Thesis (PhD (Forest and Wood Science))—University of Stellenbosch, 2007. / It is evident that existing, nominal, functional, national and international policies and legislation continue to be ineffective in combating the disastrous environmental and socioeconomic consequences of unsustainable forest management. Several underlying causes to this failure were identified as: i) the lack of involvement or omission of the full range of stakeholders, in particular resource users, in the various steps and procedures of policy and legislation formulation and implementation; ii) these stakeholders are excluded in the review and updating of obsolete policies and legislation; iii) little emphasis is placed on sustainable forest management through the scientific understanding of natural forests and woodlands, including the dynamics of their ecology and socio-economics. This study identified the key/critical aspects of the development process of policy and strategy for the sustainable management of non-timber forest products (NTFPs). This research study reviewed existing policies and legislation and the current status of the NTFP sector, conducted a series of community consultation meetings on resource use and management, user surveys and economic valuation, resource surveys and economic valuation, and made policy recommendations for the development of a concept and strategy for the sustainable management of NTFPs. The main focus was on the edible and medicinal NTFPs in the four ecological zones of Swaziland...

Thesis (PhD (Forest and Wood Science))—University of Stellenbosch, 2007. / Developing sustainable mechanisms for use-management of forest products by user communities has been suggested as a possible solution to the often-observed conflict between forest use and the conservation of protected forests. In Zimbabwe, the use of forest products in protected forests by local communities has a long history, but few studies have explored both the socio-economic and ecological aspects of this use. This study was conducted in the Baikiaea plurijuga forests and woodlands in and around Fuller Forest in western Zimbabwe, protected since 1943. It explored the characteristics and dynamics of forest products use by communities surrounding this protected forest. Further, the demography and dynamics of commonly harvested woody species was examined in order to establish the present status of populations of these species. This examination, focusing on diameter class distributions, was aimed at informing whether species populations were expanding, stable or declining in view of their capacity to continue providing required goods and services. Results indicated that all households, rich and poor, were harvesting at least some forest resources from the protected forest, with the most frequently harvested resources being firewood, wood for curios, thatch grass, wild fruits, timber for construction and fencing and those who owned livestock used the forest for livestock grazing. The extraction and use of 23 different products was recorded across the villages. The top five harvested forest products in terms of the mean proportion of households using them were fuelwood, building poles, thatch grass, wild fruits and broom grass. Forest products were harvested both for own consumption and for sale. At present Baikiaea plurijuga, Colophospermum mopane, Brachystegia spiciformis, Diplorhynchus condylocarpon, Commiphora mocambicensis and Bauhinia petersiana out of 14 commonly harvested species appear to have relatively stable populations as indicated by their inverse J-shaped diameter class distribution profiles. Preliminary indications from this baseline information point towards the successful integration of local use of forest products and conservation objectives noting that there is need for caution until further studies as recommended in this study are taken.

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 (Forest and Wood Science))—University of Stellenbosch, 2006. / Experiments carried out in this study sought to contribute to the understanding of the ecological interactions involved in Uapaca kirkiana seedling establishment and growth in a natural woodland ecosystem. These include soil pH reactions, plant root surface pH change, root exudates that affect the chemical behaviour of the soil in the vicinity of the root, and microbial effects. Although it was difficult to determine which of these factors play a dominant role in the soil-plant relationship, the study contributed to the understanding of the mycorrhizal fungi-host plant association. It revealed the diversity of mycorrhizal fungal species occurring in the different ecological sites, and also analysed the relationship between soil factors. Soil pH and K had significant influences on the fungi population diversity. K was considered important in its role in the translocation of auxins to the root sites where they enhance root susceptibility to mycorrhizal fungal infection. More work needs to be undertaken to establish the role of soil pH.

