Dissertations / Theses on the topic 'Environmental aspects of Wood preservatives'

In this work, different aspects on the re-use of wood based fibres have been studied, focusing on ink detachment of flexographic ink from model cellulose surfaces and changes in porous structure of kraft fibres following different treatments. New model systems for evaluation of ink detachment and ink-cellulose interactions were used. Ink detachment was studied using Impinging jet cell equipment, taking into consideration the influence of storage conditions, surface roughness and surface energy of the cellulose substrate. A micro adhesion measurement apparatus (MAMA) was used to directly study ink-cellulose interactions, from which the adhesive properties between ink and cellulose, having various surface energies, could be derived. UV-light, elevated temperatures, longer storage time, decreased surface energy, i.e. making the cellulose surface more hydrophobic, and high surface roughness all negatively affected ink detachment. Attenuated total reflectance - fourier transform infra red (ATR-FTIR) and atomic force microscopy (AFM) was used to evaluate structural and chemical changes of ink and cellulose upon storage at elevated temperature or under UV-light. After storage at elevated temperatures, ATR-FTIR spectra indicated that a hydrolysis or an oxidative reaction took place as a peak at 1710 cm-1 appeared. AFM revealed that storage at elevated temperatures caused the latex particles present in the ink to form a film, most likely due to annealing. Less ink detached from hydrophobic cellulose surfaces. Ink detachment decreased for rougher cellulose substrates due to an increased molecular contact area.

Fibre pore structure and water retaining ability influenced fibre/fibre joint strength and different paper strength properties. Investigations took into account the effect of pulp yield, counter-ion types, pH, salt, hornification and strength enhancing additives. Nuclear magnetic resonance relaxation (NMR), inverse size exclusion chromatography (ISEC) and water retention value (WRV) measured the changes that occur in the fibre wall upon varying the conditions. Each different measuring technique contained unique information such that a combination of the techniques was necessary to give as complete a picture as possible over the changes that occurred in the fibre wall upon varying the conditions for the fibre. A correlation between fibre pore radius and sheet strength properties was found, suggesting that fibres with larger pores allow for a larger molecular contact area between fibres to be formed during drying and consolidation of the paper. Fibre/fibre joint strength, fibre flexibility, and the number of efficient fibre/fibre contacts also controlled sheet strength. The effect of different strength enhancing additives on fibre pore structure and paper strength was investigated. Larger pores in the fibres allowed for additives to penetrate into the fibre wall. Additives with low molecular mass (Mw) penetrated into the fibre wall to a larger extent than additives with a high Mw, causing an embrittlement of the fibre. However, low Mw additives gave higher sheet tensile strength despite a leveling out in strength at high additions, indicating that the fibre wall can only adsorb a limited amount of chemical. Polyallylamine hydrochloride (PAH) and polyelectrolyte complexes (PEC) of PAH and polyacrylic acid (PAA) were added separately to the pulp. PEC significantly improved both tensile strength and Z-strength, whereas PAH alone did not increase the strength properties to the same extent unless the sheets were heated to 150°C for 10 minutes. The results suggested that the effect of PEC was dominated by an improvement in fibre/fibre joint strength, whereas the effect of PAH was significantly affected by an improvement of the intra-fibre bond strength

Many low molecular weight chlorinated organic compounds produced by the pulp and paper industry during kraft bleaching of the wood pulp are toxic. Mass balance studies suggest that mineralization of chlorinated organics is occurring in pulp and paper mill wastewater treatment systems. To understand the nature of dechlorination activity, molecular tools such as oligonucleotide primers and corresponding DNA probes were developed to monitor the presence of microorganisms possessing key genes (dehalogenases) responsible for the degradation of chloroaliphatic organics in kraft pulp mill effluent treatment systems. Oligonucleotide primers designed from the coding sequence of known dehalogenases and a methane monooxygenase gene, which is known to catalyze dehalogenation reactions, were used for polymerase chain reaction (PCR) analysis, using genomic DNA extracted from dehalogenating bacterial isolates and total community DNA extracted from water and sediments of lagoon treatment systems. PCR amplification with dhlB oligonucleotide primers, designed from the haloacid dehalogenase of Xanthobacter autotrophicus, revealed the presence of dehalogenase genes in both aerated lagoons and stabilization basins. Similar results were obtained with mmoX primers designed from the methane monooxygenase gene of Methylococcus capsulatus. DNA sequence analysis of several PCR fragments showed significant similarity to known dehalogenase genes. The molecular tools developed in this study revealed the presence of different types of microorganisms with dechlorination potential in the microbial community of pulp mill effluents.

On the way towards a more biobased economy, the sustainable use of global wood resources remains a challenge as several trade-offs arise, e.g., from an increased energetic use of wood, an increased use of innovative but probably less recyclable wood composites, or from the need to conserve other forest ecosystem services. The aim of this study is to identify existing environmental indicators and methods for an evaluation of the sustainability of wood products in consideration of all life cycle stages, site-dependent aspects and later use in corporate decision-making. We chose a systematic literature review to answer the research questions explicitly and comprehensively. Qualitative content analysis was used to code indicators and scientific methods according to the Pressure-State-Response (PSR) framework. The sample (N = 118) is characterized by a high number of life cycle assessment (LCA) case studies. In 51% of all studies, the study authors use a combination of different methods. A total of 78 indicators and 20 site-dependent aspects could be identified in the sample. The study findings represent a first step towards a holistic environmental assessment of wood products.

On the way towards a more biobased economy, the sustainable use of global wood resources remains a challenge as several trade-offs arise, e.g., from an increased energetic use of wood, an increased use of innovative but probably less recyclable wood composites, or from the need to conserve other forest ecosystem services. The aim of this study is to identify existing environmental indicators and methods for an evaluation of the sustainability of wood products in consideration of all life cycle stages, site-dependent aspects and later use in corporate decision-making. We chose a systematic literature review to answer the research questions explicitly and comprehensively. Qualitative content analysis was used to code indicators and scientific methods according to the Pressure-State-Response (PSR) framework. The sample (N = 118) is characterized by a high number of life cycle assessment (LCA) case studies. In 51% of all studies, the study authors use a combination of different methods. A total of 78 indicators and 20 site-dependent aspects could be identified in the sample. The study findings represent a first step towards a holistic environmental assessment of wood products.

Land application of wood ash is becoming more appealing, as a disposable alternative, to landfilling options. It is estimated that 110,000 tonnes of wood ash is produced annually in Alberta by cogeneration systems, a large percentage produced in Central and Peace River Regions of Alberta. Alkaline (pH-13) properties and nutrient content of wood ash provides an alternative for the acidic and nutrient deficient soils within these regions. The objective of this field study was to determine the effect wood ash applications would have under field conditions on: the chemical and physical properties of soils; barley dry matter production; grain and seed yield of barley and canola; and the nutrient and metal uptake by crop tissue. Ash applications significantly increased dry matter and seed yield, improved crop nutrient quality, increased soil pH and improved soil nutrient availability, while not infringing on any environmental regulations.
xxiii, 142 leaves : ill. ; 28 cm.

Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2018.
Soil ecosystems in urban, rural and agricultural environments receive chemical input from diverse sources of contamination, such as wastewater, industrial discharge, agricultural and urban runoff, fertilizers, vehicle leakages, landfill seepage, and animal waste overspill. Agricultural activities, transportation and industrial activities are suspected to be the highest sources of metal contamination in Cape Town. Although scientists generally have a good understanding of the toxicity of individual chemical pollutants, there is a great need to bridge the gap between our understanding of the toxic effects of exposure to individual contaminants and those effects from exposure to mixtures of chemicals. Woodlice and other soil detritivores have a particularly important ecosystem function in mineralising organic matter. Woodlice experience stress when exposed to toxic levels of metals in the diet, which can reduce feeding rates and may combine with natural stresses to reduce fitness and lower 'performance', thereby possibly resulting in these organisms being unable to completely fulfil their ecological function. The objectives of this study were: to compare how aluminium and manganese are bioaccumulated in Porcellio scaber in terms of the contribution of the hepatopancreas in metal storage compared to the rest of the body; and to determine whether mixtures of aluminium and manganese affect each other’s bioaccumulation and distribution in Porcellio scaber. Woodlice collected from a clean field site (Kirstenbosch Botanical Garden) were experimentally exposed in the laboratory to a range of environmentally relevant aluminium and manganese concentrations. The woodlice were exposed to these metals in single and mixed metal experiments. Oak leaves, collected from a clean site, were contaminated with aluminium and manganese. Therefore, the woodlice were exposed via their food source. A control experiment, where oak leaves were not contaminated, was also prepared. At week 0 and after five weeks of exposure, a sample of the woodlice (5 per exposure group) were dissected to remove the hepatopancreas. Hepatopancreas and rest of the body samples were acid digested and analysed for the metals by means of the ICP-MS. Contrary to the existing knowledge of metals accumulating in the hepatopancreas of woodlice when ingested, this study showed a higher bioaccumulation of aluminium in the rest of the body of woodlice after 5 weeks of exposure than in the hepatopancreas. This result was interpreted as a possible detoxification mechanism by woodlice through the use of the exoskeleton during the moult cycle. A similar result was found when woodlice were exposed to mixtures of aluminium and manganese. This translated to the fact that woodlice were unable to effectively deal with the toxicity caused by the mixture of aluminium and manganese. In the group of woodlice exposed to manganese alone, it was found that manganese concentrations in the rest of the body of woodlice exposed for 5 weeks were statistically higher than the manganese concentrations in the rest of the body of woodlice at the start of the exposure (week 0). However, in the hepatopancreas, there were no statistical differences between the manganese concentrations in week 0 woodlice and the manganese concentrations in week 5 woodlice. Furthermore, manganese concentrations in the rest of the body of week 5 woodlice were statistically higher than manganese concentrations in the hepatopancreas of week 5 woodlice. This was interpreted as further proof that woodlice would accumulate certain metals (aluminium and manganese in this case) in their exoskeleton so that elimination can follow during the moult cycle.

This study investigated the use of activated carbon and ion exchange for the removal of color and dissolved solids from pulp and paper wastewater generated by the Union Camp Corporation mill in Franklin, Virginia. The objective of the treatment was to provide a high quality effluent suitable for direct recycling. This advanced treatment followed pretreatment by lime, alum, or ferric chloride. Required effluent quality was defined as being 5 Pt-Co units color and 75 mg/L chloride. Granular and powdered carbons, manufactured by the Westvaco Corporation, were utilized in the study. The ion exchange resin investigated was Amberlite IRA-68, manufactured by Rohm and Haas. Carbon treatment consisted of batch and column operation; ion exchange column treatment was used. The results of the study indicated that the required effluent quality was achieved by activated carbon and ion exchange treatment of wastewater that had been chemically pretreated. The most successful treatment schemes for the biotreated effluent were pretreatment with 500 mg/L alum or 2500 mg/L lime, followed by carbon column treatment for color polishing and ion exchange for chloride removal. The lime pretreated sample produced an effluent containing less than 5 Pt-Co units color as necessary for reuse, while the alum pretreated sample would require dilution with make-up water or additional treatment (i.e. ion exchange) to obtain recycle quality. The use of ion exchange for chloride removal is not practical due to the preferential exchange for sulfates. Until such time as sulfate can be eliminated from the wastewater source, other methods of dissolved solids removal should be investigated.
M. Eng.

The stability of hydrogen peroxide (H2O2) is a critical factor for the brightening of mechanical pulps. Inorganic ions, including Fe, Mn and Cu catalytically decompose H2O2. These troublesome metals promote the rapid transformation of H2O2 to nonselective hydroxyl radicals that degrade the cellulose fibres and decrease yields.
The interaction of aqueous metal•complexes with magnesium metal (Mg°) or bimetallic mixtures of magnesium with either palladium (Pd°/Mg°) or silver (Ag°/Mg°) were optimized to remove metals (Mn, Cu and Fe) from solution with concomitant release of the complexing reagent. The analyte metals were removed by both cementation on the surfaces of the excess Mg° and by precipitation as hydroxides. Overall, the reactions were rapid (3 or 10 min) and very efficient. The accelerators (Ag or Pd) were deposited on the surfaces of the Mg°. In a separate study, the excess of Mg° could be reused to mediate more metals removal without apparent loss of reactivity. Among the other iminodiacetate analogs (CDTA, MEDTA, EGTA, HEDTA, DPTA and MTBE), the EGTA and HEDTA proved to be possible substitutes for both efficient metal removal of Mn, Cu and Fe from solution and efficient release of chelating reagent. The measurement of particle size, performed by laser granulometry, demonstrated that smaller particles of precipitate were generated from metal-EDTA complexes by reaction with NaOH than by reaction with Pd°/Mg° bimetallic mixture. If the suspensions of particles were analyzed in the absence of ultrasound, the particles became aggregated into large flocs (up to 150 mum3 ). The reactivity of the bimetallic mixtures was exploited to remove Cu, Mn, Fe, Zn and Al that had been initially chelated with EDTA or DTPA from a thermomechanical pulp (TMP). After 15 min, the metals had been removed efficiently with the bimetallic mixtures. The EDTA released from the TMP filtrate could be recycled efficiently for a total of three cycles. On the other hand, the DTPA was not released as efficiently. Measurements of turbidity and chemical oxygen demand (COD) indicated no appreciable difference between the pulp samples with either chelating reagent. Residual H2O2 and ISO brightness measurements indicated no apparent differences among pulps that had been treated wi

