No description available.

No description available.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1956. / Includes bibliographical references (p. 58-60).

Thesis (MScFor)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Individual tree models, as opposed to stand models, have the potential to greatly improve sensitivity of forest growth models to changing conditions such as silvicultural amendments, irregular stand structures, etc. It was the purpose of this study to extend two sub-components of a European individual tree growth model to introduce individual tree growth modelling concepts in South Africa using Pinus elliottii as a study species. Two main objectives were established: Modelling the potential height of stands across different site qualities and modelling diameter increment using a potential modifier approach with a combination of competition indices that change in importance according to the edaphic conditions of the site. Potential height modelling used three steps in order to achieve this objective. The first was to compare site index models based on different model fitting techniques, namely nonlinear least squares, generalised nonlinear least squares and nonlinear mixed effects models. The nonlinear mixed effects model proved to be superior in terms of achieving the principles of regression assumptions and model fit for the data range observed. The second step was to fit potential height using nonlinear quantile regression on observed spacing trial height measurements. This proved to be a robust technique able to capture potentials according to the defined Chapman-Richards model structure. The final step was to use the predicted site index as a site classification variable in order to predict potential height. While some small deviation occurred, potential height seems to be well correlated to site index and validation on selected sites suggested that site index can be used to model potential height until a more sophisticated site classification model is used for future improvement of the model. Diameter increment modelling followed six major steps in order to apply the full parameterisation methodology of an age-independent diameter increment model dependent on tree diameter and competition. Diameter increment potentials were fit using site index as a predictor of the potential height curves. Multiple competition indices were tested on two sites to obtain a combination of two indices, which can capture overtopping and local crowding effects. Principle components analysis and variance inflation factors calculation were applied to test for collinearity between indices. Suitable combinations were tested resulting in a combination of the KKL and Local Basal Area competition indices. Changing importance of the two indices were observed on the two sites tested indicating a shift in the mode of competition according to a water gradient. These were combined in a deterministic potential modifier model, which mimicked competitive stages over age; however the validation showed a skewed distribution, which was not sensitive to stand density gradients. A stochastic model was constructed to model variance from observed residual plots using linear quantile regression to determine bounds for a truncated normal distribution which generates random deviates for a predicted increment. The stochastic element significantly improved the performance and sensitivity of the model, however the model was still not sensitive enough at very high and very low spacing densities. All in all two key models for an adaptation of an individual tree growth simulator to South African conditions were successfully demonstrated. The two main objectives were achieved; however some indicated improvements could be made, especially for the competition indices where the sensitivity of competition to changing resource limitation according to site and temporal scales needs to be further investigated. Furthermore, the full set of models for simulating individual tree growth still needs to be applied. Overall, as a methodological approach, the study outlined problems and future improvements, introduced new concepts and can serve as a guideline for future parameterisation of an individual tree growth model. / AFRIKAANSE OPSOMMING: In vergelyking met vakgroeimodelle, het individuele-boomgroeimodelle die potensiaal om die sensitiwiteit van plantasiegroeimodelle vir veranderende omstandighede soos aanpassings in boskultuur, onreëlmatige