Department of Forest Operational Management and Techniques

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Factors affecting the consumption of working time and the strain on the worker in some
(Sokoine University of Agriculture, 1975) Harstela, Pertti
The purpose of the study was to formulate an ergonomic model for forest work to serve as frame of reference for theoretical and empirical analysis, to examine the correlations of independent variables in play in forest work such as human, conditions and working method variables with consumption of working time and the physical strain on the worker. The investigation was confined in the empirical material to the cutting of roll-seedlings and the lifting of seedlings in the nursery-, and to the cutting of pulpwood by two working methods, i.e. mediumheavy and heavy work. The final aim was to formulate and test hypotheses of forest work science, postulate new hypotheses and outline an overall theory on the basis of systems analysis. An additional special object was to study the application of the principle of comparative time study in an empirical material and to apply the same principle in pulse rate investigations. This is termed the principle of comparative work study. The work performance was illustrated by a system scheme (Fig. 1). The scheme comprised the following main groups of elements: worker’s inclination for work, working capacity, reflexes and instincts, decision process, environmental factors, working methods and habits, work performance, output, earnings, and effects on the worker. The model was made up parallclly from abstract and concrete concepts, the aim being to make it suitable for the set of concepts of the theory of work study and the level of theory formulation. The model included the feedback from the effects on the worker-sample element group to the worker’s qualities. The literature on forest work studies in which some correlations introduced in the model were investigated is reviewed in Chapter 23. Owing to the great number of output studies they were treated as an example. The greatest part of the research activity has been analysis of the relations between environmental factors — and of them primarily the work difficulty factors — and the work output. The previously outlined system formula is examined in Chapter 24 as a cybernetic, probabilistic system in which the elements as such were conceived to embrace complex linkages and to be of the black-box type. The information transfer of these sample elements was illustrated by only one channel and information was consequently analysed merely as a symbolical expression of space and event. The decision process and the effects of reflexes and instincts were examined as the self-regulatory mechanism of the model. Feedbacks were established both within the worker and between the worker and environment. Principles influencing the formulation of the theory' of work science were postulated on the basis of the general properties of the system, such as threshold values, correlations, the principles of isomorphism and homomorphism: — If a correlation proves to be significant it is relevant at least in the population represented by the material and possibly also in other populations. — On the other hand, if no significant correlation is established between some independent variables there may nevertheless be a significant correlation in some other population or after some threshold values. — Il is useful for development of the theory' to explain the trend of the correlations and the internal conformities to law and mechanism of the elements. — It is assumed hypothetically that the constancy of the relative per-worker working time and strain value is influenced by the difference between the worker’s capabilities that the working methods and working conditions require and by his attitude to the working methods under comparison and his experience. — model taken from nature through simplifications is the more servicable the more deterministic it is. — Empirical work study generally' observes coded messages by indirect means and it is therefore seldom possible to demonstrate direct physiological causal relationships; what results is explanations of the ”either-or” or ”both-and” type. The system description of the work was developed in Chapter 25 by hypothetical insertion in the model of elements formed by the set of concepts of work study principles (Fig. 2). The concepts are: speed of work, physical strain, ratio between physical strain and maximal performance, total strain during the working day, psychic strain, relative consumption of time, average consumption of time, deviation of consumption of time, average strain, deviation of strain, relative strain, and attitudes to work. The quantitative and abstract levels of the concepts of the model were studied using the M-67-meta theory. Fig. 3 shows the concept hierarchies and the measuring features of the concepts. In processing the measuring features for formulation of the theory in the empirical part, concepts of the same quantitativencss arc used which are sub-concepts of the high real theoretical concepts: the worker’s capacity' and inclination for work, effects on the worker, performance, output and environmental factors. Fig. 4 shows the processes as a being model: performance — output and performance — effects on the worker, the worker’s resources (capacity for work) and feelings (inclination for work) and working conditions (environment) which influence the interrelations of these processes. The Jiving organism state of equilibrium. It logical theories that if a was found to be a system which seeks to preserve a was assumed from reference to physiological and psychofactor causes a greater deviation in the equilibrium of the organism than the conditions of other factors, that factor dominates the behaviour of the organism. This theory was applied in the empirical part to explain the phenomena established. In the empirical part the effect was examined of different factors on the consumption of working time, the physical strain on the worker, and the application of certain work study principles in the nursery to the cutting of roJlseedlings, the lifting of pine seedlings and the logging of pulpwood in grapple piles alongside the strip road (working method 2) and a 4-m wide zone for which the bunch size required was reduced (working method 1). The material and the measurements made are described in Chapter 32. The most important results were as follows. Owing to the paucity of degrees of freedom which interfered with testing they were distributed into statistically significant correlations and hypothetical correlations: — Consumption of working time was explained significantly in regression analysis by so-called work difficulty factors, working method, moving speed which illustrates the speed of the work, the time of the working day, the ordinal number of the working day and some independent variables that portray the worker.