Thesis (PhD (Forest and Wood Science))—University of Stellenbosch, 2007. / Sustainable livestock production in semi-arid Botswana could be improved through tree planting on-farm to provide much needed protein and shade. Such action can be encouraged if the growth, productivity, nutritional value of trees and their contribution to mass gain of livestock are known.. A study at Malotwana investigated two indigenous species, Acacia galpinii and Faidherbia albida, and two exotic species, Leucaena diversifolia and L. leucocephala, at three spacings in a randomised complete block design replicated five times. The three spacings represented 400, 317 and 241 trees per hectare. The study was conducted over 6.5 years. Indigenous trees were sampled biennially and exotics annually to evaluate crown width, height, stem diameter, stem number and stem volume index. Complete plant harvesting of exotic trees at 2.5, 4.5 and 6.5 years evaluated agroforestry production. Leaves from all four species and pods of exotic species were analysed for chemical composition. Two groups of eight lambs were balanced for mass at selection for an on-farm feeding trial. Browse from exotic trees, comprising a 2:1 ratio of pods to leaves, was fed at 30% as supplement to hay to one group whose mean mass was contrasted with that of the control group fed sorghum bran at 30%. A. galpinii was a promising species, adaptable to planting away from its origin. Its crown width ranged from 5.86 m in high density plots to 6.08 m at low density and was significantly different among stands (p = 0.0406) at 6.5 years. Diameter at breast height (dbh) was significantly different among stands aged 6.5 years (p = 0.0003) and ranged between 10.38 cm at high density to 12.48 cm in low density plots, demonstrating a capacity to provide both shade and poles on-farm. At 4.5 years, F. albida attained a mean height of 4.5 m and 4.5 cm in dbh but suffered 67% mortality during a severe drought. Annual fodder production of 0.647 and 0.996 metric tonnes ha-1 for leaves and pods of L. diversifolia and 1.237 and 1.431 for L. leucocephala was recorded in years of average rainfall. Yields of 0.3 and 0.59 metric tonnes ha-1 were recorded for both species in the driest year. Equally good agroforestry production was obtained from both low and high density stands suggesting that low density plantings, which foster higher plant survival and reduce disease incidence, are best suited to the semi-arid conditions of Botswana. The crude protein of leaves ranged between 16.26 (L. diversifolia) and 25.25% (F. albida). They were highly digestible with more than twice the calcium content livestock require. Crude protein and digestibility measures were significantly different among leaves and varied significantly at different spacings (p<0.0001). Pods of the exotic species contained significantly more protein than the leaves (p<0.0001). Lambs supplemented with browse gained 102.33 g per animal per day while the control group gained 83.95 g. There were significant differences between groups during growth (p<0.05). Growing of A. galpinii, complemented with L. diversifolia and L. leucocephala, can supply short and long term feed, and greatly enhance livestock production while diversifying farm feed sources

Thesis (PhD (Forest and Wood Science))--University of Stellenbosch, 2006. / The discolouration of South African softwood during kiln drying can reduce the value of furniture grade lumber. Thermal discolouration of wood, as found due to heat treatment, produces a homogeneously browner colour in wood than is normally expected. This type of discolouration is attributed to reactions of the macromolecules present in wood and is found in both hard- and softwoods. Yellow stain and kiln brown stain can severely alter the colour of the outer few millimeters of a wooden board and is attributed to the reaction of water-soluble sugars and nitrogenous compounds, present in the wood sap, after deposition at the wood surface due to liquid or capillary water flow during drying. A discussion of the mechanism of discolouration due to yellow stain and kiln brown stain would be incomplete without a good understanding of the liquid flow of water during drying above fibre saturation point. This thesis brings the two concepts of liquid water flow and discolouration in context and is presented in four chapters: • an introduction motivating the aims of the investigation (Chapter 1); • a literature review of factors which may influence discolouration and liquid water flow during drying (Chapter 2); • original manuscripts describing the discolouration of South African softwood and liquid water flow in hard- and softwood (Chapter 3); and • a final conclusion that links up the results from the investigations (Chapter 4). The investigations into the occurrence of yellow stain and kiln brown stain showed that the intensity of these types of discolouration was influenced by geographical origin (and/or climate), tree species, planing depth of dried lumber, and kiln schedule parameters like dry- and wet bulb temperature and time. The characteristic discolouration pattern of yellow stain and kiln brown stain indicated that this stain type was related to the wetline phenomenon that is found during the liquid water flow phase of drying wet wood. Thermal discolouration, on the other hand, occurred homogeneously throughout the volume of lumber and is, therefore, not related to free water flow, but to chemical changes of the macromolecules in wood. The results of the liquid water flow investigations support the invasion percolation theory of drying that states that the largest meniscus will retract into a drying liquid-filled capillary network until it is not the largest meniscus anymore. Fluctuations in the rate of moisture loss from the cores of wood pieces above fibre saturation point were also found. The pattern of fluctuation differed appreciably between Betula verrucosa and Pinus radiata. In both cases, the start of the last phase in rate of moisture loss from the core coincided with a reduction in the cross-sectional area of the drying wood piece. This behaviour is explained by the hypothesis that distinct capillary size classes are emptied of free water, in order, from large to small. As smaller capillaries are emptied, the capillary forces become greater, to the point where the forces are great enough to cause permanent or temporary deformation of the remaining water-filled capillaries. Classification and regression tree analysis was a useful statistical technique to analyse a large multivariate dataset. The importance of kiln schedule temperatures and planing depth to control yellow stain and kiln brown stain was clearly pointed out by the technique, which can help to simplify the control of colour quality during the industrial processing of wood.