The majority of low income households in South Africa have limited access to electricity, and typically cook on stoves fuelled by paraffin. Paraffin represents a fossil fuel. It is a relatively cheap fuel in South Africa. Another fuel that can also be used for cooking is wood pellets, which is a renewable fuel. It can be used in a similar way to that of paraffin and is relatively cheap compared to other renewable energy sources. To investigate if living conditions among low income households can be improved the focus of the study was to evaluate the sustainability of cooking on paraffin and wood pellets. This was done by comparing social, environmental and economic aspects associated with the two cooking fuels. The social aspects were investigated through an interview study, the environmental aspect through a comparative life cycle assessment (LCA) and the economic aspects through a partial life cycle cost analysis (LCCA) focusing on the user phase.   The interview study showed that paraffin users considered four aspects as the most important when cooking, namely safety, health, affordability and quality. The study also found that the majority were willing to change to another cooking fuel if these aspects were fulfilled. The LCA showed that both systems score the highest on 9 out of 18 environmental impact categories over a 16-year perspective. The economic analysis showed that the user phase of the wood pellet system is more economically beneficial during the 16-year time period than the paraffin system. It was concluded that wood pellets could be used as an option to paraffin for cooking and would most likely increase living conditions for low income households.
Majoriteten av låginkomsthushåll i Sydafrika har begränsad tillgång till elektricitet och vanligtvis sker matlagningen på paraffinspisar. Paraffin är ett fossilt bränsle. Det är ett relativt billigt bränsle i Sydafrika. Ett annat bränsle som också kan användas för matlagning är träpellets som är ett förnyelsebart bränsle. Det kan användas på liknande sätt som för paraffin och är ganska billigt i jämförelse med andra förnybara energikällor. För att undersöka om levnadsförhållanden för låginkomsthushåll kan förbättras låg fokus för denna studie på att utvärdera hållbarheten för att laga mat på paraffin och träpellets. Detta genomfördes genom att jämföra sociala, miljömässiga och ekonomiska aspekter associerade med dessa bränslen för matlagning. De sociala aspekterna undersöktes genom en intervjustudie, de miljömässiga aspekterna genom en jämförande livscykelanalys (LCA) och de ekonomiska aspekterna gjordes genom en livscykelkostnadsanalys (LCCA) för användarfasen.   Intervjustudien visade att paraffinanvändare anser att fyra aspekter är de viktigaste vid matlagning, nämligen säkerhet, hälsa, kostnad och kvalitet. Studien visade också att majoriteten var villiga att byta till ett annat bränsle för matlagning om dessa aspekter var uppfyllda. Livscykelanalysen visade att båda systemen hade högst miljöpåverkan i 9 av 18 miljöpåverkanskategorier vardera inom ett 16-årsperspektiv. Den ekonomiska analysen visade att under en 16-årsperiod var användarfasen mer kostnadseffektiv för matlagning på träpellets jämfört med paraffin. Studien visade att träpellets kan användas som ett alternativ för paraffin vid matlagning och kommer troligtvis öka levnadsförhållanden för låginkomsthushåll.

The majority of low income households in South Africa have limited access to electricity, and typically cook on stoves fuelled by paraffin. Paraffin represents a fossil fuel. It is a relatively cheap fuel in South Africa. Another fuel that can also be used for cooking is wood pellets, which is a renewable fuel. It can be used in a similar way to that of paraffin and is relatively cheap compared to other renewable energy sources. To investigate if living conditions among low income households can be improved the focus of the study was to evaluate the sustainability of cooking on paraffin and wood pellets. This was done by comparing social, environmental and economic aspects associated with the two cooking fuels. The social aspects were investigated through an interview study, the environmental aspect through a comparative life cycle assessment (LCA) and the economic aspects through a partial life cycle cost analysis (LCCA) focusing on the user phase. The interview study showed that paraffin users considered four aspects as the most important when cooking, namely safety, health, affordability and quality. The study also found that the majority were willing to change to another cooking fuel if these aspects were fulfilled. The LCA showed that both systems score the highest on 9 out of 18 environmental impact categories over a 16-year perspective. The economic analysis showed that the user phase of the wood pellet system is more economically beneficial during the 16-year time period than the paraffin system. It was concluded that wood pellets could be used as an option to paraffin for cooking and would most likely increase living conditions for low income households.
Majoriteten av låginkomsthushåll i Sydafrika har begränsad tillgång till elektricitet och vanligtvis sker matlagningen på paraffinspisar. Paraffin är ett fossilt bränsle. Det är ett relativt billigt bränsle i Sydafrika. Ett annat bränsle som också kan användas för matlagning är träpellets som är ett förnyelsebart bränsle. Det kan användas på liknande sätt som för paraffin och är ganska billigt i jämförelse med andra förnybara energikällor. För att undersöka om levnadsförhållanden för låginkomsthushåll kan förbättras låg fokus för denna studie på att utvärdera hållbarheten för att laga mat på paraffin och träpellets. Detta genomfördes genom att jämföra sociala, ekologiska och ekonomiska aspekter associerade med dessa bränslen för matlagning. De sociala aspekterna undersöktes genom en intervjustudie, de miljömässiga aspekterna genom en jämförande livscykelanalys (LCA) och de ekonomiska aspekterna gjordes genom en livscykelkostnadsanalys (LCCA) för användarfasen. Intervjustudien visade att paraffinanvändare anser att fyra aspekter är de viktigaste vid matlagning, nämligen säkerhet, hälsa, kostnad och kvalitet. Studien visade också att majoriteten var villiga att byta till ett annat bränsle för matlagning om dessa aspekter var uppfyllda. Livscykelanalysen visade att båda systemen hade högst miljöpåverkan i 9 av 18 miljöpåverkanskategorier vardera inom ett 16-årsperspektiv. Den ekonomiska analysen visade att under en 16-årsperiod var användarfasen mer kostnadseffektiv för matlagning på träpellets jämfört med paraffin. Studien visade att träpellets kan användas som ett alternativ för paraffin vid matlagning och kommer troligtvis öka levnadsförhållanden för låginkomsthushåll.

The influence of nitrogen (N) and phosphorus (P) limitation on pulp and paper mill activated sludge (AS) floc properties was studied using a bioreactor fed with synthetic Kraft mill effluent. The bioreactor and synthetic effluent were designed and shown to perform like the real mill system providing the AS, establishing the in vivo relevance of the results. Limitation of either N or P produced inadequate effluent biotreatment, shown by poor BOD5 and suspended solids removal, and by decreased biomass health, performance, and floc settling. Greatly enhanced poly-beta-hydroxybutyrate (PHB) (but not carbohydrate or extracellular polymeric substances [EPS]) synthesis was the common response of the floc microbial community to N limitation over many days. In contrast, P-limitation increased total carbohydrate and EPS, but not PHB.
N limitation, but not P limitation, caused the net floc surface charge to be much more negative, while P-limitation, but not N-limitation, increased the floc bound water content and surface hydrophobicity. Thus, in real pulp and paper mill AS systems, careful manipulation of N or P additions may be useful to optimize the key process of charged polymer-assisted AS dewatering.