Bark-stripping and food habits of blue monkeys in a forest plantation in mount Meru, Tanzania
(UNIVERSITY OF IDAHO, 1989-04) Maganga, S. L. S
Bark-stripping of Cupressus lusitanica (cypress) and Pinus patula (pine) by blue monkeys (Cercopethicus mitis kibonotensis) in Meru Forest Plantations has been a problem since they were established in the early 1950s. This study was conducted in 1987 in the Sokoine University of Agriculture determine the magnitude of bark-stripping in relation to the food habits of blue monkeys. assessed in compartments with trees 3 to 14 years old, and the pattern of debarking was monitored throughout the year. On the average, 79.5 % cypress and 88.7% pine trees were debarked. Blue monkeys preferred dominant cypress trees to intermediate trees. In contrast, intermediate pine trees were more damaged than dominant trees. In both species, suppressed trees were least damaged. In all types of trees, the most severe bark damage occurred at the middle and top of the tree trunks. Twisted bole was the most common defect developed by damaged trees; 34% cypress and 38% pine trees were twisted at the middle and top sections. Bark-stripping was low in the rain season and increased in the dry season peaking at 22% of trees damaged in June and July. ■ The food habits data were collected from the indigenous forest at two sites within the plantation. A total of 38 plant species were eaten by blue monkeys. Fruits were the Training Forest, a portion of the Meru Forest Plantations, to The extent, intensity and effects of bark damage were Bark-stripping of Cupressus lusitanica (cypress) and iv most frequently consumed food item and averaged 76% of the monthly feeding records. Leaves were the next important food item but they were inversely related to the feeding on fruits. The other food items (flowers, shoots, petioles and bark) were similarly inversely related to the feeding on fruits. Bark stripping was negatively correlated to the feeding on fruits, and thus increased when the feeding on fruits declined. Fruits of Ficus thonningii were the prime item in the diet of blue monkeys contributing 50 to 60% of the monthly feeding records. The amount of fruit on these trees in the area was also inversely related to extent of bark damage in the plantation. The water and carbohydrate in the bark of cypress and pine trees was determined to examine if they influenced the bark-stripping. These were poorly correlated to the monthly debarking of both tree species.
Comparing Productivity and Costs of Three Subgrading Machines
(1993) Abeli, W.S.
Production rates and costs of three forest road construction machines (Ford County 1164 tractor, D4D and D6D Caterpillar bulldozers) were analysed and compared. Results showed that differences in production rates were attributed mainly by the type and the size of the machine, driver's working experience and the nature of the terrain side slope. Compared to other subgrade productivity studies, machine production rates found in this study were considered to be reasonably high. The mean production rates for the D6D, D4D and the County tractor were 129.0 m3/h, 41.0 mVh and 28.1 mVh respectively. High productive time, easily workable soils and few obstacles encountered during earthworks operation were the major factors which contributed to high machine production rates. Cost analysis showed that the higher the machine production rate the lower the subgrading cost and vice versa. The mean production costs for the D6D, D4D and the County were estimated to be US$ 0.49/m3, US$0.79/m3 and US$0.76 /m3 respectively. The estimated machine production costs were more or less the same as those estimated elsewhere. Although low machine production cost is usually the criterion used in choosing the machine to be used for road construction works, this paper recommends that other factors be considered.
