Thesis (PhD (Forest and Wood Science))--Stellenbosch University, 2007. / ENGLISH ABSTRACT: There has been a reported reduction in the durability of creosote treated, wooden utility poles in South Africa in recent years. Several factors could have been responsible for this. In this study, Eucalyptus grandis pole drying schedules currently used, methods of measurement of moisture content (MC) after drying and drying defects were investigated. Relationships involving drying defects and MC gradient before treatment which may help in the development of simple nondestructive methods of assessing defects such as surface checking, honeycomb and collapse, and MC gradient were also explored. The long term goal of this study was to increase the durability of treated poles by avoiding unacceptable drying defects and MC values before treatment. The results of this investigation are presented in the following chapters: an introduction motivating the aims of the investigations (Chapter 1); a review of literature relevant to MC and drying defects in sawn or round wood (Chapter 2); ready for press manuscripts on MC and drying defects in kiln-dried E. grandis poles (Chapters 3 to 7) and a general conclusion that links up chapters 3 to 7, and recommendations (Chapter 8). The auger drill method gave reliable MC values when samples in increments of 25 mm depths into the pole were taken. However, when single samples of 50 mm and 75 mm depths were considered, the auger drill MC measurements were unreliable. It was concluded that SABS SM 983 (2000), which specifies taking single radial auger drill samples of depth 70±5 mm at pole mid length, is not a reliable method of measuring MC in a kiln-dried E. grandis pole. Correlation results indicated that tree growth factors such as sapwood depth, green MC and heartwood percentage were related to final drying defects and may be used as criteria for pole sorting before kiln drying. Also, the number of valleys per unit length (VPUL) of the circumference at the theoretical ground line (TGL) was positively correlated with honeycomb and closed surface checks, implying that VPUL as a parameter of the pole circumference profile can be used to assess invisible, internal defects. The dry bulb temperature (Tdb) of 80oC, used to dry poles in industry, was too high and resulted into unacceptable levels of drying defects in kiln dried E. grandis poles. In addition, the drying period of 8 days was too short to attain an acceptable MC gradient in poles. It is, therefore, recommended that: To use the auger drill method to reliably determine the moisture content of a pole, samples in increments of 25 mm should be taken. MC measurements should be made at the most critical zones of a pole such as the TGL and not higher up since there is normally considerable MC variation in the longitudinal direction. It is also important to consider sampling more than one position on the pole circumference to cater for the MC variation in the tangential direction. For poles with large sapwood depths i.e. >15mm, mild drying conditions at the beginning of a drying run should be used, since such poles may be more susceptible to surface checking. Poles with large heartwood percentages should also be dried with suitable kiln schedules, i.e. with low Tdb to minimise honeycomb and collapse. In general, Tdb lower than 80oC should be considered in order to reduce the defects to acceptable levels. Poles should be dried for longer than 8 days even at Tdb as high as 80oC to reduce the MC to acceptable values and gradients. Since only three schedules were tested, more drying schedules should be investigated to make reliable conclusions about the effect of schedule on drying defects. In addition, more poles per schedule should be considered in order to obtain statistically reliable results. The relationship of pole diameter and drying defects also requires further investigation. Since a limited sample was used to test for the effect of source of poles and drying schedules on defect correlations, further studies should be done on sufficient samples to come up with more reliable conclusions. It is also necessary to further investigate the possible variation in correlation of VPUL and internal defects on a large sample of poles from specific sources and