Thesis (MSc (Forest and Wood Science))—University of Stellenbosch, 2007. / The utilization and commercialization of indigenous fruit trees has in the past been overlooked by extension agencies due to the misconception that they do not play a major role in contributing to the rural livelihoods. There is new and increasing emphasis on the contribution of non-timber forest products (NTFPs) on improving the livelihoods and sustainable management of forest ecosystems of the Miombo woodlands. This study was conducted around Mwekera area in the Copperbelt province, Zambia to determine the role of indigenous fruit trees in the rural livelihoods. A total of 70 households were interviewed in the survey using semi-structured questionnaires, in-depth open ended interviews and focus group meetings to collect information on the use of indigenous fruits. The study revealed that 99% of the households experience ‘hunger’ during the rainy season from November to April every year. Ninety seven percent (97%) of the households collect indigenous fruit, with the most collected fruits being Uapaca kirkiana (74%), Anisophyllea boehmii (71%) and Parinari curatellifolia (67%). Additionally, there is very little selling of indigenous fruit (31%) but that Uapaca kirkiana and Anisophyllea boehmii account for 95% of the fruits sold. Forty six percent (46%) of the households process fruits of U. kirkiana, A. boehmii and P. curatellifolia into juice and/or porridge. Furthermore IFTs are also used as traditional medicine. Sixty three percent (63%) of the households used IFTs for medicinal purposes with two-thirds of the respondents citing Anisophyllea boehmii as an important medicinal tree species. The study also showed that 85% of the respondents have seen a change in the forest cover resulting into loss of biodiversity with 70% of the respondents indicating that the change is with respect to reduction in forest size and scarcity of some species; and that charcoal production and clearance of land for cultivation are the major causes of the scarcity of indigenous fruit trees. It is concluded that the major contribution of IFTs in the study area is in filling the gap during times of hunger rather as being a source of income through selling. Charcoal production and clearance for agriculture are the main contributing agents for the loss of biodiversity and scarcity of IFTs. It is recommended that domestication of IFTs and sustainable forestry and agricultural management practices be employed to ensure that future generations continue to benefit from the forest resource.

Thesis (MFor)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: This study is aimed at testing the possibility of using woody biomass from three invasive woody vegetation types (Spider Gum, Myrtle and Acacia) for production of bioenergy in the Cape Agulhas Plain. Physical recoverability of the woody biomass was studied by means of a semi-mechanized harvesting system to evaluate potential productivity, operational costs and the estimated yield energy gain. The system consisted of five components: manual harvesting, motor-manual harvesting, extraction, chipping and road transport. Data on the system productivity was obtained using activity sampling and time study techniques. Activity sampling was applied on manual and motor-manual harvesting in order to record harvesting time and standard time study techniques were used to obtain time data for extraction, chipping and road transport operations. Findings revealed benefits associated with the utilisation of invasive woody vegetation as energy feedstock. Therefore, the problem of exotic tree species can be dealt with by transforming them into energy feedstock, thus minimising the effect of invasive plants. At the same time essential biomass energy can be produced, while some of the cost of production could be offset by the benefits accruing from the biomass energy. The Acacia site, characterized by larger mature dense trees, had the highest amount of harvested biomass compared to the rest of the vegetation types (i.e. Myrtle and Spider Gum). The overall system productivity was found to be significantly influenced by a low equipment utilisation rate, estimated at 50%. This resulted in low production rates in general. The low supply rate of material to the chipper by the three-wheeled loader (1.5 – 5.3 oven-dry tonne per production machine hour) was found to be a major constraint in the chipping process, especially when considering that the chipper is potentially capable of chipping 4 – 9.4 ODT PMH-1 at the harvesting sites. This resulted in a significant energy balance of 463 GJ between output and input energy of the system. The overall total supply chain system costs based various road transport distances of species ranged from R 322.77 ODT-1 to R 689.76 ODT-1 with an average of R 509 ODT-1. This was found to be costly compare to the case where high machine utilisation rate and optimal productivity are used (average of R 410 ODT-1), biomass recoverability in this field trial had a higher total system cost due to low productivity, resulting from the low equipment utilisation rate applied. / AFRIKAANSE OPSOMMING: Hierdie studie was gemik daarop om die moontlikheid van die gebruik van houtagtige biomassa, afkomstig van uitheemse plantegroei (Bloekom, Mirte en Akasias) op