Optimal road spacing for manual skidding sulkies
(Forest Research Institute Malaysia, 1993-09) Abeli, W. S.; Magomu, G. M.
An optimal road spacing is the one which minimizes the overall sum of skidding costs, road construction and road maintenance costs. As road spacing increases, skidding cost increases while road construction and maintenance cost decreases. Each skidding means has its own optimal skidding distance and road spacing. This study analyses skidding productions and optimal road spacing for hand sulkies skidding logs in one of the forest plantations in Tanzania. Results from this study indicate that when undertaking thinning operations especially in flat to gentle sloping terrains, sulky skidding could be considered as a better alternative to tractor and manual skidding methods. Besides being simple and cheap, the system causes minimum stand and soil damages, creates employment opportunities for the rural people and does not demand foreign capital .The average skidding distance in this study was measured to be 71 m while average skidding production was estimated to be 1.21 m3/man-hour. An optimal road spacing which minimizes the overall total costs in this forest was found to be 137 m.
Productivity and physical workload of cutting crews in sao hill softwood plantations
(Sokoine University of Agriculture, 1996) Malisa,Emilson Jeremiah
Physical workload and cutting of productivity two-man raker and peg toothed saws were compared when clearfelling a Pinus elliottii compartment in Sao Hill forest plantation. Three logging crews working with the two types of saw were studied between July and October 1990. Heart rate data was collected after every 30 seconds using a SPORT TESTER while maximum aerobic power was estimated using sub-maximal tests on a cycle ergometer respectively. A total of 1271 trees with an average Dbh of 25 cm were felled and bucked into logs. Analysis of the data revealed that: (a) Effective cutting time when using raker and peg toothed saws were 8.8 and 9.6 min/tree respectively. For a 7 hour workday only about 4.7 hours were spent for productive work. (b) Raker-toothed saws had higher rates than peg-toothed saws. cutting production Production rates raker and peg- toothed saws ranged from 3.25 for 3.6 and 2.98 - 3.16 m3/crew - h respectively. (c) The heart rates of the workers during effective cutting time were 112 - 117 and 115 - 118 beats/minIll when using raker and peg-toothed saws respectively. Maximum aerobic power of the workers averaged 2.54 1/min ranging from 2.37 to 2.74 1/min. (d) Oxygen consumption rate was on the average 1.23 1/min ranging from 1.11 1.30 1/min when using raker- toothed saws. The demand averaged 1.28 1/min with peg-toothed saws ranging from 1.14 - 1.38 1/min. Thus energy demand when using peg-toothed saws was about 28% higher than for raker-toothed saw cutting. This indicated that raker- toothed saws could be a better choice for cutting operation. (e) Physical workload on the workers when cutting using the two types differences. of saws showed no significant The workload indices during effective cutting time using raker and peg-toothed saws were 43.7 52.6 % and 44.8 53.6% respectively. This showed that the cutting operation was a moderate energy demanding job.
The influence of logging and animal grazing on the litter layer and water infiltration rate of soils in plantation forests
(Journal of Tropical Forest Scienc, 1999) Abeli, W. S.; Sawe, C. T.
The influence of logging and animal grazing on the litter layer and water infiltration rate of soils in plantation forests. Investigations to show the extent of soil disturbance caused by logging and animal grazing were carried out in one of the forest plantations in Tanzania. Water infiltration capacity and ground litter thickness were used as a measure to determine the extent of soil disturbance. Data on infiltration rate and litter depth on stands under different management practices were collected, analysed and compared with data from the nearby undis- turbed natural forests. The study found that logging and animal grazing reduced water infiltration rate in the soil and deposition of ground litter. Depending on the management practice or the condition of the stand, the rate of water infiltration was reduced from 36 to 96% when compared to water infiltration rate experienced in the nearby natural forest. While in undisturbed natural forest the mean litter depth was 11.1 cm, on clearfelled and grazed stands, the litter depth was only 0.9 cm. The effects of low water infiltration rates and low litter deposition are discussed and measures aimed at increasing water infiltration rate and litter deposition are suggested.