drying schedules. / AFRIKAANSE OPSOMMING: Die afgelope paar jaar is waargeneem dat kreosootbehandelde transmissiepale 'n afname in duursaamheid toon. Verskeie faktore kan hiervoor verantwoordelik wees. In hierdie studie is huidige Eucalyptus grandis oonddrogingskedules en voggehalte- (VG) bepalingsmetodes vóór en na droging asook drogingsdefekte ondersoek. Verwantskappe tussen drogingsdefekte en VG-gradiënt vóór behandeling wat kan meehelp om nie-destruktiewe metodes te ontwikkel om defekte soos oppervlaktekrake, interne barste en instorting en VG-gradiënt te bepaal, is ook bestudeer. Die langtermyn doelwit van hierdie studie is om die duursaamheid van behandelde pale te verbeter deur onaanvaarbare drogingsdefekte en voggehaltes vóór behandeling te vermy. Die resultate van hierdie ondersoek word in die volgende hoofstukke bespreek: 'n inleiding waarin die doelwitte van die onderskeie ondersoeke motiveer word (Hoofstuk 1); 'n oorsig van die literatuur relevant tot VG en drogingsdefekte in gesaagde en rondehout (Hoofstuk 2); persklaar manuskripte oor VG en drogingsdefekte in oondgedroogde E. grandis pale (Hoofstukke 3 tot 7) en 'n algemene gevolgtrekking wat bevindings uit hoofstukke 3 tot 7 saamvat gevolg deur aanbevelings (Hoofstuk 8). Die augerboor-metode kon betroubare VG-waardes lewer indien monsters van 25mm diepteinkremente in die paal geneem is. Augerboor-voggehaltemetings met enkel 50mm en 75mm monsters was egter onbetroubaar. Daar is bevind dat SABS SM 983 (2000), wat 'n enkel radiale augerboormonster tot op 'n diepte van 70±5 mm in die middel van die lengte van die paal spesifiseer, nie 'n betroubare VG-bepalingsmetode vir oondgedroogde E. grandis pale is nie. Die resultate het aangetoon dat boomgroeifaktore soos spinthoutdiepte, groen voggehalte en die persentasie kernhout aan drogingsdefekte verwant is en as basis vir sortering van pale vóór oonddroging gebruik kan word. Ook kon die aantal valleie per eenheidslengte (e. VPUL) van die omtrek by die teoretiese grondlyn (TGL) positief met interne barste en geslote oppervlaktekrake korreleer word wat impliseer dat VPUL as parameter van die omtrekprofiel van die paal gebruik kan word om onsigbare, interne defekte mee vas te stel. Die droëbaltemperatuur (Tdb) van 80oC wat in die industrie gebruik word, was te hoog omdat dit onaanvaarbare vlakke van drogingsdefekte in oondgedroogde E. grandis veroorsaak het. Daarbenewens was die drogingsperiode van 8 dae by 'n Tdb van 80oC te kort om 'n aanvaarbare VG-gradiënt te lewer. Die volgende word derhalwe aanbeveel: Om betroubare VG-resultate d.m.v. die augerboormetode te verkry, behoort monsters in inkremente van 25mm geneem te word. VG-metings behoort in die mees kritiese dele van 'n paal gedoen te word byv. by TGL en nie hoër nie omdat daar normaalweg beduidende VG-variasie in die longitudinale rigting is. Dis ook belangrik om op meer as een posisie op die omtrek te meet om vir die variasie in die tangensiale rigting voorsiening te maak. Ligte drogingstoestande behoort aan die begin van die drogingsproses by pale met groot spinthoutdieptes, bv. > 15mm, gebruik te word omdat sulke pale meer geneigd tot oppervlaktekrake is. Pale met hoë kernhoutpersentasies moet ook met geskikte drogingskedules, bv. met lae Tdb, gedroog word om interne barste en ineenstorting te verminder. Oor die algemeen behoort Tdb laer as 80oC oorweeg te word om die omvang van defekte by aanvaarbare vlakke te hou. Selfs by Tdb so hoog as 80oC behoort pale langer as 8 dae te droog om die VG tot by aanvaarbare waardes en 'n gradiënt te bring. Omdat slegs drie skedules evalueer is, behoort meer skedules ondersoek word om betroubare gevolgtrekkings oor die effek van skedule op drogingsdefekte te verskaf. Addisioneel behoort meer pale per skedule oorweeg word om statisties betroubare resultate te verkry. Die verwantskap tussen paaldeursnee en drogingsdefekte benodig ook verdere ondersoek. Aangesien 'n beperkte aantal pale gebruik is om die herkoms en drogingskedule met defekte te korreleer, behoort verdere studie op genoeg pale gedoen te word om meer betroubare gevolgtrekkings te kry. Dit is ook noodsaaklik om die moontlike variasie in die korrelasie tussen VPUL en interne defekte op 'n groot aantal pale van spesifieke herkoms en drogingskedules vas te stel.

