Thesis (MScFor (Dept. of Forest and Wood Science)--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This study aims to quantify the benefits of implementing an operational harvesting plan in forest harvesting operations. This is to be achieved by comparing productivity and costs from unplanned and planned harvesting operations. The study was conducted on a Pinus radiata plantation owned by Mountain to Ocean Forestry Company (Pty) Ltd (MTO) located near the town of Grabouw in the Western Cape Province of South Africa. MTO conducts harvesting operations using semi-mechanised tree-length harvesting systems. A wheeled H67 Clark Ranger cable skidder is used to extract tree-lengths from infield to the landing. Data was obtained both manually (work study) and from GPS tracking. Choking and dechoking data was obtained through time and method studies. GPS tracking was used to measure travel loaded and travel empty times, as well as travel distances and travel speeds. The aim of using both manual techniques and GPS tracking was to obtain detailed and spatially accurate information about the operation. The operating costs were estimated using South African Harvesting and Transport Costing Model. Productivity of the newly introduced tagline system (45.97 m³/pmh) exceeded that of mainline system (37.85 m³/pmhh) by 26%. The unit production cost of using tagline system (R20.21/m³) was 10% lower than the unit production cost of using mainline system (R22.54/³3). There were no benefits to be gained from improving the level of skid trail construction by removal of logging residue or cutting down stumps to as near the ground level as possible. A combination of manual (time and method studies) data collection and GPS tracking provided more detailed and accurate information on the semi-mechanised harvesting system. / AFRKAANSE OPSOMMING: Hierdie studie beoog om die voordele van die uitvoering van 'n operasionele inoestingsplan te kwantifiseer. Dit word bereik deur produktiwiteit en kostes van beplande en onbeplande inoestingswerksaamhede te vergelyk. Die studie is gedoen in Pinus radiata opstande van Mountain to Ocean Forestry Company (Pty) Ltd (MTO) naby Grabouw in die Wes-Kaap provinsie van Suid Afrika. MTO gebruik semi-gemeganiseerde boomlengte inoestingstelsels in hul inoestingswerksaamhede. . H67 Clark Ranger wielsleeptrekker met kabel en wenas is gebruik om boomlengtes van die veld na die pad te sleep. Data is versamel deur van beide hand (werkstudie) en GPS-opsporing gebruik te maak. Afhaak en aanhaak data is verkry deur van tyd- en metodestudies gebruik te maak. Gelaaide en ongelaaide tyd, spoed en afstande is met behulp van die GPS gemeet. Deur van beide hand en GPS versamelingsmetodes gebruik te maak, kon omvattende sowel as ruimtelik akkurate inligting oor die werksaamhede verkry word. Die bedryfskostes is verkry van die South African Harvesting and Transport Costing Model. Produktiwiteit van die nuut ingestelde verbindingslynstelsel (45.97 m³/pmh) het die hooflynstelsel (37.85 m³/pmh) met 26% oorskry. Die eenheidsproduksiekoste van die verbindingslynstelsel (R20.21/m³) was 10% laer as die eenheidsproduksiekoste van die hooflynstelsel (R22.54/m³). Daar was geen voordeel in die verbetering van die sleeppad konstruksie deur afval te verwyder of stompe nader aan die grondvlak af te sny nie. 'n Kombinasie van hand (tyd- en metodestudies) dataversameling en GPS-opsporing het meer akkurate en omvattende inligting oor die semi-gemeganiseerde inoestingstelsel verskaf.

