Assignment (MFor)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: The ongoing environmental destruction that results from the continuous use of the woodland resources for economic purposes has caused extensive changes in the original vegetation of Goba area of southern Mozambique. Developing alternative sources of income for communities can reduce their dependence on the production of charcoal, building materials and wood carvings. The lack of infrastructure and remoteness of these localities from the markets make alternatives economically unfeasible and thus unsustainable for rural development. Ineffective policy planning that does not address the problem in a holistic way causes the dilemma of local people in remote areas. The challenge at Goba is to develop alternative livelihoods that are economically, socially and ecologically sustainable. Nature-based tourism has been identified as such an alternative to realize this goal. However, this development requires incentives for sustainable resource use, which can be created either by expanding the benefits accruing from the efficient use of the resource or by changing the distribution of the benefits and cost in favor of the users. In many cases, local communities have developed tourism initiatives in ecologically fragile, remote areas, without sound planning based on detailed ecological and socio-economic information. Uncontrolled flows of tourists in unplanned tourist destinations degrade these areas. These destinations lose their aesthetic appeal; tourism flow decreases and consequently new attractions are opened. This study is of a land use planning nature and follows a combination of existing framework tools. The primary aim of this study was to develop simple guidelines for nature-based tourism that contribute to the conservation and management of the rural woodland areas as well as to the improved socio-economic welfare of rural communities in the Goba area. The study used baseline information for planning, focusing on the tourism market and on the ecological and socia-economical aspects of the siudy area. Two strategies were used to obtain the information, namely market research and attraction resources analysis. The market research in the southern part of Mozambique shows that: International tourist flows are at present from Southern African countries mostly South Africa (more than 50%), North America, Europe and Australia or Asia. Mozambique is perceived mainly as a sunny beach destination for vacations and weekends though most of the tourists were engaged in multi-destination itineraries that included safari, wildernesses, bird watching, touring and curiosity. There was no evidence from any tourist that nature tourism was the reason to visit Mozambique, but many of them said that they would visit ecotourism and nature tourism destinations if available. The average daily expenditure per tourist was found to be US$47. Tourists from long-haul distances had higher disposable expenditures and stayed longer in both attraction assets and in the country. Sixty nine per cent (69%) of surveyed tourists were over 50 years of age and they were mostly males (57%). The results show clearly that many issues must be taken into consideration where the development of ecotourism and nature-based tourism, especially in rural areas, is concerned. Such considerations should include (i) careful planning of the destinations based on the local developmental policy; (ii) developing saleable tourist products and packages and (iii), promotional strategies to expand the market to capture tourists with high average daily expenditure. The rural communities can then have a chance to develop nature-based tourism that uses outstanding natural resources. The resources analysis study results revealed that: The rugged topographic, climatic conditions of Goba water catchment area and the distance from settlements have naturally preserved local forest resources from human utilization. The area has well conserved and differentiated natural scenic landscape. These scenic landscapes have recreational values as well as environmental contrast, scientific discovery potential and retention of vanishing biological species. To preserve or improve the management of these landscapes, it is essential to consider recreation use in relation to all other potential values. Few existing landscapes showed a relative ability to absorb impacts produced by facility development with a minimum negative effect on the visual and ecological quality of the landscape. The majority of the landscapes have some potential for primitive and sensitive recreational spectrum. All these results are consistent with results from similar studies on watershed and water catchment ecology. Given the constraints on the environmental settings of the Goba landscapes, it is recommended that the basic and logic framework development should attract tourists interested in the more primitive portion of the recreational spectrum and should have fewer facilities of small-scale building. These facilities should be rustic in character with less service and more emphasis on self-reliance. Improved management of the Goba ecosystem is needed to maintain the ecological functions of the catchment and local culture and rurality. In conclusion, this study suggests that, if on these remote fragile ecosystems local communities can protect and market attractive quality-of-life-amenities, maintain a relatively low cost of living, and offer serviceable links to global telecommunication infrastructures in order to attract tourists and retirees, these communities can survive and may even thrive as local economies. An incentive planning method and sustained extension outreach effort in rural development, which focuses on nourishing local action at the grassroots level, will complement such a policy strategy. / AFRIKAANSE OPSOMMING: Omvattende verandering van die natuurlike plantegroei in die Goba area van suiderlike Mosambiek is teweeg gebring deur die deurlopende