Teses / dissertações sobre o tema "Black wattle"

This thesis explores the effect of Acacia mearnsii on streamflow in the Eastern Cape. There is a need for data on the localised effects of removing alien trees from the riparian zones within the Fynbos Biome. Fynbos catchments throughout the Western and Eastern Cape yield large quantities of good quality water which is an essential resource in the region. To convince local land owners to manage their riparian zones, small scale experimental results will prove invaluable to assure them of the immediate advantages for themselves and for downstream water users. Three permanent weirs were built 500 m apart to monitor the effect of removing A. mearnsii on streamflow in the Sand River, Eastern Cape. Consecutive weirs allowed for the comparison of streamflow between a cleared and uncleared section of the river without significant differences in riparian conditions, channel morphology and vegetation densities. A site survey confirmed comparable densities of A. mearnsii in both sections. A sample of trees was weighed and a relationship was found between diameter at breast height and above ground wet biomass. Between the first two weirs, 2.5 ha of riparian zone was cleared amounting to approximately 160tlha. Streamflow was monitored from the 10th of January 1996 to the 9th of September 1996. The average streamflow reduction for the duration of the experiment was 15.1 m³/ha/day or 551 mm per annum. Initially, after a period of above average rainfall, streamflow was augmented by discharge from the riparian zone but as conditions dried out, there was a net uptake of water with the highest average uptake of 23. 7m³/ha/day in June. A comparison between weather conditions and streamflow reduction indicated there is a complex relationship, with evidence of A. mearnsii exhibiting control of water loss during dry conditions. Acacia mearnsii trees in the riparian zone have been shown to cause significant streamflow reduction. Permanent weirs were found to be appropriate for this type of study. There is a need for further research on the effect of alien trees in riparian zones around South Africa as there is potential for significant increases in streamflow.

The black wattle (Acacia mearnsii De Wild.), it is constituted on second main forest essence planted in Rio Grande do Sul, just losing for the Eucalyptus. The culture of that species is of fundamental importance for the tannin industries, foils and cellulose in the state, front to the good results economical coming of the exploration of the same, because the peel is sold for the extraction of tannins and the wood is marketed for conversion in cellulose, foils and energy. The black wattle has been considered as one of the main planting alternatives in the agricultural area of the state. In the present work, it was studied the productivity of the Acacia mearnsii De Wild. (black wattle) in function of different spacings, with initial base of one thousand hundred sixty trees, distributed in five treatments and three repetitions, originated of research developed jointly among the Empresa SETA (Sociedade Extrativa de Tanino de Acácia Ltda.) and the Centro de Pesquisas Florestais (Cepef) of Universidade Federal de Santa Maria (Santa Maria-RS), in the district of Capão Comprido belonging to the municipal district of Butiá-RS, in area of the company. The company uses a spacing of 3,0 m x 1,33 m in their plantings, for accomplishing them with machine, however the results obtained in the test d.m.s. they point that for the united analysis of the treatments analyzed in the period from 2002 to 2004, the volumetric average of the treatment 5 differs statisticaly of all the other ones; the treatments 1, 4 and 3 don't differ statisticaly amongst themselves and the treatment 2 differs statisticaly of all the other ones at the level of significance of 5%, being concluded the treatment 5 as soon as (3,0 m x 2,50 m) it is the most suitable for the planting of the black wattle (Acacia mearnsii De Wild.), tends in view the largest volumetric average. In the aspect regarding the analyzed period, the results obtained in the test d.m.s. they appear that so much for the analysis individual as united of the treatments, the three years-old volumetric averages differ statisticaly amongst themselves at the level of significance of 5%, and the year of 2004 in all of the treatments presented the largest volumetric average
A acácia negra (Acacia mearnsii De Wild.), constitui-se na segunda principal essência florestal plantada no Rio Grande do Sul, perdendo apenas para o Eucalipto. A cultura dessa espécie é de fundamental importância para as indústrias de tanino, chapas e celulose no Estado, frente aos bons resultados econômicos advindos da exploração da mesma, pois a casca é vendida para a extração de taninos e a madeira é comercializada para conversão em celulose, chapas e energia. A acácia negra tem sido considerada como uma das principais alternativas de plantio na área agrícola do Estado. No presente trabalho, foi estudada a produtividade da Acacia mearnsii De Wild. (acácia negra) em função de diferentes espaçamentos, com base inicial de hum mil cento e sessenta árvores, distribuídas em cinco tratamentos e três repetições, originadas de pesquisa desenvolvida conjuntamente entre a Empresa SETA (Sociedade Extrativa de Tanino de Acácia Ltda.) e o Centro de Pesquisas Florestais (Cepef) da Universidade Federal de Santa Maria (Santa Maria RS), no distrito de Capão Comprido pertencente ao município de Butiá-RS, em área da Empresa. A empresa utiliza um espaçamento de 3,0 m x 1,33 m em seus plantios, por realizá-los com máquina, no entanto os resultados obtidos no teste d.m.s. apontam que pela análise conjunta dos tratamentos analisados no período de 2002 a 2004, a média volumétrica do tratamento 5 difere estatisticamente de todos os outros; os tratamentos 1, 4 e 3 não diferem estatisticamente entre si e o tratamento 2 difere estatisticamente de todos os outros ao nível de significância de 5%, concluindo-se assim que o tratamento 5 (3,0 m x 2,50 m) é o mais indicado para o plantio da acácia negra (Acacia mearnsii De Wild.), tendo em vista a maior média volumétrica. No aspecto referente ao período analisado, os resultados obtidos no teste d.m.s. apontam que tanto pela análise individual quanto conjunta dos tratamentos, as médias volumétricas dos três anos diferem estatisticamente entre si ao nível de significância de 5%, sendo que o ano de 2004 em todos os tratamentos apresentou a maior média volumétrica