Thesis (MScFor) -- Stellenbosch University, 2003. / ENGLISH ABSTRACT: Fire is a threat to all forest plantations. As a result, growers are forced to take active measures to reduce the incidence and extent of fires in their plantations. This thesis is an attempt to collate 846 fire records for eight Komatiland Forests (KLF) plantations in Mpumalanga North for the period 1950 to 1999. Up to now, these reports and the information therein, were not utilised by KLF for planning or for evaluating fire management practices. The only other studies in South Africa, using similar data, were conducted by LeRoux (1988) and Kromhout (1990). A brief background of the forestry industry in South Africa, and in particular Mpumalanga is presented. The main text of the report covers a presentation on fire causes, extent of damage (both in area and in Rand value) and various aspects related to time of ignition and response times. A detailed analysis was done to identify possible relationships between the variables related to compartment, climate and different fire suppression activities. A cause and frequency prediction model was developed that will assist fi re managers in identifying and determining probabilities of fires per cause. Statistical guidelines regarding the planning of fire management around fires caused by honey hunters, lightning, work-related factors, and the activities of people (public, own labour, contractors) are presented. Conclusions were drawn from the results of the analyses of the fire data, which covered a period of 47 years. Recommendations regarding guidelines for strategic fi re management for the Mpumalanga North plantations were made. The main conclusions are: • Statistics on previous fires are very useful in fire management planning as it supplies valuable information on fire causes, time of ignition , past performance related to response times, fire fighting times and damaged caused. • • • • The average area lost due to fires in the study area is 209.9 ha or 0.43% of the plantation area per annum. People-related fires (arson, smokers, picnickers, children and neighbours) caused most of the wild fires (48%), followed by lightning (22%). Some plantations performed poorly, with the occurrence of up to double the number of fires per 1 000 ha of plantation compared to other plantations in the same geographic area. There are definite patterns in the frequency of fires per cause with month of the year. These patterns are valuable for the development of strategies to manage fires caused by honey hunters, lightning fires and work-related fires. / AFRIKAANSE OPSOMMING: Brande is 'n bedreiging vir aile bosbou plantasies. Dit is dus noodsaaklik dat kwekers maatreeHs tref om die voorkoms en omvang van brande in plantasies te beperk. Hierdie tesis poog om 846 vuurverslae se inligting te ontleed ten opsigte van agt Komatiland Forests (KLF) plantasies in Mpumalanga Noord vir die tydperk 1950 tot 1999. Tot op hede is min van die inligting wat in die verslae vervat is deur KLF vir beplanning- en evalueringsdoeleindes ten opsigte van brandbestuur gebruik. Die enigste soortgelyke studies wat op brandverslagdata in Suid-Afrika gedoen is, is gedoen deur Le Roux (1988) en Kromhout (1990). 'n Kort agtergrond oor die bosbouindustrie in Suid-Afrika en spesifiek Mpumalanga word gegee. Die tesis gee 'n oorsig oor brandoorsake, skade wat deur brande veroorsaak word (oppervlakte sowel as finansieHe waarde) en verskeie aspekte rakende brandbestuur soos tyd van ontstaan en reaksietye. Data is volledig ontleed om moontlike verwantskappe te probeer vind tussen vak-, klimaat- en brandbestuursveranderlikes. 'n Oorsaak- en frekwensievoorspellingsmodel is ontwikkel wat brandbestuurders sal help om waarskynlikhede van brande per oorsaak te identifiseer. Statistiese riglyne ten opsigte van bestuursbeplanning vir weerligvure, brande deur heuninguithalers, brande as gevolg van plantasiewerksaamhede en ook brande deur mense (publiek, eie arbeid en kontrakteurs) is daargestel. Brandrekords wat oor 'n periode van 47 jaar gestrek het, is ontleed. Afleidings wat uit die resultate gemaak is, kan benut word om riglyne daar te stel vir strategiese brandbestuur in Mpumalanga Noord plantasies. Die hoof gevolgtrekkings is: • Statistiek van vorige vure is baie nuttig in brandbestuursbeplanning aangesien dit waardevolle inligting verskaf oor brand oorsake, tyd van ontstaan, historiese werkverrigting rakende reaksietye en blustye, sowel as skade wat veroorsaak is. Die gemiddelde oppervlakte beskadig in die studie area is 209.9 ha, of 0.43% van die plantasie oppervlakte per jaar. Menslike aktiwiteite (brandstigting, rakers, piekniekvure, kinders en vure van bure) het die meeste brande veroorsaak (48%), gevolg deur weerlig (22%). Sommige plantasies het swak gevaar en het tot soveel as dubbel die aantal vure per 1 000 ha plantasie gehad in vergelyking met ander plantasies in dieselfde geografiese gebied. Daar is duidelike patrone gevind in die frekwensie van brande per oorsaak oor maande van die jaar. Hierdie patrone is nuttig vir die ontwikkeling van bestuurstrategie vir brande wat veroorsaak word deur heuningversamelaars, weerlig en werkverwante aktiwiteite (plantasieaktiwiteite).