bentting van die omgewing deur die misbruik van die natuurlike hulpbronne vir ekonomiese wins. Die ontwikkeling van alternatiewe inkomstebronne vir plaaslike gemeenskap kan hul afhanklikheid van hout vir die produksie van houtskool, boumateriaal en houtsneewerk verminder. Die gebrek aan infrastruktuur en die groot afstande na markte maak die verkoop van die houtprodukte in stedelike gebiede onprakties en dus nie 'n volhoubare oplossing vir landelike ontwikkeling nie. Oneffektiewe beleidsbeplanning wat die probleem nie holisites benader nie veroorsaak 'n dilemma vir inwoners in afgeleë gebiede. Die uitdaging in Goba is om alternatiewe bronne van inkomste te ontwikkel wat ekonomies, sosiaal en ekologies volhoubaar is. Natuurgebaseerde toerisme is geïdentifiseer as 'n moontlike alternatief wat aan die doel kan beantwoord. Die ontwikkeling van eko-toerisme sal egter net slaag indien die plaaslike bevolking genoegsaam aangemoedig word om die natuurlike hulpbronne op 'n volhoubare basis te benut. Dit kan gedoen word óf deur winste terug te ploeg in die omgewing en so die toerisme basis te vergroot óf deur winsdeling op 'n gebruikersgunstige voordele- en kostebasis te behartig. In baie gevalle het plaaslike gemeenskappe toerisme inisiatiewe in sensitiewe, afgeleë gebiede ontwikkel, sonder deeglike beplanning wat op uitgebreide ekologiese en sosio-ekonomiese inligting berus. Die onbeheerde toeriste aanloop na onbeplande areas lei tot die stelselmatige vernietiging daarvan. Hierdie bestemmings verloor hul estetiese waarde en het tot gevolg dat toeriste ander ongerepte areas gaan soek. Hierdie studie handeloor die beplanning van grondgebruik en volg 'n kombinasie van bestaande raamwerk prosedure. Die primêre doel van hierdie ondersoek is om eenvoudige riglyne vir natuurgebaseede eko-toerisme te ontwikkel wat 'n bydra kan lewer tot die bewaring en bestuur van die natuurlike wonde en wat die sosioekonomiese welvaart van die plaaslike bevolking van Goba sal bevorder. Die studie maak gebruik van basiese inligting vir beplanning, en fokus op die toeristemark sowel as op die ekologiese en sosioekonomiese aspekte van die studie-area. Die twee strategieë wat gevolg is om inligting in te win is marknavorsing en die analise van toeriste-attraksie hulpbronne. Marknavorsing in die suide van Mosambiek toon dat die meerderheid internasionale besoekers aan Mosambiek afkomstig is van lande in Suidelike Afrika (Suid-Afrika alleen 50%), en daarna uit Noord- Amerika, Europa and Australië/Asië. Mosambiek word hoofsaaklik as 'n sonnige strandoord-bestemming vir vakansies en naweke beskou, hoewel die meeste toeriste 'n multi-bestemming reisplan volg wat safaris, ornitologie, reis en besoeke aan besienswaardighede insluit. Daar is geen bewys gevind dat enige toeris Mosambiek besoek het met eko-toerisme as doel nie, maar baie sou belangstelom dit te doen indien ekoen natuurgebaseerde toeriste-betemmings beskikbaar was. Die gemiddelde daaglikse uitgawe per toeris was US$47. Toeriste wat groot afstande moes aflê om hul bestemming te bereik het meer beskikbare fondse en bly langer, beide in die land en by verskillende attraksies. Van die toeriste by wie die opname gemaak is 69% ouer as 50 jaar en die meerderheid (57%) was mans. Die resultate toon dat daar talle faktore is om in ag te neem by die ontwikkeling van 'n landelike area vir natuurgebaseede en eko-toerisme. Daar moet aandag gegee word aan (i) deeglike beplanning van die bestemming gebaseer op die plaaslike ontwikkelingsbeleid; (ii) die ontwikkeling van verkoopbare toeriste produkte en pakkette;en (iii), promosie strategieë om die mark uit te brei om toeriste wat meer spandeer te lok. Die landelike gemeenskappe word sodoende die geleentheid gebied om hul besondere natuurlike hulpbronne te ontwikkel vir natuurgebaseerde toerisme. Die hulpbron-analise toon dat die afgeleë en bergagtige topografie en die klimaatsomstandighede van Goba se wateropvangsgebied as natuurlike beskerming vir inheense woude teen die benutting deur die plaaslike bevolking gedien het. Die area is goed bewaar met skouspelagtige natuurtonele. Die skouspelagtige landskap beskik oor rekreasiewaarde sowel as omgewingskontras, potensiaal vir wetenskaplike ontdekkings en vir bewaring van seldsame fauna en flora. Om hierdie landskap te bewaar of die bestuur daarvan te verbeter, moet gebruik vir rekreasie in verhouding tot die ander potensiële waardes beskou word. Daar is beperkte areas wat die vermoë besit om ontwikkeling te absorbeer en waar die verbouing van fasiliteite slegs 'n minimale negatiewe effek op die visuele en ekologiese kwaliteit sal hê. Die potensiaal bestaan egter vir alle areas om op 'n beperkte skaalontwikkel te word vir die primitiewe en sensitiewe sektor van die rekreasie spektrum. Die resultate van die vavorsing stem ooreen met soortgelyke studies van waterskeiding- en wateropvangsgebied-ekologie en ontwikkeling. Vir die gegewe omgewingsbeperkings van Goba word dit aanbeveel dat ontwikkeling op 'n basiese vlak geskied om daadie proporsie van die toeriste te lok wat in die sogenaamde wildernis-ervaring belangstel. Geboue en beperkte fasiliteite moet slegs op klein skaal opgerig word. Die fasiliteite moet by die omgewing inpas en die klem moet op selfvoorsiening eerder as op dienstelewering val. Die bestuur van die Goba ekosisteem moet egter verbeter om die ekologiese funksie en die plaaslike kultuur en landelikeid te behou. Die bevinding van die studie is dat indien ver-afgeleë en sensitiewe ekosisteme deur die plaaslike bevolking bestuur en beskerm word, dit tot ekonomiese welvaart van die landelike gebiede kan lei. Hierdie areas moet bestuur word sodat die landelike karakter as toeriste aantreklikheid behou word, dat die lewenskoste relatief laag bly en dat verbindings met die buitewêreld op telekommunikasie vlak ingestel word. Beplanning moet op 'n aansporingsbasis gegrond wees met uitreikingsprogramme met landelike ontwikkeling as doel. Aanmoediging van plaaslike aksie op grondvlak behoort so 'n beleidstrategie te versterk.