vakstrukture, ensovoorts, drasties te verbeter. Die doel van hierdie studie was om twee subkomponente van ‘n Europese individuele-boomgroeimodel uit te brei om sodoende individuele-boomgroei modelleringskonsepte in Suid-Afrika bekend te stel. Pinus elliottii is gebruik as studiespesie. Twee hoofdoelstellings is bepaal. Eerstens, die modellering van hoogtegroei potensiaal van opstande oor verskeie vlakke van groeiplek kwaliteit. Tweedens, die modellering van deursnee-aanwas deur gebruik te maak van ‘n potensiaal matigingsbenadering “potential modifier approach“ met ‘n kombinasie van kompetisie-indekse waarvan die belangrikheid verander volgens die edafiese toestande van die groeiplek. Die hoogtepotensiaalmodellering bestaan uit drie stappe. Tydens die eerste stap word groeiplek bonniteitsmodelle vergelyk op grond van verskillende modelpassingstegnieke, naamlik nie-lineêre minimum kwadrate, algemene nie-lineêre minimum kwadrate en nie-lineêre gemengde effek modelle. Laasgenoemde het die beste gevaar in terme van die beginsels van regressiemodelle asook die mate waarin die model die waargeneemde data pas. Tweedens is hoogtegroei potensiaal gemodelleer deur nie-lineêre kwantielregressie op waargeneemde hoogtes van spasiëringseksperimente toe te pas. Die metode is robuust en in staat om potensiale volgens die gedefinieerde Chapman Richards modelstruktuur vas te vang. Laastens is die voorspelde bonniteits indeks as ‘n groeiplek klassifasie veranderlike gebruik om sodoende die hoogtegroei potensiaal te voorspel. Alhoewel klein afwykings voorgekom het, blyk hoogtegroei potensiaal goed gekorreleer te wees met bonniteits indeks. Uit validasie op geselekteerde groieplekke blyk dit dat bonniteits indeks gebruik kan word om hoogtegroei potensiaal te modelleer totdat ‘n meer gesofistikeerde groeiplek klassifikasiemodel beskikbaar is wat die model verder sal kan vebeter. Die volledige parametriseringsmetodiek van ‘n ouderdoms-onafhanklike deursnee-aanwas model wat afhanklik is van boomdeursnee en kompetisie bestaan uit ses hoof prosesse. Nie-lineêre kwantielregressie is gebruik om deursnee-aanwaspotensiale te pas vir verskeie groeiplekke. Dié is gekombineer met ‘n bonniteits indeks om ‘n nuwe model te vorm waarmee hoogtegroeipotensiaal kurwes voorpel kon word. Daar is met veelvuldige kompetisie-indekse op twee groeiplekke geëksperimenteer om ‘n kombinasie van slegs twee indekse te vind wat die effekte van oorskaduwing en plaaslike verdringing kan vasvang, te vind. Hoof komponent analise “Principle components analysis” en variansie inflasie faktore berekening “variance inflation factors calculation” is gebruik om vir kollineariteit tussen die indekse te toets. Gepaste indekskombinasies is getoets. ‘n Kombinasie van die KKL en plaaslike basale oppervlakte “Local Basal Area” kompetisie-indekse het die beste resultate gelewer. Die twee indekse is as volg geselekteer. Veranderings in die belangrikheid van elk van die indekse is waargeneem op die twee toetspersele. Dit dui op ‘n verskuiwing in die modus van kompetisie afhangend van ‘n watergradiënt. Die twee indekse is gekombineer in ‘n deterministiese potensiaal matigings model wat die kompeterende stadiums oor ouderdom naboots. Validasie het egter ‘n skewe verdeling wat nie sensitief vir opstandsdigtheidsgradiënte is nie, gewys. ‘n Stogastiese model is ontwikkel om variansie in die residuele grafieke te modelleer. Lineêre kwantielregressie is gebruik om grense vir ‘n afgestompte normaalverdeling wat ewekansige afwykings vir ‘n voorspelde aanwas te bepaal. Die stogastiese element het die prestasie van die deterministiese model merkbaar verbeter. Selfs met die stogastiese element, is die model egter steeds nie sensitief genoeg vir baie hoë en baie lae opstandsdigthede nie. Ter opsomming is twee modelle vir ‘n aanpassing van ‘n individuele-boomgroeisimuleerder vir Suid- Afrikaanse toestande suksesvol gedemonstreer. Die twee hoofdoelstellings is bereik. Daar is egter steeds ‘n paar aangeduide verbeterings wat aangebring kan word. Die sensitiwiteit van die kompetisie-indekse op hulpbronbeperkings wat verander op grond van die ruimtelike en temporale skale moet veral verder bestudeer word. Verder moet die volle stel modelle wat benodig word om individuele-boomgroei te modelleer nog toegepas word. As ‘n metodologiese benadering, het die studie probleme uitgewys en toekomstige verbeterings aangedui, nuwe konsepte bekendgestel en kan dus dien as ‘n riglyn vir toekomstige parametrisering van individuele-boomgroeimodelle.