Dissertation (PhD (Bosb))--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: This study was conducted to evaluate and compare the water and nutrient relations of three indigenous deciduous tree species, viz., Cordia africana Lam., Croton macrostachyus Del., Millettia ferruginea (Hochst.) Baker and two widely planted eucalypts, viz., Eucalyptus camaldulensis Dehnh and Eucalyptus globulus Labill from Ethiopia. The study was organized as glasshouse and field observations in Ethiopia. Owing to the lack of baseline studies on the water and nutrient relations of the deciduous tree species, the glasshouse experiments involved a wide range of water and nutrient applications. Seedlings were grown with the supply of various levels of water and nutrients during which gas exchange, water potential, relative water content, tissue nutrient content and biomass production were measured. The field observations were limited to the study of surface root distribution and leaf nutrient composition of mature trees and their effects on soil nutrient pool. The observations were made on isolated trees and mixed or pure stands of trees in Badessa area, Eastern Ethiopia. The field site was selected because of the availability of the study species and suitability of the trees for the study. In the glasshouse, increased water deficit significantly reduced predawn leaf water potential, relative water content, stomatal conductance, photosynthetic rate, whole plant water use efficiency, plant height, diameter, leaf area and biomass production. Both of the eucalypts did not grow faster than the deciduous species under well-watered conditions unlike under water stress conditions. C. macrostachyus and C. africana had higher transpiration rates and tissue nutrient accumulations than the other species. They also demonstrated higher biomass allocation to roots than all the other species to support the intensive water and nutrient uptake rate. Due to the ability to re-orient its leaves to avoid direct solar irradiance, M. ferruginea maintained higher tissue water potential and relative water content than all the other species under water stress regimes. The impact of imposed drought was quick and more damaging to the eucalypts compared to the deciduous tree species indicating that the eucalypts may not survive extreme drought conditions unlike the deciduous species that drop their leaves and may remain dormant for weeks. The current study gave new experimental proof that E. globulus was more vulnerable to drought than E. camaldulensis. Soil N stress resulted in an overall reduction of tissue N concentration, N:P ratio, photosynthetic rate, stomatal conductance and photosynthetic water use efficiency in all the species studied. Pants with high foliar nitrogen concentration had higher photosynthetic capacities indicating that N plays a key role in photosynthesis and growth of all the studied species. The current study showed that for all the tree species, more attention has to be given to soil N than to P as soil P had minor effects on the photosynthetic activities of plants of all species compared to N.The investigation on tissue nutrient composition confirmed that N:P ratio could be used to detect Plimitation in plants. However, N:P ratio could not distinguish between N-limitation and combined limitations of N and P. The study of isolated C. africana and C. macrostachyus trees on soils in Badessa, Eastern Ethiopia indicated improved soil N, P and K under tree canopies whereas no effects were observed on the other soil nutrients studied. Similar to glasshouse conditions, C. macrostachyus and C. africana produced extensive surface roots, interfering with crops grown in association. Due to their high nutrient cycling potential the net effect on soil was positive. Comparison of E. camaldulensis woodlot and a mixed stand composed of deciduous species indicated that the fine root biomass in the surface soil under E. camaldulensis was about three times that under the mixed stand. The fine root biomass of E. camaldulensis inside the stand and 10 meters away from the stand were comparable in the surface soils showing the presence of root competition with adjacent crops. Therefore, planting of E. camaldulensis in association or adjacent to croplands should be avoided. Nutrient and carbon pool of soil inside the mixed stand was generally higher than that of E. camaldulensis indicating that trees of the mixed stand recycled more nutrients to the soil. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die verskille tussen water- en voedingstofverhoudings van drie inheemse blaarwisselemde boomsoorte te vergelyk, viz., Cordia africana Lam., Croton macrostachyus Del., Millettia ferruginea (Hochst.) Baker en twee bekende eucalyptus spesies, viz., Eucalyptus camaldulensis Dehnh en Eucalyptus globulus Labil van Etiopië. Die studie het bestaan uit kweekhuis- en veldobservasies in Etiopië. As gevolg van beperkte navorsing ten opsigte van water- en voedingstofverhoudings in bladwisselende boomsoorte, het die kweekhuis-eksperimente bestaan uit 'n wye verkeidenheid water- en voedingstoftoetse. Saailinge is gegroei deur verskillende vlakke van water- en voedingstowwe by te voeg. Gaswisseling, waterpotensiaal, relatiewe hoeveelheid water, hoeveelheid voedingstowwe en produksie van biomassa is gemeet. Die veldobservasies was beperk tot oppervlak-wortelverspreiding en blaarvoedingstof hoeveelhede van volwasse bome, sowel as die effek op grondvoedingstowwe. Observasies was beperk tot geïsoleerde, gemengde en een spesie opstande, in die Badessa area, Oos Etiopië. Die studiearea was gekies op grond van die voorkoms van die gekose boomsoorte, sowel as die toepaslikheid van die bome vir die studie. In die kweekhuis is gevind dat die verhoogte watertekort die pre-sonop blaarwaterpotensiaal, relatiewe hoeveelheid water, stomatiese geleiding, fotosintetiese tempo, heelplant water-gebruikseffektiwiteit, plant hoogte, diameter, blaararea en biomassa produksie beduidend verminder het. Nie een van die eucalyptus spesies het vinniger as die bladwisselende spesies onder voldoende hidrasie gegroei nie. Dit was egter nie die geval onder die waterbeperkte toestande nie. C. macrostachyus en C. africana het ‘n hoër transpirasie tempo sowel as weefselvoedingstof waardes gehad as die ander spesies. Hierdie boomsoorte se wortelbiomassa was ook meer as die ander spesies, om vir die tempo van water- en voedingstofopname te akkomodeer. As gevolg van die vermoë om blare te kan oriënteer om direkte sonlig te vookom, het M. ferruginea ‘n hoër water-weefselpotensiaal en relatiewe waterinname gehad in vergelyking met die ander boomsoorte in beperkte water toestande. Die impak van gëinisieerde droogte het vinnig voorgekom en het meer skade aan die eucalyptus aangerig in vergelyking met die bladwisselende boomsoorte. Dit dui aan dat die eucalyptus-spesie nie ekstreme droogte kan oorleef nie, waar bladwisselende spesies hul blare laat afval en vir weke aan een dormant kan bly. Hierdie studie gee eksperimentele bewyse dat E. globulus minder bestand is teen droogte as E. camaldulensis. Beperkte N in die grond het veroorsaak dat daar ‘n algemene vermindering van weefsel Nkonsentrasie, N:P ratio, fotosintetiese tempo, stomatiese geleiding en fotosintetiese watergebruiks effektiwiteit in al die bestudeerde spesies was. Plante wat oor hoër blaar-stikstofkonsentrasiesbeskik, het hoër fotosintetiese kapasiteite wat aandui dat N ‘n belangrike rol in fotosintese en die groei van al die bestudeerde spesies speel. Die oorhoofse bevindings van die studie was, dat daar meer aandag gegee moet word aan grond-N as P omdat grond-P net ‘n kleiner rol speel in die fotosintetiese aktiwiteite van plante van al die spesies in vergelyking met N. Die ondersoek na weefselvoedingstof hoeveelhede het bewys dat die N:P ratio gebruik kan word om P-tekorte in plante aan te dui. Die N:P ratio kan egter nie die verskil in N-tekorte en gekombineerde tekorte van N en P aandui nie. Die studie van die geïsoleerde C. africana en C. macrostachyus bome op grondtipes in Badessa, Oos Etiopië het verbeterde grond-N, P en K onder kroondak gebiede getoon, daar was egter geen verskille in die ander grondvoedingstowwe wat bestudeer is nie. In toestande gelykstaande aan die van die kweekhuis, het C. macrostachyus en C. africana meer oppervlaksswortels ontwikkel. Die toename aan oppervlakswortels het ingedring op gewasse wat in assosiasie gegroei is, dit het egter ‘n positiewe effek op die grond gehad as gevolg van die hoë voedingstof-siklus-potensiaal. Die E. camaldulensis opstand is gevergelyk met ‘n gemengde opstand van bladwisselende spesies waar daar gevind is dat die fynwortel biomassa in die oppervlak grond onder die E. camaldulensis ongeveer drie keer soveel was as die van onder die gemengde opstand. Kompetisie met aangrensende gewasse is aangeui deurdat die fynwortel biomassa van E. camaldulensis binne die opstand en 10 meter weg van die opstand vergelykbaar was in die oppervlakgronde. Dit dui dus aan dat die plant van E. camaldulensis in assosiasie of aangrensend aan gewasse vermy moet word. Die teenwoordigheid van voedingstowwe en koolstof in die grond van die gemengde opstand was oor die algemeen hoër as die van die E. camaldulensis. Dit is ‘n aanduiding dat die bome van die gemengde opstand meer voedingstowwe aan die grond verskaf.