Coliform bacteria have long been used to indicate fecal contamination of food, water, and solid surfaces, and thus the presence of a health hazard. In this study, the in-mill water and external effluent treatment systems of seven typical Canadian pulp and paper mills were shown to support the growth of numerous coliforms, especially Klebsiella spp, Escherichia coli, Enterobacter spp., and Citrobacter spp . Mill coliforms were shown to be not just simple transients from feedwater or furnish (wood), but to be continuously growing, especially in the primary clarifiers. Therefore, coliforms and fecal coliforms cannot be used as fecal contamination indicators in pulp and paper mill water and effluent treatment systems.
N2-fixing coliform populations were detected in mill water systems and were analyzed using N2-fixation assays and nitrogenase gene (nifH) probing. Both active in situ populations and cultured microbial isolates were tested. Active N2-fixation was demonstrated in six primary clarifiers. Measurement of the numbers and composition of the total culturable bacterial community in a primary clarifier revealed that approximately 50% of all aerobic cells contained nifH , of which >90% were Klebsiella. Coliforms growing on MacConkey agar plates from the primary clarifier were all identified as Klebsiella and 100% of these Klebsiella contained the nifH gene. Preliminary estimates indicate that the amount of N2 fixed per day is substantial in some clarifiers.

The importance of ecological systems in supporting social systems has been identified as one of the most important facets of sustainable development. Consequently, a number of international and local laws and policy interventions have been established to ensure that natural resource use remains sustainable. In rural areas, overdependence on fuel wood has commonly been identified as one of the biggest threat to forestry ecosystems. This in turn has led to environmental degradation that includes among others species depletion, soil erosion and decline in water and air quality. Based on the myriad problems caused by over-reliance on fuel wood, this study sought to identify usage, management and perceived implication of woodland exploitation in Port St Johns local municipality in the Eastern Cape, South Africa. Using interviews and questionnaires for key respondents in the local community, the study identified two key threats to socio-ecological stability resulting from wood fuel exploitation namely; high poverty levels and lack of coordination in the management of wood fuel resources. Apart from using fuel wood for domestic use, local fuel wood exploitation has been commercialized to augment household incomes. Lack of coordination in the management of natural resources has also created a vacuum in the exploitation and management of fuel wood resources. The study did not have inclination towards statistics such as chi-square and t-tests since the research questions and objectives did not refer to any relationship or significance level. The study recommends non-wood based alternative sources of energy, improved coordination and harmonization of functions among different stakeholders and emphasis on collaboration between traditional and local governance in the management fuel wood and the local physical environment. The study further recommends resuscitation of indigenous knowledge and socio-ecological stability

Thesis (MScFor)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: The role that forestry plays in climate change mitigation is well recognized by countries that ratified the Kyoto protocol agreement. Though climate change mitigation strategies provide a strong incentive to quantify current patterns of forest carbon sources and sinks, this exercise (carbon accounting) is not as simple as it sounds. This is proven by the vast number of techniques and methodologies available, from models to softwares programmes created in response to the need to estimate carbon sequestration. The study aimed at gaining an understanding of the current carbon sequestration estimation methodology and models in use by the South African Forestry Industry. A survey was undertaken amongst forestry industry stakeholders in which 77% of respondents agreed to the need for a carbon sequestration model for South Africa. This model should have qualities that the forestry industry and all stakeholders agreed with. . A search of freely available models and software was conducted. The aim was to find freely available model(s) that would be readily applicable and adoptable to South African conditions. A Multi Criteria Analysis was carried out using “ideal qualities” for a carbon model as weighting. This resulted in the selection of two models, CASMOFOR and CBM CFS 3, which obtained the highest sum product total from the analysis. These together with FICAT, which came as a recommendation from the questionnaire survey, were compared in the analysis. Carbon values were calculated from yield table volumes by Kotze et al. (2012). A conversion of these volumes to biomass and carbon was done using Dovey (2009) biomass expansion factors and a biomass to carbon conversion value of 0.5 g C/g dry matter, following procedures by Matthews (1993). The first comparison was made on how the model results related to the yield table estimates from Kotze et al. (2012). When carbon values were compared per hectare, it was found that the FICAT model differed significantly from the rest. A second comparison looked at the models’ prediction of the carbon accumulated in NCT’s Enon plantation outside Pietermaritzburg. The Hungarian model, CASMOFOR, was the better predictor as it produced the lowest Mean Squared Error (MSE). Based on the results from the survey and model analysis a number of recommendations can be made regarding the current carbon accounting situation in South Africa. One of the main recommendations is that information sharing among the industry’s stakeholders should improve if the industry is to reach consensus on which methodology to adopt in their business practices.
AFRIKAANSE OPSOMMING: Die rol wat bosbou speel in klimaatsverandering-bekamping is welbekend onder lande wat die Kyoto protokol ooreenkoms onderteken het. Alhoewel klimaatsverandering-bekamping strategieë ‘n sterk aansporing bied om huidige patrone van woudkoolstof bronne en sinkte te kwantifiseer, is hierdie oefening nie so maklik soos dit klink nie. Die bewys hiervan is die groot aantal tegnieke en metodes, wat wissel van modelle tot sagteware programme wat ontwikkel is om koolstofsekwistrasie te meet. Die doelwit van die studie was om die huidige koolstofsekwistrasie metodes en modelle wat deur die Suid Afrikaanse Bosbou Bedryf gebruik word, beter te verstaan. ‘n Vraelysopname is onderneem onder bosbou-industrie deelnemers, waarin 77% van respondente saamgestem het dat dit nodig is dat Suid Afrika ‘n koolstofsekwistrasie model moet hê. Die model moet eienskappe hê waarmee die bosbou-industrie en alle deelnemers saamstem. ‘n Soektog na vrylik beskikbare koolstofmodelle en sagteware programme is onderneem. Die doelwit was om modelle te vind wat geredelik aangepas kan word vir Suid Afrikaanse toestande. ‘n Multi-kriteria analise is uitgevoer met die “ideale eienskappe”vir ‘n koolstofmodel as gewigte. Die resultaat was die seleksie van twee modelle, CASMOFOR en CBM CFS 3, wat die hoogste telling in die ontleding behaal het. Hierdie modelle, tesame met FICAT, wat aanbeveel is deur respondente van die vraelys opname, is vergelyk in ‘n ontleding. Koolstofwaardes is bereken vanaf opbrengstabelle wat deur Kotze et al. (2012) ontwikkel is. Die omsetting van hierdie volumes na biomassa en koolstof is gedoen deur Dovey (2009) se biomassa uitbreidingsfaktore en ‘n biomassa na koolstof omsettings faktor van 0.5 g C/g droëmassa te gebruik (Matthews, 1993). In die eerste vergelyking van die modelle is gekyk hoe die modelle vergelyk met koolstof berekeninge vanaf die Kotze et al. (2012) opbrengstabelle. Wanneer koolstofwaardes per hektaar vergelyk word is gevind dat FICAT beduidend verskil van die ander modelle. In ‘n tweede vergelyking is gekyk na hoe die modelle die koolstof wat in NCT se Enon plantasie buite Pietermaritzburg versamel is, voorspel. Die Hongaarse CASMOFOR model was die beste voorspeller. Anders as die FICAT en CBM CFS 3 modelle het dit die laagste Gemiddelde Vierkante Fout gehad. Na gelang van die resultate van die vraelysopname en die modelontleding kan ‘n aantal aanbevelings gemaak word oor die huidige koolstofberekening situasie in Suid Afrika. Een van die hoof aanbevelings is dat die uitruil van inligting tussen industrie deelnemers moet verbeter as die bedryf eenstemmigheid oor die metode van koolstofberekening wil bereik.

