NRU :: Browsing by Author "Tumwebaze, Susan Balaba"

Browsing by Author "Tumwebaze, Susan Balaba"

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Allometric Biomass Equations For Tree Species Used In Agroforestry Systems In Uganda
(Agroforestry systems, 2013) Tumwebaze, Susan Balaba; Bevilacqua, Eddie; Briggs, Russell; Volk, Timothy
Estimates of above-ground biomass are required for better planning, sustainable management and monitoring of changes in carbon stocks in agroforestry systems. The objective of this study was to develop and compare biomass equations for Markhamia lutea, Casuarina equisetifolia, Maesopsis eminii and Grevillea robusta grown in a linear simultaneous agroforestry system in Uganda. These species were established in single rows in the middle of fields in 1995 from four-month old seedlings. A total of 57 trees were sampled for this study, 13 for M. lutea, 12 for C. equisetifolia, 16 for M. eminii and 16 for G. robusta. Biomass values of the various tree components (stem, branches and foliage) as well as the total above-ground biomass were fitted to linear and non-linear allometric models using total height, diameter-at-breast height (DBH), crown width as predictor variables. Although both DBH and height are typically used as independent variables for predicting above-ground biomass, the addition of height in biomass equations did not significantly improve model performance for M. eminii, M. lutea and G. robusta. However, addition of height significantly increased the proportion of variation explained in above-ground biomass for C. equisetifolia, while DBH did not significantly improve the prediction of biomass. The study confirmed the need for developing species-specific biomass equations.
Drivers of Household Decision-Making on Land-Use Transformation: An Example ofWoodlot Establishment in Masindi District, Uganda
(Forests, 2019) Ahimbisibwe, Vianny; Auch, Eckhard; Groeneveld, Jürgen; Tumwebaze, Susan Balaba; Berger, Uta
Land use transformation at the farm level is attributed to household decision-making, reflected by the behavior and activities of smallholder farmers. Unfortunately, household decision-making in local communities and its determinants are site-specific and hardly understood. This study uses multistage purposive selection of households as a unit for the analysis to investigate the transformation from pure agriculture to farm forest mosaics, especially through woodlot establishment. We use key informants, household surveys, and observations to obtain data on decision-making amongst 84 farm households in Nyantonzi parish, Masindi district, Uganda, as an example. Specifically, the study addresses four research questions. Firstly, what is the current status of gender-based decision-making at the household level? Secondly, is decision making within farm households individualistic or collective? Thirdly, which factors are considered to select annual, perennial and tree-crop farm management regimes? Fourthly, what determinants influence the decision-making process and the likelihood of woodlot establishment? A multilevel analysis comprising parametric statistical models and binary logistic regression is applied to assess difference in household natural, physical, human, and social capital, highlight gender roles, and obtain factors associated to selection of crops and determinants of woodlot establishment at the farm level, respectively. Results reveal that gender based decision-making is clearly disaggregated on the basis of husbands and wives and it is individualistic, mostly dominated by husbands with lower participation by wives and other family members. Households consider various factors before making any decisions, e.g., market prices for both annual and perennial crops, food consumption for annual crops, ease of management, and yields from the previous season for the tree-crop management regimes. The likelihood for woodlot establishment is positively influenced by the willingness and intention of households to establish woodlots and relative age of household head. However, knowledge of land use Policies, Laws, and Regulations (PLRs) in relation to tree planting and harvesting and access to non-farm income reduce the likelihood of woodlot establishment. Here, we recommend that current and future forest land restoration initiatives focus on reducing the gender gap and increase women’s participation in decision making, provide market information platforms on wood products, and include woodlot farmers in social organization. Current PLRs on tree tenure should be improved and clearly communicated by using the existing communication assets and social gatherings as channels of change and influence for decision-making.