The role of local knowledge and organizations in sustainable conservation of biodiversity: a case study of Udzungwa mountains, Tanzania
(Sokoine University of Agriculture, 2000) Mbwambo, Jonathan Stephen
To some extent the conservation of biodiversity in Tanzania is currently vested on local communities. This strategy is clearly stipulated in the National Forest Policy of 1998. The success of this strategy depends largely on people's local knowledge, organizations and their underlying institutions. Local knowledge and organizations constitute essential component for attempts to facilitate local level engagement in conservation and utilization of natural resources. However local knowledge and organizations were neglected in the past until recently when their importance have been stressed in rural development and conservation of natural resources in particular. This study was conducted to identify different local knowledge systems, organizations and their underlying institutions in the management and conservation of Udzungwa Mountains National Park. Specifically the study sought to: assess changes occurred in the forest resource base over time, identify and assess the role of the existing local organizations (both internally and externally sponsored) and their underlying institutions in biodiversity conservation and to assess the state of conflict between externally and internally initiated organizations. Other specific objectives include identification of indigenous practices and their role in the conservation of biodiversity in Udzungwa Mountains National Park, identification of socio-economic factors including gender, which enable or constrain local people participation in biodiversity conservation and propose a model that will ensure sustainable conservation of biodiversity for Udzungwa Mountains National Park. The study was carried under two phases. Phase one of the study involved Participatory Rural Appraisal techniques in two villages namely Msolwa and Sonjo. Participatory Rural Appraisal techniques were designed to quickly generate information about local conditions, livelihood and social formation around Udzungwa Mountains National Park. The second phase involved structured questionnaire surveys as the major tool for data collection. Questionnaire survey was done in four villages namely Msolwa, Sonjo, Ichonde and Kisawasawa. The sample size in each village was 5 percent of the total number of households. Other tools used were checklist and participant observation. Data collected by using Participatory Rural Appraisal techniques in phase one were analyzed with the help of the communities and the results were communicated back to them. The Statistical Package for Social Science was used to analyze quantitative data whereas Content and Structural-Functional Analysis were used for qualitative data. The study revealed the presence of various internally initiated organizations. These include village governments, village Community Conservation Committees, fire brigades, women groups, religious organizations, primary schools and cooperative unions. Ranking of these organizations by farmers indicated that village government, village Community Conservation Committee, fire brigades are more effective in decision making in joint management of natural resources in Udzungwa Mountains National Park. About 49 percent of respondents described the role of these organizations as being both tree planting and enforcement of rules and regulations. The study also identified two externally sponsored organizations, namely World Wildlife Fund and Tanzania National Parks. More than 85 percent of the respondents said that there is no conflict between externally and internally sponsored organizations. Similarly more than 75 percent of the respondents participate in tree planting and that both men and women participate^ equally in tree planting. Pollarding, pruning and the use of ash against termites are some of the indigenous management practices pointed out by most respondents. The presence of traditional institutions such as Bokela, traditional healing and sacred groves in the Udzungwa Mountains National Park is the evidence that the resource base has been protected and conserved by the local people even before the advent of externally sponsored institutions. The study concludes by saying that local people could work and provide the means for sustainable management and conservation of Udzungwa Mountains National Park. The study recommends strengthening the present agroforestry program through joint ownership of tree nurseries, formation of agroforestry demonstration plots and more emphasis should be put on education and extension. The study also recommends carrying out inventory and identification of traditional medicines to ascertain their distribution for effective conservation. Carrying out effective ecological monitoring and evaluation are other recommendations of the study.