Thesis (MFor ) -- University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The bulk of paper grades destined for the printing industry are produced on modern paper machines which continuously become wider and faster. In order to improve printability, print quality and dimensional stability, such papers contain a large percentage of mineral pigments either in the form of internal loading or external coatings. Although mineral pigments exercise a substantial beneficial effect on paper surface quality, unfortunately these minerals do not contribute towards sheet strength and machine runnability. Today's papermakers are faced with the dilemma of producing highly filled and coated printing papers with low grammages on faster running paper machines, but often lacking the required quality of fibre resources to secure a smooth runnability of such at high speeds. Standard fibre furnishes will have to be upgraded with special types of reinforcing fibres in order to meet the demands of sheet strength and machine runnability. The investigation had succeeded to identify a new suitable fibre resource, which would satisfy the demand of a reinforcing type natural material. / AFRIKAANSE OPSOMMING: Die oorgrootte meerderheid tipes papier wat vir die drukkersbedryf bestem is, word op moderne papiermasjiene vervaardig wat steeds breër en vinniger word. Om die drukbaarheid, drukkwaliteit en dimensionele stabiliteit te verbeter, bevat sulke papiere groot hoeveelhede minerale pigmente wat in die vorm van interne ladings of as eksterne bestrykings teenwoordig is. Alhoewel minerale pigmente -n merkbare voordelige effek op die papier oppervlakte-kwaliteit uittoefen, dra sulke pigmente ongelukkig nie by tot die sterkte en loopvermoë van die papier nie. Die hedendaagse papiervervaardiger word konfronteer met die dilemma om swaar gevuldeen bestrykte drukpapiere met lae oppervlaktegewig op vinniger lopende papiermasjiene te vervaardig. Dit gebeur dikwels sonder die beskikbaarheid van die nodige hoëkwaliteit veselbronne om te verseker dat die loopvermoë van die papier teen hoë spoed nie benadeel word nie. Standaard veselsamestellings salopgegradeer moet word met spesiale tipe versterkingsvesels om aan die uitdaging van hoë velsterkte en masjien-Ioopvermoë te voldoen. Hierdie ondersoek het daarin geslaag om 'n nuwe geskikte veselbron te dentifiseer en wat aandie behoeftes van 'n versterkingsvesel sal voldoen.

Thesis (MScFor)--Stellenbosch University, 1980. / No Abstract Available

Thesis (MSc (Forest and Wood Science))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The Saasveld solar kiln, valued at US$ 10,000 (R 70,000), is a greenhouse-type solar kiln requiring no additional heating. A unique auto-regulated process of natural dehumidification at night controls the humidity, and uses no venting system, nor any human/controller intervention. The natural dehumidification is achieved by circulating the humid kiln air through an air jacket on the periphery of the solar kiln. Diurnal temperature fluctuations allow condensation in the air jacket when air is cooled to below its dew-point temperature. The process is simple as colder night temperatures are a certainty. Almost no research has been done on similar kilns. The purpose of this thesis was to study the operation and performance of a solar drying kiln to dry high density hardwoods utilising natural dehumidification. The kiln load consisted of 20.1m 3 of a high density hardwood, Eucalyptus diversicolor, with air-dry density of 893kg/m 3 . The ZA Dry Q drying quality assessment indicated outstanding moisture distribution with little drying stress, a few surface checks and no internal checks, collapse, short bow or surface discolouration. The results conformed to the ZA Dry Q softwood appearance grade specification, except for end checks – remarkable for the drying of any hardwood. The final moisture content (MC) distribution was extremely tight with MC average of 11.5 per cent (%), standard deviation of 0.97% and the moisture gradient averaged 1.49%, standard deviation of 0.5%. The MC and MG were equally distributed in all three geometric directions throughout the load. The timber dried in 130 days. The kiln operation was analysed by temperature and humidity parameters at five positions inside and outside the kiln while monitoring the MC. The extent of moisture evaporation from the timber and the dehumidification of air were derived from this data. The results showed that the average of the daily kiln temperature, independent from the external temperature, increased from 18.0°C initially to 25.7°C. A maximum temperature of 38.1°C was recorded at the end of drying. Cell collapse did not occur under these low temperatures. Evaporation occurred generally from 07h30 to 16h45. The rate reduced at lower moisture contents. There was no effect of stack width. Natural dehumidification by condensation happened generally from 17h00 to 07h30. The equilibrium moisture content (EMC) decreased automatically from an initial daily average of 18.1% (variation 5%) to 8% (variation 2%) finally. It was similar to a smoothed T3C2–schedule. The mild drying conditions, with EMCs above 7.3%, ensured minimal moisture gradients and drying stresses. This reduced surface and internal checks. Nocturnal equalising and conditioning, comparable to intermittent schedules, resulted from: no evaporation, improved diffusion of heated timber and adsorption of moisture on the wood surface. The kiln protected the timber in extreme climatic conditions. It was found that the main circulating fan could be switched off from 17h00 to 07h30. A 30-minute manual venting at noon was permitted once fibre saturation point had been reached. Beneficiaries to this study can include hardwood processors who need to dry high density hardwoods within a reasonable time to an excellent drying quality. Processors in developing countries or who have little drying expertise could also benefit. / AFRIKAANSE OPSOMMING: Die Saasveld sondroër, met ‘n beraamde waarde van US$ 10,000 (R70,000), is ‘n groentetonneltipe sondroër met geen addisionele verhitting nie. ‘n Unieke auto-reguleerder beheer die humiditeit snags deur natuurlike dehumidifikasie. Dit gebruik geen ventileerder of enige menslike/kontroleerder inmenging nie. Die natuurlike dehumidifikasie word verkry deur die vogtige lug te sirkuleer deur ‘n lugkussing op die omtrek van die tonnel. Dag-en-nag temperatuur skommelings laat kondensasie toe binne-in die lugkussing sodra die lug benede die doupunttemperatuur afkoel. Dit is ‘n eenvoudige proses