Thesis (MSc (Forest and Wood Science))--University of Stellenbosch, 1979. / 368 leaves printed on single pages, preliminary pages i-vii and numbered pages 1-211. Includes bibliography, list of figures. / Digitized at 600 dpi grayscale to pdf format (OCR), using a Bizhub 250 Konica Minolta Scanner.

Thesis (MSc)-- Stellenbosch University, 1951. / No abstract.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2006. / Producing high quality end products, rather than focusing on volume production, is slowly but surely becoming the main driving force in the wood processing industry of South Africa. Drying defects such as surface checks and discolouration by yellow stain and kiln brown stain are major factors in softwood timber downgrades when selecting furniture grade timber. Previous efforts to control these defects have focused on schedule adaptation, but as the industry is still mainly concerned with volume production, and because of the varying lumber price, longer schedules to control these drying defects have not yet been that attractive for the larger sawmills. In ongoing research in this laboratory, a dip treatment of freshly sawn softwood boards in an aqueous solution containing a surfactant called sodium lauryl sulphate (SLS) was used to try to influence the mechanism involved in the development of these stains. Further, complementary research is reported in this study. Firstly, the possibility of using SLS solutions to control surface mould development and bluestain was investigated. Results showed that SLS did control the development of blue stain and mould growth in open-stacked boards for up to three weeks, using concentrations as low as 0.1%, and up to two weeks in closed-stacked timber when using concentrations of 0.2%. Secondly, it was investigated whether SLS treatment would have a detrimental effect on downstream product quality; in particular, kiln dried boards and glued components for furniture manufacturing. Since SLS influenced fluid water flow during kiln drying, the treatment could have exacerbated the occurrence of surface checking due to altered moisture distribution profiles. Results of this investigation showed that the SLS treatment did not result in increased surface checking. Thirdly, as furniture quality timber treated with SLS would be glued, (and also finished with surface coatings), it was further considered important to determine if SLS treatment influenced adhesion properties of wood surfaces. Based on shear test results, it was established that SLS did not influence the adhesion properties of wood when glued with two most commonly used glues in the furniture industry i.e. polyvinyl acetate (PVAc) and urea formaldehyde (UF).

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2009. / jfl2010 / ENGLISH ABSTRACT: The past forest management strategies in Zambia did not allow participation of local communities in the management of Forest Reserves and sharing of benefits. The Zambia forest sector was reviewed between 1987 and 1997 culminating into the National Forestry Policy of 1998 and Forests Act of 1999, which provided for joint or participatory forestry management and share of derived benefits. In 2000, the Forestry Department initiated a pilot project to develop and implement JFM. This study was conducted in Dambwa JFM area in Livingstone to evaluate local people’s participation in JFM; perceptions on the effect of JFM on local livelihoods; and the impact of JFM on forest condition. The study was conducted through the use of household questionnaires, interviews with key informants, focus group discussions, field observation, and vegetation assessment. The results showed that more than half (68%) of the respondents were aware of JFM and almost the same number (64%) participated in JFM project. Participation of men in JFM activities was higher than women, although more women attended meetings than men. The results further showed that local management structures existed at district, forest area and village levels for coordination of JFM activities. Forest User Groups (FUGs) were also established in the area. The prominent FUG was the Mungongo oil pressing and was the only FUG functional at the time of the study. Forest Management Committee, Village Resources Management Committee and FUG members were found to be more involved in JFM activities than other members of the local community. Only a small number (8%) of local people reported improvement in household socio-economic conditions after the introduction of JFM, while the majority (79%) perceived the Forestry Department to be the major beneficiary in the JFM. The study revealed that there was a loss of enthusiasm in JFM among local people largely due to the absence of economic benefits and limited decision-making powers. However, the