Impact of Collaborative Forest Management on Forest Status and Local Perceptions of Contribution to Livelihoods in Uganda
(Journal of Sustainable Development, 2013) Turyahabwe, Nelson; Tumusiime, David Mwesigye; Byakagaba, Patrick; Tumwebaze, Susan Balaba
This study assessed the impacts of Collaborative Forest Management (CFM) initiatives on forest status of Budongo Forest reserve in Uganda and perceptions of the participating communities on the contribution of CFM towards their livelihood. Impact on conservation was assessed by applying a Participatory community based Forest Resource Assessment (PFRA) method to examine population structure, dynamics, and incidences of human disturbance across two forest compartments under CFM and comparing these with the status in two compartments without CFM, but otherwise similar to the former in terms of forest type, history of resource use-patterns, silvicultural management practices and location (in the production zone of the forest and close proximity to local communities). Impact on local livelihoods was examined through a survey that involved ten focus group discussions and semi-structured interviews among 140 randomly selected forest neighbours. With the exception of tree regeneration, CFM improved forest status in terms of more live stems of timber, pole tree species, trees with harvestable logs, merchantable volume, and lowered incidences of human disturbances. However, local people do not perceive CFM to have contributed to their livelihoods because whereas CFM created opportunities for income generation particularly through bee keeping, the in-forest activities it halted were superior sources of livelihood. As a result, nearly 50% of the respondents explicitly reported dissatisfaction with the CFM arrangements. Other reasons for dissatisfaction included the inability of CFM to deliver benefits as promised in the signed agreements, local people were frequently not consulted or involved in making key management decisions, and inequality in sharing CFM benefits amongst members of the local community. CFM at Budongo forest reserve has thus contributed to improving forest status, but is perceived to have had limited benefits to local livelihoods
Influence Of Rooting Media And Indole-3-Butyric Acid (IBA) Concentration On Rooting And Shoot Formation Of Warburgia Ugandensis Stem Cuttings
(African Journal of Plant Science, 2011) Akwatulira, Florence; Gwali, Samson; Okullo, John Bosco Lamoris; Ssegawa, Paul; Tumwebaze, Susan Balaba; Mbwambo, John Richard
This study investigated the influence of different rooting media and indolebutryic acid (IBA) hormone concentration on root and shoot development in stem cuttings ofWarburgia ugandensis. Stem cuttings were treated with three different levels (0.3, 0.6 and 0.8% w/w) of IBA concentration (including a control- no IBA hormone) and propagated in three rooting media (milled pine bark, top forest soil and sand) under non-misting propagators. Data on root and shoot development, callusing, number and length of roots and shoots were analyzed using analysis of variance (ANOVA) and Chi square test. Callusing, root and shoot development were significantly (p<0.05) influenced by rooting media and IBA concentration. Milled pine bark and 0.8% w/w IBA concentration gave the highest percentages of stem cuttings that callused, rooted and shooted (38, 37, 41% and 57, 41, 59%), respectively. Similarly, milled pine bark and 0.8% w/w IBA concentration gave the greatest number and longest roots and shoots per stem cutting. Vegetative propagation of W. ugandensis through stem cuttings can be appropriately achieved by treating the cuttings with 0.8% w/w IBA hormone using milled pine bark as a growth medium.
Integrating local knowledge with tree diversity analyses to optimize on-farm tree species composition for ecosystem service delivery in coffee agroforestry systems of Uganda
(Agroforestry Systems, 2019) Bukomeko, Hannington; Jassogne, Laurence; Tumwebaze, Susan Balaba; Eilu, Gerald; Vaast, Philippe
Coffee agroforestry systems deliver ecosystem services (ES) critical for rural livelihoods like food but also disservices that constrain livelihoods like fostering coffee-pests. Since such ES are tree-based, maximizing ES and limiting constraints requires knowledge on optimizing on-farm tree composition especially trees adapted to local conditions. The study was in three sites along a rainfall gradient in Central Uganda where we: assessed tree diversity in coffee agroforestry; ranked tree suitability for providing ES according to farmers’ knowledge; and then proposed an approach for optimizing on-farm tree composition for delivery of ES. We collected data on tree diversity and, farmers’ knowledge of tree species and the ES they provide. Farmers ranked ES in order of importance to their livelihoods (‘Needs rank’) and ranked trees according to suitability for providing ES. Using Bradley Terry modeling, we grouped trees into ‘ES groups’ according to suitability for providing different ES and ranked ‘ES groups’ according to tree diversity (‘Diversity rank’). Tree-suitability for providing ES and importance of ES to farmers varied with rainfall regime but tree diversity did not match farmers’ needs for ES. We propose the FaD–FaN (matching farm tree diversity to farmers’ needs) approach for optimizing tree species composition with respect to tree-suitability for farmers’ priority ES. Farmers locally prioritize ES needed and identify trees that best serve such ES. The approach then focuses on modifying on-farm tree diversity to match/suit farmers’ priority ES. The FaD–FaN approach caters for varying socio-ecological conditions; it’s adaptable for other coffee and cocoa-growing areas worldwide.