A produção de criogéis de celulose para adsorção de petróleo torna-se um estudo interessante, já que a celulose é uma fonte econômica, renovável, biodegradável e abundante no meio ambiente. Dentro deste contexto, o objetivo do presente trabalho foi desenvolver criogéis de celulose com capacidade de adsorção de petróleo e resistência mecânica. Para isso, nessecitou-se da utilização de tratamentos químicos como a silanização e a adição de hidróxido de sódio (NaOH) nas concentrações de 4 e 8% (m/m). Na silanização dois métodos foram estudados: a adição de metiltrimetoxisilano (MTMS) à suspenão de celulose e a deposição a vapor de MTMS no criogel. A suspensão de celulose foi obtida a partir de fibrilação mecânica de 1,5% (m/m) de celulose fibra longa não branqueada (FLNB) da espécie Pinus elliottii por 5 h a 2500 rpm. A suspensão foi então congelada a -80ºC por 24 h e então liofilizada a – 40ºC por 70 h. Diversos ensaios de caracterização foram realizados nos criogéis, entre eles: massa específica e porosidade, microscopia eletrônica de varredura por emissão de campo (MEV-FEG), difração de raios-X (DRX), índice de cristalinidade, espectroscopia de infravermelho com Transformada de Fourier (FTIR), compressão, hidrofobicidade, capacidade de adsorção e dessorção, cinéticas e isotermas de adsorção. Entre os métodos de silanização, a deposição a vapor de MTMS apresentou os maiores valores de capacidade de adsorção experimental homogênea (65,18 g.g-1) e heterogênea (68,42 g.g-1). Em relação à adição de NaOH, o criogel produzido com adição de 4% apresentou uma resistência à compressão 28% maior que o criogel sem tratamento. Com isso, o estudo do processo de adsorção foi realizado com o criogel produzido com 4% de NaOH e deposição a vapor de MTMS (FLNB-4D). A capacidade de adsorção experimental heterogênea e a resistência à compressão do criogel FLNB-4D foram de 21,80 g.g-1e 93,16 kPa, respectivamente. No estudo da cinética o modelo que mais se ajustou ao processo foi pseudossegunda ordem e para o estudo do equilíbrio de adsorção foi Langmuir. Por fim, conclui-se que o processo de adsorção de petróleo pelo criogel de celulose pode ser definido como fisissorção e ocorre em monocamada. Além de que, o criogel de celulose desenvolvido no presente trabalho apresenta-se adequado para a utilização na adsorção de petróleo. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-09-21T17:36:25Z No. of bitstreams: 1 Dissertacao Lidia Kunz Lazzari.pdf: 2711668 bytes, checksum: b1ec6ddc08b2f61fd363bf64acaa5662 (MD5) / Made available in DSpace on 2017-09-21T17:36:25Z (GMT). No. of bitstreams: 1 Dissertacao Lidia Kunz Lazzari.pdf: 2711668 bytes, checksum: b1ec6ddc08b2f61fd363bf64acaa5662 (MD5) Previous issue date: 2017-09-21 / The production of cellulose cryogels for oil adsorption becomes an interesting study since cellulose is an economical, renewable, biodegradable and abundant source in the environment. Within this context, the aim of the present work was to develop cellulose cryogels with oil adsorption capacity and mechanical strength. The use of chemical treatments such as silanization and the addition of sodium hydroxide (NaOH) at concentrations of 4 and 8% (m/m) were used. In the silanization two methods were studied: the addition of methyltrimethoxysilane (MTMS) to cellulose suspension and the vapor deposition of MTMS in the cryogel. The cellulose suspension was obtained from mechanical fibrillation of 1.5% (w/w) unbleached long fiber cellulose (FLNB) of Pinus elliottii for 5 h at 2500 rpm. The suspension was then frozen at -80°C for 24 h and then freeze-drying at -40°C for 70 h. Various characterization assays were performed on the cryogels, including: specific mass and porosity, field emission scanning electron microscopy (FEG-SEM), X-ray diffraction (XRD), crystallinity index, Fourrier transform infrared spectroscopy (FTIR), compression, hydrophobicity, adsorption and desorption capacity, adsorption kinetics and isotherms. Among the silanization methods, the vapor deposition of MTMS presented the highest values of homogeneous (65.18 g.g-1) and heterogeneous (68.42 g.g-1) experimental adsorption capacity. About the addition of NaOH, 4% added cryogel exhibited a 28% higher compressive strength than untreated cryogel. Thus, the adsorption process was performed with cryogel produced with 4% NaOH and vapor deposition of MTMS (FLNB-4D). The heterogeneous experimental adsorption capacity and the compressive strength of the FLNB- 4D cryogel were 21.80 g.g-1 and 93.16 kPa, respectively. In the study of the kinetics, the model that best fitted the process was pseudosecond order and for the study of the adsorption equilibrium was Langmuir. Finally, it is concluded that the process of adsorption of oil by cellulose cryogel can be defined as physisorption and occurs in monolayer. In addition, the cellulose cryogel developed in the present work is suitable for use in the adsorption of petroleum.