Thesis (MSc)--Stellenbosch University, 1968. / ENGLISH ABSTRACT: Trees are needed on the semi-arid Highveld of the western Transvaal for shelterbelts, woodlots, fodder, honey, shade and ornament. A brief history of tree planting in the area, more particularly at Lichtenburg and Potchefstroom, is given. Relatively few species can be grown successfully in the western Transvaal because of the unfavourable climate. Hot, dry winds blow almost continuously off the Kalahari between August and October before the first, spring rains; cold winds and frosts are experienced in winter, although the summers are hot; the rainfall is erratic and low, averaging about 600 mm. a year and occurring mainly in the form of heavy thunderstorms during summer; hail is common. The geology of the area is complex. In the north-west an overburden of wind-transported sand obscures the underlying formations. The soils are mostly of a light, sandy or loamy consistency, with a fairly high base-saturation value. Concretions, sometimes forming a continuous hardpan, are characteristic of certain types. Various indigenous trees are found in some localities. These are small,and are mainly confined to rocky hillsides and stream banks. In the past they have been much exploited for rough building timber, fence posts and firewood. Their growth is very slow, and exotics have proved to be more vigorous as well as more useful in cultivation. Possible adaptations of trees to dry climates are discussed. It is concluded that'apparent adaptations observed in the field are of little value in selecting trees for dry areas. No practical alternative therefore exists at this stage to the introduction of species from .areas with a similar climate and testing these under local conditions. Parts of the world having a climate similar to that of the western Transvaal are in.dicated. Summarised results of species trials in the western Transvaal are given in tabular form, and recommendations for tree planting in the area are made. In an appendix, trials of BB species in arboreta at Lichtenburg and Potchefstroom are fully described and discussed.

Thesis (MScFor)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Wood scarcity remains the main challenge for many rural households who still rely on natural resources for energy needs. This study aimed to investigate the relationship between fuel use and quality and quantity of fuel in two rural villages (Ongulumbashe and Onaitembu) in the Omusati Region of Namibia. It investigated the impact of fuel quality and quantity and the corresponding sales of firewood on households’ energy consumption. Data was collected between April and June 2012 from the two villages by means of questionnaire surveys, biomass assessment and laboratory assessment. Interviews were conducted with seventy-seven households, four firewood sellers, government officials, and local leaders. The study quantified the amount of fuelwood consumed and collected per household per week using user-recall and physical measurement, respectively. The most preferred fuel species or fuel materials were identified and their physical properties, calorific value, moisture content, ash content and density were measured under laboratory conditions. Differences between the two villages in terms of fuelwood collected and consumed were found. Due to wood scarcity households from Onaitembu village used other alternatives (buying fuelwood and cutting live firewood) rather than collecting dead firewood. The study found a link between fuelwood use, quality and quantity, with households changing their consumption and harvesting based on season, fuelwood demand and availability of fuelwood. The average weekly fuelwood consumption per household ranged from 66 kg to 79 kg for a firewood abundant area and from 59 kg to 67 kg for an area with a shortage of firewood. Mopane was the most preferred species due to its ability to burn efficiently and its abundance. Wood scarcity affected