Critique of decentralized political structures in water resource management in Tanzania: the case of Pangani river basin
(WIT PRESS, 2011-05) Olemako, T. R; Munishi, P. K. T; Kadigi, R. M. J
Tanzania adopted the river basin model in 1950s and declared it as an essential feature for economic development. Since 1990 management of water resources in Tanzania is based on the nine river basins that do not follow administrative boundaries as defined under the system of decentralized political structures. Water is a key resource in the river basin; however, it is not a driver of economic development. Drivers of economic development are outside the water sector such as energy, agriculture and mining. The non-water sectors fall under decentralized political structures from the central government ministries, regional administration to local government authorities. The system of political structures cut across different varieties of governance from central to local government levels. Variance in governance under these structures has intensified water scarcity and as an institutional and legal tool is more rhetorical rather than practical. Total water withdrawal in Tanzania is estimated to be 5,142 million m 3 out of which agriculture development consumes more than 85% and the rest accounts for the domestic sector, livestock development and industry. Water scarcity hinders the effectiveness of the adopted river basin model as competition of water use between hydropower production and irrigation is intense. This paper addresses the main questions as to what effectsthese structures have on institutional policy design and discourse in the river basin management. Do the structures promote or block institutional reforms? How is the sustainability of the reforms ensured? This paper suggests a mainstream institutional set up of a non-water sector into the river basin model from the central to local government levels.
Insects feeding on Sesbania species in natural stands and agroforestry systems in southern Malawi
(Kluwer Academic, 2012-04) Sileshi, G.; Maghembe, J. A; Rao, M. R; Ogol, C. K. P. O; Sithanantham, S.
Pest and disease interactions in agroforestry systemsis a little studied area.Surveys were conducted in the Mangochi and Zomba districts of southern Malawi between December 1997 and February 1998 to identify insects feeding on Sesbania species in natural stands and in agroforestry systems at the research station and on farms, and the host range of the insects. Out of a total of 30 insect species recorded in natural stands, Brachyplatys testudonigro, Mesoplatys ochroptera, Exosoma sp. and Ootheca sp. were the most commonly found insects feeding on S. sesban. Afrius figuratus, Glypsus conspicuus, Macrorhaphis acuta, Mecosoma mensor, Rhinocoris segmentarius and Cyaneodinodes faciger were recorded for the first time as natural enemies of Mesoplatys ochroptera in Malawi. The defoliating beetles, M. ochroptera, Exosoma sp. and Ootheca sp., were the most frequently found insects infesting S. sesban on farms. M. ochroptera attacked only Sesbania species, and usually higher populations of this beetle were recorded on annual Sesbania species (S. tetraptera, S. bispinosa, S. leptocarpa and S. sericea) than on perennial types. Although the sap-sucking bug, B. testudonigro, was relatively less common on sesbania on farms, it has been found to infest a number of other legumes of the genera Aeschynomene, Crotalaria, Desmodium, Indigofera, Mucuna, Phaseolus, Tephrosia and Vigna. Given the wide variety of plant species it attacks, B. testudonigro may become a potential pest of many agroforestry tree species. The insects Anoplocnemis curvipes, Aphis fabae, Hilda patruelis, Megaleurothrips sjostedti, Mylabris dicincta, Nezara viridula and Ootheca sp. also have the potential to become pests of agroforestry systems, as they can damage many agroforestry trees, including Sesbania, and crops. There is a need to study the biology and ecology of potential insect pests of S. sesban to plan for their integrated management in agroforestry.
Socio-economic impact of ox skidding project to the surrounding villages of Mount Meru forest plantations, Northern Tanzania
(Southern African Forestry Journal, 2012-05-09) Abeli, W. S.; Maximillian, J. R.; Kweka, A. E.; Shemwetta, D. T. K.