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 (PhD (For))--Stellenbosch University, 2002. / ENGLISH ABSTRACT: This study aims to evaluate the effects of forestry policy on the sustainability of forest resources in Southern Africa. However, the study has confirmed that forestry policy does not operate independently of other policies. Its scope is defined by overarching framework legislation and policy, while it functions within a complex mesh of crosscutting and sectoral policies. Therefore, the implications of these external policies for forest conservation have also been assessed. The method used employs predominantly qualitative assessment of documentary data, which constitute the main contents of the three case studies: South Africa, Tanzania and Zambia. This qualitative information has been transformed into quantitative data, using a scoring scale of one to five for certain indicators of sustainable forest management (SFM). The average score for each country makes up a forest conservation index (FCI), which provides a comprehensive insight into the performance of a country's forestry and other resource conservation policies. South Africa's FCI is estimated at 3, while Tanzania and Zambia's indices have been rounded to 2 each. As South Africa's forestry policy and other biological resource conservation policies came into existence as recent as the mid- and late 1990s, this index suggests that these policies will lead to SFM subject to satisfactory implementation. Indeed, South Africa has a congruous forestry legislation whose regulatory mechanisms are appropriately blended with financial and framework incentives. Its overarching framework legislation and policy define forestry policy, while the crosscutting policies reinforce it. However, the country's performance on intergovernmental and intersectoral policy co-ordination is poor, as well as on the economic valuation of its natural forest resources. Furthermore, the formulation of South Africa's forestry policy was not founded on up-to-date forest resource data. Contrary to the South African case, Tanzania and Zambia's indices indicate the likelihood of unsustainable forest use and management. These countries' existing forestry and other resource conservation policy-making processes are narrow-based and gender-insensitive, rendering them unpopular among policyaffected and policy-connected stakeholders. These inappropriate policies and their blunt instruments distort markets for forest resources, i.e., create situations in which benefits are dissociated from costs, prices from scarcities, rights from responsibilities and actions from consequences. Both forestry policies and their governing tools were not founded on contemporary forest resource data, i.e., they are not issue centred. The countries' framework laws have also failed to institutionalise environmental impact assessment, monitoring and evaluation, intersectoral policy co-ordination, participatory approaches to natural resource management and ownership of environmental assets such as land and forest resources by local communities. The administration of forestry policy requires competent professional and technical staff. South Africa has adequate human resources in the forestry sector, although the personnel appear to lack the necessary skills for participatory forest management for poverty reduction. Tanzania has adequate but ineffective forestry personnel, resutting in lack of law enforcement and corruption while Zambia lacks professional staff to interpret and implement the existing forestry policy. The ineffectiveness and the lack of professional and technical staff, inter alia, is reflected in the high rates of deforestation, which have been estimated at 91,000 halannum for Tanzania and 851,000 halannum for Zambia. Unlike South Africa, both Tanzania and Zambia's sectoral policies fail to cultivate concerns for forest conservation. This situation is aggravated further by the pervasive lack of intra- and intersectoral policy coordination among biological resource conservation divisions and departments. The coherence of South Africa's forestry and other resource conservation policies is attributable to the scarcity of natural forests in the country. Approximately, 7.0% of South Africa's landscape is under