O objetivo deste estudo foi avaliar a dinâmica do crescimento em consórcios de Eucalyptus globulus e Acacia mearnsii e suas interações. O experimento foi instalado no ano de 2005, em duas fazendas localizadas no município de Piratini - RS, onde foram plantadas as espécies Eucalyptus globulus (E) e Acacia mearnsii (A), em monocultivo (100%E e 100%A) e consorciadas em linhas simples (50%E:50%A - LS) e em linhas duplas (50%E:50%A - LD). Para avaliarmos os efeitos dos consórcios no crescimento das espécies, os tratamentos foram analisados nos anos de 2006, 2007, 2008, 2010 e 2013; no ano de 2014 foi realizada a cubagem pelo método de Smalian e a determinação da biomassa de folhas, galhos, lenho e total e do índice de área foliar (IAF) pelo método destrutivo. A classificação da capacidade produtiva das espécies foi realizada pelo método da curva-guia em função da altura dominante (Hd) e idade. Foram testados três diferentes modelos de crescimento, seis modelos de equações hipsométricas e o modelo de Clutter para a estimação e predição da produtividade por unidade de área. Além disso, foi realizada a modelagem da distribuição diamétrica a partir da estimação dos parâmetros da função densidade de probabilidade (f.d.p.) Weibull de dois parâmetros e testado o emprego das redes neurais artificiais (RNA) para a estimação da altura. A acácia-negra teve seu crescimento em altura beneficiado pelo consórcio, já para o eucalipto não foi possível observar vantagens no crescimento em altura. O DAP para ambas espécies foi influenciado pelos consórcios, positivamente para a acácia-negra e negativamente para o eucalipto, diferenças que são explicadas pelas variações dos espaçamentos proporcionadas ao se manter o espaçamento convencional de plantio das espécies nos tratamentos consorciados. O volume individual teve alta correlação com o DAP (0,92). A produtividade da acácia-negra nos consórcios foi superior a 50% a da monocultura, o que não ocorreu para o eucalipto. As produtividades totais dos consórcios foram iguais estatisticamente as das monoculturas. Os sistemas consorciados foram eficazes em diminuir a mortalidade da acácia-negra. Quando analisada a compartimentalização da biomassa individual acima do solo e o IAF, não foram encontradas diferenças significativas entre os modelos de consórcio e as monoculturas. A classificação da capacidade produtiva das espécies pelo método da curva-guia mostrou-se eficiente, sendo capaz de classificar os tratamentos em diferentes sítios de produção, demonstrando a relação das variáveis do povoamento com a capacidade produtiva dos locais. O único modelo, de crescimento e de relação hipsométrica, que foi capaz de estimar as variáveis com precisão foi o de Chapman-Richards e o H∼∫ (DAP, Hd, AS, Idade), respectivamente. O modelo de Clutter foi indicado tanto para os modelos de consórcio quanto para os monocultivos. A f.d.p. Weibull de dois parâmetros captou de forma precisa a distribuição dos diâmetros e o sistema de equações proposto para a recuperação dessa distribuição pode ser empregado nas diferentes situações de manejo testadas. As RNA possuem potencial de uso para a estimação da altura em monocultivos de eucalipto e acácia-negra, bem como nos consórcios entre essas espécies, gerando estimativas precisas e com pequena tendenciosidade.
The objective of this study was to evaluate the growth dynamics in a mixed-species plantations of Eucalyptus globulus and Acacia mearnsii and their interactions. The experiment was installed in 2005, on two farms in municipality of Piratini - RS, where was planted the species Eucalyptus globulus (E) and Acacia mearnsii (A), in monoculture and mixed in simple lines (50%E:50%A - LS) and double lines (50%E:50%A - LD). To evaluate the effects of mixed-plantings in the growth of the species, the treatments was analysed in 2006, 2007, 2008, 2010 and 2013; in 2014 was realized the volume evaluation by the Smalian method and the determining of the biomass of leaves, twigs, wood and total and the leaf area index (LAI) by the destructive method. The site index of each species was realized by the guide-curve method in function of the dominant height (Hd) and ages. Three different growth models, six different height-diameter models and the Clutter model to estimate and predict the productivity per unit area, were tested. Moreover, modeling the diametric distribution as of the estimation of the parameters of the probability density function two parameters Weibull and the use of the artificial neural network (ANN) for the height estimate was tested. The black wattle had their height growth benefited for the mixed-plantations, for eucalyptus was not observed advantages in height growth. The DBH was influenced by the mixed-plantings for both species, positively to the black wattle and negatively for eucalyptus, differences that are explained by variations in spacing provided to keep the conventional spacing of planting the species in the intercropping treatments. The individual volume had high correlation with DBH (0,92). The productivity of black wattle in the mixed-plantings was higher than 50% of monoculture, which did not occur for eucalyptus. The total productivity of mixed-plantings were statistically equal the monocultures. Mixed-plantings were effective in reducing mortality of black wattle. When analyzing the compartmentalization of the individual aboveground biomass and the IAF, there were no significant differences between the mixedplantings models and monocultures. The site index classification of the species using the guide-curve method was effective, being able to classify out the treatments at different production indexes, showing the relation between the stand variables and productive capacity of local. The only model of growth and height-diameter ratio, which was able to estimate the variables with accuracy was the Chapman-Richards and H∼∫(DBH, Hd, AS, Age), respectively. The Clutter model was indicated both for the models of mixed-plantings as for the monocultures. The probability density function two parameters Weibull represented accurately the distribution of diameters and the system of equations proposed for the recovery of this distribution can be used in different management situations tested. The ANN have potential use for the estimation of height in eucalyptus and black wattle monocultures and in mixed-plantations with these species, with accurate and little bias estimates.

Neste estudo a dinâmica de quebra de galhos de acácia negra foi investigada com análise de séries temporais e modelagem ecológica, em conjunto de dados obtidos durante oito anos, visando compreender como se dá o comportamento de Oncideres impluviata (Colepotera, Cerambycidae) em diferentes áreas de plantios florestais, em fazendas localizadas em diferentes municípios do Rio Grande do Sul. A diversidade de cerambicídeos também foi analisada em duas fazendas localizadas no município de maior abundancia de O. impluviata. Os resultados sugerem que a maior abundância de galhos quebrados se dá em Cristal e Encruzilhada do Sul. O município de Piratini exibiu menor densidade de galhos quebrados, entretanto, a projeção dos valores médios de galhos seguiu um padrão aparentemente exponencial para Cristal e Encruzilhada do Sul e sigmóide para Piratini. As funções de autocorrelação e autocorrelação parcial não evidenciaram claras tendências de ciclos nas séries para os três municípios, mas as tendências de ocorrência de picos similares aos surtos diferiram nos três municípios quando a análise espectral foi aplicada. A dinâmica analisada pela equação de Ricker indicou a ocorrência de equilíbrio estável, ciclo limite e comportamento caótico nos três municípios, porém, com menor prevalência de caos em Piratini. A migração espacial mostrou maior poder de estabilização populacional em Cristal e Encruzilhada do Sul em razão das maiores taxas de crescimento presentes nestes municípios. Quinze espécies de cerambicídeos foram encontradas em duas fazendas pertencentes ao município de Encruzilhada do Sul e Oncideres impluviata, Nesozineus alphoides e Ygapema delicata foram as espécies de cerambicídeos mais abundante nas áreas analisadas. As curvas de rarefação atingiram assíntotas de forma satisfatória, comprovando a suficiência do esforço amostral.