The ox skidding project was initiated with the objective ofusing oxen for transporting logs from the stump sites to the landings. Itwas supposed to be a participatory research project aimed at integrating scientific knowledge with practical skills and resource base ofthe local farmers. Specifically the main objective of the project was to encourage local farmers (villagers) to use their animals to skid logs in the surrounding forest plantations in order to improve their incomes and create employment opportunities to the surrounding communities especially the youth. A socio-economic survey was carried out after 6 years to assess the impact ofthe project to the oxowners who have been participatingin the project, the oxhandlers, the surrounding villages and the forest plantations. Data was collected through administering semistructured questionnaires to ox owners, village leaders, ox handlers and the management of the forest plantations. Results indicate that the ox skidding project has been a reliable andvaluable source ofincome besides offering employment to young people with only limited education. The project has improved the household income, life style and standard ofliving ofsome farmers and above all, changed the local peoples' attitudes towards the importance of the surrounding forest resources. Most of the local people feel that they are now part of the surrounding forests as they participate to some extent in the management and protection ofthese forest resources. The project has in addition created awareness among the community that oxen can also be used in forest operations besides undertaking agricultural activities. The project found that given the operating conditions of the skidding tractors in this area, ox skidding was more reliable and more cost effective than the tractor skidding system. Through this project, it has been possible to improve the workingrelationships between the surroundlngvillagesandforest plantations management. The projecthas also led to some ofthe surroundingvillages establishing village environmental committees, which work very closely with forest plantation management. The sustainability of the ox skidding system introduced in this area is likely to continue since farmers surrounding these plantations keep cattle and there are not many alternative job opportunities for the young people.
Carbon storage potential and climate change mitigation: a case of pugu forest reserve, Kisarawe district, Tanzania
(Sokoine University of Agriculture, 2013) Beda, Goodluck
Pugu Forest Reserve is a coastal forest covering an area of 2,410 hectares; but has been significantly altered by on-going extraction and conversion to other land uses which releasing carbon dioxide into the atmosphere thus making the forest a net emitter of the greenhouse gases. Though some empirical data exist regarding carbon storage in African coastal forests, little has been done to assess and quantify the carbon stocks and emissions associated with deforestation and/or degradation in all coastal forests, Pugu Forest Reserve inclusive. This study estimated carbon storage of Pugu FR to quantify the above ground carbon in the tree component, the understory carbon components and carbon storage in the soil. An inventory was conducted using a 20m x 40 m (0.08 ha) plots. Above ground tree carbon was determined using an allometric model that uses trees DBH ≥ 5 cm as predictor variable. Carbon storage in litter, herbs and dead wood was determined using Loss of Ignition method, while Walkley-Black method was used to analyse soil carbon. The total carbon density for all 5 pools was 30.95 t C ha-1 equivalents to 113.59 t CO2e ha-1. The mean carbon densities for the above ground components was 6.75 t Cha-1 (24.77 t CO2e ha-1) in which the tree component accounted for 4.5 t C ha -1 equivalent to 16.5 t CO2e ha-1 ( 14.5%); understory components of litter accounted for 0.52 t C ha-1 equivalent to 1.9 t CO2e ha-1 (1.7%); dead wood 1.01 t C ha-1 equivalent to 3.7 t CO2e ha-1 (3.3%), herbs 0.72 t C ha-1 equal to 2.6 t CO2e ha-1 (2.3%) and soil organic carbon stock was 24.2 t C ha-1 equivalent to 88.8 t CO2e ha-1 (78.2%). The mean carbon stored in this forest is lower compared to other coastal forests especially in the above ground component indicating an alarming degradation and destruction. Improved management and restoration of degraded parts can greatly increase the C storage potential and emission mitigation by this forest. Using this information as the baseline carbon stocks; can be potential for participation in carbon trading under the current REDD+ initiatives with contribution to alternative livelihoods and sustainable development to adjacent communities.
Tanzanian rangelands in a changing climate: impacts, adaptations and mitigation
(2014) Sangeda, A. Z.; Malole, J. L.
