Bibliography: leaves 227-244. This study is conceived to address various aspects of western myall (Acacia papyrocarpa Benth) recruitment, lifespan, distribution and the effects of major vertebrates on the species' ecology over the major part of its range in South Australia. A study of the population dynamics of the species is done to assess the adequacy of net recruitment. Population structure is examined across the woodlands. The new concept of "fossil paddocks" is adopted to investigate the historical impact of introduced herbivores on the landscape.

Bibliography: leaves 227-244. / xiv, 244 leaves : ill.[some col.], maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This study is conceived to address various aspects of western myall (Acacia papyrocarpa Benth) recruitment, lifespan, distribution and the effects of major vertebrates on the species' ecology over the major part of its range in South Australia. A study of the population dynamics of the species is done to assess the adequacy of net recruitment. Population structure is examined across the woodlands. The new concept of "fossil paddocks" is adopted to investigate the historical impact of introduced herbivores on the landscape. / Thesis (Ph.D.)--University of Adelaide, Dept. of Environmental Science and Rangeland Management, 1997

Wong, Man Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 149-164). / Abstracts in English and Chinese; appendix in Chinese. / Abstract --- p.i / Abstract (in Chinese) --- p.iii / Acknowledgements --- p.iv / Table of contents --- p.vi / List of tables --- p.x / List of figures --- p.xii / List of plates --- p.xiv / List of appendices --- p.xv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Study background --- p.1 / Chapter 1.2 --- Conceptual framework of the study --- p.3 / Chapter 1.3 --- Objectives of the study --- p.10 / Chapter 1.4 --- Significance of the study --- p.10 / Chapter Chapter 2 --- Literature Review --- p.12 / Chapter 2.1 --- Overview of world plantations --- p.12 / Chapter 2.2 --- Restoration through the establishment of exotic plantations --- p.13 / Chapter 2.2.1 --- Rationale for restoration --- p.13 / Chapter 2.2.2 --- Restoration principles --- p.14 / Chapter 2.2.3 --- Use of exotic plantations in restoration --- p.15 / Chapter 2.2.4 --- Role of exotic species in plantations --- p.16 / Chapter 2.2.5 --- Problems associated with exotic plantations --- p.18 / Chapter 2.3 --- Transforming exotic woodlands to native forests --- p.21 / Chapter 2.3.1 --- Options of woodland transformation --- p.22 / Chapter 2.3.2 --- Woodland transformation in Hong Kong --- p.26 / Chapter 2.4 --- Summary --- p.28 / Chapter Chapter 3 --- The Study Area --- p.29 / Chapter 3.1 --- Introduction --- p.29 / Chapter 3.2 --- Geological setting of Hong Kong --- p.29 / Chapter 3.2.1 --- Climate --- p.29 / Chapter 3.2.2 --- Geology --- p.30 / Chapter 3.2.3 --- Soils --- p.31 / Chapter 3.2.4 --- Vegetation --- p.32 / Chapter 3.3 --- Study area --- p.33 / Chapter 3.3.1 --- Site selection --- p.33 / Chapter 3.3.2 --- Tai Lam Country Park and characteristics of Acacia confusa plantations --- p.34 / Chapter 3.3.3 --- Site description --- p.35 / Chapter 3.3.4 --- Site management --- p.38 / Chapter 3.3.5 --- Feral cattle disturbance --- p.40 / Chapter Chapter 4 --- Environmental Changes after Clearfelling --- p.41 / Chapter 4.1 --- Introduction --- p.41 / Chapter 4.2 --- Materials and methods --- p.42 / Chapter 4.2.1 --- Instrumentation and microclimatic measurements --- p.42 / Chapter 4.2.2 --- Data processing and statistical analysis --- p.44 / Chapter 4.3 --- Results and discussion --- p.44 / Chapter 4.3.1 --- Solar