In this study, the dynamics of black wattle broken branches was investigated with time series analysis and ecological modeling in dataset obtained during eight years, in order to understand how O. impluviata (Coleoptera, Cerambycidae) behaves in different forests placed in farms of different municipalities of the Rio Grande do Sul, Brazil. The diversity of cerambycids wal also analysed in two farms placed in the municipality with the highest abundance of O. impluviata. The results suggest that higher abundance of broken branches occurs in Cristal and Encruzilhada do Sul. Piratini exhibited the lowest density of broken branches, however, the projection of mean values of branches followed an apparently exponential pattern in Cristal and Encruzilhada do Sul and sigmoid in Piratini. The autocorrelation and partial autocorrelation functions did not show clear trends of cycles in the series of the three municipalities, but the peak occurrence trends similar to the outbreaks differed in the three municipalities when the spectral analysis was applied. The dynamics analysed with the Ricker equation indicated stable equilibrium, limit cycle and chaos in the three municipalities, but, with lower prevalence in Piratini. The spatial migration showed higher power to stabilize population in Cristal and Encruzilhada do Sul in response to high growth rates in these municipalities. Fifteen species of cerambycids were found in the two farms in Encruzilhada do Sul and O. impluviata, Nesozineus alphoides and Ygapema delicate were the most abundant species in the areas. The rarefaction curves showed satisfactory asymptotes, confirming the adequacy of the sampling effort.

A preservação ambiental e o uso de combustíveis fósseis para geração de energia têm estimulado a realização de pesquisas na busca de alternativas para a redução das emissões de gases poluentes como CO2, CO, SO2 e NOx. O uso da biomassa em sistemas de co-combustão em leito fluidizado é mencionado como uma destas alternativas. O presente trabalho utilizou biomassa residual da indústria de extração de tanino, o Resíduo de Cascas de Acácia Negra (RCAN), em conjunto com carvão mineral da Mina de Candiota – RS com o objetivo de estudar a fluidodinâmica entre diferentes composições destes materiais em sistema de leito fluidizado com areia em escala de laboratório e em uma unidade piloto. Também foi realizada a avaliação dos parâmetros operacionais e das emissões dos gases gerados na co-combustão das misturas em planta piloto com reator de leito fluidizado borbulhante. Durante a fluidização no sistema de escala laboratorial, os valores da velocidade mínima de fluidização, Umf, variaram consideravelmente com o aumento da concentração de RCAN no leito em relação à fluidização utilizando-se somente o carvão mineral Da mesma forma, a queda de pressão, ΔP, diminuiu com o aumento da concentração da biomassa no leito. Nas operações de co-combustão em planta piloto, as misturas de carvão mineral e RCAN necessitaram de menores porcentagens de excesso de ar (99,7% a 65,2%) no reator em comparação à queima apenas de carvão mineral (108,4% a 107,5%) para que se atingisse a temperatura de operação do leito. Em particular, a condição de maior quantidade de biomassa na alimentação pode se observar a menor porcentagem de excesso de ar (50,8%). Ainda, a co-combustão do RCAN com carvão mineral favoreceu a diminuição das concentrações de SO2 nos gases gerados em mais de 90%, mantendo as emissões em níveis aceitáveis conforme os limites de emissão estabelecidos pela resolução CONAMA Nº 436, de 22/12/2011 e Resolução SEMA Nº 016 de 2014.
The environmental issues brought by the use of fossil fuels for power generation have led to the development of research in the exploration for alternatives to reduce emissions of greenhouse gases or pollutants such as CO2, CO, SO2, and NOx. The biomass use in cofiring systems with fluidized bed has been mentioned as one of these alternatives. The present work used biomass waste from tannin extraction industry, Black Wattle Bark Waste (BWBW), jointly with coal for the purpose of studying the fluid dynamics biomass mixtures with coal and sand in different proportions of the materials in laboratory scale fluidized bed system. Also, operational parameters and emissions generated in a cofiring pilot plant with bubbling fluidized bed reactor were evaluated. The fluidization tests performed on a bench scale showed that the values of the minimum fluidization velocity, Umf, varied considerably with increasing concentration of BWBW compared with the fluidization of coal. Likewise, the pressure drop through the bed, ΔP, decreased with increasing concentration of biomass in the bed. In the cofiring operations, coal and mixtures BWBW required smaller percentages of excess air in the reactor (99,7% a 65,2%) in comparison with the pure coal (108,4% a 107,5%) burning to obtaining the bed operating temperature. The burning of the mixture with higher amounts of biomass in the reactor feed had the lowest percentage of excess air (50.8%). It was also evidenced a decrease of SO2 generation in more than 90% for the flue gas generated in the coal with BWBW cofiring keeping emissions at acceptable levels in comparison with emission limits of current legislation CONAMA Nº 436, from 22/12/2011 and legislation SEMA Nº 016 of 2014.

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The general goal of this work is to evaluate the possibility of utilizing tannin from black wattle and lignocelullosic derivatives in the preparation of foundry sand, as well as to evaluate the utilization of tannins as glueing for the confection of briquettes of vegetal residues. The work has been divided into two chapters, which comprise distinct experiments. In the first chapter tannin and cellulignin were used as constituents of foundry sand for the fabrication of pieces of pure aluminum alloy or aluminum-silicon eutectic alloy (11,0 a 13,0 % of Si). In the second chapter the use of tannin was evaluated in the production of briquettes of vegetal residues for application as a source of energy. The traces of foundry sand normally use clay as glueing and mogul (corn starch) with the goal of enhancing the resistance to compression and workability of the mold thus produced. It is common practice the use of mineral coal as a reducing agent in the mixture, and so the effects of its substitution by cellulignin, because of its high carbon content, were evaluated. Tannin, for its adhesive properties, acted as glueing together with clay, and replaced molasses, which is a component of foundry sand, perfectly. The resistance analysis produced good results and the process will generate molds with good visual aspect and adequate mechanical properties. Sawdust obtained in a eucalyptusprocessing sawmill was used in the confection of the briquettes. Tannin demonstrated great affinity to water in the composition of the standard mixture for briquetting. In natura sawdust, without any beneficiation, was used for briquetting. The results revealed that tannin is effective in the production of briquettes, where acted as an element of adhesion between the sawdust particles.