households economically, culturally and nutritionally. The study found that households in degraded areas spend an average of N$ 50 per week on fuelwood, and many households depended on government grants and small cash income activities. The study found that the government, through the Ministry of Agriculture, Water and Forestry, is trying to improve rural households’ energy use by constructing firewood outlets. The study concluded that there is a high level of illegal trade in firewood that will require government to increase the number of staff in the region as well as to strengthen its policy on cross-border trading. There is an imbalance in fuel species use in areas of rich biomass and over-utilization of resources in degraded areas. These require the Directorate of Forestry to educate the community about the value of other possible fuel species and the impact of harvesting live firewood on households’ livelihood and on the environment. / AFRIKAANSE OPSOMMING: Houtskaarsheid bly die grootste uitdaging vir baie landelike huishoudings, wat nog steeds staatmaak op natuurlike hulpbronne vir energie behoeftes. Hierdie studie het gepoog om die verhouding tussen brandstof gebruik en kwaliteit en kwantiteit van brandstof in twee plattelandse dorpies (Ongulumbashe en Onaitembu) in die Omusati-streek van Namibië te ondersoek. Die impak van brandstof kwaliteit en kwantiteit en verkope van brandhout op huishoudings se energie gebruik is ondersoek. Data is ingesamel in April en Junie 2012 in die twee dorpe deur middel van vraelys opnames, biomassa assessering en laboratorium ontledings. Onderhoude is gevoer met 77 huishoudings, vier brandhoutverkopers, regeringsamptenare, en plaaslike leiers. Die studie het die hoeveelheid vuurmaakhout verbruik en versamel per huishouding per week gekwantifiseer deur gebruik te maak van gebruikergeheue en fisiese meting van vuurmaakhout. Die mees gewilde brandstof spesies of brandstof materiaal is geïdentifiseer en hul fisiese eienskappe, kaloriewaarde, voginhoud, asinhoud en digtheid is onder laboratorium toestand gemeet. Verskille tussen die twee dorpe in terme van brandhout versamel en verbruik is gevind. As gevolg van houtskaarsheid gebruik huishoudings in ONA ander alternatiewe energiebronne, soos om brandhout te koop of om vars hout te saag, in plaas van om dooie hout te versamel. Die studie het ‘n skakel gevind tussen brandhout gebruik en die gehalte en hoeveelheid wat beskikbaar is. Huishoudings het hulle brandhout verbruik aangepas by die seisoen, aanvraag en beskikbaarheid van brandhout. Die gemiddelde weeklikse brandhout verbruik per huishouding het gewissel tussen 66 kg tot 79 kg vir 'n area met ‘n oorvloed van brandhout en 59 kg tot 67 kg vir 'n gebied met 'n tekort aan brandhout. Mopanie was die mees gewilde spesie as gevolg van sy besikibaarheid en vermoë om doeltreffendheid te brand. Houtskaarstes beinvloed huishoudings op ekonomies, kulturele en voedings vlakk. De studie het bevind dat huishoudings in ’n area met ‘n houtskaarste gemiddeld N$50 per week spandeer om brandhout te koop en dat baie huishoudings afhanklik is van staatstoelaes en klein kontant inkomste-aktiwiteite. Die studie het gevind dat die regering, deur middel van die Ministerie van Landbou, Water en Bosbou, probeer om landelike huishoudings se energie gebruik te verbeter deur die bou van brandhout afsetpunte. Die studie het tot die gevolgtrekking gekom dat daar 'n hoë vlak van onwettige handel in brandhout is wat sal vereis dat die regering die aantal amptenare in die streek moet vermeerder en sy beleid rakende handel oor landsgrense heen moet verbeter. Daar is 'n wanbalans in die gebruik van brandstofspesies in 'n gebied met baie biomassa, en oorbenutting van hulpbronne in gedegradeerde gebiede. Die Direktoraat van Bosbou moet die gemeenskape oplei oor die waarde van ander moontlike brandstofspesies en die impak van die oes van lewendige bome op huishoudings se lewensbestaan en op die omgewing.