radiation and temperature after clearfelling --- p.44 / Chapter 4.3.2 --- Relative humidity and wind velocity after clearfelling --- p.48 / Chapter 4.3.3 --- Effect of clearfelling on exotic woodland transformation --- p.52 / Chapter 4.4 --- Summary --- p.53 / Chapter Chapter 5 --- Changes in Soil Properties after Clearfelling --- p.55 / Chapter 5.1 --- Introduction --- p.55 / Chapter 5.2 --- Materials and methods --- p.58 / Chapter 5.2.1 --- Soil sampling --- p.58 / Chapter 5.2.2 --- Laboratory analysis --- p.58 / Chapter 5.2.2.1 --- Texture --- p.59 / Chapter 5.2.2.2 --- Soil reaction pH --- p.59 / Chapter 5.2.2.3 --- Soil organic carbon (SOC) and organic matter (SOM) --- p.59 / Chapter 5.2.2.4 --- Tokal Kjeldahl nitrogen (TKN) --- p.60 / Chapter 5.2.2.5 --- Carbon: nitrogen ratio --- p.60 / Chapter 5.2.2.6 --- Available phosphorus --- p.60 / Chapter 5.2.2.7 --- Exchangeable cations --- p.60 / Chapter 5.2.3 --- Data processing and statistical analysis --- p.61 / Chapter 5.3 --- Results and discussion --- p.61 / Chapter 5.3.1 --- Temporal change of soil texture and reaction pH after clearcutting / Chapter 5.3.2 --- Temporal change of soil organic matter after clearcutting --- p.65 / Chapter 5.3.3 --- Temporal change of Total Kjedahl Nitrogen after clearcutting --- p.69 / Chapter 5.3.4 --- Temporal change of exchangeable cations after clearcutting --- p.71 / Chapter 5.3.5 --- Temporal change of available phosphorus after clearcutting --- p.74 / Chapter 5.3.6 --- Soil nutrient status after clearfelling --- p.76 / Chapter 5.3.7 --- Importance of tree retention on nutrient cycling --- p.78 / Chapter 5.4 --- Summary --- p.80 / Chapter Chapter 6 --- Soil Nitrogen Fluxes after Clearfelling --- p.81 / Chapter 6.1 --- Introduction --- p.81 / Chapter 6.2 --- Materials and methods --- p.83 / Chapter 6.2.1 --- In situ core incubation --- p.84 / Chapter 6.2.2 --- Sampling method --- p.84 / Chapter 6.2.3 --- Laboratory analysis of mineral N --- p.86 / Chapter 6.2.4 --- "Calculation of N mineralization, leaching and uptake" --- p.86 / Chapter 6.2.5 --- Statistical analysis --- p.89 / Chapter 6.3 --- Results and discussion --- p.89 / Chapter 6.3.1 --- Seasonal variation of NH4-N and N03-N --- p.89 / Chapter 6.3.2 --- "Net ammonification, NH4-N leaching and NH4-N uptake" --- p.92 / Chapter 6.3.3 --- "Net nitrification, NO3-N leaching and NO3-N uptake" --- p.94 / Chapter 6.3.4 --- "Net mineralization, leaching and uptake" --- p.95 / Chapter 6.3.5 --- Mineral nitrogen budget --- p.101 / Chapter 6.4 --- Summary --- p.103 / Chapter Chapter 7 --- Growth Performance of Recruited Trees and Restocked Species after Clearfelling --- p.105 / Chapter 7.1 --- Introduction --- p.105 / Chapter 7.2 --- Materials and methods --- p.106 / Chapter 7.2.1 --- Species identification --- p.106 / Chapter 7.2.2 --- Sampling method --- p.106 / Chapter 7.2.3 --- Statistical analysis --- p.107 / Chapter 7.3 --- Results and discussion --- p.107 / Chapter 7.3.1 --- Effect of overstorey removal on the growth of recruited native trees / Chapter 7.3.2 --- Effect of overstorey removal on growth of restocked native seedlings --- p.112 / Chapter 7.3.3 --- Importance of tree retention and seedling restocking in native forest re-establishment --- p.114 / Chapter 7.3.4 --- Species selection for clearcut site --- p.115 / Chapter 7.3.5 --- Browsing damage by feral cattle and its prevention --- p.118 / Chapter 7.4 --- Summary --- p.120 / Chapter Chapter 8 --- Effect of Shade and Water on the Growth of Selected Native Species --- p.121 / Chapter 8.1 --- Introduction --- p.121 / Chapter 8.2 --- Materials and methods --- p.124 / Chapter 8.2.1 --- Study