die Agulhasvlakte vir bio-energie te ondersoek. Potensiële produktiwiteit, bedryfskostes en die geskatte energie opbrengs toename is gebruik, om die fisiese opbrengs van houtagtige biomassa van ʼn semi-gemeganiseerde ontginningstelsel te evalueer. Die stelsel het uit vyf komponente bestaan: Handontginning, motor-handontginning, uitsleep, verspandering en padvervoer. Data oor die stelselproduktiwiteit is uit tydstudie en aktiwiteit steekproewe verkry. Aktiwiteit steekproewe is toegepas op hand- en motorhandontgining om ontginingstyd te verkry, terwyl tydstudie standaardtegnieke gebruik is om tyd data vir uitsleep, verspandering en padvervoer werksaamhede te verkry. Bevindings het die voordele met bettrekking tot die gebruik van uitheemse plantegroei as energiebron bevestig. Die uitdaging rondom die verspreiding van uitheemse plantegroei kan dus aangespreek word deur dit as energiebron te benut. Die produksiekoste vir die toegang tot die bruikbare biomassa kan moontlik voorsien word uit die voordele van die gebruik van die energie wat uit die benutting van die biomassa verkry word. Die groter meer volwasse en digte Akasia opstand het die meeste ontginde biomassa gelewer vergeleke met die ander opstande in die studie (d.i. Mirte en Bloekom). Die stelselproduktiwiteit is beduidend beïnvloed deur die lae toerustinggebruik wat minder as 50% beloop het. Dit het ook laer produksievermoë in die algemeen tot gevolg gehad. In die verspandering werksaamheid blyk die lae invoer tempo (1.5 – 5.3 oonddroog ton per produktiewe masjienuur) van die driewiellaaier die beperking op die proses te wees, veral as in ag geneem word dat die verspandering teen 4-9.4 ODT PMH-1 kan geskied. Die resultaat was ʼn beduidende energie balans van 463 GJ tussen uitset- en invoerenergie van die stelsel. Die totale toevoerketting kostes gegrond op verskeie padvervoer afstande van die spesies was tussen R 322.77 ODT-1 tot R 689.76 ODT-1, met ʼn gemiddelde rondom R 509 ODT-1. Die resultaat is duur gevind in vergeleke met gevalle waar hoë masjiengebruik en optimale produktiwiteit (gemiddeld van R 410 ODT-1), moontlik was. Die biomassaherwinning in die studie het ʼn hoër totale stelselkoste gehad veroorsaak deur lae produktiwiteit, wat verwant is aan die laer toerusting gebruikstempo wat verkry is.

Thesis (MScFor)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Site Index is used extensively in modern commercial forestry both as an indicator of current and future site potential, but also as a means of site comparison. The concept is deeply embedded into current forest planning processes, and without it empirical growth and yield modelling would not function in its present form. Most commercial forestry companies in South Africa currently spend hundreds of thousands of Rand annually collecting growth stock data via inventory, but spend little or no money on the default compartment data (specifically Site Index) which is used to estimate over 90% of the product volumes in their long term plans. A need exists to construct reliable methods to determine Site Index for sites which have not been physically measured (the socalled "default", or indirect Site Index). Most previous attempts to model Site Index have used multiple linear regression as the model, alternative methods have been explored in this thesis: Regression tree analysis, random forest analysis, hybrid or model trees, multiple linear regression, and multiple linear regression using regression trees to identify the variables. Regression tree analysis proves to be ideally suited to this type of data, and a generic model with only three site variables was able to capture 49.44 % of the variation in Site Index. Further localisation of the model could prove to be commercially useful. One of the key assumptions associated with Site Index, that it is unaffected by initial planting density, was tested using linear mixed effects modelling. The results show that there may well be role played by initial stocking in some species (notably E. dunnii and E. nitens), and that further work may be warranted. It was also shown that early measurement of dominant height results in poor estimates of Site Index, which will have a direct impact on inventory policies and on data to be included in Site Index modelling studies. This thesis is divided into six chapters: Chapter 1 contains a description of the concept of Site Index and it's origins, as well as, how the concept is used within the current forest planning processes. Chapter 2 contains an analysis on the influence of initial planted density on the estimate of Site Index. Chapter 3 explores the question of whether the age at which dominant height is measured has any effect on the quality of Site Index estimates. Chapter 4 looks at various modelling methodologies and compares the resultant models. Chapter 5 contains conclusions and recommendations for further study, and finally Chapter 6 discusses how any new Site Index model will effect the current planning protocol. / AFRIKAANSE OPSOMMING: Hedendaagse kommersiële bosbou gebruik groeiplek indeks (Site Index) as 'n aanduiding van huidige en toekomstige groeiplek moontlikhede, asook 'n metode om groeiplekke te vergelyk. Hierdie beginsel is diep gewortel in bestaande beplanningsprosesse en daarsonder kan empiriese groeien opbrengsmodelle nie in hul huidige vorm funksioneer nie. SuidAfrikaanse bosboumaatskappye bestee jaarliks groot bedrae geld aan die versameling van groeivoorraad data deur middel van opnames, maar weinig of geen geld word aangewend vir die insameling van ongemete vak data (veral groeiplek indeks) nie. Ongemete vak data word gebuik om meer as 90% van die produksie volume te beraam in langtermyn beplaning. 