O objetivo geral deste trabalho foi avaliar a possibilidade de utiliza??o de tanino de ac?cia negra e de derivados lignocelul?sicos na prepara??o de areias de fundi??o, bem, como avaliar a utiliza??o dos taninos como aglomerante para confec??o de briquetes de res?duos vegetais. O trabalho foi dividido em dois cap?tulos, constituindo experimentos distintos. No primeiro cap?tulo foram utilizados o tanino e a celulignina como constituintes de areia preparadas de fundi??o para a fabrica??o de pe?as em ligas de alum?nio puro ou alum?nio-sil?cio eut?tica (11,0 a 13,0 % de Si). No segundo cap?tulo, avaliou-se a utiliza??o do tanino na obten??o de briquetes de res?duos vegetais para aplica??o como fonte de energia. Os tra?os de areia preparada de fundi??o normalmente usam a argila como aglomerante e o mogul (amido de milho) com a finalidade de melhorar a resist?ncia ? compress?o da areia e a trabalhabilidade do molde produzido. ? pr?tica comum a utiliza??o do carv?o mineral como elemento redutor na mistura, e assim, foram avaliados os efeitos de sua substitui??o pela celulignina, em fun??o do seu teor elevado de carbono. O tanino, por suas propriedades adesivas, atuou como aglomerante em parceria com a argila, e ainda substituiu perfeitamente o mela?o, que ? um componente da areia preparada de Fundi??o, obtendo-se bons resultados na an?lise das resist?ncias, gerando moldes de bom aspecto visual e propriedades mec?nicas adequadas. Na confec??o dos briquetes, foi utilizada serragem obtida em serraria que processa madeira de eucalipto. O tanino demonstrou grande afinidade com a ?gua na composi??o da mistura padr?o para a briquetagem. Na briquetagem, foi utilizada a serragem in natura, sem qualquer tipo de beneficiamento. Os resultados revelaram que o tanino mostrou-se efetivo na fabrica??o de briquetes, onde atuou como elemento de ades?o entre as part?culas de serragem.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Density management diagrams (DMD) is a tool used to carry out the prognosis of production in density, basal area and volume in order to establish management strategies for forest planning. The aim was to build a density management diagram for Acacia mearnsii De Wild. Data from 12 cities in the northeastern region of Rio Grande do Sul were used for the DMD construction. Since the Tang model had the best evaluation, it was used to select the maximum population density estimative, thus the density 1x1 was used to construction of the DMD. With the same model, self-thinning graphs and Stand Density Index (SDI) were generated; adopting a standard quadratic mean diameter of 10cm. Density levels were determined proportionally to SDI maximum density in 200 class intervals, with higher 2400 and lower 1400 SDI. The DMD were produced with an average diameter and density control, and volume and green rind bark weight per hectare. A second DMD model was developed in order to insert a site production control through the dominant height of the stand. These DMD models allowed estimating the volume and green rind bark with great precision, from the control of diameter, density and dominant height.
O Diagrama de Manejo da Densidade (DMD) é uma ferramenta utilizada para realizar a prognose da produção em densidade, área basal e volume a fim de estabelecer estratégias de manejo para o planejamento florestal. O objetivo do presente foi construir um diagrama de manejo da densidade para Acacia mearnsii De Wild., com dados dendrométricos provenientes de 12 municípios da região nordeste do Rio Grande do Sul. A máxima densidade populacional foi estimada pelo modelo de Tang, ajustado com dados de parcelas em espaçamento 1x1m. Com este modelo foram gerados os gráficos de autodesbaste e Índices de Densidade de Povoamento (IDP) para um diâmetro padrão de 10cm. Os níveis de densidade foram determinados, proporcionalmente, a partir da máxima densidade, por índice de densidade de povoamento (IDP), em intervalos de classe de 200, com IDP máximo 2400 e mínimo 1400. Os DMDs foram elaborados com controle de diâmetro médio e densidade populacional, e como variável de resposta o volume por hectare e o peso de casca verde por hectare. Um segundo modelo de DMD foi elaborado com o objetivo de inserir um controle produtivo dos sítios, através da altura dominante do povoamento. Estes modelos de DMD permitiram estimar o volume e peso de casca verde com ótima precisão, a partir do controle do desenvolvimento do diâmetro, densidade e altura dominante.

Conselho Nacional de Desenvolvimento Científico e Tecnológico
The proposed work aimed to investigate the entomological aspects in homogeneous stands of Acacia mearnsii (black wattle). It was considered: insects identification and damage quantification on seeds; treatment effect of seeds and the insecticides application on the aerial part of plants of direct sowing; the survey qualiquantitative by light traps mean; the main species of Coleoptera present in the suppressed trees; the attack characterization of Oncideres impluviata and its influence on wood volume of black wattle. The experiments were carried out in cultivated areas of black wattle situated at the municipality of Butiá and Minas do Leão in the carboniferous region of Rio Grande do Sul during March 2004 to July 2006. It was verified that the Stator limbatus (Coleoptera: Chrysomelidae) caused expressive damage to the black wattle seeds. There was no statistical increase in relation to the use of insecticides to the directly sowing, however black wattle plants submitted to thiamethoxam application on the aerial part showed better development. Among the 11 orders collected by light traps the populations of lepidoptera, coleoptera and hemiptera were quantitatively pointed. Sigara sp. (Hemiptera: Corixidae), Conoderus alfredense (Coleoptera: Elateridae) and Plectris crassa (Coleoptera: Scarabaeidae) were the species more frequents, abundant and constants collected by the light traps. At the qualitative survey made in suppressed trees it was observed 40 species of Coleoptera distributed in ten families, focusing in Curculionidae with twelve representatives, Cerambycidae with ten and Scarabaeidae with nine species. It was verified that O. impluviata attacks the high parts of the tree, independent of age, from the borders into the stand and cuts the branches averaging 14mm of diameter and 1.4 m of length. These branches present high contents of nitrogen and phosphorus in their chemical composition when compared to non-cut branches. The attack of O. impluviata did not reduce the wood volume produced for black wattle trees.