aangesien kouer nagte ‘n gegewe is. Byna geen navorsing is nog op soortgelyke sondroërs gedoen nie. Die doel van die tesis was om die werking en werkverrigting van ‘n sondroër wat hoë digtheid loofhout met behulp van natuurlike dehumidifikasie droog, te bestudeer. Die houtvrag het bestaan uit 20.1m 3 van hoë digtheid loofhout, Eucalyptus diversicolor, met ‘n gemiddelde lug-droë digtheid van 893 kg/m 3 . Die ZA Dry Q drogingskwaliteit toets het uitstaande resultate getoon. Daar was min drogingspannings, ‘n paar oppervlak krake en geen interne krake, sel-ineenstorting, kort-boog of oppervlak-verkleuring nie. Die resultate bevredig die ZA Dry Q naaldhout voorkomsgraad spesifikasie, behalwe vir end-krake – merkwaardig vir die droging van enige hoë digtheid loofhout. Die finale vogverspreiding was nou-verspreid met ‘n gemiddelde voggehalte van 11.5%, standaard afwyking van 0.97% en ‘n gemiddelde vog-gradiënt van ‘n 1.49%, standaard afwyking van 0.5%. Die voggehalte en vog-gradiënt was eweredig verspreid in al drie geometriese rigtings van die houtvrag. Die hout het in 130 dae gedroog. Die werking van die sondroër is geanaliseer deur temperatuur- en humiditeits-parameters by vyf posisies binne- en buite die droogkamer tegelykertyd met die voggehalte te monitor. Die omvang van vogverdamping uit die hout en dehumidifikasie van die lug is afgelei van hierdie data. Die gemiddelde daaglikse sondroër-temperatuur, wat onafhanklik van die buite temperatuur was, het verhoog van 18.0°C aanvanklik tot 25.7°C. Die maksimum temperatuur van 38.1°C is gemeet aan die end van droging. Sel-ineenstorting het nie voorgekom by hierdie lae temperature nie. Verdamping het algemeen voorgekom vanaf 07h30 tot 16h45, teen ‘n vertragende verdampingstempo by laer voggehaltes. Die stapelwydte-effek was van geen belang nie. Natuurlike dehumidifikasie deur kondensasie het gereeld voorgekom vanaf 17h00 tot 07h30. Die ewewigsvoggehalte (EVG) het outomaties verminder vanaf ‘n aanvanklike daaglikse gemiddelde van 18.1% (variasie van 5%) na 8% (variasie van 2%). Dit was soortgelyk aan ‘n gelykmatige T3C2 –drogingskedule. Die matige drogingskondisies, met EVG bokant 7.3%, het minimale vog-gradiënte en drogingspannings verseker wat oppervlak-krake en interne-krake verhoed het. Nagtelike houtvog egalisasie en kondisionering, vergelykbaar met puls-humiditeit skedules, was die gevolg van: geen verdamping, verbeterde diffusie in verhitte hout en adsorpsie van vog op die hout oppervlak. Die droogkamer het die hout beskerm teen buitengewone klimaatstoestande. Daar is gevind dat die hoof-waaier afgeskakel kan word vanaf 17h00 tot 07h30 en dat ‘n 30-minute nie-outomatiese ventilering smiddae kan plaasvind sodra veselversadigingspunt bereik is. Hierdie studie sal van nut wees vir die loofhout verwerkers wat hoë-digtheid loofhout moet droog binne ‘n redelike tydperk met ‘n uitstekende drogings-kwaliteit, asook houtverwerkers in opkomende lande of met gebrekkige drogingsvaardighede.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: A lab scale combustion unit was designed, in order to characterise the performance of various woody and wood-based biofuels commonly used for energy production, cooking and heating. The unit was constructed in a way that it could be repeatedly reused and provide similar testing conditions, such as airflow for all samples. The requirements were that it was big enough to contain a fire large enough to yield good time/temperature profiles and at the same time easy to handle, operate and clean. It also had to allow the insertion of the thermocouples and flue gas probe. Time / temperature profiles were obtained and O2, CO2 and CO levels in the flue gas determined for each biofuel. The samples consisted of the five most commonly used fuel wood species in the Western Cape, namely Rooikrans, Camelthorn, Bluegum, Black wattle and vine stumps and five processed products, namely wood pellets, wood briquettes, commercial charcoal, commercial briquettes and handmade briquettes. Combustion time/temperature profiles were obtained for all samples and characteristic values, such as the maximum temperature and coal temperature compared. This allowed an indication of which product performed better than others in the different combustion phases and is more suitable for different requirements, such as industrial heating, or domestic cooking. Even though Bluegum and Camelthorn performed best overall they were not necessarily suited, for example, for large scale industrial use. It was found that wood pellets and charcoal were the best biofuel for industrial purposes, whereas Rooikrans was found to be the best option for small scale use. / AFRIKAANSE OPSOMMING: ‘n Laboratoriumskaal verbrandingseenheid was ontwerp vir die toets en karakterisering van verskeie houtgebaseerde biomassa soorte algemeen in gebruik vir energie opwekking, kook en verhitting. Daar was besluit om ‘n eenheid te bou vir herhaalde gebruik wat die omstandinghede vir elke toets konstant kan hou, bv. ‘n damper om lugvloei deur die sisteem the beheer. Die eenheid moet groot genoeg wees om veilig ‘n groot genoeg vuur the bevat waarmee ‘n goeie tyd/temperatuur profiel verkry kan word, maar terselfdetyd klein genoeg wees om te hanteer, operateer en skoon te maak. Die eenheid moes ook voorsiening maak vir die insteek van die termostate en gas peilstif. Tyd/temperatuur profiele is verkry en O2, CO2 en CO vlakke in die uitlaatgas is bepaal vir elke bio-brandstof. Die monsters was saamgestel uit vyf van die mees algemeen gebruikte brandhout spesies in die Wes Kaap, naamlik Rooikrans, Kameeldoring, Bloekom, Swartwattel en wingerdstompies, asook vyf geprosesseerde produkte naamlik houtpille, houtbrikette, kommersiële steenkool, kommersiële brikette and handgemaakte brikette. Verbranding tyd/temperatuur profiele is verkry vir al die monsters en verteenwoord waardes is daarvan afgelees, bv. die maksimum temperatuur wat bereik is of die temperatuur waar die vlamme uitgesterf het en slegs koolhitte gemeet word. Hierdie profiele het dit moontlik gemaak om te identifiseer watter produk het beter gevaar as ander gedurende die verskillende verbrandingsfases en is beter gepas vir verskillende gebruike, bv. huishoudelike kook en verhitting. Resultate het gedui dat die Bloekom en Kameeldoring die beste gevaar het oor all die toetse heen, maar was nie noodwendig ideaal vir elke spesifieke doel nie. Dit was bevind dat die steenkool en houtpille die beste gepas is vir industriele gebruik en dat die Rooikrans beter geskik is vir huishoudelike en kleinskaalse gebruik.