sites --- p.124 / Chapter 8.2.2 --- Experimental design --- p.124 / Chapter 8.2.3 --- Light and water treatments --- p.124 / Chapter 8.2.4 --- Growth performance analysis --- p.126 / Chapter 8.2.5 --- Statistical analysis --- p.127 / Chapter 8.3 --- Results and discussion --- p.127 / Chapter 8.3.1 --- Height growth --- p.127 / Chapter 8.3.2 --- Basal diameter growth --- p.132 / Chapter 8.4 --- Summary --- p.135 / Chapter Chapter 9 --- Conclusions --- p.136 / Chapter 9.1 --- Introduction --- p.136 / Chapter 9.2 --- Summary of major findings --- p.137 / Chapter 9.3 --- Implications of the study --- p.141 / Chapter 9.3.1 --- Transformation of Acacia confusa woodland into native forest by clearfelling --- p.141 / Chapter 9.3.2 --- When and where to undertake clearfelling --- p.144 / Chapter 9.4 --- Limitations of the study --- p.146 / Chapter 9.5 --- Suggestions for further study --- p.147 / References --- p.149 / Appendices --- p.165

by Au Pui Sze. / Thesis submitted in: December 2000. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 135-150). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (in Chinese) --- p.iii / Acknowledgement --- p.iv / Table of contents --- p.vi / List of tables --- p.x / List of figures --- p.xi / List of appendices --- p.xii / Chapter Chapter one --- Introduction / Chapter 1.1 --- The role of plantations in ecosystem rehabilitation --- p.1 / Chapter 1.2 --- Reforestation history in Hong Kong --- p.2 / Chapter 1.3 --- Conceptual framework of the study --- p.5 / Chapter 1.4 --- Objectives of the study --- p.15 / Chapter 1.5 --- Scope and significance of the study --- p.16 / Chapter 1.6 --- Organisation of the thesis --- p.17 / Chapter Chapter two --- The Study Area / Chapter 2.1 --- Geographical setting of Hong Kong --- p.18 / Chapter 2.1.1 --- Climate --- p.18 / Chapter 2.1.2 --- Geology --- p.20 / Chapter 2.1.3 --- Soils --- p.20 / Chapter 2.1.4 --- Vegetation --- p.21 / Chapter 2.2 --- Site selection --- p.23 / Chapter 2.3 --- Site description --- p.26 / Chapter 2.4 --- Nature and extent of disturbance prior to planting --- p.30 / Chapter 2.5 --- Planting techniques and post-planting maintenance --- p.31 / Chapter Chapter Three --- Stand Characteristics of Acacia Plantations / Chapter 3.1 --- Introduction --- p.33 / Chapter 3.2 --- Methodology --- p.37 / Chapter 3.2.1 --- Sampling plots design --- p.37 / Chapter 3.2.2 --- Tree density --- p.37 / Chapter 3.2.3 --- Tree growth parameters --- p.38 / Chapter 3.2.4 --- Data processing and statistical analysis --- p.38 / Chapter 3.3 --- Results and discussion --- p.39 / Chapter 3.3.1 --- Growth dynamics of acacias --- p.39 / Chapter 3.3.2 --- Growth characteristics of the reforested species --- p.44 / Chapter 3.3.3 --- Sustained growth and natural regeneration of acacia plantations --- p.48 / Chapter 3.3.4 --- Rehabilitation of degraded lands by exotic species plantations --- p.52 / Chapter 3.4 --- Conclusion --- p.54 / Chapter Chapter Four --- Cover Soil Characteristics of Acacia Plantations / Chapter 4.1 --- Introduction --- p.56 / Chapter 4.2 --- Methodology --- p.60 / Chapter 4.2.1 --- Soil sampling --- p.60 / Chapter 4.2.2 --- Laboratory analysis --- p.61 / Chapter 4.2.3 --- Texture --- p.61 / Chapter 4.2.4 --- Soil pH --- p.61 / Chapter 4.2.5 --- Organic carbon --- p.62 / Chapter 4.2.6 --- Total Kjeldahl nitrogen --- p.62 / Chapter 4.2.7 --- Carbon : nitrogen ratio --- p.63 / Chapter 4.2.8 --- Mineral nitrogen (NH4-N and N03-N) --- p.63 / Chapter 4.2.9 --- Available phosphorus --- p.64 / Chapter 4.2.10 --- Exchangeable cations --- p.64 / Chapter 4.3 --- Data processing and statistical analysis --- p.64 / Chapter 4.4 --- Results and discussion --- p.65 / Chapter 4.4.1 --- Effect of acacias on soil texture and pH --- p.65 / Chapter 4.4.2 --- "Effect of acacias on SOM, TKN and mineral N" --- p.69 / Chapter 4.4.3 --- Effect of acacias on the available P and exchangeable cations… --- p.77 / Chapter 4.4.4 --- Soil nutrient status of the plantations --- p.82 / Chapter 4.5 --- Conclusion --- p.90 / Chapter Chapter Five --- Understorey Vegetation of Acacia Plantations / Chapter 5.1 --- Introduction --- p.92 / Chapter 5.2 --- Methodology --- p.96 / Chapter 5.2.1 --- Understorey plant sampling --- p.96 / Chapter 5.2.2 --- Species identification and nomenclature --- p.98 / Chapter 5.2.3 --- Plant growth parameters --- p.98 / Chapter 5.2.4 --- Data processing and statistical analysis --- p.99 / Chapter 5.3 --- Results and discussion --- p.100 / Chapter 5.3.1 --- Floristic composition of the acacia plantations --- p.100 / Chapter 5.3.2 --- "Species richness, diversity and woody abundance of the understories" --- p.101 / Chapter 5.3.3 --- Species composition and structure of the understories --- p.106 / Chapter 5.3.4 --- Mechanisms and pathway of succession in the exotic plantations --- p.115 / Chapter 5.4 --- Conclusion --- p.116 / Chapter Chapter Six --- Conclusion / Chapter 6.1 --- Summary of findings --- p.118 / Chapter 6.2 --- Implications of the study --- p.122 / Chapter 6.2.1 --- Ecological value of exotic plantations in Hong Kong --- p.122 / Chapter 6.2.2 --- Restoration strategies for borrow areas --- p.125 / Chapter 6.2.3 --- Enrichment planting after fire --- p.128 / Chapter 6.3 --- Limitations of the study --- p.131 / Chapter 6.4 --- Suggestion for future study --- p.132 / References --- p.135 / Appendices --- p.151

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Human-modified habitats form increasingly large components of landscapes, threatening biodiversity and creating challenges for conservation. In some cases altered habitats form entirely novel ecosystems that may support new combinations of species and species abundances, and create habitat space in otherwise transformed landscapes. In the Western Cape of South Africa, woody invasive species contribute to landscape-level habitat transformation and form novel ecosystems. Invasive Australian Acacia species are especially problematic in lowland areas where they create dense thickets and substantially transform both biotic communities and abiotic processes. Despite the prominence of Acacia thickets across the Western Cape, their ability to support native fauna is not well understood and the objective of this study was to assess the significance of Acacia thickets as habitat for the region’s avifauna. Birds were surveyed in Acacia thickets in the south-western Western Cape in three seasons to examine species richness, abundance and functional abundance. Furthermore, I examined the extent to which differences in patch-level vegetation structure alter bird communities. Between survey sites and seasons, significant variation was observed in assemblage richness, density, median body size and biomass. Variation in vegetation density, stem density, mean vegetation height and total canopy cover best explained variation in bird assemblages. Eighty species were estimated to utilize Acacia thickets and assemblages had a mean density of 7.78 birds per ha. The most abundant feeding guilds were the mixed feeders and insectivores. The median body size observed was 15.2 g and the body size frequency distribution of all species in Acacia spanned a similar range compared to the body size frequency distribution for the species list for the entire Western Cape. The mean