O trabalho proposto teve como objetivo o estudo de aspectos entomológicos em povoamentos homogêneos de Acacia mearnsii (acácia-negra), considerando a identificação de insetos e quantificação de seus danos em sementes; o efeito do tratamento de sementes e a aplicação de inseticidas na parte aérea de plantas de semeadura direta; o levantamento quali-quantitativo, por meio de armadilha luminosa; as principais espécies de Coleoptera presentes em sub-bosque; a caracterização do ataque de Oncideres impluviata e a sua influência no volume de madeira de acácia-negra. Os experimentos foram realizados em áreas de plantio e povoamentos de acácia-negra situados nos municípios de Arroio dos Ratos, Butiá e Minas do Leão, na região carbonífera do Rio Grande do Sul, no período de março de 2004 a julho de 2006. Verificou-se que Stator limbatus (Coleoptera: Chrysomelidae) causa expressivos danos a sementes de acácia-negra. Não houve diferença significativa em relação ao uso de inseticidas para a semeadura direta. Das 11 ordens coletadas por meio de armadilha luminosa, destacam-se quantitativamente as populações de lepidópteros, coleópteros e hemípteros. Sigara sp. (Hemiptera: Corixidae), Conoderus alfredense (Coleoptera: Elateridae) e Plectris crassa (Coleoptera: Scarabaeidae) foram as espécies muito freqüentes, muito abundantes e constantes, coletadas através de armadilha luminosa. No levantamento qualitativo realizado em sub-bosques foram observadas 40 espécies de Coleoptera, distribuídas em dez famílias, com destaque para os Curculionidae com doze representantes, Cerambycidae com dez e Scarabaeidae com nove espécies. Constatou-se que O. impluviata ataca nas partes mais altas da árvore, independente da idade, tanto nas bordas como no interior de povoamentos. O. impluviata anela galhos com diâmetros e comprimentos médios de 1,4 cm e 1,4 m, respectivamente. Estes galhos apresentam maiores teores de nitrogênio e fósforo em sua composição química quando comparados com galhos não-anelados. O ataque de O. impluviata não reduziu o volume de madeira produzido por árvores de acácia-negra.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The Acacia mearnsii De Wild. is widely cultivate for the tannin extraction of its bark, while the wood, exported to the Asian countries, can be converted in cellulosic pulp. Although the efficiency of this wood on pulping is proved, in Brazil the specie is rarely used for this purpose. Thus, the aim of this work was to characterize technologically the Acacia mearnsii wood, trough chemical, anatomical and basic density analysis, and evaluate the cellulosic pulp quality, produced by the kraft process. It was collected ten trees, five from a seed production area (APS) and five from clonal plantations, which were felled and divided in discs and prepared in accordance with TAPPI T264 om-88 standart. The basic density was performed in accordance with NBR 11941 (2003) standart, and the wood description was set trough the preparation of histological slides and of macerated, according to Burger and Richter (1991) and by the nitric-acetic method, respectively, followed by anatomical measurements on microscope. It was performed quantitative analysis of the chemical components, besides the syringyl/guaiacyl ratio and the total carbohydrates content by high efficiency liquid chromatography. The kraft pulps were carried out only in APS chips, keeping constant the time, sulfidity and the temperature of cooking, changing just the active alkali charge, which ranged from 14 to 24%. In cellulosic pulps, it was evaluated the yields, kappa number and rejects content, besides the analysis of solid content in black liquor. The basic density results showed that Acacia mearnsii wood from APS and clones did not presented significant difference, with values of, approximately 0,544g/cm³. In wood description, the anatomical elements presented values much similar to the genre Eucalyptus sp., with thin to thick wall fibers (± 3,3 μm) and anatomical indices indicating suitable fibers for paper production. The chemical analysis revealed an ashes content of, approximately 0,35%, total extractives of 4,5 to 4,8%, Klason lignin of 16,2 to 17,1%, holocellulose and alpha-cellulose of 76 to 77% and 46%, respectively. The glucose content was 51,7 and 49,7% for clone and APS, while the hemicelluloses (xylose, arabinose, mannose and galactose) totaled circa 19%. The S/G ratio was 2,69 and 2,93 in clone and APS, respectively. The pulps made with different charges of active alkali presented satisfatory yields and kappa numbers. The best pulping condition was obtained with active alkali of 14%, resulting in a screened yield of nearly 57%, kappa number of 16, rejects content of ± 0,2% and solids content of 12,7%. According with the results, the Acacia mearnsii wood presents a great potential as a source of short fibers in cellulosic pulp production.
A Acacia mearnsii De Wild. é amplamente cultivada para a extração de tanino de sua casca, enquanto que sua madeira, exportada para países asiáticos, pode ser convertida em polpa celulósica. Embora existam estudos que comprovem sua eficiência na polpação, no Brasil a espécie é pouco utilizada para este fim. Desta forma, o objetivo deste trabalho foi caracterizar tecnologicamente a madeira de Acacia mearnsii, através de análises químicas, anatômicas e de densidade básica, e avaliar a qualidade de sua polpa celulósica, produzida pelo processo kraft. Foram coletadas dez árvores, cinco provenientes de área de produção de sementes (APS) e cinco clones, que foram abatidas, seccionadas em discos e preparadas em amostras conforme a norma TAPPI T264 om-88. A densidade básica foi obtida de acordo com a norma NBR 11941 (2003), e a descrição do lenho foi determinada através da preparação de lâminas histológicas e de macerado conforme Burger e Richter (1991) e pelo método nítrico-acético, respectivamente, seguidas de medições anatômicas em microscópio. Foram realizadas análises químicas quantitativas, além da relação siringil/guaiacil e o teor de carboidratos totais por cromatografia líquida de alta eficiência. Os cozimentos kraft foram realizados somente em cavacos de APS, mantendo-se constantes o tempo, a sulfidez e a temperatura, alterando apenas a carga de álcali ativo, que variou de 14 a 24%. Nas polpas celulósicas foram avaliados os rendimentos, o número kappa e o teor de rejeitos, além da análise de sólidos dissolvidos no licor negro. Os resultados de densidade básica mostram que a madeira de Acacia mearnsii de APS e clone não apresentam diferença significativa, com valor de aproximadamente 0,544 g/cm³. Com relação a descrição do lenho, os elementos anatômicos apresentaram valores muito próximos ao gênero Eucalyptus sp., com fibras de paredes finas (de ± 3,3 μm) e índices anatômicos indicando fibras adequadas para a produção de papéis. As análises químicas revelaram um teor de cinzas de aproximadamente 0,35%, extrativos totais de 4,5 a 4,8%, lignina Klason de 16,2 a 17,1%, holocelulose e alfa-celulose de 76 a 77% e 46%, respectivamente. O teor de glicose foi de 51,7 e 49,7% para clone e APS, enquanto que as hemiceluloses (xilose, arabinose, manose e galactose) somaram aproximadamente 19%. A relação S/G foi de 2,69 e 2,93 em clone e APS, respectivamente. As polpas produzidas com diferentes cargas de álcali ativo apresentaram rendimentos e número kappa satisfatórios. A melhor condição de polpação foi obtida com álcali ativo de 14%, resultando em um rendimento depurado de aproximadamente 57%, número kappa de 16, teor de rejeitos de ± 0,2% e teor de sólidos de 12,7%, valores utilizados pelas indústrias de celulose. De acordo com os resultados, a madeira de Acacia mearnsii apresenta grande potencial como fonte de fibras curtas na obtenção de polpa celulósica.