'n Behoefte bestaan om betroubare metodes te ontwikkel om groeiplek indeks te bereken vir groeiplekke wat nog nie opgemeet is nie. Die meeste vorige pogings om groeiplek indeks te beraam het meervoudige linêre regressie as model gebruik. Alternatiewe metodes is ondersoek; naamlik regressieboom analise, ewekansige woud analise, hibriedeof modelbome, meervoudige linêre regressie en meervoudige linêre regressie waarin die veranderlike faktore bepaal is deur regressiebome. Regressieboom analise blyk geskik te wees vir hierdie tipe data en 'n veralgemeende model met slegs drie groeiplek veranderlikes dek 49.44 % van die variasie in groeiplek indeks. Verdere lokalisering van die model kan dus van kommersiële waarde wees. 'n Sleutel aanname is gemaak dat aanvanklike plantdigtheid nie 'n invloed op groeiplek indeks het nie. Hierdie aanname is getoets deur linêre gemengde uitwerkings modelle. Die toetsuitslag dui op 'n moontlikheid dat plantdigtheid wel 'n invloed het op sommige spesies (vernaamlik E. dunnii en E. nitens) en verdere navorsing kan daarom geregverdig word. Dit is ook bewys dat metings van jonger bome vir dominante hoogtes gee aanleiding tot swak beramings van groeiplek indekse. Gevolglik sal hierdie toestsuitslag groeivoorraad opname beleid, asook die data wat vir groeiplek indeks modellering gebruik word, beïnvloed. Hierdie tesis word in ses hoofstukke onderverdeel. Hoofstuk een bevat 'n beskrywing van die beginsel van groeiplek indeks, die oorsprong daarvan, asook hoe die beginsel tans in huidige bosbou beplannings prosesse toegepas word. Hoofstuk twee bestaan uit ń ontleding van die invloed van aanvanklike plantdigtheid op die beraming van groeplek indeks. In hoofstuk drie word ondersoek wat die moontlike invloed is van die ouderdom waarop metings vir dominante hoogte geneem word, op die kwaliteit van groeplek indeks beramings het. Hoofstuk vier verken verskeie modelle metodologieë en vergelyk die uitslaggewende modelle. Hoofstuk vyf bevat gevolgtrekkings en voorstelle vir verdere studies. Afsluitend, is hoofstuk ses ń bespreking van hoe enige nuwe groeiplek indeks modelle die huidige beplannings protokol kan beïnvloed.

Thesis (MScFor)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: This study sought to determine the possible socio-economic impacts of the phasing out of nearly 22 500 ha of plantations within the Southern and Western Cape regions of South Africa as a result of a decision made by Government in September 2000. None of the previous studies undertaken focussed on the socio-economic impacts within the specific regions and plantations, but were based on wider environmental and economic considerations. Data was collected in 2007 from three plantations managed by Mountain to Ocean Forestry (MTO) (PTY) LTD: one located in Grabouw (Western Cape) and two in George (Southern Cape), among three different plantation stakeholder groups. These three groups were: (i) Forest Dependent Communities, (ii) Stakeholders among the forestry value chain and (iii) Indirect stakeholders. Within the first group, a total of 70 persons representing households were interviewed. A total of 26 primary and secondary processing company respondents were interviewed. Information on all of the indirect stakeholder groups was gathered, either through interviews with the stakeholders or from data received from MTO. This study indicated that there are significant differences between the potential impacts within the Southern Cape and Western Cape regions. The data collected showed that among communities within the Western Cape, the dependency on the plantations in terms of employment, income and fuelwood is low. This is in stark contrast to the communities within the Southern Cape, who are dependent on the plantations for their employment and income, and as a result will be affected greatly by the phasing out process. Company respondents in the Western Cape were less concerned than their Southern Cape counterparts about the future decrease in timber supply and indicated that they will source timber from elsewhere, whereas companies within the Southern Cape indicated that they would likely have to shut down. The dependency of indirect stakeholders on the plantations to be phased out, and the resulting impact was found to be minimal. The study concluded with an evaluation of an existing nine step plan for the implementation of social and economic actions within natural resource planning. Three main aspects were identified that need to be addressed namely: (i) To increase public awareness and participation among communities and companies to be impacted on by the phasing out process, (ii) Provide necessary training and thus increased skills level of workers who face unemployment; and (iii) The identification of alternative employment opportunities for the unemployed affected by the phasing out process. / AFRIKAANSE OPSOMMING: Hierdie studie het die potensiële sosio-ekonomiese impak van die