forest cover, while Tanzania and Zambia have 37% and 42%, respectively. Decreasing supplies of forest coupled with the increasing demands for forest resources causes the value of forest resources to appreciate. Naturally, there is a stronger need for the forest-scarce South Africa to pursue prudent conservation policies to protect its limited forest than Tanzania and Zambia whose governments treat their respective vast land and forest resources as a safety valve for economic hardship without adequate investment in SFM. In summary, forest resource use and management in Tanzania and Zambia are littered by market and policy failures. It is envisaged that the opportunities and constraints identified in each market and policy failure will inform future forestry and related policy-making process, not only in the concerned countries but also in other African countries experiencing similar forest conservation problems. / AFRIKAANSE OPSOMMING: Hierdie studie het ten doel om die effekte te evalueer wat bosboubeleid het op die volhoubaarheid van woudhulpbronne in Suidelike Afrika. Hierdie studie het egter bevestig dat bosboubeleid nie onafhanklik van ander beleidspunte funksioneer nie. Die omvang daarvan word gedefinieer deur oorkoepelende raamwerkwetgewing en beleid, terwyl dit binne 'n komplekse netwerk van oorkruisende en sektorale beleid funksioneer. Daaom is die implikasies van hierdie eksteme beleidspunte vir woudbewaring ook bepaal. Die metode gebruik, wend hoofsaaklik kwalitatiewe beraming van dokumentere data aan, wat die hoofinhoud van die drie gevallestudies, nl. Suid-Afrika, Tanzania en Zambia uitrnaak. Hierdie kwalitatiewe informasie is omvorm na kwantitatiewe data, deur gebruik te maak van 'n skaal van een tot vyf vir sekere indikators van vohoubae bosbestuur (VBB). Die gemiddelde punt vir elke land vorm 'n woudbewaringsindeks (WBI), wat 'n omvatlende insig verskaf van die land se uitvoering van die bosbou- en bewaringsbeleid van ander hulpbronne. Suid-Afrika se WBI is beraam op 3, terwyl Tanzania en Zambia sa indekse elk tot 2 afgerond is. Siende dat Suid-Afrika se bosbou- en bewainqsoeleld van ander biologiese hulpbronne eers so onlangs as die middel- en laat 1990's in werking getree het, stel hierdie indeks voor dat die beleid sal lei tot VBB, onderhewig aan bevredigende uitvoering daarvan. Suid-Afrika het inderdaad 'n gepaste bosboubeleid, waarvan die regulerende meganismes toepaslik vermeng is met finensiele en raamwerk aansporings. Die oorkoepelende raamwerkwetgewing en beleid definieer bosboubeleid, terwyl oorkruisende beleidspunte dit versterk. Die land se uitvoering van interregerings- en intersektorale beleidkoordinasie, is egter swak, asook in die ekonomiesa waardering van sy natuurlike woudhulpbronne. Verder, is die formulering van Suid-Afrika se bosboubeleid nie gegrond op woudhulpbrondata wat op hoogte was nie. In teenstelling met die Suid-Afrikaanse geval, toon die indeksa van Tanzania en Zcrnbia die waCl'skynlikheid van onvomoubae bosbenutting en -bestuur. Hierdie lande se bestaande beleidvormingsprosasse vir bosbou en bewaring van ander hulpbronne, is eng-gebaseer en geslags-onsensitief, wat dit onpopulsr maak onder beleidgeaffekteerde en beleidverbonde insethouers. Hierdie ontoepaslike beleidspunte en stomp instrumente verdraai markte vir woudhulpbronne, d.i. skep situasies waarin voordele gedissosieer is van kostes, pryse van skaashed, regte van verantwoordelikhede en aksies van nagevolge. Beide bosboubeleidspunte en die leidingsinstrumente is nie gegrond op kontemporere woudhulpbrondata nie, d.w.s. hulle is nie rondom die kwessie gesentreer nie. Die lande se raamwerkwette het ook gefaal daarin om omgewingsimpakberamings, monitering en evaluering, intersektorale beleidkoordinering, deelnemende benaderings tot natuurlike hulpbronbestuur en plaaslike gemeenskappe sa eienaaskai van omgewingsbates, SODS grond en woudhulpbronne in te stel. Die administrasie van bosboubeleid verg bevoegde professionele en tegniese personeel. Sui-Afrika het voldoende menslike hulpbronne in die bosbousektor, hoewel dit voorkom of die personeel nie die nodige vaadiqhede het vir deelnemende bosbestuur vir die veligting van arnoede nie. Tanzanie het voldoende, maa oneffektiewe bosboupersoneel, wat 'n gebrek aan wetstoepassing en