Thesis (MScFor)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Individual tree models, as opposed to stand models, have the potential to greatly improve sensitivity of forest growth models to changing conditions such as silvicultural amendments, irregular stand structures, etc. It was the purpose of this study to extend two sub-components of a European individual tree growth model to introduce individual tree growth modelling concepts in South Africa using Pinus elliottii as a study species. Two main objectives were established: Modelling the potential height of stands across different site qualities and modelling diameter increment using a potential modifier approach with a combination of competition indices that change in importance according to the edaphic conditions of the site. Potential height modelling used three steps in order to achieve this objective. The first was to compare site index models based on different model fitting techniques, namely nonlinear least squares, generalised nonlinear least squares and nonlinear mixed effects models. The nonlinear mixed effects model proved to be superior in terms of achieving the principles of regression assumptions and model fit for the data range observed. The second step was to fit potential height using nonlinear quantile regression on observed spacing trial height measurements. This proved to be a robust technique able to capture potentials according to the defined Chapman-Richards model structure. The final step was to use the predicted site index as a site classification variable in order to predict potential height. While some small deviation occurred, potential height seems to be well correlated to site index and validation on selected sites suggested that site index can be used to model potential height until a more sophisticated site classification model is used for future improvement of the model. Diameter increment modelling followed six major steps in order to apply the full parameterisation methodology of an age-independent diameter increment model dependent on tree diameter and competition. Diameter increment potentials were fit using site index as a predictor of the potential height curves. Multiple competition indices were tested on two sites to obtain a combination of two indices, which can capture overtopping and local crowding effects. Principle components analysis and variance inflation factors calculation were applied to test for collinearity between indices. Suitable combinations were tested resulting in a combination of the KKL and Local Basal Area competition indices. Changing importance of the two indices were observed on the two sites tested indicating a shift in the mode of competition according to a water gradient. These were combined in a deterministic potential modifier model, which mimicked competitive stages over age; however the validation showed a skewed distribution, which was not sensitive to stand density gradients. A stochastic model was constructed to model variance from observed residual plots using linear quantile regression to determine bounds for a truncated normal distribution which generates random deviates for a predicted increment. The stochastic element significantly improved the performance and sensitivity of the model, however the model was still not sensitive enough at very high and very low spacing densities. All in all two key models for an adaptation of an individual tree growth simulator to South African conditions were successfully demonstrated. The two main objectives were achieved; however some indicated improvements could be made, especially for the competition indices where the sensitivity of competition to changing resource limitation according to site and temporal scales needs to be further investigated. Furthermore, the full set of models for simulating individual tree growth still needs to be applied. Overall, as a methodological approach, the study outlined problems and future improvements, introduced new concepts and can serve as a guideline for future parameterisation of an individual tree growth model. / AFRIKAANSE OPSOMMING: In vergelyking met vakgroeimodelle, het individuele-boomgroeimodelle die potensiaal om die sensitiwiteit van plantasiegroeimodelle vir veranderende omstandighede soos aanpassings in boskultuur, onreëlmatige vakstrukture, ensovoorts, drasties te verbeter. Die doel van hierdie studie was om twee subkomponente van ‘n Europese individuele-boomgroeimodel uit te brei om sodoende individuele-boomgroei modelleringskonsepte in Suid-Afrika bekend te stel. Pinus elliottii is gebruik as studiespesie. Twee hoofdoelstellings is bepaal. Eerstens, die modellering van hoogtegroei potensiaal van opstande oor verskeie vlakke van groeiplek kwaliteit. Tweedens, die modellering van deursnee-aanwas deur gebruik te maak van ‘n potensiaal matigingsbenadering “potential modifier approach“ met ‘n kombinasie van kompetisie-indekse waarvan die belangrikheid verander volgens die edafiese toestande van die groeiplek. Die hoogtepotensiaalmodellering bestaan uit drie stappe. Tydens die eerste stap word groeiplek bonniteitsmodelle vergelyk op grond van verskillende modelpassingstegnieke, naamlik nie-lineêre minimum kwadrate, algemene nie-lineêre minimum kwadrate en nie-lineêre gemengde effek modelle. Laasgenoemde het die beste gevaar in terme van die beginsels van regressiemodelle asook die mate waarin die model die waargeneemde data pas. Tweedens is hoogtegroei potensiaal gemodelleer deur nie-lineêre kwantielregressie op waargeneemde hoogtes van spasiëringseksperimente toe te pas. Die metode is robuust en in staat om potensiale volgens die gedefinieerde Chapman Richards modelstruktuur vas te vang. Laastens is die voorspelde bonniteits indeks as ‘n groeiplek klassifasie veranderlike gebruik om sodoende die hoogtegroei potensiaal te voorspel. Alhoewel klein afwykings voorgekom het, blyk hoogtegroei potensiaal goed gekorreleer te wees met bonniteits indeks. Uit validasie op geselekteerde groieplekke blyk dit dat bonniteits indeks gebruik kan word om hoogtegroei potensiaal te modelleer totdat ‘n meer gesofistikeerde groeiplek klassifikasiemodel beskikbaar is wat die model verder sal kan vebeter. Die volledige parametriseringsmetodiek van ‘n ouderdoms-onafhanklike deursnee-aanwas model wat afhanklik is van boomdeursnee en kompetisie bestaan uit ses hoof prosesse. Nie-lineêre kwantielregressie is gebruik om deursnee-aanwaspotensiale te pas vir verskeie groeiplekke. Dié is gekombineer met ‘n bonniteits indeks om ‘n nuwe model te vorm waarmee hoogtegroeipotensiaal kurwes voorpel kon word. Daar is met veelvuldige kompetisie-indekse op