A produção de criogéis de celulose para adsorção de petróleo torna-se um estudo interessante, já que a celulose é uma fonte econômica, renovável, biodegradável e abundante no meio ambiente. Dentro deste contexto, o objetivo do presente trabalho foi desenvolver criogéis de celulose com capacidade de adsorção de petróleo e resistência mecânica. Para isso, nessecitou-se da utilização de tratamentos químicos como a silanização e a adição de hidróxido de sódio (NaOH) nas concentrações de 4 e 8% (m/m). Na silanização dois métodos foram estudados: a adição de metiltrimetoxisilano (MTMS) à suspenão de celulose e a deposição a vapor de MTMS no criogel. A suspensão de celulose foi obtida a partir de fibrilação mecânica de 1,5% (m/m) de celulose fibra longa não branqueada (FLNB) da espécie Pinus elliottii por 5 h a 2500 rpm. A suspensão foi então congelada a -80ºC por 24 h e então liofilizada a – 40ºC por 70 h. Diversos ensaios de caracterização foram realizados nos criogéis, entre eles: massa específica e porosidade, microscopia eletrônica de varredura por emissão de campo (MEV-FEG), difração de raios-X (DRX), índice de cristalinidade, espectroscopia de infravermelho com Transformada de Fourier (FTIR), compressão, hidrofobicidade, capacidade de adsorção e dessorção, cinéticas e isotermas de adsorção. Entre os métodos de silanização, a deposição a vapor de MTMS apresentou os maiores valores de capacidade de adsorção experimental homogênea (65,18 g.g-1) e heterogênea (68,42 g.g-1). Em relação à adição de NaOH, o criogel produzido com adição de 4% apresentou uma resistência à compressão 28% maior que o criogel sem tratamento. Com isso, o estudo do processo de adsorção foi realizado com o criogel produzido com 4% de NaOH e deposição a vapor de MTMS (FLNB-4D). A capacidade de adsorção experimental heterogênea e a resistência à compressão do criogel FLNB-4D foram de 21,80 g.g-1e 93,16 kPa, respectivamente. No estudo da cinética o modelo que mais se ajustou ao processo foi pseudossegunda ordem e para o estudo do equilíbrio de adsorção foi Langmuir. Por fim, conclui-se que o processo de adsorção de petróleo pelo criogel de celulose pode ser definido como fisissorção e ocorre em monocamada. Além de que, o criogel de celulose desenvolvido no presente trabalho apresenta-se adequado para a utilização na adsorção de petróleo. / The production of cellulose cryogels for oil adsorption becomes an interesting study since cellulose is an economical, renewable, biodegradable and abundant source in the environment. Within this context, the aim of the present work was to develop cellulose cryogels with oil adsorption capacity and mechanical strength. The use of chemical treatments such as silanization and the addition of sodium hydroxide (NaOH) at concentrations of 4 and 8% (m/m) were used. In the silanization two methods were studied: the addition of methyltrimethoxysilane (MTMS) to cellulose suspension and the vapor deposition of MTMS in the cryogel. The cellulose suspension was obtained from mechanical fibrillation of 1.5% (w/w) unbleached long fiber cellulose (FLNB) of Pinus elliottii for 5 h at 2500 rpm. The suspension was then frozen at -80°C for 24 h and then freeze-drying at -40°C for 70 h. Various characterization assays were performed on the cryogels, including: specific mass and porosity, field emission scanning electron microscopy (FEG-SEM), X-ray diffraction (XRD), crystallinity index, Fourrier transform infrared spectroscopy (FTIR), compression, hydrophobicity, adsorption and desorption capacity, adsorption kinetics and isotherms. Among the silanization methods, the vapor deposition of MTMS presented the highest values of homogeneous (65.18 g.g-1) and heterogeneous (68.42 g.g-1) experimental adsorption capacity. About the addition of NaOH, 4% added cryogel exhibited a 28% higher compressive strength than untreated cryogel. Thus, the adsorption process was performed with cryogel produced with 4% NaOH and vapor deposition of MTMS (FLNB-4D). The heterogeneous experimental adsorption capacity and the compressive strength of the FLNB- 4D cryogel were 21.80 g.g-1 and 93.16 kPa, respectively. In the study of the kinetics, the model that best fitted the process was pseudosecond order and for the study of the adsorption equilibrium was Langmuir. Finally, it is concluded that the process of adsorption of oil by cellulose cryogel can be defined as physisorption and occurs in monolayer. In addition, the cellulose cryogel developed in the present work is suitable for use in the adsorption of petroleum.