korrupsie tot gevolg het, terwyl Zambie 'n tekort het aan professionele personeel om die bestaande bosboubeleid te interpreteer en te implementeer. Die oneffektiwiteit en die gebrek aan professionele en tegniese personeel, onder andere, word gerefiekteer in die hoe tempo van ontbossing, wat beraam is op 91,000 ha/jaCl'vir Tenzenie en 851,000 ha/jaCl'vir Zembie. Anders as Suid-Afrika, faal beide Tanzanie en Zambia se sektorale beleidspunte daain om belange vir woudbewaring te kweek. Hierdie situasie word verder vererger deur die deurdringende gebrek aan intra- en intersektorale beleidkoordinering onder afdelings en departemente van biologiese hulpbronbewaring. Die verband tussen Suid-Afrika se bosbou- en bewaringsbeleid van ander hulpbronne word toegeskryf aan die skaarsheid van natuurlike woude in die land. Ongeveer 7.0% van die Suid-Afrikaanse landskap is bedek met woude, terwyl Tanzanie en Zambia onderskeidelik 37% en 42% bedek is. Verlaagde voorraad van woude, gepaard met die toenemende vraag na woudhulpbronne, het tot gevolg dat die waade van woudhulpbronne styg. Natuurlik is daar 'n groter behoefte vir die woud-arm Suid-Afrika om verstandige bewaingsbeleid na te streef om sy beperkte woude te beskerm as Tanzanie en Zambie, waa hulle regerings hul onderskeie ge\Yeldigegrond en woudhulpbronne behandel as 'n veiligheidsklep vir ekonomiese ontbering, sonder voldoende belegging in VBB. As opsomming, is die benutting en bestuur van woudhulpbronne in Tanzania en Zambia met mark- en beleidsmislukking besaai. Dit word beoog dat die geleenthede en beperkinge wat met elke mark- en beleidsmislukking ge'identifiseer is, toekomstige bosbou en verwante beleidvormingsproses kan inlig, nie net in die betrokke lande nie, maar ook in ander Afrika lande wat soortgelyke woudbewarings probleme ondervind.

Thesis (PhD(For))--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Widdringtonia whytei is a tropical endemic, fire-adapted pioneer coniferous tree species within natural fire-fragmented Afromontane forest patches in a confined area on Mulanje Mountain in Malawi. Natural and anthropogenic fires within the surrounding fire-prone landscape, insect attacks, and uncontrolled harvesting of mature trees for timber threaten the survival of W. whytei. This study investigated the effects of population fragmentation on the reproductive biology of W. whytei, through four specific studies: effects of population size, tree size and crown position on viable seed output; seed rain variation among population sizes; effects of temperature and light on viability and germination of W. whytei seeds; and the influence of population size on natural regeneration patterns. The study was conducted during 2008 and 2009 on three sites using three W. whytei population sizes: small (≤10 reproductively mature cone-bearing W. whytei trees), medium (11-20 cone-bearing trees) and large (>20 cone-bearing trees). Data were collected using field and laboratory experiments and a review of secondary information. The effect of fragment size and crown position on viable seed output and seed rain pattern was tested with a nested linear mixed model. The influence of stem diameter (dbh) on viable seed output was tested using a separate data set. The variation in seed rain was explored with a generalised linear model (GLM) with a negative binomial link function. Variations in seed germination was analysed with a Weibull regression model. The influence of fragment size on seedling regeneration was tested with a GLM (binary logistic regression). Viable seed output from W. whytei cones was very low (23%) and was not affected by population size, tree diameter or crown position. W. whytei population size influenced seed rain with large fragments having higher seed rain densities. Number of dispersed seeds was generally very low and poorly dispersed. W. whytei cones are semiserotinous and depends on moderate to severe fires for heavy seedfall and wider dispersal. Such fires did not occur during the study period. Temperature is a critical factor for seed germination. Seeds germinate between 15 and 25°C with the optimum at ~ 20°C either under light or dark conditions. Regeneration density followed the seed rain pattern indicating that seed availability is a critical factor for