uitfasering van plantasies in die Suid- en Wes-Kaap gebiede van Suid-Afrika ondersoek. Die besluit om 22 500 ha plantasies uit te faseer is in September 2000 deur die Suid-Afrikaanse Regering geneem. Geen vorige studies wat onderneem is het gefokus op die moontlike sosio-ekonomiese impakte in die spesifieke gebiede en plantasies nie, maar was gebaseer op groter omgewings- en ekonomiese oorwegings. Data insameling het in 2007 geskied in drie Mountain to Ocean Forestry (MTO) plantasies: een geleë in Grabouw (Wes-Kaap) en twee in George (Suid-Kaap), en onder drie verskillende plantasie belangegroepe. Hierdie drie groepe was (i) Gemeenskappe afhanklik van plantasies; (ii) Belangegroepe in die Bosbou-waardeketting en; (iii) Indirekte belangegroepe. ‘n Totaal van 70 huishoudings in die eerste groep is ondervra, en 26 primêre en sekondêre verwerkingsmaatskappye in die tweede groep is ondervra. Inligting oor al die indirekte belangegroepe is ingesamel, hetsy deur middel van onderhoude of deur data wat van MTO ontvang is. Die studie het aangedui dat daar betekenisvolle verskille tussen die potensiële impakte binne die Suid-Kaap en Wes-Kaap streke bestaan. Die versamelde data het getoon dat die afhanklikheid van gemeenskappe in die Wes-Kaap op die plantasies in terme van werk, inkomste en brandhout laag is. Dit is in skrille kontras met die gemeenskappe in die Suid-Kaap, wat afhanklik is van die plantasies vir hul werk en inkomste, en as gevolg daarvan grootliks geraak sal word deur die uitfasering proses. Maatskappy respondente in die Wes-Kaap was minder bekommerd as hulle eweknieë in die Suid- Kaap oor die toekomstige afname in die saaghoutvoorraad en het aangedui dat hulle saaghout van elders sal bekom, terwyl maatskappy respondente in die Suid-Kaap aangedui het dat hulle waarskynlik hul deure sal moet sluit. Die afhanklikheid van indirekte belanghebbendes op die plantasies wat uitgefaseer word, en die gevolglike impak blyk minimaal te wees. Die studie is afgesluit met 'n evaluering van ‘n bestaande nege stap plan vir die implementering van maatskaplike en ekonomiese kwessies in natuurlike hulpbron beplanning. Die drie belangrikste aspekte is geïdentifiseer wat aangespreek moet word naamlik: (i) Die verhoging van openbare bewustheid van en deelname tussen gemeenskappe en maatskappye wat deur die uitfasering proses geraak sal word, (ii) Die verskaffing van nodige opleiding en dus die verhoging van die vaardighede van werkers wat werkloosheid in die gesig staan; en (iii) Die identifisering van alternatiewe werksgeleenthede vir die werkloses wat deur die uitfasering proses geraak sal word.

Thesis (MScFor) (Forest and Wood Science)--University of Stellenbosch, 2003. / Planting of upperstorey trees along boundaries has been introduced in KabaleUganda with good reception from local farmers. Trees have been planted along agricultural fields, but both Alnus acuminata and Grew/lea robusta out-compete food crops. Managing competition between trees and crops for water, light, and nutrients to the benefit of farmers is a determinant of successful agroforestry. The scarcity and fragmentation of farmland coupled with the hilly nature of Kabale, highlights the need to address the question of tree-crop competition for resources if the technology of on-farm tree planting is to be widely disseminated and adopted in its different guises. Five-year old trees of A acuminata and G. robusta were subjected to treatments of pollarding, or a combination of pollarding and one side root pruning and compared with unpruned controls. The objectives were to assess their potential in reducing competition with food crops and providing firewood to farmers as well as their effects on tree growth. Pollarding has many benefits to farmers because it provides firewood and stakes for climbing beans, it reduces competition for resources between trees and crops and enables continued tree planting on-farm. Continued on-farm tree planting alleviates problems associated with limited land and contributes to environmental resilience. To ensure this, effect of pollarding and root pruning of upperstorey boundary trees of A acuminata and G. robusta was tested on 12 farmers' fields in Kabale. Food crops (beans and maize) grown in the sequence beans-maize-beans, grew very well at less than 50 em from trees that had been pollarded and root pruned one side. In general, pooled data from 12 sites over 5 m away from trees indicated that a combination of pollarding and root pruning increased bean yield by 240% and maize by 154%, while pollarding alone increased bean yield by 181% and maize yield was increased by 123% in comparison to non-pruned trees. However, pollarding and root pruning treatments reduced tree growth rates.Notable was more competition with crops by A. acuminata than by G. robusta. This was attributed to differences in root architecture, diameter at breast height (dbh) sizes, crown spread and crown density between the two species. Five-year-old A. acuminata had bigger dbh (12.40 cm), wider crown spread (6 m) and a dense crown, while G. robusta had dbh 10.82 em, 3 m crown spread and a light crown. A. acuminata also had more branches per tree (34) compared to G. robusta with only 25. These factors influence water uptake, light penetration through the canopy and transpiration rates, and thus affect tree-food crop competition. It is concluded that pollarding and root pruning have a great potential to reduce tree-crop competition, thereby paving the way for continued on-farm tree planting. The effect of pollarding on timber quality, moisture seepage into timber through the cut surface, if any, and the extent of its damage are areas for further research. The rate of root recovery is also to be followed closely to determine an appropriate frequency for cutting back of roots to recommend to farmers how often they need to prune their trees. It is also suggested that a thorough study be conducted on the amount of water uptake from the soil by each of the species Alnus acuminata and Grevillea robusta. This will help further explain the differences in competition between the two species.