twee groeiplekke geëksperimenteer om ‘n kombinasie van slegs twee indekse te vind wat die effekte van oorskaduwing en plaaslike verdringing kan vasvang, te vind. Hoof komponent analise “Principle components analysis” en variansie inflasie faktore berekening “variance inflation factors calculation” is gebruik om vir kollineariteit tussen die indekse te toets. Gepaste indekskombinasies is getoets. ‘n Kombinasie van die KKL en plaaslike basale oppervlakte “Local Basal Area” kompetisie-indekse het die beste resultate gelewer. Die twee indekse is as volg geselekteer. Veranderings in die belangrikheid van elk van die indekse is waargeneem op die twee toetspersele. Dit dui op ‘n verskuiwing in die modus van kompetisie afhangend van ‘n watergradiënt. Die twee indekse is gekombineer in ‘n deterministiese potensiaal matigings model wat die kompeterende stadiums oor ouderdom naboots. Validasie het egter ‘n skewe verdeling wat nie sensitief vir opstandsdigtheidsgradiënte is nie, gewys. ‘n Stogastiese model is ontwikkel om variansie in die residuele grafieke te modelleer. Lineêre kwantielregressie is gebruik om grense vir ‘n afgestompte normaalverdeling wat ewekansige afwykings vir ‘n voorspelde aanwas te bepaal. Die stogastiese element het die prestasie van die deterministiese model merkbaar verbeter. Selfs met die stogastiese element, is die model egter steeds nie sensitief genoeg vir baie hoë en baie lae opstandsdigthede nie. Ter opsomming is twee modelle vir ‘n aanpassing van ‘n individuele-boomgroeisimuleerder vir Suid- Afrikaanse toestande suksesvol gedemonstreer. Die twee hoofdoelstellings is bereik. Daar is egter steeds ‘n paar aangeduide verbeterings wat aangebring kan word. Die sensitiwiteit van die kompetisie-indekse op hulpbronbeperkings wat verander op grond van die ruimtelike en temporale skale moet veral verder bestudeer word. Verder moet die volle stel modelle wat benodig word om individuele-boomgroei te modelleer nog toegepas word. As ‘n metodologiese benadering, het die studie probleme uitgewys en toekomstige verbeterings aangedui, nuwe konsepte bekendgestel en kan dus dien as ‘n riglyn vir toekomstige parametrisering van individuele-boomgroeimodelle.

Thesis (PhD (Forest and Wood Science))--University of Stellenbosch, 2006. / This study aims at examining technical and institutional capacity in local organisations to manage decentralised forest resources in Uganda. Specifically the study assessed the roles, responsibilities, powers and legal instruments, incentives, facilities and human and fiscal resources of local organisations to undertake decentralised forest governance. Semistructured and key informant interviews were conducted in local organisations and legal and policy documents reviewed to ascertain strategies for implementing decentralised forestry. An inventory of selected forests was conducted to assess effect of decentralisation policy on the condition of forests in Uganda. Chi-square tests were used to show the factors that motivate local organisations to participate in decentralised forest governance. Tree species diversity and richness, density, diameter at breast height and basal area and sings of human disturbance were used to compare the condition of forests under local government and those under private and central government ownership. Similarity between the forests was assessed using a Two Way INdicator SPecies Analysis, while the differences in the composition and structural characteristics of trees among forest ownership categories were compared by oneway analysis of variance. Multiple regression analysis was used to show the influence of household pressure, forest size, the distance of the forest from roads and forest administrative office, and the market demand of the forest produce on the capacity of forest agencies to regulate timber harvesting. The findings reveals that local organisations supported devolved forest management functions such as forest monitoring, tree planting, environmental education, networking, collaborative and integrated planning, resource mobilisation and formulation of byelaws. The role of forestry in the livelihoods of the people, the desire to control forest degradation and access to forest revenue, donor and central government fiscal support were the most important incentives in decentralised forest management. However, limited capacity in terms of qualified staff, funds, facilities and equipment and inadequate decision-making powers over fiscal resources from forestry, inequitable distribution of forest revenue and unclear forest and tree tenure hindered decentralised forest management. The diversity and richness indices, density, diameter at breast height and basal area of trees were significantly higher in central forest reserves, intermediate in private and lower in local forest reserves. The frequency of human disturbances was significantly higher in local forest reserves than in private and central forest reserves. The variation in composition and structure of the local forest reserves is partly attributed to human disturbances. The capacity of the forest agencies to regulate forest resources use in the Mpigi forests was significantly affected by the size of forest, and its location in relation to the well-maintained roads, forest administrative office and the number of households in close proximity and the market demand of the forest produce. Large forests in close proximity to densely populated areas and far a way from roads and the forest administrative office were more affected by timber harvesting. The results demonstrated that local governments are not yet efficient in monitoring and regulating forest use and maintaining the condition of forests in Uganda. Local organisations need to play an increased role in the implementation of the Forest Policy, the National Forestry and Tree Planting and the Local Government Acts for successful decentralisation of forest management and to recruit more technical staff, strengthen internal sources of revenue and develop integrated forestry work plans. There is also a need for the central government to integrate and co-ordinate local and central interests, and facilitate a working relationship with local governments, civil society and the private sector involved in forestry. Forest owners and managers in the Mpigi forests and Ugandaâ s tropical forests in general need to manage human impacts so as to balance utilisation and conservation forest resources. There is need for longterm studies to fully understand the real significance of ownership on the composition and structure of the Mpigi forests and forests in other districts of Uganda.