relationship between local people and Forestry Department was reported to have improved. The overall forest stocking was found to be low (219 SPH) with nearly all (90%) of the stems below 30 cm DBH, including the selected valuable tree species of Baikiaea plurijuga, Pterocarpus angolensis, Guibourtia coleosperma, Afzelia quanzensis and Colophospermum mopane. This implies that the forest area was previously overexploited rendering it uneconomical for commercial exploitation to provide benefits to local people on sustainable basis. However, the results showed a lot of saplings (10,000 SPH) in the Forest Reserve signifying adequate regeneration, including that of the valuable species, except for Afzelia quanzensis and Guibourtia coleosperma. The abundant natural regeneration implies that there was adequate forest protection and management following the introduction of JFM, which enhances regeneration. It is recommended that the Forestry Department should continue with public awareness on JFM to increase understanding and stakeholders’ involvement. The Forests Act of 1999 should be commenced and amended to support full implementation of JFM. The value of the forest also needs to be enhanced to increase benefit for local people and long-term conservation.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2005. / This study is about marketing of Uapaca kirkiana fruit in Zambia, a fruit that has great economic value especially among the rural and urban poor. It contributes to general food security. In southern Africa, farmers and other stakeholders have identified Uapaca as a priority species for domestication. Current agroforestry initiatives are promoting integration of indigenous trees into farming systems to provide marketable products for income generation. Domestication of trees however, depends on expanding the market demand for tree products. There is considerable evidence that expanding market opportunities is critical for the success of domestication innovations but farmers have been introduced to domestication with little consideration for marketing. The existing market potential can be achieved through sound knowledge on markets and marketing. Information on the marketing of Uapaca fruit is inadequate. This study, therefore, aimed at generating information on the marketing of Uapaca kirkiana fruit, including the basic conditions of demand and supply of the fruit. The main study was conducted in Chipata and Ndola districts in the Eastern and Copperbelt provinces respectively, while fruit pricing was conducted in Lusaka district in Lusaka Province. Questionnaires and participatory research methods were used to collect the data. A total of 37 markets involving 49 collectors, 59 retailers, 189 consumers and 20 government forest workers are included in the study. The study reveals that there is demand for the fresh and secondary products of the fruit and hence substantial fruit trading exists in Zambia. However, the marketing system is characterised by underdevelopment. There is insufficient capacity to satisfy the demand for the fruit and institutional /policy support to Uapaca fruit market expansion. Currently, only basic technology for product development exists. The results suggest a need to address policy and capacity development for expansion of Uapaca kirkiana fruit industry. To improve the Uapaca trade industry, the study proposes developing and scaling up policy strategies, fruit processing sector, research-extension-trader-agribusiness linkages, infrastructure development and knowledge generation for improved understanding of the Uapaca fruit markets.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Balau, a group consisting of 21 Shorea species, is widely used for outdoor application. In South Africa, Balau is one of the most popular materials used for decking. Due to the increasing scarcity of Balau, it is of economic importance to investigate the possibility of a substitute timber for decking material. One possible timber could be Colorado, a mixture containing one or more of the following: Eucalyptus camaldulensis, Eucalyptus tereticornis and their hybrids. These two species and their hybrids are extensively cultivated in countries such as Australia, India and parts of South America because of their short rotation period and easy adaptability to a wide variety of soil and climatic factors. The timber was initially utilized as raw material for the pulp and paper industry but is now gaining importance in structural uses like furniture, flooring and decking. The aim of this exploratory study was to investigate relevant material properties and to examine the natural and accelerated weathering behaviour of Colorado and Balau to predict Colorado’s suitability as decking material. It was found that Colorado had smaller