Livestock are central to the livelihoods of Tanzanians who rely on them for income via sales of milk, meat, skins and draught power. Owning livestock is amongst the ways in which many Tanzanians could diversify their risks, increase assets and improve their resilience to changes in climate. Though local coping strategies can deal with shocks in the short-term, they are hardly able to cope with more frequent and severe climate events. Observably, temperature, rainfall and atmospheric CO2 concentration interact with grazing and land cover change to influence rangeland quality and composition. Increased temperature increases drought stress and tissue lignifications in plants and, consequently, affects their digestibility and decomposition rate. Increased temperature and lower rainfall also increases vegetation flammability resulting in a shift in species composition due to increased fire frequency. Literature indicates that, Tanzania rangelands receiving between 400 and 1000 mm of rain per year (e.g. Kongwa, Monduli, Kiteto, Simanjiro, Ngorongoro, Babati, Hanang, Mbulu and Karatu) have greatest impact on climate change on surface drainage. A 10% drop in rainfall of 1000 mm per year in a rangeland results in a decline in surface drainage of only 17%, while in areas of 500 mm per year will result in a 50% decline. Interventions such as controlled animal stocking rates, sustainable yield and use of good pasture will lessen the negative impacts of climate change on rangelands. Opportunities for reducing greenhouse gas emissions on rangelands include maintaining or increasing carbon sequestration through better soil management and reducing methane production by altering animal management practices on rangelands. There is a need to focus on enabling herd mobility through securing better access to water resources, land use planning, and improve early warning systems and supporting a diversification of livelihoods.
Market signals of unsustainable and inequitable forest extraction: assessing the value of illegal timber trade in the Eastern Arc mountains of Tanzania
(Elsevier, 2014) Schaafsma, M; Burgess, N. D; Swetnam, R. D; Ngaga, Y. M; Treue, T; Turner, R. K
Natural forests and woodlands of the Eastern Arc Mountains (EAM) in Tanzania are under threat from deforestation and degradation. The estimated annual revenues from EAM hardwood for domestic use are USD 10 million in terms of planks, and twice as much when processed into furniture. Timber profits are largely captured by people whose livelihoods do not directly depend on other EAM ecosystem services. Market data, such as declining plank sizes and shifts to low-quality timber species, contain possible early warning signals of unsustainable hardwood harvesting. Policy recommendations include simplifying regulations for legal trade, developing sustainable financing, and increasing softwood supply.
Learn by doing: modelling the effect of training and job interruptions on tree cutting time for chainsaw operators in plantation forests, Tanzania
(2014-11) Silayo, Dos Santos A.; Migunga, George A; Shemwetta, Dunstan T. K.
Timber harvesting in Tanzania uses semi-mechanized and labour – intensive logging systems. Manual or semi- mechanized logging operations by using hand tools are more favoured due to cheap labour availability. For example, tree cutting is done manually using two-man crosscut saws, axes or chainsaws. This study was conducted at Sokoine University of Agriculture Training Forest to assess the effect of training and job interruptions for chainsaw operators during tree cutting operations in softwood plantation forests in Tanzania. Tree cutting operations using experienced and inexperienced chainsaw operators were studied in three experiments; before training, after training and after the break. Time study and work sampling techniques were used for data collection. Descriptive statistics and modeling was performed for each crews’ performance. Results show that generally, experienced crew spends lesser time in cutting as compared to inexperienced crews. However, start up chainsaw crew spent 32% higher time for preparation before tree felling. However, the crew showed significant improvement after training unlike the experienced one. The analysis of the delay times start up crew was had a significant proportion of the delay times during the first engagement which decreased substantially in the other two experiments. Generally, there was an improvement of the cutting time after training for all crew categories with decrease after the break. This observation signifies that job interruptions impact the productivity of the crews. Therefore, on job training on resumption of the operations may significantly improve crews’ productivity, safety as well as ensuring product quality.