Thesis (PhD (For))--Stellenbosch University, 2012. / ENGLISH ABSTRACT: A primary reason for the existence of the forest industry is to provide a renewable and natural resource for much needed timber and fibre products. Substantial improvements in management practices are required to increase forest volume and pulp yields for increased demand. Eucalyptus grandis clonal trees of age 6.75 years, grown in a Nelder 1a spacing experiment, were sampled and analysed to describe the effect of planting density on i) growth and yield, ii) wood properties and iii) pulp and paper quality. The main objective was to populate a fibre productivity index (FPI) which would be suitable from technical and economical perspectives. A material study was conducted on the wood and in addition, two methods were developed to further describe the variability of the forest resource to i) separate growth rings by means of wood density peaks from gamma-ray densitometry and ii) calibrate near infrared (NIR) prediction models. The results indicated that planting density did not influence the variability of wood density but mechanisms affecting available soil water are important. NIR prediction models were developed to rapidly and reliably assess wood properties on a non-destructive basis. The validation models for wood density, total pulp yield, kappa number and insoluble lignin returned high predictive ability. When applied to predict chemical properties from an independent data set, the outcomes were accurate in comparison with measured data. Growth and yield functions were developed for tree survival, dominant height and basal area. They accurately predicted outcomes as demonstrated by the goodness of fit and their logical behaviour tested over the range of planting densities. When the most extreme stand density treatments, 6809 and 275 trees per hectare (TPH) were evaluated for wood and fibre properties, the larger trees grown at 275 TPH, produced wood of better quality for pulp processing; basic wood density at 0.520 g cm–3 (21 % higher), fibre cell wall thickness at 2.10 μm (18.6 % thicker) and fibre lumen diameter at 8.16 μm (9.9 % lower) than for 6809 TPH. Intra-specific tree variability of wood and product properties increased from diameter at breast height (DBH) to 35 % and then decreased to 65 % of tree height. The effect of planting density was carried throughout the product value chain up to the paper manufacturing phase. Paper with higher bulk mass and thickness and more porous sheets is most likely to be made from lower planting densities (801 and 275 TPH), and stronger, smoother and denser paper is most likely to be made with trees at high planting densities (6809 or 2336 TPH). From the growth and yield and materials investigation, technical indicators identified to populate a fibre productivity index were: i) mean annual increment (MAI) as a forestry growth indicator, ii) wood density, summarising the composition of wood and, iii) pulp yield, the indicator of the amount of fibre processed through a chemical cooking process. Delivered cost of timber to the mill, was identified as the most suitable economic indicator which included fixed costs elements, variable costs and aspects of mill efficiency. The product of the technical and economic indicators concluded in a profit/loss scenario of producing 1 ton of pulp was deemed the best index to describe the entire and integrated value chain. This index, termed the Fibre Productivity Index (FPI) at the Mill, denoted as FPMill, is an integrated index that is easy to interpret in the realms of a forestry - pulp manufacturing, and can be used for differential pricing of timber for wood quality. / AFRIKAANSE OPSOMMING: 'n Primêre rede vir die bestaan van die bosbouindustrie is om ‘n hernubare, natuurlike hulpbron vir hout en vesel te voorsien. Aansienlike verbeterings in bestuurspraktyke is nodig om die houtvolume en pulpopbrengste vir die toename in aanvraag te verhoog. Eucalyptus grandis klonale bome met ‘n ouderdom van 6.75 jaar en wat in 'n Nelder 1a spasiëring eksperiment gegroei is, is versamel en ontleed om die effek van opstandsdigtheid te beskryf op a) groei en opbrengs, b) houteienskappe en c) pulp- en papiergehalte. Die hoofdoel was om 'n veselproduktiwiteitsindeks (FPI), wat geskik sou wees in terme van tegniese en ekonomiese perspektiewe, te ontwikkel. 'n Materiaalkundigestudie is op hout uitgevoer. Twee metodes is ontwikkel om die variasie in hout as natuurlike hulpbron te beskryf deur a) vroeëhout- en laathoutdigtheidspieke deur gammastraal-densitometrie van mekaar te skei en variasie in groeiringe te beskryf en b) daarstelling van naby-infrarooispektroskopiese (NIR) voorspellingsmodelle. Die resultate het aangedui dat aanplantingsdigtheid nie ‘n invloed het op die variasie van houtdigtheid nie, maar dat meganismes wat beskikbare grondwater bepaal, belangrik is. NIR-voorspellingsmodelle is ontwikkel om houteienskappe op 'n nie-destruktiewe manier betroubaar te kan evalueer. Die validasiemodelle vir houtdigtheid, pulpopbrengs, kappanommer en onoplosbare lignien, openbaar akkurate voorspellingsvermoë. Wanneer dit toegepas word om chemiese eienskappe van 'n onafhanklike datastel te voorspel, was die resultate akkuraat in vergelyking met gemete data. Groei- en opbrengsfunksies is ontwikkel vir mortaliteit, dominante boomhoogte en basale area. Akkurate voorspellingsuitkomste is verkry soos gedemonstreer deur die logiese gedrag wat getoets is vir alle plantdigthede. Toe die mees ekstreme opstansdigtheidbehandelings vir hul hout- en veseleienskappe geëvalueer is, was die hout van die groter bome, teen 275 stamme per hektaar (SPH), van beter gehalte. Dit was veral prominent vir houtdigtheid van 0.520 g cm-3 (21 % hoër), veselselwanddikte van 2.10 μm (18.6 % dikker) en vesellumendeursnit van 8.16 μm (9.9 % laer) as by die hoër (6809) SPH. Intra-spesifieke boomvariasie van hout- en produkeienskappe het toegeneem van deursnee op borshoogte (DBH) tot 35 % en dan weer afgeneem tot 65 % van die boomhoogte. Die effek van plantdigtheid is regdeur die produkwaardeketting tot by die papiervervaardigingstadium sigbaar. Papier met hoër basismassa en dikte, en meer poreuse papiervelle kan meer waarskynlik van laer aanplantdigtheid (801 en 275 TPH) bome gemaak kan word. Papier wat sterker, gladder en digter