vessel lumina, fewer vessels/m2 and smaller rays than Balau and had a higher density than Balau. Although both timbers had a relatively low FSP, Colorado’s FSP was 2.3 percentage points higher than Balau’s. The swelling coefficients (radial and tangential) of Colorado were slightly higher than Balau’s but Colorado’s lower swelling anisotropy can result in a lower tendency to twist in service. Colorado had a higher water soluble extractive content than Balau, which can lead to the rapid initial colour changes when the timber is exposed uncoated. The weathering performance of Colorado and Balau was investigated by exposing samples in a QUV accelerated weathering apparatus and to natural weathering at an inland and a marine location. During weathering Colorado showed a slightly higher colour change ( E*) than Balau. Balau showed a higher increase in roughness (Rz), surface checking and check formation than Colorado. Colorado showed slightly more cup than Balau, however, Balau showed much larger amounts of twisting than Colorado. No statistically significant differences were found between the hydrophobicity of the two timbers. A coating was effective in increasing the initial hydrophobicity of samples and could maintain a relatively hydrophobic surface during weathering. No statistically significant differences were found in the effect of sample cut on timber species surface wettability. Although only long term exposure studies and using substantially more samples can confirm its weathering performance, the results of this exploratory weathering study indicated that Colorado can successfully be used as a substitute decking material for Balau. / AFRIKAANSE OPSOMMING: Balau, ‘n houtsoort wat ongeveer 21 Shorea-spesies verteenwoordig, word wyd in buitenshuise aanwendings benut. In Suid-Afrika is Balau een van die mees gewilde materiale wat vir dek-doeleindes gebruik word. As gevolg van die toenemende skaarsheid van Balau, is dit van ekonomiese belang om die gebruik van ‘n moontlik plaasvervangende houtsoort vir dek-materiaal te ondersoek. Colorado, ‘n mengsel van een of meer van die volgende: Eucalyptus camaldulensis, Eucalyptus tereticornis en hibriede daarvan, kan as ‘n moontlike plaasvervanger gebruik word. Hierdie twee spesies en hulle hibriede word op groot skaal in lande soos Australië, Indië en dele van Suid-Amerika gekweek vanweë hul kort rotasieperiode en goeie aanpasbaarheid by ‘n wye verskeidenheid grond- en klimaatsfaktore. Die spesies is aanvanklik as grondstof in die pulp- en papierbedryf gebruik maar word tans al hoe belangriker in strukturele aanwendings soos byv. meubels, vloer- en dek-materiaal. Die doel van hierdie verkennende studie was om relevante materiaaleienskappe te ondersoek en om die versnelde en natuurlike verweringsgedrag van Colorado en Balau vas te stel om sodoende ‘n aanduiding van die geskiktheid van Colorado as dek-materiaal te kan kry. Daar is gevind dat Colorado kleiner vat-lumina, minder vate/m2 en kleiner strale as Balau besit en dat Colorado ‘n hoër digtheid het as Balau. Alhoewel beide houtsoorte relatiewe lae veselversadigingspunte (VVP) besit, is Colorado se VVP 2.3% persentasiepunte hoër as dié van Balau. Die swellingskoëffisiente (radiaal en tangensiaal) van Colorado is effens hoër as dié van Balau, maar Colorado se laer swellingsanisotropie kan op ‘n kleiner neiging tot skeeftrek dui. Colorado het ‘n hoër wateroplosbare ekstrakstofinhoud as Balau bevat, wat tot aanvanklik vinnige kleurveranderings kan lei wanneer die hout sonder oppervlaktemiddel blootgestel word. Die verweringsgedrag van Colorado en Balau is ondersoek deur monsters aan versnelde en natuurlike verwering bloot te stel. Eersgenoemde is in ‘n QUV versnelde verweringsapparaat uitgevoer en laasgenoemde in ‘n binnelandse en ‘n mariene lokaliteit. Tydens verwering het Colorado ‘n effens hoër kleurverandering ( E*) as Balau getoon. Balau het ‘n hoër toename in rofheid (Rz), oppervlaktekrake en kraakvorming as Colorado getoon. Colorado het effens meer kromgetrek terwyl Balau meer skeefgetrek het as Colorado. Geen statisties beduidende verskille kon tussen die waterwerende eienskappe van die twee houtsoorte vasgestel word nie. ‘n Oppervlakbedekking was effektief om die aanvanklike toename in waterwerende vermoë te verhoog en gedurende verwering te kon behou. Geen statisties beduidende verskille kon tussen die invloed van snit van die monster op die oppervlaktebenatbaarheid van die houtsoorte vasgestel word nie. Alhoewel slegs langtermyn blootstellingstudies en die gebruik van beduidend veel meer monsters die verweringsgedrag kan bevestig, dui die resultate van hierdie verkennende ondersoek aan dat Colorado suksesvol as ‘n plaasvervangende dekmateriaal vir Balau gebruik kan word.

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.