biomass of bird communities was 0.224 kg per ha. Using data on bird density and biomass, Acacia thickets across the Fynbos Biome support and estimated average of over 21 million birds with a combined biomass of over 600 thousand kg. This study found that Acacia thickets in the Western Cape support a subset of the region’s birds with the most abundant species being small mixed feeders, which are also frequently urban-adapted. Compared with other habitat types, Acacia support bird assemblages with moderate species richness and density. This study shows that Acacia thickets, as a novel habitat, provide a significant amount of habitat space in a highly transformed landscape and highlights the need for comprehensive evaluation of altered habitats before assumptions are made about their ecological value. / AFRIKAANSE OPSOMMING: Getransformeerde habitatte maak vermeerderend groot deel uit van die omgewing, dit bedreig biodiversiteit en skep groter uitdagings vir bewaring. In sommige gevalle vorm hierdie getransformeerde habitatte geheel nuwe ekosisteme wat moontlik nuwe kombinasies van spesies en spesie volopheid kan onderhou. Verder skep nuwe ekosisteme habitat spasie in anders veranderde landskappe. In die Wes-Kaap van Suid-Afrika dra die Australiese Acacia indringer spesies is veral problematies in laagliggende areas, aangesien dit digte ruigtes vorm, asook beide die biotiese gemeenskappe en die abiotiese prosesse aansienlik transformeer. Ten spyte daarvan dat daar volop Acacia ruigtes in die WesKaap is, word min verstaan van hul vermoë om inheemse fauna te onderhou. Die hoofdoel van hierdie studie was om die belang van Acacia ruigtes as habitat vir die area se voëllewe te bepaal. Voël-opnames in die suidwestelike dele van die Wes-Kaap is gedoen in Acacia ruigtes oor drie seisoene, om spesierykheid, volopheid en funksionele volopheid te ondersoek. Verder is die mate waartoe verskille in die plotte van die plantegroei struktuur, die voëlgemeenskappe verander, geondersoek. Daar was aansienlike variasie waargeneem in die spesiesamestelling rykheid, voorkoms digtheid, mediaan liggaamsgrootte en biomassa van die voëls tussen die onderskeie voëlopnaam plotte en die seisoene. Die variasie in plantegroei digtheid, stam digtheid, mediaan plantegroeihoogte en totale kroonbedekking verduidelik hierdie variasie in spesiesamestelling die beste. Tagtig voëlspesies Acacia ruigtes benut en die populasiesamestelling het ‘n gemiddelde digtheid van 7,78 voëls per ha. Die mees algemene voel-voeding-guldes was die gemengde-voedsel-vreters en insekvreters. Die median liggaamsgrootte waargeneem was 15,2 g en die liggaamsgrootte frekwensieverspreiding van alle spesies in Acacia ruigtes is ooreenkomstig met die liggaamsgrootte frekwensieverspreiding vir die spesielys vir die hele Wes-Kaap. Die gemiddelde biomassa van voel gemeenskappe was 0.224 kg per ha. Acacia ruigtes oor die fynbosbioom wat ‘n geskatte gemiddelde van meer as 21 miljoen voels ondersteun, met ‘n gesamentlike biomassa van meer as 600 duisend kg. Hierdie studie het bevind dat Acacia ruigtes in die Wes-Kaap ‘n onderafdeling van die streek se voels ondersteun, met die mees algemene spesies as die klein gemengde-voedsel-vreters, wat ook dikwels stedelik aangepas is. In vergelyking met ander habitattipes ondersteun Acacia ruigtes voel samestellings met matige spesierykheid en digtheid. Hierdie studie toon dat die Acacia ruigtes, as ‘n nuwe habitat, ‘n beduidende hoeveelheid habitat ruimte in ‘n hoogs getransformeerde omgewing skep en beklemtoon die behoefte aan ‘n omvattende evaluering van veranderde habitatte, voor aannames gemaak word oor hul ekologiese waarde.

