, increased domestic demand for food and forest products, poverty, lack of knowledge, lack of an effective extension service, market failures such as breakdown of traditional management systems due to commercialization of demand for resources, government failures such as inefficient government policies, risks and uncertainty in farming (pests, diseases and vagaries of climate) insecure land rights under customary land tenure system, traditional or cultural barriers, conflicting objectives between land users, failure to control protected areas such as Forest Reserves and decline in forest product supply and lack of income from outside agriculture and forestry. It seems the government has not been able to control landuse problems through policy measures or coercion. Also the market has not been able to do so, due to its failure to provide negative feedback loops to check landuse problems. Widespread market and government failures largely account for this situation since, they provide incentive for poor landuse practices. Rural poverty and efforts to adapt to economic hardships at the local level have a significant influence on landuse problems. Vaguely defined, unequitable and uncertain land tenure conditions, lack of knowledge and traditional barriers have added a complicating dimension to landuse problems. The poor local people, the direct agents of degradation and deforestation pressure, have been made to rely on unreliable access to credit markets due to the absence of guarantees (collateral), caused by lack or uncertainty of tenure. The effect has been to increase landuse problems. Since the welfare and survival of the local people in the Nguru mountains, are inextricably linked with agriculture and the environment, they must improve current landuse practices, in order to come to terms with the reality of resource limitation and carrying capacity of their ecosystem. Wise management of land and forest resources requires appropriate landuse practices, to alleviate landuse problems in order to improve the standard of living and preserve the biological systems, especially the tropical rainforest upon which they depend. The strategy recommended requires landuse planning for efficient use of resources and integrated planning to harmonize conflict between land uses. Other measures include family planning to control population growth, education to enhance change of attitude on resource use, by overcoming communication breakdown between resources users and protectors through direct dialogue and community involvement, giving some specific rights to property in reserved forests, and benefits to villagers to meet their needs while protecting the resources, improving traditional landuse systems and traditional knowledge, incorporating agroforestry in farming systems, removal of institutional barriers to wise landuse by government through appropriate policy changes, and improvement of rainforest management methods to enhance forest protection.