Identifying ecosystem service hotspots for targeting land degradation neutrality investments in south-eastern Africa
(Elsevier, 2017-05) Willemen, L; Crossman, N.D; Quatrini, S; Egoh, B; Kalaba, F.K; Mbilinyi, B; Groot, R.d
Land degradation response actions need motivated stakeholders and investments to improve land management. In this study we present methods to prioritise locations for degradation mitigation investments based on stakeholder preferences for ecosystem services. We combine participatory and spatial modelling approaches and apply these for Zambia, South Africa, and Tanzania to: i) prioritise ecosystem services in each country; ii) to map the supply of these ecosystem services in each country, and; iii) prioritise areas important for investment for the continuous delivery of these ecosystem services based on their vulnerability to land degradation. We interviewed 31 stakeholders from governmental and non-governmental organizations to select the most important ecosystem services per county. Stakeholders were also asked to indicate on national maps the hotspots of these ecosystem services and locations with a high degradation risk. We then assessed the supply of the stakeholder-selected ecosystem services and land degradation risk using GIS-based spatial models. We found that for each country the spatial extent and magnitude of ecosystem services supply and land degradation based on GIS data coincides with stakeholder knowledge in some locations. In the context of supporting national level policy to achieve land degradation neutrality as proposed by the United Nations Convention to Combat Desertification we argue that the correct representation, the level of acceptance, and use of modelled outputs to support decisions will be greater when model outputs are corroborated by stakeholder knowledge. Ecosystem services that are identified as “important” by diverse stakeholder groups have a broader level of awareness and could therefore drive motivations, commitments, and actions towards improved land management, contributing to land degradation neutrality.
Stump diameter : a potential predictor of removed biomass through tree cutting
(Tanzania Journal of Forestry and Nature Conservation, 2021) Mugasha, W.A; Mauya, E; Karlsson, K; Malimbwi, R.E.
Stump diameter (SD) has been rarely considered as an important tree parameter in forestry. It is until recently that SD has been found to be important predictor of tree diameter at breast height (D) and forest stand parameter such as volume and biomass. This study, developed D-SD relationships for nine different forest cover type in Tanzania mainland. A total of 32265 sample trees covering miombo woodlands, humid montane, lowland forests, bushlands, grasslands, mangroves, cultivated land, wetlands forests and plantations (Pines and Eucalyptus species) were used for fitting D-SD models. The findings revealed a linear relationship between D and SD for all forest covers. In addition, we found forest covers having similar D-SD allometry while others had unique D-SD allometry. This prompted fitting Generalised Linear Model where three forest cover groups were generated, i.e. group 1 (bushlands, woodlands, lowlands and grasslands); group 2 (mangroves, cultivated land, plantation and wetlands); and group 3 (humid montane). We fitted linear model to each forest cover group. Large variations in D were adequately explained by SD for each forest cover group. We further compared AGB values estimated from the measured D and estimated D from the D-SD equation. The estimated AGB from both approach did not differ significantly. We therefore, recommend the developed D-SD relationships models be applied to predict D of the missing trees for which their stumps still exist.
Resource use efficiency in beekeeping using modern beehives: a case of Sikonge district, Tabora - Tanzania
(Tanzania Journal of Forestry and Nature Conservation, 2022) Wawa, M.M.; Lusambo, L.P.; Mbeyale, G.E
This study revealed detailed information concerning resource use efficiencies using modern beehives essential in planning to improve yield and profit of beekeeping in Sikonge District. Choices made by a beekeeper to use what and how much resources in beekeeping vary among beekeepers basing on availability of the resource itself. This study analysed the resource use efficiency in beekeeping activities in Sikonge District. The specific objective for this study was to evaluate resource use efficiency of beekeeping using modern beehives. Data was collected by semi-structured questionnaire, key informants’ interview, focus group discussion and direct field observation. This study was done in four wards; Chabutwa, Tutuo, Kipanga and Kiloleli. The wards were randomly selected out of the 15 wards of Sikonge District. Descriptive statistics were obtained using Statistical Package for Social Science (SPSS) computer programme as analytical tool. Results revealed that the number of beehives and number of man-days for hired labour were underutilised with resource use efficiency coefficient (r) values of 1.5 and 121 respectively while family labour man-days were over utilised (r = - 91.82). It is recommended that beekeepers in Sikonge utilize the available resources optimally to maximize yield and profit of their beekeeping activities.

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