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The black wattle (Acacia mearnsii De Wild.) is, the third forest specie of larger economical importance, more than 189 thousand ha are cultivated now, in Rio Grande do Sul, Brazil. According its socio-environmental importance it can be considerate the first in importancy in this state regarding the enormous benefits given to the black-wattle grower and to the environment, such as: regenerator of degraded soils specie; short life pioneering specie; quickly covering the soil; not presenting stump sprouting; it doesn't inhibit the local succession and the high deposition of their nitrogen rich leaves, cause the enriching of the soil. Black wattle has also the capacity of making symbiosis with microorganisms fixatives of atmospheric nitrogen. Producing quality wood for energy and cellulose; the tannin extracted from its peel is used for leather curing industry and in wines and beers clarification. More or less 60% of black wattle growers are of small producers, about 40 thousand families live from that activity. One of the limiting factors in the uniformity of the black-wattle's seedlings production is the low of quality of their seeds. The quality of the seedlings and the forest produced by them will depend on the dormancy and on the method used for its break. With the objective of accelerating and standardization of the germination in the process of seedlings production, we went after an alternative method that should be more practical and efficient, in the break of black-wattle s seed dormancy. To reach these objectives the mechanical scarification method was tested, using sand to polish as scarificant material and the model GDA-8 escarificator. This GDA-8 scarificator was developed as part of the research project during Post Graduation Program in Science and Technology of Seeds of FAEM (Faculdade de Agronomia Eliseu Maciel) / UFPEL, by comparing it to the conventional method that uses hot water. The black-wattle seeds used in this research are originated from trees that were three, four, five and six years old, in Joca Tavares district in Bagé / RS. Scarification was made using the following proportion: one part of seeds was used to three parts of sand with thin granularity average of 0,75 mm, for 1 1/2 minute. Mechanical damage, germination, first counting and weight of green and dry matter tests were developed, in the Laboratory of Analysis of Seeds of FAEM and Emergency and Emergency Velocity Index (IVG) in the vegetation home of Votorantim Cellulose and Paper s dependences, located in Capão do Leão/RS municipal district. The random experimental work was with three repetitions and the averages compared by the test of Tukey at the level of 5%.
A acácia negra (Acacia mearnsii De Wild.) é a terceira espécie florestal de maior importância econômica para o RS, no qual são cultivados mais de 189 mil ha atualmente. Considerando-se a importância sócio-ambiental, é a primeira neste estado, haja vista os enormes benefícios auferidos pelos acacicultores e ao meio ambiente, como: espécie recuperadora de solos degradados, espécie pioneira de vida curta, que cobre rapidamente o solo, não apresenta rebrota de cepa, não inibe a sucessão local e enriquece o solo pela elevada deposição de folhedo rico em nitrogênio. Também tem capacidade de efetuar simbiose com microrganismos fixadores de nitrogênio atmosférico. Produz madeira de qualidade para energia e celulose, de sua casca é extraído o tanino usado na indústria, desde o curtimento de couros, até clarificação de vinhos e cervejas. Cerca de 60 % dos acacicultores, da região produtora, são pequenos produtores, e 40 mil famílias vivem dessa atividade. Um dos fatores limitantes na produção de mudas uniformes de acácia negra é a baixa qualidade de suas sementes. Da dormência e do método utilizado para a sua superação, dependerá a qualidade das mudas e das florestas produzidas por estas sementes. Com o objetivo de acelerar e padronizar a germinação no processo de produção de mudas, buscou-se estudar um método alternativo que fosse prático e eficiente, na superação da dormência em sementes de acácia negra. Para alcançar estes objetivos, foi testado o método de escarificação mecânica, utilizando-se areia como material escarificante e, escarificador modelo GDA-8, concebido como parte do projeto de pesquisa desenvolvido durante o P.P.G. em Ciência e Tecnologia de Sementes da FAEM / UFPEL comparado ao método convencional que utiliza água quente. As sementes de acácia-negra, utilizadas nesse trabalho, foram provenientes de cultivos com três, quatro, cinco e seis anos, localizados no distrito de Joca Tavares em Bagé / RS. Para a escarificação, usou-se a proporção de uma parte de sementes para três de areia com granulometria fina, com média de 0,75 mm, durante um minuto e meio. Foram realizados testes de dano mecânico, germinação, primeira contagem e peso de matéria verde e seca, no Laboratório de Análise de Sementes da FAEM e Emergência e Índice de Velocidade de Emergência em casa de vegetação nas dependências da Votorantin Celulose e Papel, localizada no município de Capão do Leão / RS. O delineamento experimental foi o inteiramente casualisado, com três repetições e as médias comparadas pelo teste de Tukey ao nível de 5 %.

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
In order to reduce the environmental impacts caused by chemical harmful to the environmental and to human health, the development of natural substances that are able to substitute these dangerous components have been increased. Tannins are a group of natural poliphenolic components extracted from plants that could be used as corrosion inhibitors. This study investigates the utilization of two bark of black wattles (Acacia mearnsii) as corrosion inhibitors, Weibull and Macrospec, in acidic medium and in atmospheric environment and in aqueous CO2 rich medium under high pressure. API 5L X65 steel samples were exposed to a corrosive medium (0.1 M HCl) with different tannin concentrations. The best results were duplicate to an environmental with CO2 saturated water at 15 MPa and 50?C. In order to characterize the specimens scanning electron microscopy by gun field emission, energy dispersive spectroscopy, X ray diffraction, mass loss tests and potenciodynamic polarization tests were used. The results indicated that both tannins, at atmospheric pressure and 0.1 M HCl corrosive environment have similar performance as corrosion inhibitors, and the higher dosage tested (12 g/L) exhibited the best efficiency. However, when the tannins were tested in environment with presence of CO2 under high pressure (15 MPa) and 50?C the results were different, and only Macrospec tannin had an inhibitory action under the conditions tested.