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2005. / Like in many developing countries, forest and woodland resources contribute significantly to ensure the sustainability of livelihoods of rural people of Eritrea. However, the contribution made by forest and woodland resources has been masked due to the inability of the traditional economic valuation methods to reveal the hidden values of forest resources. As a result they do not reflect in GDP accounting, development planning and conservation policymaking. The underestimation of the importance of forest and woodland resources to the rural subsistence economy results in both market and policy failures. These in turn lead to escalated forest degradation, livelihood insecurity, value conflicts and ineffective conservation programmes. The forest and woodlands of administrative sub-zone Dighe were selected as a case study as they comprise trees, shrubs and other non-woody plants of outstanding importance both in terms of socio-economics and biodiversity richness. However, these resources are being rapidly depleted as a result of clearing for commercial agriculture and are under growing pressure due to resettlement of returnees and needs of other social actors. The study was carried out in three representative administrative areas of the sub-zone. A literature survey was carried out to identify the best of traditional neo-classical economic valuation methods to use in this study. Complementary methods from various streams of economics, ethnobotany, ecological anthropology and rural sociology were reviewed. The sub-set of selected marketable items were quantified and monetised based on market-based valuation approaches; and compared with non-marketable roles to indicate the magnitude of full values of the forest and woodland resources. Values that could not be quantified were described qualitatively. A production-consumption analysis of dom palm scrub leaf harvesting for household utensils was carried out. Forest health was investigated based on observation, semi-structured interviews and secondary information. The study revealed that local forests and woodlands provide essential goods and services for subsistence use, to generate income and to reduce vulnerability during times of hardships. Riverine forests, acacia woodlands and scattered trees and shrubs of grassland are the three vegetation types found in the study area. The riverine forest, dominated by dom palm, is a most valuable resource as it provides for multiple uses. Among the many marketable and non-marketable benefits, forests and woodlands provide wild food, construction material, livestock feed, household utensils, firewood, traditional medicine, shade, climate amelioration, erosion control, cultural heritages and scenic values. All members of rural households regardless of age, gender and wealth extract forest products, which minor variation between households and administrative areas. Variability of consumptive use values between households and between administrative areas and other non-marketable values are determined by relative wealth status, seasonality, resource availability and distribution, market outlets and local institutions. The study revealed that the riverine forests and woodland values of the Dighe administrative sub-zone alone have contributed economical values many times greater than US $ 1.43 million per annum for selected quantifiable items only. This would be higher if the other non-marketable forest values were monetised including the livestock grazing and access to watering points. Beyond any doubt, the high local values of forest and woodlands and consequently the contribution to the national economy justify the conservation of the remaining forest. Moreover, the production-consumption analyses showed that the present level of dom scrub leaf harvesting is sustainable. Forest health situation analysis indicates, however, that the entire forest is under immense pressure. Moreover, the findings of this study suggest that conserving forest resource for local values is compatible with the millennium global development agendas.