Thesis (MScFor)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The study aims at developing models for predicting aboveground biomass for selected drought tolerant Eucalyptus (E) species (E. cladocalyx, E. gomphocephala and E. grandis x camaldulensis) from the dry west coast. Biomass models were fit for each of the species and a cross-species model was parameterised based on pooled data for all the three species. Data was based on destructive sampling of 28 eucalypt trees which were 20 years of age and additional five five-year old E. gomphocephala trees. Preliminary measurements on diameter at breast height (dbh), height (h) and crown height were recorded in the field. The sampled trees were then felled and samples of discs, branches and foliage were collected. Density of the wood discs and the bark was determined by a water displacement method and computer tomography scanning (CT-scanner). Stem biomass was reconstructed using Smalian’s formula for volume determination and the calculated densities. Upscaling of the crown was carried out by regression equations formulated by employing the sampled branches. Further assessment was carried out on a sub-sample by subjecting the samples to different drying temperatures in a series between 60 and 105ºC. Linear models were parameterised by a simultaneous regression approach based on Seemingly Unrelated Regression (SUR) using the “Systemfit” R statistical package. The predictor variables employed in the study were dbh, d2h and h in which the coefficient of determination (R2), Mean Standard Error (MSE) and Root Mean Standard Error (RMSE) were used to determine the goodness of fit for the models. Akaike Information Criteria (AIC) was also used in the selection of the best fitting model. A system of equations consisting of five models was formulated for each Eucalyptus species. The biomass prediction models had degrees of determination (R2) ranging from 0.65 to 0.98 in which dbh and d2h were the main predictor variable while h improved the model fit. The total biomass models were the best fitting models in most cases while foliage biomass had the least good fit when compared to other models. When the samples were subjected to different drying temperatures, stem wood had the largest percentage change of 6% when drying from 60ºC to 105ºC while foliage had the lowest percentage change of less than 2%. / AFRIKAANSE OPSOMMING: Die doel met hierdie studie is om modelle vir die voorspelling van die bogrondse biomassa van drie droogte-bestande Eucalyptus (E) spesies (E. cladocalyx, E. gomphocephala en E. grandis x camaldulensis), gekweek op die droë kusvlakte in Wes-Kaapland, te ontwikkel. Biomassa modelle vir elk van die spesies is gepas en ’n model gegrond op die gekombineerde data van al drie die spesies, is geparameteriseer. Verder is die biomassa variasie onder verskeie droogingstemperature vasgestel. Die data versameling is uitgevoer gegrond op die destruktiewe mostering van 28 Eucalyptus bome wat 20 jaar oud was en ’n bykomende vyf vyfjarige E. gomphocephala bome. Die aanvanklike mates, naamlik deursnee op borshoogte (dbh), boomhoogte (h) en kroonhoogte is in die veld opgemeet. Die gemonsterde bome is afgesaag en monsters van stamhout skywe, takke en die bas is versamel. Die digtheid van die skywe en die bas is deur die waterverplasing metode, en Rekenaar Tomografie skandering (“CT-scanning”) vasgestel. Stam biomassa is rekonstrukteer deur gebruik te maak van Smalian se formule vir die vasstelling van volume en berekende digtheid. Die opskaal van die kroon biomassa is gedoen met behulp van regressie vergelykings van gekose takmonsters. Submonsters is onderwerp aan ’n reeks van verskillende drogingstemperature tussen 60 en 105ºC. Lineêre modelle is deur ’n gelyktydige regressie benadering gegrond op die Seemingly Unrelated Regression (SUR) wat ’n“Systemfit” R statistiese pakket gebruik, parameteriseer. Die voorspeller veranderlikes wat in hierdie studie gebruik is, is dbh, d2h en h waarin die koëffisient van bepaling (R2), gemiddelde standaardfout (MSE) en vierkantswortel van die gemiddelde standaardfout (RMSE) gebruik is om vas te stel hoe goed die model pas. Akaike Inligting Kriteria is gebruik vir die seleksie van die gepaste model. ’n Reeks vergelykings wat bestaan uit vyf modelle is vir elke Eucalyptus spesie geformuleer. Die biomassa voorspelling model het waardes vir die koëffisiente van bepaling (R2) opgelewer wat strek van 0.65 to 0.98% en waarin dbh en d2h die hoof voorspelling veranderlikes is, terwyl h die pas van die model verbeter. Die totale biomassa model het in die meeste gevalle die beste gepas en die blaarbiomassa die swakste as dit met die ander modelle vergelyk word. Tydens droging vind die grootste persentasie verandering van 6% by stamhout plaas tussen temperature van 60ºC tot 105ºC, en die kleinste persentasie verandering van minder as 2% by blare.