Thesis (MScFor)--Stellenbosch University, 2002.
ENGLISH ABSTRACT: Namaqualand has a very unusual diversity of plant life, with many endemic plant species. The fundamental question of this thesis is how this system, damaged by strip-mining activities, can be rehabilitated. The aim was to base the rehabilitation methods on ecological processes. In order to answer this question an overview of the relevant literature was needed in order to identify possible research needs and also to evaluate the work that has been done in the field of strip-mine rehabilitation in arid areas. An understanding of community and ecosystem dynamics would help to establish aims and methods for site-specific rehabilitation. In Namaqualand, South Africa, there is also a need for experimentation to establish which of the many factors is most limiting to long-term ecosystem recovery. It is important to have a good knowledge of the successional processes and disturbance history of the land which needs to be rehabilitated. The vegetation on unmined areas and mined areas of different ages and treatments after mining, were sampled. It was shown that some areas could be expected to show a large degree of recovery in the space of a few years, whilst others would show little or no recovery over a period of decades. It is important to recognise rehabilitation as a gradual process that takes place at different rates in different areas and in different years. The planting of Atriplex nummularia and sowing of Atriplex semibaccata did not facilitate the return of indigenous, perennial species, but rather seem to inhibit their return. In view of the importance of topsoil in terms of the fertility of the soil and the seed bank present in the topsoil, the influence of topsoil removal and stockpiling due to strip-mining activities were tested. The soil fertility was tested by means of radish bioassays and soil laboratory analysis, whilst species diversity and richness were tested with seedling emergence trials. As expected a higher plant species diversity was found on the unmined soils and radishes grew larger on these soils. The topsoil deteriorated in terms of plant species richness, diversity and soil fertility whilst it was stockpiled. Direct replacement of topsoil would ensure a planting medium closer to the pre-disturbance level that could lead to fairly rapid and successful recolonization of the mined area. Successful plant recruitment also depends on the microsites to which seeds are dispersed. The effect that different microsites had on seed germination, seedling growth and survival was tested. It was found that micro catchments always yielded the highest numbers. The establishment and survival of seedlings in the other microsite types (under single shrubs, under clumped shrubs and in the open) varied, depending on the amount of rainfall received in the particular year. Lastly, I experimented with the translocation of three local, indigenous, succulent plant species. These plants were transplanted either in clumps of three together or alone, since I hypothesized that planting them together would facilitate their survival. However, it was found that it depended largely on the morphology of the plant and the amount of rainfall received in a particular year, whether these plants will compete with each other for limiting resources or facilitate each other's survival. The thesis contributes to the understanding of vegetation dynamics in the Succulent Karoo after strip-mining has taken place. Guidelines are provided based on ecological processes, for strip-mine rehabilitation in the Succulent Karoo.
AFRIKAANSE OPSOMMING: Namakwaland is bekend vir sy ongewone diversiteit van plante, met baie endemiese spesies. Die fundamentele vraag wat deur hierdie tesis gevra word is hoe hierdie sisteem, wat beskadig is deur oppervlak mynbou, gerehabiliteer kan word. Die doel is om die rehabilitasie metodes te baseer op ekologiese prosesse. 'n Oorsig van die relevante literatuur was nodig om moontlike areas van verdere navorsing te identifiseer en ook die navorsing wat reeds gedoen is oor rehabilitasie van oppervlak myne in ariede gebiede, te evalueer. 'n Goeie begrip van gemeenskap en ekosisteem dinamika sal help om doelwitte en metodes daar te stel vir die rehabilitasie van spesifieke areas. Dit is ook nodig om in Namakwaland, Suid -Afrika, uit te vind watter van die baie faktore, die lang-termyn herstel van 'n ekosisteem, die meeste verhinder. Dit is baie belangrik om In goeie kennis te hê van die versteurings geskiedenis van die area wat gerehabiliteer moet word, asook die suksessionele prosesse wat werksaam is. Plantegroei van areas wat op verskillende tye gemyn en verskillend behandel is, asook ongemynde areas is ondersoek. Sekere areas het In groot mate van herstel gewys in 'n tydperk van 'n paar jaar, terwyl ander, min of geen hersteloor 'n periode van dekades getoon het nie. Dit is belangrik om rehabilitasie as 'n geleidelike proses te sien, wat teen verskillende tempos plaasvind tydens verskillende jare en in verskillende areas. Daar is bevind dat die plant van Atriplex nummularia asook die saai van Atriplex semibaccata nie die terugkeer van inheemse, meerjarige spesies bevoordeel nie, maar dit eerder inhibeer. Aangesien die bo-grond so belangrik is in terme van die grondvrugbaarheid en ook die saadbank wat teenwoordig is, word die invloed van die verwydering en opberging van die bogrond getoets. Die grondvrugbaarheid was bepaal deur groei-toetse op radyse en laboratorium analise op die grond te doen. Die plant spesie diversiteit en rykheid was bepaal met In saad ontkieming studie. In ooreenstemming met die verwagte uitkoms, was die plant spesie diversiteit hoër op die ongemynde bo-grond en die radyse het groter geword op dieselfde grond. Dit kom voor asof die plant spesie diversiteit en rykheid, asook die grond vrugbaarheid afneem met tyd wat die bo-grond geberg word. Die direkte verspreiding van die bo-grond nadat dit verwyder is, sal In medium vir die plante verseker wat nader is aan die vlak voordat die grond versteur is. Dit sal oak sorg vir redelike vinnige en suksesvolle terugkoms van plante op die gemynde grond. Die suksesvolle vestiging van plante hang ook af van die mikro areas (klein areas in terme van die grootte van 'n saad, wat In eie mikro-klimaat vorm), waarna saad versprei word. Die effek van sulke mikro-gebiede op die ontkieming van saad, die groei van die saailinge en die oorlewing van die saailinge was bepaal. Mikro-water- opvanggebiede het in al drie bogenoemde gevalle die hoogste syfers getoon. Die vestiging en oorlewing van saailinge in die ander mikro-gebiede (die area onder enkel struike, die area onder groepe struike en oop areas) het gevarieer afhangend van die hoeveelheid reënval wat ontvang is in die spesifieke jaar. Laastens, is daar ge-eksperimenteer met die oorplant van drie plaaslike, inheemse, sukkulente spesies. Hierdie plante was alleen geplant of in groepies van drie, bymekaar. Die hipotese was dat huloorlewingskanse beter sal wees as hulle saam geplant word. Dit was egter bevind dat die hoeveelheid reënval in 'n spesifieke jaar en die morfologie van die plant, bepaal of hulle sal kompeteer vir die beperkte bronne en of hulle deur saam te groei huloorlewingskanse sal verhoog. Hierdie tesis dra by tot die verstaan van die plantegroei dinamika in die Sukkulente Karoo nadat oppervlak mynbou plaasgevind het. Riglyne vir die rehabilitasie van oppervlak myne, gebasseer op ekologiese prosesse, word ook voorgestel.