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The discussion on climate change is leading to a re-evaluation of tree plantations in South Africa; prompting the adoption of forest bioenergy system as one of the cost effective ‘carbon mitigation options’. In an analysis of this changing paradigm, emphasis was placed on the socio-economic aspects of integrated commercial tree plantations and forest bioenergy systems with special attention to harvest residues recovery for bioelectricity production and construction and operation of a bioelectricity plant. The study also explored the direct and indirect benefits that adjacent communities derive from tree plantations in South Africa in order to determine the potential impact of integrated timber and bioelectricity production on rural livelihood and conventional forestry operations. Structured questionnaires and in-depth interviews were used in randomly sampling twelve villages on Mondi tree plantations in the Piet Retief and Iswepe areas of South Africa. Six villages from each area were selected; and a systematic random sampling of ten households per village was carried out. The possibility of using harvest residues from final clear felling from these plantations for bioelectricity production was examined. The study developed and described a scenario for a five megawatt bioelectricity generation facility, requiring an annual volume of 19,569.85 dry tonnes of residues as feedstock for its operation. The study revealed that adjacent rural communities to Mondi plantations in Piet Retief and Iswepe areas enjoy direct benefits such as employment opportunities, utilization of harvest residues, utilization of non-timber resources, and free accommodation. Indirect benefits that these communities enjoy include: free farmland and graze-land and various social benefits. Issues of concern and dislike such as: lack of electricity; poor health and sanitation and transportation problems were also identified. Using NPV and IRR, the study estimated the economic impacts of integrated pulpwood and bioelectricity production, compared to conventional pulpwood production operation. The study concluded that integrated pulpwood and harvest residue recovery for bioelectricity production is a profitable means of producing renewable energy. The approach was found to increase the profitability of conventional forest operations. / AFRIKAANSE OPSOMMING: Besprekings rondom klimaatsverandering lei tot ‘n her-evaluasie van boom plantasies in Suid Afrika wat aanleiding gee tot die aanvaarding van bio-energie stelsels as een van die koste effektiewe “koolstof versagtende opsies”. In ‘n ontleding van hierdie paradigma verandering, is klem geplaas op die sosio-ekonomiese aspekte van die integrasie van boom plantasies en bos bio-energie stelsels. Spesiale aandag is gegee aan onginningsafval herwinning vir bio-energie produksie en die konstruksie en werking van ‘n bio-elektriese kragsentrale. Die studie ondersoek ook die direkte en indirekte voordele wat gemeenskappe, aangrensend aan boom plantasies in Suid Afrika verkry, om sodoende die potensiële effek van geintegreerde hout en bio-elektriese produksie op landelike lewensbestaan en konvensionele bosbou operasies te bepaal. Gestruktureerde vraelyste en indiepte onderhoude is gebruik om ‘n lukraakte steekproef van twaalf dorpies op Mondi boom plantasies in die Piet Retief en Iswepe areas van Suid Afrika uit te voer. Ses dorpies in elke area is gekies en ‘n sistematiese lukraakte steekproef van tien huishoudings per dorpie is uitgevoer. Die moontlikheid om ontginningsafval van finale kaalkap van hierdie plantasies vir bio-elektrisiteit te gebruik is ook ondersoek. Die studie het ‘n senario ontwikkel en beskryf van ‘n vyf megawatt bio-elektriese kragsentrale wat ‘n jaarlikse volume van 11,708 droë ton ontginningsafval benodig as voermateriaal vir kragopwekking. Die studie het getoon dat aangrensende landelike gemeenskappe langs Mondi plantasies in die Piet Retief en Iswepe areas direkte voordele soos werksgeleenthede, gebruik van ontginningsafval, gebruik van nie-hout hulpbronne en gratis akkommodasie geniet. Indirekte voordele wat gemeenskappe geniet sluit in gratis toegang to landbou grond en weiding, sowel as sosiale voordele. Probleemfaktore waarmee hulle saamleef is ‘n gebrek aan elektrisiteit, swak gesondheids en sanitasie dienste en vervoerprobleme. Deur die gebruik van NPV en IRR analitiese metodes is die ekonomiese impak van geintegreerde pulphout en bio-elektrisiteits produksie bepaal en vergelyk met konfensionele pulphout produksie. Die gevolgtrekking is dat geintegreerde pulphout en ontginningsafval herwinning vir bio-elektrisiteit produksie ‘n winsgewende manier van hernubare energie produksie is. Die benadering kan die winsgewendheid van konfensionele bosbou operasies verbeter.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The purpose of the study was to investigate the potential tree taxa that could be grown as a source of biomass in the Cape Winelands region. The trials comprises of two different aspects. The first being the estimation of potential volume, density and biomass of a pair of six year-old stands of E. gomphocephala and E. cladocalyx families at two climatically different sites within the study region. The second part of the study was the early growth assessment of alternative taxa that could be planted in the region compared to the regional mainstay E. cladocalyx. The volume of families was estimated using appropriate volume equations and using the form height were none were available. The best volume yield varied from 4.6 to 11.2 m3 ha-1a-1, at the dry and sub-humid sites, respectively. Wood density, estimated from non-destructive samples at both sites, varied from 620 (sub-humid) to 588 kg m-3 (dry site). The estimated biomass production rate of the top producing families yielded 2.7 and 6.9 t ha -1a -1 at the dry and sub-humid sites, respectively. In terms of estimated biomass and survival, E. gomphocephala was more suited to the dry site, while E. cladocalyx displayed superior yield than E. gomphocephala on the sub-humid site, but not significantly so. Early growth assessment of the trial of alternative taxa found that the hybrid E. grandis × camldulensis and E. grandis × urophylla had superior biomass indices, but were more susceptible to infestation by Thaumastocoris peregrinus and Gonipterus scuttelatus. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om potensiële boom taksa vir gebruik as ’n bron van biomassa in die Kaapse Wynlandstreek te ondersoek. Die proewe behels twee aspekte: eerstens die beraming van die potensiële volume, digtheid en biomassa van sesjaaroue opstande met families van E. gomphocephala en E. cladocalyx by twee klimatologies verskillende groeiplekke in die studiegebied; tweedens die beoordeling van die vroeë groei van alternatiewe taksa wat in die streek geplant kan word in vergelyking met die streek se historiese staatmaker-spesie E. cladocalyx. Die volume van die families is beraam deur gebruik te maak van toepaslike volumevergelykings, en met behulp van ’n vormfaktor waar vergelykings nie beskikbaar was nie. Die volume aanwas by die droë en sub-humiede groeiplekke was onderskeidelik 4.6 en 11.2 m3 ha-1j-1. Houtdigtheid is beraam deur nie-destruktiewe monsters uit die opstand te neem. Gemiddelde digthede het variëer van 588 (sub-humied) tot 620 kg m-3 (droë groeiplek). Die beraamde biomassaproduksie van die top-families beloop onderskeidelik 2.7 en 6.9 t ha -1j -1 vir die droë en sub-humiede groeiplekke. In terme van beraamde biomassa en oorlewing, is E. gomphocephala meer geskik vir droër groeiplekke , terwyl E. cladocalyx by die sub-humiede groeiplek ’n hoër opbrengs as E. gomphocephala getoon het, hoewel nie betekenisvol nie. Beramings van die vroeë groei by die proef met alternatiewe taksa het getoon dat die basters E. grandis × camldulensis en E. grandis × urophylla hoër biomassa-indekse het, maar meer vatbaar is vir besmetting deur Thaumastocoris peregrinus en Gonipterus scuttelatus. / Centre for Renewable and Sustainable Energy Studies

Thesis (MScFor)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Free-ranging lions (Panthera leo) in the Kgalagadi Transfrontier Park (KTP) have been subject to persecution by farmers following livestock depredation in adjacent grazing areas. In recent years at least one adult female was killed annually from a sub-population of five boundary prides that have home ranges adjoining these livestock grazing areas. While no long-term records of human-caused mortality are available, the impact of current rates of human-caused mortality is uncertain. Female-based, age-structured models were thus used to estimate the long-term viability of the KTP lion sub-population subjected to human-caused mortality under deterministic and stochastic environmental conditions. Population parameters incorporated in the models included age-class specific natural mortality, female fecundity and birth sex ratio. In so doing sustainable threshold rates of persecution were established, so that effective conservation measures can be taken, if required, to ensure the continued survival of boundary prides in the park. Sensitivity analyses of natural survival rates indicated that adult female survivorship is the most important population parameter with respect to maintaining population viability, compared to younger female age-classes, fecundity or birth sex ratio. Hence adults were also the most sensitive age-class with respect to human-caused mortality, as adult survival repeatedly acts upon individuals with the highest reproductive value. In the deterministic model, with the most optimistic survival parameter values, fecundity and birth sex ratio (female-biased) estimates, the sub-population is only able to sustain an annual persecution of three adult females, before the sub-population exhibits a sustained decline. In the worst-case scenario, where fecundity and sex ratio estimates are at their lower extremes, the maximum sustainable age-class specific persecution rate is zero, for all age-classes. Whilst these hypothetical scenarios are unrealistic, they do highlight the extreme thresholds of potentially sustainable persecution rates. Under the most optimistic scenario using the stochastic model, the highest achievable survival probability of the sub-population, when subjected to a persecution rate of one adult annually, was 78%. Although increased fecundity and birth sex ratio biased towards females may increase the survival probability, these parameters are generally at their mean values in the long-term, and may thus not necessarily prevent a sustained population decline. The models therefore suggest that the current persecution rate of one adult annually (or 4% of the adult sub-population), appears unsustainable in the longterm. To ensure the survival of existing boundary prides and to maintain a viable subpopulation, adult lionesses should, as far as possible, be afforded protection from persecution. / AFRIKAANSE OPSOMMING: Vrylewende leeus (Panthera