Thesis (MScFor)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: One of the major objectives in plantation forestry is to achieve a high level of homogeneity of distribution and dimension of trees within the stand. Precise planting geometries, intensive silviculture and genetic selection are used to achieve this homogeneity. However, a natural variability is still introduced by micro-­‐site conditions and disturbances. A substantial source of variation is caused by edge effects of neighbouring stands or other land use forms. The edge effect causes trees at the stand edge to develop differently from trees in the interior of the stand. The overarching objective of this study is to simulate the edge effect based on average stand interior variables as typically received from an enumeration and spatial information on the current and historic stand neighbourhood. With re-­‐introducing this natural variance as well as its spatial pattern, we expect to derive improved planning information. A major aim is thus separating the effect of the edge interaction from the other factors contributing to stand variance and quantifying the result in terms of stand output. A methodology is introduced for quantifying interaction at stand edges between a given stand and its neighbouring stands over its lifetime. Transferring the edge interaction value from the edges to all the trees within the stand is then done by applying inverse distance weighting interpolation from the edges to the tree position within the stand. Once an edge interaction value has been calculated for each point, the extent of the edge effect is quantified. The spatial extent of the edge effect is derived empirically from an existing fully spatially mapped stand by means of breakpoint regression. The expected variance as a result of edge influence is then quantified by producing a set of models, which can reproduce the effect of the edge interaction on tree height, diameter and volume. The edge effect is treated as a dynamic interaction for which the temporal aspect needs to be considered, because the current spatial structure of a stand is influenced by its current neighbourhood, but also by the historic development of the neighbourhood in relation to the stand in question. Each stand therefore undergoes an edge effect which is completely unique to that stand, within a given time period. For this reason the presented methodology is a spatial-­‐temporal one, aimed at providing a way in which growth and yield forest modelling can be augmented by the inclusion of the edge effect in a practical way. To explicitly quantify edge effects, the natural variance had to be separated into a component explained by edge effect and a second component introduced by other factors such as micro site conditions and disturbance. The second component is treated as an unexplained residual variance. In order to provide a realistic simulation of a stand output at a finer, tree level, this second stand variance needs nonetheless to be quantified. The variance attributable to factors other than the edge effect is mimicked by generating a random number by means of a parameterised stochastic process based on the variance of the inner stand region, which is beyond the reach of the edge effect. In this way, a realistic spatial pattern of a plantation forest stand, taking into account the edge effect and combining it with the natural stand variance is achieved. This study, within the field of plantation forest management, aspires to land use optimization both in terms of productive capacity estimation and for the provision of information for effective land use management planning. It makes use of open source software resources namely the R framework and QGIS and explores aerial stereophotogrammetry as an option for data collection. / AFRIKAANSE OPSOMMING: Een van die hoofdoelwitte in plantasie bosbou praktyk is hoё vlakke van homogeniteit met betrekking tot die verspreiding en die dimensies van die bome in die plantasie opstand. Simetriese aanplantings, intensiewe bosboupraktyk en genetiese seleksie word gebruik om hierdie homogeniteit te verkry. Natuurlike verskille word egter nog steeds gevind as gevolg van groeiplek mikro toestande en ander versteurings in die opstand. Een van die hoofbronne van hierdie variasie is die randeffekte van buurplantasies en ander gebruike van grond. Hierdie randeffekte veroorsaak dat bome aan die rand van die opstand anders ontwikkel as die bome binne in die opstand. Die oorhoofse doelwit met hierdie navorsing is om die randeffekte te simuleer. Hierdie randeffekte is gegrond op die gemiddelde binneopstand boom veranderlikes soos afgelei uit die opmeting en uit ruimtelike inligting oor die huidige en geskiedkundige toestande in die omgewing. As hierdie natuurlike variasies asook die ruimtelike patrone weer in berekening gebring word, verwag ons om beter beplanningsinligting te bekom. ’n Belangrike doelwit tydens hierdie navorsing is