Thesis (MSc)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: Bush encroachment in savannas leads to reduced diversity, productivity and profitability of rangelands. This holds important implications for the livestock and eco-tourism industries, as well as for subsistence ranchers in the South African semi-arid savannas, who depend on this vegetation type for economic and livelihood purposes. Soil moisture, nutrients, rue and herbivory are generally regarded as the principal factors determining vegetation structure and function within savannas. The factors and processes involved in the determination of the tree:grass ratio within savannas are, however, not clearly understood. We investigated the role of soil type and management strategy (cattle, game and communal grazing) in the determination of the presence and distribution of plant species in general, and on the presence and distribution of the encroaching tree species, Acacia mellifera, specifically. Both shortand long-term trends were investigated. The study area, the Kimberley Triangle, (Northern Cape Province, South Africa), was ideal for this kind of study because it has different management strategies practised on several soil types, and bush encroachment is a widespread phenomenon. Contrary to the belief that heavy livestock grazing is the main cause of increases in the tree:grass ratio, we found that soil type, through its effects on plant growth and on the presence and availability of soil moisture and nutrients, is more important in determining vegetation composition than management strategy. It was found that the various types of grazing management mainly influenced vegetation structure and function by affecting the competitive interactions between Ns-fixing woody species and non-Ns-fixing grasses. Of the soil factors affecting vegetation composition, soil texture was a good indicator of the physical conditions for plant growth in an area, and also of the presence and availability of soil moisture and nutrients. We found that sand and clay soils are relatively resistant to bush encroachment as compared to loamy-sand and -clay mixes. This is because woody growth is impaired in the first-mentioned habitats by soil texture, soil moisture regimes and heavy utilisation. In soils with combinations of loam, sand and clay, soil texture and moisture are not limiting to woody growth and if the repressive competitive effect of grasses on woody vegetation is removed, opportunities are created for recruitment of woody species and encroachment. Additionally, rockiness increases soil moisture infiltration. In the study area, woody species, and specifically A. mellifera, are associated with these areas. We suggest that in the study area, rocky areas are naturally encroached. This is in agreement with the patchdynamic approach to savanna vegetation dynamics. Because soil moisture is such an important factor in the determination of the tree:grass ratio in the study area, we further suggest that in above-average rainfall years, when soil moisture conditions are optimal for woody seed germination, establishment and growth, heavy grazing should be avoided, as it would provide the opportunity for encroachment. Keywords: Bush encroachment; N2-fixing species; game, cattle, communal grazing; soil texture; soil moisture; soil nutrients; Acacia mellifera; tree-grass competition.
AFRIKAANSE OPSOMMING: Bosindringing in savanna gebiede het verlaagde diversiteit, produktiwiteit en winsgewendheid van natuurlike weivelde tot gevolg. Behalwe dat dit die Suid-Afrikaanse vee- en ekotoerisme bedrywe raak, is verskeie bestaansboerderye afhanklik van die plantegroei-tipe vir oorlewing. Grondvog, grondvoedingstowwe, vuur en beweiding word algemeen aanvaar as die belangrikste faktore wat die struktuur en funksie van savannas bepaal. Daar is egter nog nie duidelikheid oor die prosesse wat betrokke is in die bepaling van die boom-gras verhouding in savannas nie. In dié studie het ons ondersoek ingestel na die invloed van grond tipe en beweidingstrategieë (beweiding deur beeste, wild, of kommunale beweiding) op die algemene verspreiding van verskillende plant spesies, en ook op die van die indringer spesie, Acacia mellifera. Beide kort- en lang-termyn patrone is ondersoek. Die studiegebied, die Kimberley Driehoek in die Noord-Kaap, Suid-Afrika, was ideaal vir so 'n ondersoek omdat verskillende beweiding strategieë op verskeie grond-tipes beoefen word maar bosindringing steeds 'n algemene verskynsel in die gebied is. Ons bevinding was dat, ten spyte van die feit dat daar oor die algemeen geglo word dat swaar beweiding die hoof oorsaak van bosindringing is, grond-tipe belangriker is in die bepaling van die spesie-samestelling van 'n gebied. Dit is as gevolg van die feit dat grond-tipe die groei van plante beïnvloed deur die teenwoordigheid en beskikbaarheid van grondvog en -nutriënte te bepaal. Die verskillende beweidingstrategieë beïnvloed meerendeels die kompetatiewe interaksies tussen N2-bindende hout-agtige spesies teenoor nie-Nj-bindende gras-agtige spesies. Grond-tekstuur was 'n goeie aanduiding van die algemene toestande vir plantegroei en ook van die teenwoordigheid en beskikbaarheid van grondvog en -nutriënte. Ons het bevind dat sand en klei grond, relatief tot leem, sand en klei kombinasies, weerstandbiedend is teen bosindringing as gevolg van die tekstuur, water-regimes en swaar beweidings vlakke wat op die grond-tipes voorkom. Omdat grond-tekstuur en grondvog nie beperkend is op die leem-, sand- en klei-grond kombinasies nie, kan bosindringing maklik hier voorkom as die onderdrukkende effek wat grasse op houtagtige plantegroei het, deur swaar beweiding verwyder word. A. mellifera is ook oor die algemeen met klipperige gebiede geassosieer omdat klipperigheid lei tot verhoogde infiltrasie van grondvog. In die studie-gebied is klipperige areas dan ook van nature ingedring deur A. mellifera. Dit stem ooreen met die siening dat savannas bestaan uit "laslappe" van verskillende plantegroei (patch-dynamic approach). Dit was duidelik dat grondvog 'n belangrike bepalende faktor is in die bepaling van die boom-gras verhouding in die studiegebied. Ons stel dus voor dat in bo-gemiddelde reënval jare, swaar beweiding vermy moet word, omdat houtagtige saailinge gedurende die tydperke maklik kan ontkiem en vestig juis omdat grondvog dan nie beperkend is nie. Sleutelwoorde: Bosindringing; N2-bindende spesies; bees, wild, kommunale beweiding; grond tekstuur; grond-vog; grond-nutriënte; Acacia mellifera; boom-gras kompetisie.