In recent years research has shown that exposing seed to smoke or smoke solutions results in increased germination of some, but not all the species tested. Tests showed that exposing seeds of some commercial crops to smoke increased early plant growth. The stimulatory effects of smoke were shown to benefit the germination of species regardless of whether or not fire played a part of the species ecological cycle. In commercial forest nurseries any method of increasing the recovery rate of seed presents opportunities for realising savings of related production costs. Greater recovery rates of genetically improved seed present opportunities for capturing more related growth in field operations. Improving efficiencies of seed recovery at an early point in the production chain have multiplied effects further on down the chain. Two species of pine, namely Pinus taeda and Pinus elliottii that do not generally present high rates of germination were selected to test if applications of smoke solution could increase germination or emergence rates by more than 5%. As seed of both species are known to respond positively to existing seed pre-treatments the effects of smoke needed to be tested in combination, and apart from the pre-treatments. A secondary aim of the study was to examine the effect of smoke on early plant growth. Attempts to optimizes the concentration of the smoke solution were not undertaken as part of this study, as a rinsing treatment, included in the trials, is known to remove any inhibitory effects of a high concentration of the smoke solution. Tests to determine the variability of the seedlots was carried out for statistical purposes. The interaction between smoke application and pre-treatments were tested, firstly in Petri dishes under controlled environmental conditions, and then in nursery trays under standard commercial nursery conditions for both species. The inclusion of smoke in combination with the target moisture stratification (TMS and rinse pre treatment) had a significantly positive effect on P. taeda in a controlled environment. The same combination did not yield a positive results when tested under nursery conditions. Recommendations are made regarding future tests to see if the beneficial combination found in the controlled environment could be replicated under nursery conditions. Further motivation for conducting the tests exists in that the particular combination set gave significantly better early plant growth under nursery conditions. No other combinations tested yielded positive results. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

The global paleoclimate archive is lacking in tropical dendrochronology studies as a result of limitations from inconsistent tree-ring production imposed by precipitation-driven seasonality. The slash pine, Pinus elliottii Engelm. var. densa, is the dominant canopy species of Big Pine Key (BPK) rocklands and has been shown to produce complicated, but distinct, ring structures; however, traditional dendrochronology studies have not established correlations between ring width measurements and major climate drivers controlling South Florida precipitation. My study utilized the carbon (δ13C) and oxygen (δ18O) isotope records in the α-cellulose component of tree-rings to extract information about the physiological responses of trees to climate and tropical cyclone activity. The δ13C measurements in the earlywood and latewood of four P. elliottii var. densa trees were used to build a chronology (1922-2005) and to distinguish annual growth from intra-annual density fluctuations (IADFs). Empirical orthogonal functions were used to determine individual response to precipitation, El Niño-Southern Oscillation (ENSO), and the Atlantic Multidecadal Oscillation (AMO). There is a distinct relationship between the δ13C values of cellulose and ENSO; however the nature (direct vs. inversely correlated) is temporally controlled by the prevailing phase of the AMO. The appearance of some IADFs coincide with the timing of El Niño winters occurring during the cool AMO phase, resulting in enriched δ13C values. The additional precipitation may encourage tree growth, but subsequent dry periods may slow growth and cause the tree to employ water-conservation strategies. Tree growth is influenced by the major climate drivers and the control they exert over the timing of precipitation; however, growth is ultimately controlled by the microenvironment surrounding individual trees. The δ18O and δ13C values of the latewood cellulose were compared to tropical cyclone activity occurring within a 100km radius of BPK. Tropical storms and depressions appeared as anomalously depleted values in the δ18O residual record, reflecting large amounts of tropical rain. The effects of hurricanes varied by storm; however, many of the major hurricanes (category 3-5) were preserved as an enrichments in the δ13C value of the following earlywood season. The application of stable isotope analyses greatly increases the breadth of paleoclimate information available from the trees.