leo) in die Kgalagadi Oorgrenspark (KTP) is onderworpe aan vervolging deur boere as gevolg van predasie op vee in aangrensende weidingsgebiede. In onlangse jare is ten minste een volwasse wyfie uit ‘n subpopulasie van vyf troppe met loopareas wat aan die weidingsgebiede grens, jaarliks uitgewis. Geen langtermyn rekords van vrektes as gevolg van menslike oorsake is beskikbaar nie, en die impak van vrektes wat deur mense veroorsaak word, is dus onseker. Wyfie-gebaseerde, ouderdomgestruktureerde modelle is daarom gebruik om te voorspel wat die langtermyn lewensvatbaarheid is van die KTP leeu subpopulasie wat onderworpe is aan vrektes deur menslike invloede onder deterministiese en stogastiese omgewingsfaktore. Bevolkingsfaktore wat deur die modelle in ag geneem is, sluit ouderdomsgroep-spesifieke natuurlike vrektes, aanwas van wyfies en geboorte geslagsverhouding in. Sodoende is volhoubare uitwissingstempos bepaal sodat, indien nodig, effektiewe bewaringsmeganismes toegepas kan word om die voortbestaan van troppe in die grensgebiede van die park te verseker. Sensitiwiteitsanalises van natuurlike oorlewingstempos het aangetoon dat volwasse wyfies se oorlewing die belangrikste bevolkingsfaktor is om die bevolking se lewensvatbaarheid te volhou vergeleke met jonger wyfie ouderdomsgroepe, aanwas of geslagsverhouding by geboorte. Daarom was volwassenes ook die sensitiefste vir vrektes as gevolg van menslike invloede, omdat die oorlewing van volwassenes herhaaldelik inwerk op individue met die hoogste reproduktiewe waarde. In die deterministiese model met die mees optimistiese oorlewing, aanwas en geboorte verhouding (wyfie-gebasseerde) beramings, is die subpopulasie slegs in staat om ‘n jaarlikse uitwissing van drie volwasse wyfies te onderhou, voordat die sub-populasie ‘n volgehoue afname toon. In die uiterste geval waar aanwas en geslags verhouding skattings op die laagste is, is die maksimum volhoubare ouderdomsklasspesifieke beramings nul vir alle ouderdomsklasse. Terwyl hierdie hipotetiese senario’s onrealisties is, onderstreep dit die uiterste vlakke van potensiële volhoubare uitwissingstempos. Onder die mees optimistiese senario – ‘n uitwissingstempo van een volwassene jaarliks – met die gebruik van die stogastiese model, was die hoogste haalbare oorlewingswaarskynlikheid van die sub-populasie 78%. Alhoewel ‘n toename in aanwas en geboorte geslagsverhouding (met oorhelling na wyfies), ‘n toename in oorlewingswaarskynlikheid tot gevolg kan hê, is hierdie faktore oor die algemeen gemiddeld oor die langtermyn en sal dit nie noodwendig ‘n volgehoue afname in die populasie verhoed nie. Die modelle dui daarop dat die huidige uitwissingstempo van een volwassene (of 4% van die volwasse sub-populasie) op ‘n jaarlikse grondslag onvolhoubaar is oor die langtermyn. Om die oorlewing van bestaande troppe in die grensgebiede, asook ‘n lewensvatbare subpopulasie, te verseker, moet volwasse leeuwyfies so ver as moontlik teen vervolging beskerm word.

Thesis (MScFor)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Grobbelaar, F.R. 2000. A methodology to aid in appropriate technology decision-making for developing countries. M.Sc thesis. University of Stellenbosch. In the process of selecting what we believe to be suitable technology for timber harvesting and transport, economics are usually the determining factor, whether in the form of capital investment or personnel cost. Internationally we see a move towards mechanisation in forestry for various reasons: e.g., high wages, labour shortage, and occupational safety. The realities of South Africa highlights other issues requiring attention: e.g., high unemployment, skills' shortage, global competition, rampant AIDS pandemic, and a poor safety and security record. This should focus our attention on finding local solutions to the problem of finding suitable or appropriate technology to support South Africa's quest for sustainable development. This thesis attempts to establish a methodology for the objective evaluation of alternative technologies for a specific timber harvesting situation, considering the economic, social and environmental implications. / AFRIKAANSE OPSOMMING: Grobbelaar, F.R. 2000. A methodology to aid in appropriate technology decisionmaking for developing countries. M.Sc tesis. Universiteit van Stellenbosch. Tydens die keuse van sogenaamde toepaslike tegnologie vir houtinoesting en -vervoer is ekonomie meestal die deurslaggewende faktor, hetsy verteenwoordig deur kapitaal belegging of personeelkoste. Internasionaal is daar tans In neiging na meganisasie in bosbou vir In verskeidenheid redes: bv., hoë arbeidskoste, arbeidtekort, en beroepsveiligheid. Die werklikhede van Suid-Afrika beklemtoon egter ander sake wat daadwerklike optrede vereis: nl., hoë werkloosheid, gebrek aan vaardighede, internasionale mededinging, ernstige VIGS pandemie, en In swak veiligheid-en sekuriteit rekord. Dit behoort ons aandag te fokus op die vind van plaaslike oplossings tot die probleem met die keuse van geskikte of toepaslike tegnologie ter bevordering van Suid Afrika se strewe na volhoubare ontwikkeling. Hierdie tesis poog om In metodiek te ontwikkel vir die objektiewe beoordeling van alternatiewe tegnologieë vir houtinoesting binne bepaalde omstandighede, met inagneming van ekonomiese, sosiale en omgewings implikasies.