This thesis reports on the findings of a three year study on the economIc aspects of the woodcarving industry in Kenya. Woodcarving provides one of the most important uses of wood in Kenya both in terms of economic returns (export value estimated at US$ 20 million annually) and generation of self-employment opportunities (60,000 carvers and estimated 350,000 dependants). The industry is facing an imminent collapse owing to the depletion of prime carving tree species which has supported it since 1919. The key objectives of the study were; (a) To quantify the diversity of species in trade (volumes) and their pricing trends both for the raw materials and products (carvings); (b) determination of profit margins that accrue from carving activities and prices of these species for alternative uses; (c) to look into the possibility of onfarm production of fast growing species (Azadirachta indica) for carving, as well as Brachylaena huillensis . Each of these was pursued mainly through field surveys at seven main areas where carving is carried out in Kenya. The annual carving volume consumed in Kenya is in excess of 15,000 cubic metres concentrated on about ten tree species. However about 57% of this volume is contributed by Brachylaena huillensis. Diameter profiles of logs of the carving wood is dominated by 10-16 cm diameter timber which is an indication of resource scarcity where juvenile trees are increasingly being targeted. The prices of carving wood are distorted and are far helow the market prices largely due to the prevalence of illegal sourcing from state forests. The study has estimated that the stumpage level for Brachylaena huillensis should be raised from Ksh 4 053 to Ksh 12 000 per m3 if control on the current level of depletion is to be ensured. For the other species, the current stumpage levels need to be raised three fold. The weaknesses of the existing policies and legislation governing the access to carving wood have been examined and appropriate recommendations have been given. However, as a long term measure to benefit the carvers and conservation of the last remaining East African forests, changing buyer and carving wood sourcing behaviour from unsustainable felling of slow growing hardwoods to sustainable on-farm production is discussed. The study demonstrates that Azadirachta indica can attain a carvable size with a dbh of 16 cm in 17 years. The study has also established that potential profits (revenue) which can accrue from carvings made per unit wood volume (one cubic metre of wood or equivalent to about 20 logs of I.Sm long, 20cm diameter) can be as high as Ksh 270,000 within a period of four months. This is about four times the unit value of sawn timber of some of the finest hardwoods in the Kenyan market. The study therefore calls for restrictions on the utilization of these prime carving species on uses other than carving.
Thesis (M.Sc.)-University of Natal, Durban, 2001.

SAPPI SAJCCOR, whose factory is situated south of Durban, South Africa, is one of the few paper and pulp mills that uses the acid sulphite process with calcium and magnesium bases to produce a high-grade cellulose pulp. Four streams of effluent, namely, the calcium - spent liquor stream, the magnesium condensate stream and two streams from the bleaching effluent are produced during this sulphite pulping process and they contain a variety of organic compounds extracted from the wood. Characterisation of the effluent was based on isolation using column chromatography and identification using NMR techniques. A range of constituents, such as lignans and lignin - type precursors, a trilerpenoid and fatty acids were isolated and identified. X-ray diffraction was used to identify an inorganic residue obtained from the calcium - spent liquor stream and gas chromatography/mass spectrometry was used to identify a wax residue. which builds up in the process. In addition to this, the carbohydrate content of the four streams of effluent was detennined using UV/visiblc spectroscopy.
Thesis (M.Sc.)-University of Natal, Durban, 2001.

The wood products industry is influenced heavily by family ownership along the entire value chain. Although family ownership affects each link of the wood products value chain, there has been little research into the importance of products originating from family forestland. Specific attributes of products, such as origin or environmental certification, have been considered part of a business���s marketing strategies. This study evaluates the relevance of family forest wood product origin and environmental certification for Oregon consumers who participated in this study and Oregon specifiers and industrial customers. Data was collected from consumers, and specifiers and industrial customers in Oregon. Conjoint analysis was employed with softwood lumber as the product and price, wood origin, and environmental certification as the features. Results from this analysis for consumers show that wood origin is the most important factor followed by price and environmental certification. However, for specifiers and industrial customers, price is the most important factor followed by environmental certification and wood origin. "Family" is seen as the most preferred wood origin level for both buyer groups in the study.
Graduation date: 2013