Visando diminuir os impactos ambientais causados por subst?ncias qu?micas nocivas ao meio ambiente e ? sa?de humana, a procura por substitutos naturais destes compostos em diversas aplica??es vem sendo intensificada. Taninos compreendem uma classe de compostos polifen?licos naturais extra?dos de plantas, podendo ser usados como inibidores de corros?o em meio aquoso. Neste estudo avaliou-se a utiliza??o de dois taninos vegetais da ac?cia negra (Acacia mearnsii), Weibull (em p?) e Macrospec (l?quido), como inibidores de corros?o em meios ?cidos em ambiente atmosf?rico e em ambiente com a presen?a de CO2 a alta press?o. Corpos de prova de a?o API5L X65 foram expostos a meio acidificado com HCl 0,1 M com diferentes concentra??es de taninos e o melhor resultado no que se refere ? concentra??o do tanino para a inibi??o de corros?o foi replicado para um meio com ?gua saturada com CO2 a 15 MPa e 50?C. Para caracteriza??o foram realizadas as an?lises de microscopia eletr?nica de varredura, difra??o de raios X, medidas eletroqu?micas de polariza??o potenciodin?mica, e testes de perda de massa. Os resultados indicaram que ambos os taninos, em meio de HCl 0,1 M e press?o atmosf?rica, apresentaram desempenho similar no que diz respeito aos efeitos de inibi??o da corros?o e a maior dosagem utilizada (12 g/L) foi a que apresentou melhor efici?ncia de inibi??o. Por?m, quando testados em meio de ?gua saturada com CO2 a 50?C e 15 MPa o comportamento dos taninos foi distinto, sendo que apenas o tanino Macrospec teve a??o inibit?ria nas condi??es testadas.

The objective of this study was to quantify the biomass and to determine the optimal sampling point for nutrients quantification in four year old Acacia mearnsii trees. It was conducted in black wattle stand, located in Arroio dos Ratos city in a farm belonging to SETA S/A, having as coordinates 30° 07 12 of south latitude and 51° 57 45 of longitude, with 90 m of average altitude. The first step was the forest inventory, where 30 trees were felled, distributed in 7 diametric classes, to cover the stand heterogeneity, then the biomass and the nutrients amount in the leaves, live branches, dead branches, roots, wood and bark were determined. Samples of wood and bark were taken along the stem in the posítions of: 1, 3, 10, 20, 30, 40, 50, 60, 70, 80 and 90% of the total height. The total biomass from Acacia mearnsii trees was of 72, 91 Mg ha-1 and was divided in: 64% in the wood, 11% in the roots, 10% in the bark, 7% in the live branches, 5% in the dead branches and 3% in the leaves. The total amount of macronutrients (kg ha-1) were: 384,94 of N, 15,69 of P, 200,06 of K, 267,74 of Ca, 58,54 of Mg and 18,57 of S, and the micronutrients (g ha-1) were: 1.249,01 of B, 195,33 of Cu, 6.485,64 of Fe, 1.073,52 of Mn and 809,33 of Zn. From this total, the leaf component accumulated 20% of the N, 18% of P and Cu, 12% of the K, 5% of Ca and Fe, 10% of Mg and S, 17% of B, 19% of Mn and 6% of Zn; the roots accumulated 14% of N, Cu , Mn and Zn, 11% of P and K, 8% of Ca, 7% of Mg, 15% of S, 17% of B and 66% of Fe; the wood accumulated 21% of N, 27% of P, 30% of K, 50% of Ca, 36% of Mg, 45% of S, 26% of B and Mn, 37% of Cu, 9% of Fe and 41% of Zn; the bark accumulated 22% of N and Mg, 17% of P, 21% of P and Ca, 22% of Mg, 10% of S, Fe and Cu, 20% of B and Mn and 12% do Zn; the dead branches accumulated 8% of N, S and B, 6% of P, 4% of K, 7% of Ca, 11% of Mg, Cu and Zn, 5% of Fe and 9% of Mn; the live branches accumulated15% of N, 21% of P, 22% of K, 9% of Ca, 13% of Mg and B, 12% of S and Mn, 10% of Cu, 5% of Fe and 16% of Zn. The total amount of carbon stored in the biomass was 29,79 Mg ha-1, allocated 64% in the wood, 11% in the roots, 9% in the bark, 7% in the live branches and 4% in the dead branches and leaves. The nutrients Ca, Mg, S, B, Cu, Fe, Mn and Zn didn t show significant difference along the stem to wood and bark, indicating that there isn t an exact point for sampling along the stem to nutrients quantification. The optimal sampling point to nutrients (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn) quantification along the stem should be 50% from the total height in Acacia mearnsii trees
O objetivo deste estudo foi quantificar a biomassa e determinar o ponto ótimo de amostragem para a quantificação de nutrientes em árvores de Acacia mearnsii com quatro anos de idade. O trabalho foi realizado em um povoamento de acácia-negra localizado na cidade de Arroio dos Ratos, em uma fazenda pertencente à empresa SETA S/A, nas coordenadas 30° 07 12 de latitude sul e 51° 57 45 de longitude, com altitude média de 90m. O primeiro passo foi a realização do inventário florestal no povoamento, onde foram abatidas 30 árvores, distribuídas em 7 classes diamétricas, para cobrir a heterogeneidade do povoamento. Após foram determinados a biomassa e o teor de nutrientes dos componentes: folha, galho vivo, galho morto, raiz, madeira e casca. Para os componentes madeira e casca foram retiradas amostras ao longo de fuste nas posições de 1, 3, 10, 20, 30, 40, 50, 60, 70, 80 e 90% da altura total das árvores. A biomassa total das árvores de Acacia mearnsii com quatro anos foi de 72,91 Mg ha-1, distribuída 64% na madeira, 11% nas raízes, 10% na casca, 7% nos galhos vivos, 5% nos galhos mortos e 3% nas folhas. A quantidade total de acronutrientes, em kg ha-1, foi 384,94 de N; 15,69 de P; 200,06 de K; 267,74 de Ca; 58,54 de Mg; e 18,57 de S; e de micronutrientes (gha-1), foi 1.249,01 de B; 195,33 de Cu; 6.485,64 de Fe; 1.073,52 de Mn; e 809,33 de Zn. Deste total, o componente folha acumulou 20% do N, 18% do P e Cu, 12% do K, 5% do Ca e Fe, 10% do Mg e S, 17% do B, 19% do Mn e 6% do Zn; as raízes acumularam 14% do N, Cu , Mn e Zn, 11% do P e K, 8% do Ca, 7% do Mg, 15% do S, 17% do B e 66% do Fe; a madeira acumulou 21% do N, 27% do P, 30% do K, 50% do Ca, 36% do Mg, 45% do S, 26% do B e Mn, 37% do Cu, 9% do Fe e 41% do Zn; a casca acumulou 22% do N e Mg, 17% do P, 21% do P e Ca, 22% do Mg, 10% do S, Fe e Cu, 20% do B e Mn e 12% do Zn; os galhos mortos acumularam 8% do N, S e B, 6% do P, 4% do K, 7% do Ca, 11% do Mg, Cu e Zn, 5% do Fe e 9% do Mn; os galhos vivos acumularam 15% do N, 21% do P, 22% do K, 9% do Ca, 13% do Mg e B, 12% do S e Mn, 10% do Cu, 5% do Fe e 16% do Zn. O carbono total estocado na biomassa foi 29,79 Mg ha-1, distribuído 64% na madeira, 11% na raiz, 9% na casca, 7% nos galhos vivos e 4% nos galhos mortos e folhas. Para os nutrientes cálcio (Ca), magnésio (Mg), enxofre (S), boro (B), cobre (Cu), ferro (Fe), manganês (Mn) e zinco (Zn), não foi verificada variação significativa ao longo do fuste, para os componentes madeira e casca, indicando qualquer altura para amostragem no fuste para quantificação dos nutrientes. O ponto ótimo de amostragem, para quantificação dos nutrientes (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn) no fuste, deve situar-se a 50% da altura total das árvores de Acacia mearnsii