Effects of herbivory, fire, and tree harvesting on Acacia drepanolobium were studied using plant population dynamics as the philosophical basis of research. Specifically, growth rates, chrono-sequence of re-growth, biomass and charcoal yield, herbivory, flowering, seed production, germination, mortality and the ants of Acacia drepanolobium were studied in the black cotton ecosystem of Mpala Research Centre, Laikipia, Kenya, between September 1995 and December 2000. Acacia drepanolobium was the most abundant tree or shrub with densities ranging from 80% to 98% of all the overstorey species, but it was the least browsed of all the trees and shrubs in the black cotton ecosystem, ranging from a mean of 7.2% to 9% of the individuals browsed. The tree is inhabited by four Acacia ant species, Crematogaster mimosae, Crematogaster sjoestedti, Crematogaster nigriceps, and Tetraponera penzigi, which are believed to be obligate, and which probably play a role in the low browsing rates observed. Six herbivore treatments replicated three times (no herbivores - O; only cattle - C, all herbivores allowed - MWC {control}, mega-herbivores {elephants and giraffe} and wildlife {W} – MW only, wildlife – W - only {all wildlife except mega-herbivores} and wildlife and cattle only - WC) was the main experimental design used in understanding the dynamics of the tree species under influence of different herbivores. Mean annual height growth of A. drepanolobium trees was 24.9 cm yr-1, while the mean Relative Growth Rates ranged from 14.6 x 10 –3 cm cm-1 yr-1 to 18.7 x 10 –3 cm cm-1 yr-1. Growth rates were different among the herbivore treatments and between seasons. Shoots of the tree grew by a mean range of 6.8 cm to 9.1 cm, were similar among the treatments but differed among the seasons. Canopy volume increased over time although it fluctuated with seasons, suggesting an increase in bushiness of A. drepanolobium in the ecosystem. Trees occupied by different ant species showed differences in shoot density (number of new shoots per twig), being greater in Crematogaster nigriceps occupied trees compared with the other ant species. Swollen thorn (gall) density per unit of twig length was greatest in treatments with megaherbivores; these galls were significantly larger on trees occupied by the ant Crematogaster nigriceps. Treatments with herbivores were more spinescent than the total exclusion treatment. Spine lengths ranged from 0.8 to 2.4 cm, and recorded a progressive reduction of up to 36.36.7% in treatments without browsers suggesting a relaxation of induced defence in A. drepanolobium. Flowering in A. drepanolobium was low and staggered over the study period ranging from 0.8% to 2.0% of the trees with no differences among the treatments suggesting that the level of herbivory was not sufficient to influence reproduction of the tree in the experimental site. Consequently, seedling recruitment was very low within the experimental site. However, a nearby site recorded flowering of between 22.7% and 93.5%. Mean pod production, mean number of seeds per tree and mean weight of pods and seeds had a positive linear relationship with tree density (R2=0.77, 0.81 and 0.81 respectively). Trees occupied by Crematogaster mimosae were the most likely to flower (68%) compared with C. nigriceps (5.8%), again suggesting that ants had an effect on the tree’s reproduction. Mortality of A. drepanolobium trees averaged 0.9% to 4.2% over the study period, being significantly greater in treatments with mega-herbivores. Seedling survival ranged from 42% to 75%, being greatest in the cattle only treatment. Between 30% and 100% (mean 67.2%), of A. drepanolobium seeds were attacked by a bruchid beetle (Bruchus sp.). Seeds attacked by bruchid beetles had significantly lower germination rates. Similarly, seeds passed through a fire also recoded significantly low germination rates compared with normal seeds. Fire (3.4%) and bruchid beetles (20.7%) germination compared with (control) undamaged seeds (84%) play an important role in the population dynamics of A. drepanolobium. Fewer A. drepanolobium seeds (33%) were recovered from the surface compared with buried (72%) seeds after a fire, indicating seed loss from the effect of fire and predation. In the burn experiment, fire top-killed 16% of A. drepanolobium trees but no tree or seedling was killed. On the other hand, fire significantly reduced the density of non-A. drepanolobium trees by between 50% and 100%, with none of them showing signs of coppicing after the fire unlike top-killed A. drepanolobium trees. Woody biomass from A. drepanolobium was strongly related to stem diameter (Y = 3.77x + 1.17, R2 = 0.96, P < 0.001). Mean charcoal production from earthen kilns was 2.83 Mg ha- 1. Height and stem diameter in coppicing stands increased at a mean rate of 28.6 cm yr-1 and 0.7 cm yr-1 respectively. Biomass in coppicing stands accumulated at a mean rate of 1.3 Mg ha-1 yr-1 in a 14-year period, yielding dry biomass of 18.26 Mg ha-1 useable wood that can produce a minimum of 3.0 Mg ha-1 of charcoal. This study shows that Acacia drepanolobium populations are affected by several factors including herbivory, fire and ants. The population dynamics of this tree shows that it can be harvested for sustainable charcoal yield over a 14-year cycle. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.