Tese de Doutoramento em Ciências Agronómicas e Florestais
O nemátode da madeira do pinheiro, Bursaphelenchus xylophilus, é uma das mais sérias ameaças à floresta de pinheiros a nível mundial. Em Portugal, o nemátode afecta o pinheiro bravo (Pinus pinaster Ait.), uma espécie de coníferas de grande valor económico. Os nemátodes migram através dos canais de resina e alimentam-se de células do parênquima, induzindo rápidas alterações metabólicas nas células do parênquima, áreas de cavitação, desnaturação e necrose do parênquima e células cambiais. O objectivo deste trabalho foi avaliar o impacto das alterações bioquímicas, do stress hídrico na madeira e da perda de produção de resina devidos ao ataque do nematode nas propriedades químicas e físicas da madeira de P. pinaster, nomeadamente, a densidade básica da madeira, a composição química elementar, o teor de extractivos, as propriedades de sorção, o poder calorífico superior (PCS), e a inflamabilidade. Este estudo interdisciplinar salienta os aspectos tecnológicos e económicos relacionados com a aptidão da madeira infectada para uso nas indústrias de processamento de madeira e de produção de bioenergia. Foram estudadas amostras de madeira de P. pinaster infectada com nemátode e não infectada. Árvores sintomáticas (escurecimento/vermelhidão das agulhas) e sem sintomas foram amostradas num povoamento de pinheiro bravo na região centro de Portugal. Foram recolhidas as amostras de seções transversais do tronco (1,5 m, 6 m da base, topo) e de ramos. Para todas as amostras foi realizado o teste de identificação e contagem de nemátodes. Os valores do PCS foram determinados de acordo com a norma CEN/TS-14918 usando o calorímetro de bomba Parr-6300 automático e o calorímetro de bomba Leco- AC600 semiautomático. Na análise da composição química, foram determinados os teores de carbono, hidrogénio, azoto, enxofre e cinzas por meio da combustão instantânea com a oxidação completa. A densidade básica foi calculada com base no peso seco e no volume saturado, sendo o último medido pelo método de imersão. A análise do conteúdo de extractivos foi efectuada recorrendo a um aparelho de extracção de Soxhlet e com base nas normas Tappi 204cm-07 e Tappi 207cm-08, tendo sido utilizados dois reagentes orgânicos (diclorometano e etanol) e um não-orgânico (água destilada). Os testes para determinar a variação de humidade e o teor de humidade de equilíbrio foram realizados na câmara climática Fitoclima-300 EDTU. Os testes de inflamabilidade foram realizados num calorímetro de cone com um fluxo constante de calor de 16 kW/m2. A análise estatística dos dados foi realizada com o software STATISTICA StatSoft Inc. Foram encontradas as seguintes diferenças entre a madeira de P. pinaster infectada e não infectada para os parâmetros estudados. •Verificou-se a diferença estatisticamente significativa para o PCS e os teores de hidrogénio e de azoto, em que a madeira infectada apresenta, em média, menor poder calorífico, menor teor de azoto e maior de hidrogénio. Os teores de carbono, oxigénio, enxofre e cinzas não se diferenciaram significativamente. O valor médio do PCS da madeira infectada (19,79 MJ/kg) posiciona-se entre o PCS de madeira de folhosas (18,6-19,8 MJ/kg) e o PCS de madeira de resinosas (20,0-22,5 MJ/kg). •Verificou-se a diminuição de 2% da densidade básica da madeira, e a diminuição de 8,90% a 5,98% para o teor total de extractivos. Nas árvores infectadas, os extractivos têm distribuição inversa ao longo do tronco comparativamente com as árvores não infectados. •Diferentes valores de humidade de equilíbrio foram obtidos para certas condições ambientais (algumas das diferenças foram estatisticamente significativas). As isotermas de adsorção para a madeira infectada e não infectada têm posicionamento similar. •Verificaram-se diferenças estatisticamente significativas para o tempo de ignição e o tempo em chama, e ligeiras diferenças nos valores de perda de massa. Para todos estes parâmetros, os valores obtidos para a madeira não infectada foram inferiores aos da madeira infectada. •Para a taxa de perda de massa, verificaram-se os valores mais baixos para a madeira infectada para as amostras recolhidas das secções do tronco a 6 e 1,5 m. Já para as secções do topo dos troncos não foram observadas diferenças significativas. •A madeira infectada tem menor taxa de liberação de calor e menor energia total libertada (diminuição estatisticamente significativa) do que a madeira não infectada. Os valores do teor total dos extractivos foram correlacionados (com significância estatística) com os do tempo de ignição, do tempo em chama e da perda de massa. Por fim, foram analisados os impactos socio-económico e ambiental do nemátode no contexto de Portugal. Foram apresentados os principais aspectos e parâmetros a incluir na modelação do impacto total do nemátode, e proposta uma nova abordagem para o controlo da doença da murchidão do pinheiro baseada na estrutura de mosaico florestal com o apoio das actividades económicas relacionadas. Apesar das diferenças verificadas para os parâmetros estudados, a conclusão geral é que o nematode do pinheiro bravo tem um pequeno impacto sobre as características estudadas de madeira. No entanto, existem algumas questões relacionadas com o uso industrial da madeira de P. pinaster infectada (produção de bioenergia, produção de papel e de pasta de papel, ciclo de vida de paletes) que necessitam de estudos adicionais.
The pinewood nematode, Bursaphelenchus xylophilus, is considered one of the most serious threats to pine forest worldwide. In Portugal, this nematode affects maritime pine (Pinus pinaster Ait.): a coniferous species of a great economic value. The nematodes migrating through resin canals and feeding on parenchyma cells, induce rapid metabolic changes in ray parenchyma cells, cavitation areas, denaturation and necrosis of parenchyma and cambial cells. The objective of this research was to evaluate the impact of biochemical changes, water stress and loss of resin production due to nematode attack on the chemical and physical properties of P. pinaster wood, specifically, on wood basic density, elementary chemical composition, content of extractives, sorption properties, gross calorific value (GCV), and flammability. This interdisciplinary study stresses technological and economic aspects related with suitability of infected P. pinaster wood for use in the wood-processing and energy industries. Samples of PWD infected and uninfected wood were studied. P. pinaster trees with PWD symptoms (browning/reddening of the needles) and without symptoms were sampled in a planted pine forest in the central region of Portugal. Cross sections of the trunk at 1.5 m, 6 m from the base, top and crown branches were collected. Nematode screening, identification and quantification were performed for all sampled trees. The GCVs were determined using Parr 6300 automatic isoperibol calorimeter and Leco AC600 Semi-Automatic Isoperibol Calorimeter according to the standard method CEN/TS 14918. Chemical composition analysis was performed by determining the contents of carbon, hydrogen, nitrogen, sulfur and ash on complete and instant oxidation of samples by “flash” combustion. Wood basic density was calculated on the basis of dry weight and green volume, the last one measured by water displacement or immersion method. The extractive content analysis was carried out with a Soxhlet extraction apparatus and based on the norm Tappi 204 cm-07 and Tappi 207 cm-08 norms. Two organic (dichloromethane and ethanol) and a non-organic (distilled water) reagents were used. The tests to determine the moisture content variation end equilibrium moisture content were carried out using a climatic chamber Fitoclima 300 EDTU. Flammability tests were performed in a cone calorimeter at a constant heat flux of 16 kW/m2. Statistical data analysis was performed with STATISTICA StatSoft Inc. software. The following differences for the studied parameters were found between infected and uninfected P. pinaster wood. •Statistically significant difference was found for the GCV and the contents of hydrogen and nitrogen, in which the infected wood has on average lower calorific value, lower nitrogen content and higher hydrogen content. The carbon, oxygen, sulfur and ash contents did not differ statistically. The mean GCV of infected wood (19.79 MJ/kg) varied between the GCV of hardwoods (18.6-19.8 MJ/kg) and the GCV of softwoods (20.0-22.5 MJ/kg). •The wood basic density decreases 2%, and the total extractives content decreases from 8.90% to 5.98%. Extractives in infected trees have inverse distribution along the trunk as compared with uninfected trees. •Differences (some of them statistically significant) in the equilibrium moisture content values, determined under varying environmental conditions, were found. The adsorption isotherms for infected and uninfected wood have similar positioning. •Statistically significant differences were found for time to ignition and time in flame, and slight differences were found for mass loss. For all these parameters, obtained values for uninfected wood were lower than those for infected wood. •Lower values of the mass loss rate were found for infected wood for trunk at 6 and 1.5 m. No differences were observed for top of the trunk. •Statistically significant decrease of the values of the total energy released was found for infected wood. Statistically significant correlation was found between the total extractive content and time to ignition, time in flame and mass loss. Finally, socio-economic and environmental impacts of the PWD in the context of Portugal were analyzed. Framework for modelling of the total PWD impact was presented and new approach for the PWD control, based on forest mosaic structure supported by economic activities, was discussed. Despite the differences verified for studied parameters, the overall conclusion is that PWN has a slight impact on studied characteristics of wood. However, there are some related issues of industrial use of PWN infected P. pinaster wood (bioenergy production, pulp and paper production, pallets life cycle) that need additional studies.

Submitted in fulfillment of the requirements for the Degree of Doctor of Technology: Biological Sciences, M.L. Sultan Technikon, 2002.
The extent of diffusion and surface modification of a purified 23.6 kDa xylanase isolated from Thermomyces lanuginosus on bagasse pulp was evaluated. Polyclonal anti-xylanase antibodies were raised in two rabbits and in conjunction with immunogold labeling and microscopic studies enzyme diffusion and degradation studies were performed. The purity of the xylanase was confirmed by SDS-PAGE and western blots confirmed the antigen-antibody hybrid on the nitrocellulose membrane.
D

Export-oriented illegal logging has been recognized as a major global problem in environmental, social, and economic terms. It has been argued that export-oriented illegal logging does not benefit the community or government that should be benefited by its own natural resources. The emergence of policy initiatives targeting illegal logging could have the potential to increase the competitiveness of legally sourced timber products by removing illegal products from the market of the consuming country. The US Lacey Act amendments of 2008 set a precedent for the global trade in plants and plant products by putting in place incentives for US wood products importing companies to demand legally sourced and traded wood. This research addresses how the 2008 Lacey Act amendments have impacted the US wood industry, and how those affected by the amendments view the future of environmental policy and global illegal logging as impacted by the amendments. The majority of respondents in this study agree that steps should be taken to decrease global illegal logging, but some aren't convinced that the Lacey Act amendments will ultimately have the desired effect. According to this research, most US wood importers have made small changes to their operational practices. This study indicates the possibility that though US wood importers feel the responsibility to ensure their companies are compliant with legislation, they are not sure the 2008 Lacey Act amendments will ultimately hinder global illegal logging. Included in this study are also suggestions from US wood importers regarding policy implementation. These suggestions include an increase in communication between the US government and US wood products companies, an increase in future research, and the possibility of focusing the Lacey Act on certain high-risk regions.
Graduation date: 2012