Soil Organic Carbon Stocks Under Coffee Agroforestry Systems And Coffee Monoculture In Uganda
(Agriculture, Ecosystems & Environment, 2016) Tumwebaze, Susan Balaba; Byakagaba, Patrick
Coffee agroforestry systems (CAS) are considered as a climate change mitigation option through carbon sequestration. However, most studies on CAS have concentrated on management and productivity of the coffee plants with little known about the soil organic carbon (SOC) stocks. We conducted a study to quantify and compare the SOC stocks among Coffea arabica L. (Arabica coffee), Coffee canephora Pierre ex Froehn (Robusta coffee) agroforestry systems and Coffee monoculture (coffee monocrops) in Uganda. Soil samples were collected at 0–15cm and 15–30cm and tested using routine soil testing procedures. We found that there was higher SOC under CAS than coffee monocrops. When intercropped with non- fruit tree species, Robusta CAS produced higher SOC (57.564tC/ha) compared to the Arabica CAS (54.543tC/ha). In contrast, Arabica CAS stored more SOC (54.01tC/ha) compared to Robusta CAS (49.635tC/Kg) when intercropped with fruit trees like Artocarpus heterophyllus Lam. and Mangifera indica L. Under the coffee monocrop systems, Robusta coffee sequestered 4.86tC/ha more SOC than Arabica coffee. The study showed that a farmer growing Robusta coffee intercropped with non-fruit trees is likely to benefit more from soil carbon credits than a farmer growing Arabica coffee with the same trees. Farmers growing Arabica coffee would sequester more carbon if intercropped with fruit trees. There is need for policy incentives that encourage the planting and maintenance of shade trees in coffee plantations for the benefit of carbon sequestration.
Understanding Smallholder Farmer Decision Making In Forest Land Restoration Using Agent-Based Modeling
(Socio-Environmental Systems Modelling, 2021) Ahimbisibwe, Vianny; Groeneveld, Jürgen; Lippe, Melvin; Tumwebaze, Susan Balaba; Auch, Eckhard; Berger, Uta
Success of forest restoration at farm level depends on the farmer´s decision-making and the constraints to farmers’ actions. There is a gap between the intentions and the actual behavior towards restoration in Sub-Saharan Africa and the Global South. To understand this discrepancy, our study uses empirical household survey data to design and parameterize an agent-based model. WEEM (Woodlot Establishment and Expansion Model) has been designed based on household socio-demographics and projects the temporal dynamics of woodlot numbers in Uganda. The study contributes to a mechanistic understanding of what determines the current gap between farmer’s intention and actual behavior. Results reveal that an increase in knowledge of the current forest policies laws and regulations (PLRs) from 18% to 50% and to 100% reduces the average number of woodlots by 18% and 79% respectively. Lack of labor reduces the number of woodlots by 80%. Increased labor requirement from 4 to 8 and to 12 man-days, reduces the number of woodlots by 26% and 61% respectively. WEEM indicates that absence of household labor and de facto misconception of PLRs “perceived tenure insecurity” constrains the actual behavior of farmers. We recommend forest PLRs to provide full rights of use and ownership of trees established on private farmland. Tree fund in the case of Uganda should be operationalized to address the transaction costs and to achieve the long-term targets of forest land restoration.

Browsing by Author "Tumwebaze, Susan Balaba"

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