dus om die effek van die rand-­‐interaksie te skei van die effek van ander faktore wat bydra tot variasies binne-­‐in die opstand en om die resultaat in terme van plantasie produksie te kwantifiseer. ’n Metodiek word voorgestel vir die kwantifisering van die interaksie op die rande tussen die opstand en die buuropstande tydens die leeftyd van die opstand. Die oorplasing van die rand interaksie waarde van die rand af na al die bome in die plantasie word dan gedoen deur om geweegde inverse afstand interpolasie vanaf die rand tot by die ligging van die boom, toe te pas. As die rand interaksie waarde vir elke punt bereken is, kan die omvang van die randeffek gekwantifiseer word. Die ruimtelike omvang van die rand effek is, met die gebruik van breekpunt regressie, empiries afgelei van ’n bestaande ten volle karteerde plantasie. Die verwagte variasie as gevolg van die randeffek word dan met die gebruik van ’n stel modelle gekwantifiseer, wat dan die effek van die rand interaksie op boomhoogte, deursnit en volume kan weergee. Die randeffek word as ’n dinamiese interaksie beskou waarvan die tydsaspek in ag geneem moet word, want die huidige ruimtelike struktuur van die plantasie word beïnvloed deur die huidige omgewing asook deur die historiese ontwikkeling van die omgewing met betrekking tot die opstand onder bespreking. Elke opstand ondergaan ’n randeffek wat uniek is aan daardie plantasie op die gegewe tydstip. Die doelwit is om ’n wyse te vind waarvolgens groei-­‐en-­‐opbrengs plantasie modellering deur die insluiting van randeffek op ’n praktiese wyse, aangevul kan word. Om hierdie rede is die aanbevole metodiek ruimtelik-­‐tydelik en gerig daarop om ’n wyse te vind waarvolgens groei-­‐en-­‐opbrengs modellering deur die insluiting van die randeffek, op ’n praktiese wyse aangevul kan word. Om randeffek eksplisiet te kwantifiseer, moes die natuurlike afwyking gedeel word in die komponent wat die gevolg is van die randeffek, en ’n tweede komponent wat die gevolg is van ander faktore soos mikroligging toestande en versteurings. Die tweede komponent word behandel as ’n onverklaarde oorblywende afwyking. Hierdie tweede plantasie afwyking moet nogtans kwantifiseer word om sodoende ’n realistiese simulasie van plantasie opbrengs op ’n fyner boom vlak te verkry. Die afwyking wat toegeskryf kan word aan faktore buiten die randeffek, word nageboots deur om ’n lukrake nommer (wat gebaseer word op die afwyking van die binne-­‐plantasie gebied wat buite die strekwydte van die randeffek is) deur middel van ‘n geparameteriseerde stogastiese proses te genereer. Sodoende word ’n realistiese ruimtelike patroon van ’n plantasie opstand verkry, wat die randeffek in ag neem en dit kombineer met die natuurlike plantasie afwyking.

Thesis (PhD (Dept. of Forest and Wood Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: This study aimed to analyze under which conditions the structure, organization and integration of knowledge systems can provide the implementation of adaptive collaborative management of natural resources under conditions of high biodiversity in the humid forest zone of southern Cameroon. The study specifically did the following: characterized sustainable slash-and-burn agriculture innovations; examined the influences of local perceptions of nature and forest knowledge management systems on adaptive slash-and-burn agriculture practices; analyzed the influences of the social representation of land use patterns and their local indicators on agro-ecological sustainability; characterised the biophysical dimensions of local management of agricultural biodiversity knowledge systems; analyzed how local agricultural biodiversity knowledge is used to adapt and to satisfy household consumption needs, market preferences, and sustainable livelihoods; examined the influences of local perceptions of climate variability for the ability and adaptive capacity of people to use local knowledge to deal with the effect of pests-diseases on crop yield, corrective management actions, and adaptive slash-and-burn agriculture management. The study was conducted in three blocks within the humid forest zone of southern Cameroon along a gradient of natural resource use management intensification and population density. Data were collected via structured and semi-structured interviews, multi-disciplinary landscape assessment and a review of secondary information. Chisquare tests were used to show how local knowledge influences - natural resource management at the forest-agriculture interface, while binary logistic regressions were used to understand the influences of biophysical and socio-economic factors on farmers’ decisions to domesticate tree species and to cultivate several crop cultivars. Fourteen research and development (R&D) themes were identified and found to be equally distributed among blocks but unequally distributed across technical, marketing and socio-organisational types of innovation. There was a gap between