Browsing by Author "Mwakalukwa, Ezekiel Edward"

Now showing 1 - 4 of 4

Allometric models for estimating tree volume and aboveground biomass in lowland forests of Tanzania
(International Journal of Forestry Research, 2016) Mugasha, Wilson Ancelm; Mwakalukwa, Ezekiel Edward; Luoga, Emannuel; Malimbwi, Rogers Ernest; Zahabu, Eliakimu; Silayo, Dos Santos; Sola, Gael; Crete, Philippe; Henry, Matieu; Kashindye, Almas
Models to assist management of lowland forests in Tanzania are in most cases lacking. Using a sample of 60 trees which were destructively harvested from both dry and wet lowland forests of Dindili in Morogoro Region (30 trees) and Rondo in Lindi Region (30 trees), respectively, this study developed site specific and general models for estimating total tree volume and aboveground biomass. Specifically the study developed (i) height-diameter (ht-dbh) models for trees found in the two sites, (ii) total, merchantable, and branches volume models, and (iii) total and sectional aboveground biomass models of trees found in the two study sites. The findings show that site specific ht-dbh model appears to be suitable in estimating tree height since the tree allometry was found to differ significantly between studied forests. The developed general volume models yielded unbiased mean prediction error and hence can adequately be applied to estimate tree volume in dry and wet lowland forests in Tanzania. General aboveground biomass model appears to yield biased estimates; hence, it is not suitable when accurate results are required. In this case, site specific biomass allometric models are recommended. Biomass allometric models which include basic wood density are highly recommended for improved estimates accuracy when such information is available.
Floristic composition, structure, and species associations of Dry miombo woodland in Tanzania
(2014) Mwakalukwa, Ezekiel Edward; Meilby, Henrik; Treue, Thorsten
For the majority of forest reserves in Tanzania, biodiversity is poorly documented. This study was conducted to assess species richness (woody species), diversity, and forest structure and to examine relationships between species occurrence and topographic and edaphic factors in the Gangalamtumba Village Land Forest Reserve, a dry Miombo woodland area in Tanzania. A total of 35 nested circular plots with radii of 5, 15, and 20 m were used to collect data on woody species and soil samples across the 6,065 ha community-managed forest reserve. Stumps were measured 20 cm above ground. A total of 88 species belonging to 29 families were identified. Generally forest structure parameters and diversity indices indicated the forest to be in a good condition and have high species richness and diversity. Vegetation analysis revealed four communities of which two were dominated by the family Caesalpiniaceae, indicating large variation of site conditions and possible disturbances in the study area. The high level of diversity of woody species and the high basal area and volume indicate that the forest is in good condition, but the effect of anthropogenic activities is evident and stresses the need for proper management to maintain or enhance the present species diversity.
Management tools and potential of dry Miombo woodland in carbon cycling: the case of Gangalamtumba village land forest reserve in Iringa, Tanzania
(University of Copenhagen, 2014-09-15) Mwakalukwa, Ezekiel Edward
Tools to support sustainable management of dry Miombo woodlands and precise assessment of carbon storage and sequestration potential are in most cases lacking in Tanzania. Accordingly, using Gangalamtumba Village Land Forest Reserve as a case study area located in Iringa region, this thesis aims to develop management tools and generate information that will enhance our understanding of the actual and potential contribution of dry Miombo woodlands in carbon cycling. This is done through a detailed assessment of floristic composition, structure, species associations and through development of models for wood basic density, volume, biomass and growth. The overall research objective was thus to enhance the basis for good woodland management planning including exploring the extent to which dry Miombo woodlands in Tanzania store and sequester C from the atmosphere. Correct identification of 88 plant woody species belonging to 29 families assisted the selection of a total of 44 important species of trees (28) and shrubs (16). These species were harvested for the determination of basic wood density values and to develop wood basic density models for specific species and for groups of species, namely trees, shrubs and combined. Aboveground volume and biomass models for specific species and species groups were also developed. Growth models of the important species, Brachystegia spiciformis Benth. as influenced by three external factors; rainfall, soil fertility, and competition were also developed to assist planning of sustainable harvesting levels. Finally, an application of data on forest structure, wood basic densities for trees and shrubs, and the developed models describing aboveground biomass and growth were used in assessing C stocks and sequestration potential of the woodland based on selected scenarios. Generally, the models appear robust and can thus be used in planning sustainable management of the woodlands. The developed models estimate that the dry Miombo woodland of Gangalamtumba Village Land Forest Reserve stores substantial amounts of C; 68.64 Mg C ha'1 both in above- and below-ground soil carbon pools. Assuming that other species’ production are equal to B. spiciformis, which is the most dominant species in the study area, the estimated C sequestration potential of the dry Miombo woodlands was found to vary from 0.42 ± 0.03 Mg C ha" ’year'1 to 1.39 ± 0.08 Mg C ha^year'1, depending on scenario. Considering the vast areas covered by dry Miombo woodlands, sustainable management of this vegetation type clearly holds potential in preventing emissions of large amounts of C currently locked up in this ecosystem.
Volume and aboveground biomass models for dry miombo woodland in Tanzania
(Hindawi, 2014) Mwakalukwa, Ezekiel Edward; Meilby, Henrik; Treue, Thorsten
Tools to accurately estimate tree volume and biomass are scarce for most forest types in East Africa, including Tanzania. Based on a sample of 142 trees and 57 shrubs from a 6,065 ha area of dry miombo woodland in Iringa rural district in Tanzania, regression models were developed for volume and biomass of three important species, Brachystegia spiciformis Benth. (n = 40), Combretum molle G. Don (n = 41), and Dalbergia arbutifolia Baker (n = 37) separately, and for broader samples of trees (28 species, n = 72), shrubs (16 species, n = 32), and trees and shrubs combined (44 species, n = 104). Applied independent variables were log-transformed diameter, height, and wood basic density, and in each case a range of different models were tested. The general tendency among the final models is that the fit improved when height and wood basic density were included. Also the precision and accuracy of the predictions tended to increase from general to species-specific models. Except for a few volume and biomass models developed for shrubs, all models had R 2 values of 96–99%. Thus, the models appear robust and should be applicable to forests with similar site conditions, species, and diameter ranges