regeneration. Regular cool fires outside the forest patches and along the edges during the hot dry season, and the thick litter layer and shady conditions inside forest patches, caused most of the seedling mortality. This study highlighted the difficulties W. whytei experiences with low output of viable seed, limited seed dispersal and low seedling regeneration in and around forest patches, i.e. factors important for conservation management of this species. It is recommended that gaps with diameter equal to canopy height and occasional spot fires would promote seed dispersal onto exposed mineral soil for rapid seedling establishment and subsequent population growth. Such natural fire disturbance events may show the true seed rain and seedling establishment patterns in this species. / AFRIKAANSE OPSOMMING: Widdringtonia whytei is ‘n tropiese endemiese, vuuraangepaste pionier naaldhoutagtige boomsoort binne die natuurlike vuurgefragmenteerde Afromontane woudkolle binne ‘n beperkte area op Mulanje berg in Malawi. Natuurlike en menslike vure binne die omringende vuurgeneigde landskap, insekaanvalle, en onbeheerde kap van volwasse bome vir hout bedreig die voortbestaan van W. whytei. Hierdie studie het die effek van populasiefragmentasie op die voortplantingsbiologie van W. whytei ondersoek, deur vier spesifieke studies: die effek van populasiegrootte, boomgrootte en kroonposisie op produksie van lewenskragtige saad; saadreënvariasie tussen populasiegroottes; die effek van temperatuur en lig op lewenskragtigheid en ontkieming van W. whytei saad; en die invloed van populasiegrootte op natuurlike verjongingspatrone. Die studie is gedurende 2008 en 2009 uitgevoer op drie groeiplekke met drie W. whytei populasiegroottes: klein (≤10 keëldraende (volwasse) W. whytei bome), medium (11-20 keëldraende bome) en groot (>20 keëldraende bome). Data is versamel in veld- en laboratorium eksperimente asook 'n oorsig van sekondêre inligting. Die invloed van populasie fragmentgrootte en kroonposisie van bome op saadproduksie en die saadreënpatroon is getoets met ‘n geneste liniêre gemengde model. Die invloed van boomstamdeursnee op die produksie van kiemkragtige saad is met ‘n aparte datastel getoets. Die variasie in saadreënpatroon is met 'n algemene liniêre model (GLM) met 'n negatiewe binomiese skakelfunksie getoets. Variasies in ontkiemingspersentasie van sade is met 'n Weibull regressiemodel ontleed. Die invloed van fragmentgrootte op saailingverjonging is met 'n algemene linêre model (binêre logistiese regressie) getoets. Produksie van lewenskragtige saad in W. whytei keëls was baie lag (23%) en was nie deur populasiegrootte, boomstamdeursnee of kroonposisie beïnvloed nie. W. whytei populasiegrootte het saadreën beïnvloed en groot fragmente het groter saadreëndigthede gehad. Die aantal verspreide sade was in die algemeen baie laag en swak versprei. W. whytei keëls is semi-saadhoudend (serotinous) en is afhanklik van matige tot intense vure vir massiewe saadvrystelling en wyer saadverspreiding. Sulke vure het nie gedurende die studieperiode voorgekom nie. Temperatuur is ‘n kritiese factor vir saadontkieming. Sade ontkiem goed tussen 15 en 25°C met die optimum rondom ~ 20°C onder beide lig en donker toestande. Fragmentgrootte het nie die saailingverjonging in W. whytei beïnvloed nie. Verjongingsdigtheid het die saadreënpatroon gevolg, wat daarop dui dat saadbeskikbaarheid ‘n kritiese factor is vir saailingverjonging. Gereelde koel vure buite die woudkolle en langs die woudrand gedurende die droë warm seisoen, en die dik lae blaarval (litter) en skadutoestande binne ‘n woud, het meeste van die saailingmortaliteit veroorsaak. Hierdie studie het die probleme beklemtoon wat W. whytei ondervind met die lae produksie van kiemkragtige saad, saadverspreiding en saailingverjonging binne en rondom die woudkolle, m.a.w. faktore wat belangrik is vir bewaringsbestuur van hierdie boomsoort. Die aanbeveling word gemaak dat kroonopeninge met ‘n deursnee gelyk aan minstens die kroonhoogte, en sporadiese kolbrande binne die woudkolle kan saadverspreiding op blootgestelde minerale grond vir vinnige saailingvestiging en gevolglike populasiegroei bevorder. Sodanige vuurversteuringsgeleenthede mag die werklike patrone in saadreën en saailingvestiging in hierdie species toon.