is, kan waarskynlik gemaak word van hout van bome teen hoë aanplantdigthede (6809 of 2336 SPH). Die veselproduktiwiteitindeks wat ontwikkel is uit die materiaalondersoek en tegniese aanwysers wat geïdentifiseer is sluit in i) gemiddelde jaarlikse aanwas, as 'n bosbou groei-indikator, ii) houtdigtheid, wat ‘n opsomming van die samestelling van hout is, en iii) pulpopbrengs; die aanduiding van die hoeveelheid vesel verwerk deur 'n chemiese verpulpingsproses. Gelewerde koste van hout by die pulpmeul is geïdentifiseer as die mees geskikte ekonomiese aanwyser wat vaste kosteelemente, veranderlike koste en aspekte van die meul se doeltreffendheid insluit. Die produk van die tegniese en ekonomiese aanwysers is saamgevat in 'n wins / verlies opsie vir die vervaardiging van 1 ton pulp, en is beskou as die mees geskikte indeks om die geïntegreerde waardeketting te beskryf. Dié indeks, die sogenaamde Vesel Produktiwiteitsindeks (VPI) by die Pulpmeul, aangedui as VPMeul, is 'n geïntegreerde indeks wat maklik is om te interpreteer in 'n bosbou - pulpvervaardigingsopset, en kan gebruik word in die differensiële prysbepaling van hout waarby die kwaliteit in ag geneem word.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Mid rotation fertiliser application is generally practised in forestry to enhance nutrient availability in areas were soils are impoverished and do not provide sufficient nutrients for high productivity. Generally speaking there is great potential for mid rotation fertiliser in pine plantations, but stand and site characteristics such as water availability, soil depth, stand density and available nutrients need to be considered before fertiliser treatments are implemented. Foliar nutrient analyses were used to estimate nutrient availability. These levels were measured throughout the study and were used to implement specific fertiliser treatments that would boost nutrient availability. Treatments consisted of an unfertilised control, a single fertiliser application (1F) and two fertiliser applications over two consecutive years (2F). Leaf area index (LAI) and stem volume increment were measured in order to evaluate its influence on growth efficiency. LAI was estimated using the gap fraction method with the use of a ceptometer. Volume increment was calculated with diameter and height measurements. Basal area was calculated by means of diameter measurements. These growth responses were used to determine the effect of increased nutrient availability and although increases were found in LAI, volume increment, basal area increment and growth efficiency, none were significant. The lack of significance may be due to relatively large variations in other factors such as stand density and initial volume of the experimental plots. The 18 month monitoring period apparently did not allow complete reaction time to increased nutrient availability and limited our understanding of the responses somewhat. Despite this, the magnitude of some growth responses was large as nutrient ratios in the foliage increased to levels within the norms range. Increases in current annual volume increment (CAI) of 3.48 m3 ha-1 a-1 and 3.62 m3 ha-1 a-1 in 1F plots at Grabouw and La Motte plantations indicated that it may be economically feasible to fertilise at mid rotation age as the NPV and IRR increased over a projected 25 year rotation. The Grabouw site had the most significant response with regards to CAI in 2F treatment with a mean volume increment of 5.43 m3 ha-1 a-1. The mechanism of the response was examined further by taking water availability and soil characteristics into account. The seasonal climatic effect (length of the moisture growing season) had a significant influence on the response to fertilisation. / AFRIKAANSE OPSOMMING: Die toediening van mid-rotasie bemesting word algemeen in bosbou toegepas om voedingstofbeskikbaarheid te verhoog in areas waar voedingstowwe onvoldoende is vir hoë produktiwiteit. Daar is oor die algemeen ruim potensiaal vir mid-rotasie bemesting in denne plantasies, maar eienskappe soos waterbeskikbaarheid, gronddiepte, opstanddigtheid en beskikbaarheid van voedingstowwe moet in ag geneem word voor optimum bemestingtoedienings bepaal kan word. Blaaranalise is gebruik om voedingstofbeskikbaarheid in plantasies te skat. Hierdie voedingstofvlakke is deurgans gemeet en is gebruik om spesifieke bemestingsbehandelings te implementeer wat voedingstofbeskikbaarheid kon opstoot. Behandelings het bestaan uit ‘n onbemeste kontrole, ‘n eenmalige kunsmistoediening (1F) en twee kunsmistoedienings in opeenvolgende jare (2F). Blaar oppervlak indeks en toename in stamvolume is gemeet om die invloed daarvan op die effektiwiteit van groei te bepaal. Blaaroppervlakindeks is bepaal deur middel van die gapingfraksie metode met behulp van ‘n stralingsmeter. Toename in volume is bereken met stamdeursnee en hoogte meetings. Basale oppervlakte is bereken deur middel van deursnee metings. Hierdie groeireaksies is gebruik om die effek van verbeterde voedingstofbeskikbaarheid te bepaal. Al die groeireaksies het toegeneem maar was nie statisties beduidend nie. Die gebrek aan beduidende toename kan toegeskryf word aan variasies in opstandsdigtheid en oorspronklike volume van die bome in die navorsingspersele. Die toetstydperk van 18 maande het moontlik nie genoeg tyd gegee vir die bome om op die toename in voedingstofbeskikbaarheid te reageer nie. ‘n Goeie groeirespons is wel waargeneem waar die voedingstofverhoudings in die naalde aanvaarbare norme bereik het. Die toename in volume aanwas van tussen 3.48m3 ha-1 a-1 en 3.62 m3 ha-1 a-1 in 1F persele by Grabouw en La Motte plantasies het aangedui dat dit ekonomies lewensvatbaar is om op mid-rotasie ouderdom bemesting toe te dien aangesien die netto teenswoordige waarde en die interne opbrengs koers toegeneem het op ‘n geprojekteerde 25 jaar rotasie. Die persele op Grabouw plantasie het die mees beduidende respons getoon met betrekking tot huidige jaarlikse aanwas (5.43 m3 ha-1 a-1 in die 2F perseel). Die meganisme van die respons is verder nagevors met inagneming van waterbeskikbaarheid en grondeienskappe. Die seisoenale klimaatseffek (lengte van die vog-groeiseisoen) het ‘n beduidende impak op die respons tot bemesting.

Thesis (DSc (Forest and Wood Science))-- Stellenbosch University, 1954. / No abstract