Browsing by Author "Makero, J. S."

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Analysis of Land-Cover Changes and Anthropogenic Activities in Itigi Thicket, Tanzania
(Scientific Research Publishing, 2016-12-01) Makero, J. S.; Kashaigili, J. J.
Assessing land cover changes from the 1991 to 2011 for Itigi thicket is imperative for determining changes between land cover types and understanding anthropogenic impact during this period. Remote sensing (RS) data, Geographic Information System (GIS) techniques and forest inventory data were used. ILWIS 3.3 Academic software was used to analyze the satellite imageries to determine the land use, land cover change; while data on anthropogenic activities were analysed in MS Excel software. The results showed that between 1991/2000 and 2000/2011, the areas of thicket declined by 6.23% while non-thicket areas increased by 3.92%. The decline in thicket areas was attributed to increase in anthropogenic activities such as wood extraction, clearing for agriculture, livestock grazing and fires. The study highlights the importance of integrating remote sensing and forest inventory in understanding the thicket resources dynamics and generating information that could be used to overcome the Itigi thicket problems for the sustainability of this unique vegetation
Biomass and volume models for different vegetation types of Tanzania
(E&D Vision Publishing Ltd, 2016) Malimbwi, R. E.; Mauya, E. W.; Zahabu, E.; Katani, J. Z.; Chamshama, S. A. O.; Eid, T.; Bollandsås, O. M.; Maliondo, S. M. S.; Mugasha, W. A.; Masota, A. M.; Njana, M.; Makero, J. S.; Mshana, J. S.; Luganga, H.; Mathias, A.; Msalika, P.; Mwangi, J.; Mlagalila, H. E.
Climate change and high rates of global carbon dioxide (CO2) emissions have increased the attention paid to the need for high-quality monitoring systems to assess how much carbon (C) is present in terrestrial systems and how these change over time. The choice of a system to adopt relies heavily on the accuracy of the method for quantifying biomass and volume as important primary variables for computing C stock and changes over time. Methods based on ground forest inventory and remote sensing data have commonly been applied in the recent decade to estimate biomass and volume in the tropical forests. However, regardless of the method, accurate tree level biomass and volume models are needed to translate field or remotely sensed data into estimates of forest biomass and volume. Therefore, the main goal of this study was to develop biomass and volume models for the forests, woodlands, thickets, agroforestry systems and some selected tree species in Tanzania. Data from destructively sampled trees were used to develop volume and above- and below-ground biomass models. Different statistical criteria, including coefficient of determination (R2), relative root mean square error (RMSE %) and Akaike Information Criterion (AIC), were used to assess the quality of the model fits. The models selected showed good prediction accuracy and, therefore, are recommended not only to support the ongoing initiatives on forest C Measurement, Reporting and Verificatio (MRV) processes but also for general forest management in Tanzania.
Extent of illegal harvesting on availability of timber species in Nyanganje Forest Reserve, Tanzania
(BioOne, 2012) Makero, J. S.; Malimbwi, R. E.
The study was conducted to determine the extent of illegal harvesting of timber species in Nyanganje Forest Reserve (NFR). Data on the extent of timber stocks harvested illegally in NFR were collected using both socio-economic and ecological surveys. Linear regression analysis showed that extraction of timber species in NFR mostly occurs at the roadside. The mean annual quantity of wood harvested illegally was estimated to be 6.2 m3 per ha. Although the NFR has high potential of timber species (standing stock of 119 m3 per ha), this is threatened by the high demand for timber species. Illegal harvesting of timber species is likely in NFR because the Government is providing few resources to safeguarding this reserve. Therefore, some arrangement from the Government is immediately needed to rescue this reserve and ensure its sustainability.
Land cover dynamics and estimates of volume and biomass of thicket and tree species in Itigi thicket, Tanzania
(Sokoine University of Agriculture, 2017) Makero, J. S.
The study was carried out in Itigi thicket in Manyoni District to assess land cover dynamics and estimate biomass and volume of thicket and tree (associate trees) species. The assessment of land cover dynamics was based on data extracted from remote sensing using the 1991, 2000 and 2011 satellite images and key informants interviews. The estimation of biomass and volume of thicket and tree species, data from destructive and non-destructive sampling was used. Sixty thicket clumps and thirty trees were sampled for destructive sampling. The study covered two dominant thicket species: Combretum celastroides Laws and Pseudoprosopsis fischeri (Tab) Harms and five dominant tree species: Canthium burtii Bullock sensu R. B. Drumm, Cassipourea mollis (R. E. Fr.) Alston, Haplocoelum foliolosum L, Lannea fulva (Engl.) England and Vangueria madagascariensis J. F. Gmelin. All sampled thicket clumps and trees were destructively for above- (AGB), belowground (BGB) biomass and volume. Analysis of land cover dynamics was based on supervised image classification using maximum likelihood classifier (MLC). For modelling biomass and volume of individual thicket clump and tree, different nonlinear multiplicative model forms were tested. The final models of biomass were selected based on Akaike Information Criterion (AIC) while the final models of volume were selected based on coefficient of determination (R2) and relative root mean square error (RMSEr). Then the final selected models were applied to estimate biomass and volume of non-destructive sampling data. The results showed that thicket occupies large area in Itigi thicket. For example in 1991, the area occupied by thicket was 345 150.5 ha (67.85 %), in 2000 was 313 451 ha (61.62 %) and in 2011 was 293 444.8 ha (57.7 %). Apparently, this large area occupied by thicket declined during 1991 - 2000 and 2000 - 2011. The decline in thicket areas was attributed to increase in anthropogenic activities such as wood extraction, clearing for agriculture, livestock grazing and fires. The model fitting showed that, large parts of the variation in biomass of thicket clumps were explained by basal area weighed mean diameter at breast height (dbhw) of stems in the clump and number of stems in the clump (stem count, i.e. st), i.e. for AGB and BGB of C. celastroides Laws up to 89 % and 82 % respectively and for AGB and BGB of P. fischeri (Tab) Harms up to 96 % and 95 % respectively. For tree species most variation was explained by diameter at breast height (dbh) alone, i.e. up to 85 % and 69 % for ABG and BGB respectively. It was also noted that, for thicket, large parts of the variation in volume of thicket clumps were explained by dbhw, height (ht) and stem count, i.e. for C. celastroides Laws up to 69 % (R2) and for P. fischeri (Tab) Harms up to 93 %. For trees most variation was explained by dbh and ht, i.e. up to 93 %. Although there might be some uncertainties related to biomass and volume estimates for large areas, for practical reasons, it is recommended the selected models to be applied to the entire area where Itigi thicket extends outside the study site, and also to those thicket and tree species present that were not included in the data used for modelling. The methods used in this study to assess land cover dynamics, biomass and volume stocks of thicket and tree species highlight the importance of integrating remote sensing and forest inventory in understanding the thicket resources dynamics and generating information that could be used to overcome the Itigi thicket problems for the sustainability of this unique vegetation.