The forest product industry is keenly interested in extending the normal planting season, as well as in the comparative field performance of standard nursery bare-root seedlings and containerized rooted cuttings. The effect of seasonal planting dates on survival, above and belowground biomass allocation, water relations, gas exchange attributes and foliar carbon isotope composition (δ13C) of two stock types of slash pine (Pinus elliottii Engelm.) were examined. Slash pine bare-root seedlings (BRS) and containerized rooted cuttings (CRC) were hand planted in September, November, January, March and April in three consecutive planting seasons (2000-2001, 2001-2002 and 2002-2003) on three sites with silt loam topsoils in southwestern Louisiana. First-year mean survival of CRC across all planting dates and sites was consistently high at 96 to 98%, whereas BRS survival was significantly (P < 0.0001) lower at 59 to 81% and highly variable among study sites and dates through three planting seasons. Generally, there was a negative relationship between soil moisture at the time of planting and first-year survival of BRS planted September through March in 2001-2002 and 2002-2003 planting seasons, whereas the opposite was observed only for BRS planted in April 2002 and 2003. Survival of CRC was affected very little by the variation in soil moisture. Containerized rooted cuttings had higher early above and belowground biomass, and height and diameter than did BRS. However, three years after planting the size differences between stock types disappeared or became negligible. Early size differences among trees planted September through March also decreased after three years, although September trees were tallest. Growth of the April-planted trees was poor compared to trees planted in other months. Late-planted April trees had higher δ13C values, and higher water-use efficiency in the first growing season compared to earlier planted trees. Differences in δ13C values among the planting dates disappeared in the second growing season. Net photosynthesis rates did not differ considerably between stock types or among planting dates in the second and third growing seasons. This study indicates that it is possible to extend the planting season to as early as September and as late as March by using CRC.

The forest product industry is keenly interested in extending the normal planting season, as well as in the comparative field performance of standard nursery bare-root seedlings and containerized rooted cuttings. The effect of seasonal planting dates on survival, above and belowground biomass allocation, water relations, gas exchange attributes and foliar carbon isotope composition (&#948;13C) of two stock types of slash pine (Pinus elliottii Engelm.) were examined. Slash pine bare-root seedlings (BRS) and containerized rooted cuttings (CRC) were hand planted in September, November, January, March and April in three consecutive planting seasons (2000-2001, 2001-2002 and 2002-2003) on three sites with silt loam topsoils in southwestern Louisiana. First-year mean survival of CRC across all planting dates and sites was consistently high at 96 to 98%, whereas BRS survival was significantly (P < 0.0001) lower at 59 to 81% and highly variable among study sites and dates through three planting seasons. Generally, there was a negative relationship between soil moisture at the time of planting and first-year survival of BRS planted September through March in 2001-2002 and 2002-2003 planting seasons, whereas the opposite was observed only for BRS planted in April 2002 and 2003. Survival of CRC was affected very little by the variation in soil moisture. Containerized rooted cuttings had higher early above and belowground biomass, and height and diameter than did BRS. However, three years after planting the size differences between stock types disappeared or became negligible. Early size differences among trees planted September through March also decreased after three years, although September trees were tallest. Growth of the April-planted trees was poor compared to trees planted in other months. Late-planted April trees had higher &#948;13C values, and higher water-use efficiency in the first growing season compared to earlier planted trees. Differences in &#948;13C values among the planting dates disappeared in the second growing season. Net photosynthesis rates did not differ considerably between stock types or among planting dates in the second and third growing seasons. This study indicates that it is possible to extend the planting season to as early as September and as late as March by using CRC.