social demand and innovation offer. Innovations offered covered more technical issues, such as crop variety development, indicating their agricultural focus rather than the integration of forest and agriculture issues. The local perceptions of nature and forest resources are based on social representation of the vital space into components having a specific function for the social, physical and spiritual life of people. Needs of the human world determine the role of local forest knowledge systems in the interpretation and responses of the natural environment, and guide the trajectories of natural resource management practices. The management of agro-ecological sustainability is based on the local definition of well-being, social representation of space and on a multi-criteria approach combining bio-indicators such as plants, earthworm activities, age of vegetation or forest cover, soil colour and quality but it is also positively influenced by land use history, the use value of wild plant and crop species, the knowledge of crop qualities, the knowledge of interactions between crops, and between crops and other wild plant species, the tree size of tree species used, the future use of a current land use, the estimated land use for own use and market access. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om te bepaal onder watter omstandighede die struktuur, organisasie en integrasie van kennissisteme kan bydra tot die implementering van aanpasbare deelnemende bestuur van natuurlike hulpbronne onder toestande van hoë biodiversiteit in die vogtige woudsone van suidelike Kameroen. Die studie het spesifiek die volgende gedoen: volhoubare kap-en-brand landboukundige ontwikkelinge gekarakteriseer; die invloede van plaaslike persepsies van die natuur en woudkennisgebaseerde bestuursisteme op aanpasbare kap-en-brand landboupraktyke ge-evalueer; die invloede van die sosiale verteenwoordiging van grondgebruikspatrone en hul plaaslike indikatore op agro-ekologiese volhoubaarheid ontleed; die biofisiese dimensies van die plaaslike bestuur van landboukundige biodiversiteitskennissisteme gekarakteriseer; geanaliseer hoe die plaaslike landboukundige biodiversiteitskennis gebruik word om aan te pas by en bevrediging te verkry vir huishoudelike gebruiksbehoeftes, marksvoorkeure en volhoubare bestaansbehoeftes; die invloede en gebruik van plaaslike kennis en persepsies van klimaatsvariasie beoordeel in die vermoë en aanpassingskapasiteit van mense om die effekte van siektes-peste op gewasproduksie, regstellende aksies en aanpasbare kap-enbrand landboubestuur te hanteer. Die studie is uitgevoer in drie blokke binne die vogtige woudsone van suidelike Kameroen langs ‘n gradient van natuurlike hulpbrongebruiksbestuursintensiteit en populasiedigtheid. Data is versamel deur gestruktureerde en semi-gestruktureerde onderhoude, multi-dissiplinere landskapsevaluering en ‘n oorsig van sekondere inligting. Chi-kwadraat toetse is gebruik om te wys hoe plaaslike kennis die bestuur van die woudlandbou konneksie beinvloed asook binêre logistiese regressies om die invloede te verstaan van biofisiese en sosio-ekonomiese faktore op die boere se besluite om boomsoorte te domestikeer en om verskeie gewaskultivars te kweek. Veertien temas in navorsing en ontwikkeling (N&O) was gelyk versprei tussen die blokke en ongelyk versprei tussen tegniese, bemarking en sosio-organisatoriese tipes innovering. Daar was ‘n gaping tussen sosiale aanvraag en innoveringsaanbieding. Innoverings het meer tegniese aspekte gedek, soos ontwikkeling van ‘n verskeidenheid gewasse, wat wys op ‘n landboukundige fokus eerder as ‘n integrasie van woud en landboukundige aspekte. Die plaaslike persepsies van die natuur en woudhulpbronne was gebaseer op sosiale verteenwoordiging van lewensbelangrike ruimte in komponente met ‘n spesifieke funksie vir die sosiale, fisiese en geestelike lewe van die mense. Behoeftes van die menslike wereld bepaal die rol van plaaslike woudkennissisteme in die interpretasie van en reaksie op die natuurlike omgewing, en rig die gebruik van hulpbronbestuurspraktyke. Die bestuur van agro-ekologiese volhoubaarheid is gebaseer op die plaaslike definisie van geluk, sosiale verteenwoordiging van ruimte en op ‘n multikriteria benadering wat bio-indikatore kombineer soos plante, erdwurmaktiwiteite, ouderdom van plantegroei- of woudbedekking, grondkleur- en kwaliteit, maar is ook positief beinvloed deur grondgebruiksgeskiedenis, die gebruikswaarde van natuurlike en gewassoorte, die kennis van gewaskwaliteite, die kennis van die interaksie tussen gewasse en tussen gewasse en natuurlike plantsoorte, die boomgrootte van boomsoorte wat gebruik word, die toekomstige gebruik van ‘n huidige grondgebruik, die beraamde grondgebruik vir eie gebruik en vir toegang tot die markte.

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

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

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