The overall aim of the study was to investigate re-vegetation of disturbed sites, using nursery grown plugs (from seedling trays) of Themeda triandra, Heteropogon contortus and Hyparrhenia dregeana in order to reach practical management guidelines for re-vegetation using indigenous grass plugs. A number of field trials were set up at Kamberg Nature Reserve (29°24'S, 29°40'E) on a site that was clear felled of A. mearnsii in October 1997. The trials were established in January 1998 and January 1999. A total of approximately 52 ,000 nursery raised plugs of T. triandra, H. contortus and H. dregeana were planted into an area of approximately 7,000 m2 . In the planting density trial , plugs of H. dregeana only and a combination of T. triandra/H. contortus were planted at 15 cm and 30 cm spacings. The T. triandra/H. contortus combination at 30 spacing showed the greatest survival and lateral plant growth (tiller number and basal area) and this combination is thus recommended. In the over-sowing trials, the H. dregeana and T. triandra/H. contortus combination at both 15 cm and 30 cm spacing were over-sown with E. curvula. The survival and lateral growth of the T. triandra/ H. contortus combination at 30 cm was again greater than the other treatments. Over-sowing with E. curvula suppressed the survival and lateral growth of the planted plugs across all treatments compared to not over-sowing. The over-sown conditions showed a significant decrease in the diversity of the plots, both in the number of species present and the Shannon diversity index. An area that had been cleared of A. mearnsii and sown to E. curvula 25 years previously was shown to have a lower number of species than the neighbouring veld. Nursery raised plugs of T. triandra were planted into the mature E. curvula in an attempt to improve the biodiversity of these areas. To re-introduce T. triandra into these E. curvula swards the plugs must be planted into the centre of a gap rather than around the base of an E. curvula plant. For improved survival of the plugs the E. curvula tufts must be clipped, while for best lateral growth the E. curvula tufts must be sprayed with a glyphosate herbicide three months prior to planting and clipping. However, the added expense of spraying and clipping is not warranted as the clipped treatments also showed good growth. Transplant shock is common when planting nursery raised plugs out into the field, as there is a relatively small root volume in the plug compared to the above ground leaf biomass. Alleviation of moisture stress at planting using a starch based polymer with high water holding capacity (Terrasorb®) and a white, needle punched geo-fabric (Agrilen®) to provide a seven day period of artificial shade after planting did not show significant improvements over the control with regards to survival or plant growth. Thus these methods of moisture amelioration are not recommended in revegetation through planting of plugs at this study site. A trial was established to investigate the biomass production of six different treatments to determine their potential to support a fire. The total biomass for the plots which were over-sown by E. tef and planted to only H. dregeana were on average sufficient for a fire, but there was a discontinuous fuel load across these plots, especially in the replications that had very low survival rates and thus these plots could not be burnt. The control and herbicide sprayed plots also showed sufficient fuel load for a fire, but this fuel load was made up of A. mearnsii saplings and bramble with very little grass cover and thus a fire would not have burnt through these plots either. The T. triandra/H. contortus combination did not produce sufficient fuel load, due to poor survival. Thus only the plots over-sown with E. curvula were able to burn in this trial and as a burning trial per se the trial was abandoned. Seed bearing hay (thatch) was collected in early summer (December 1997) and late summer (April 1998). Both times of year of harvesting proved to be successful in terms of grass cover, although the early harvested thatch had a greater number of species per plot. The Shannon diversity indexes of the two treatments were not significantly different. The multi-response permutation procedure technique confirmed that there was a compositional difference between the treatments. By the end of the trial Harpochloa falx and T. triandra and H. dregeana were indicators for the early and the late harvested thatch respectively. Comparing the thatching trial and the planting density trial indicated that the T. triandra/H. contortus combination at 30 cm spacing would be recommended to maximize biodiversity. The summer months have been shown to be the best time to plant the plugs, although the actual success will be dependant on the conditions within a particular year. The plugs should not be kept in the nursery for longer than three months and larger plugs (96 seedlings per tray) should be used. Nursery raised plugs of T. triandra and H. contortus were planted in an equal mix in an area that was cleared of A. mearnsii in 1996. By June 1998 661 H. contortus seedlings and 14 T. triandra seedlings had germinated naturally. The November 1998 population consisted of 418 H. contortus seedlings and 18 T. triandra seedlings. By May 2000 the June 1998 population showed a survival of 78.4% and the November 1998 population showed a survival of 91 .1 %. In the various trials, the ability of the nursery raised plugs used for re-vegetation to suppress the regrowth of A. mearnsii was investigated by determining the number of A. mearnsii seedlings per metre squared. The plant spacing and species of plugs used did not have a significant effect on the number of A. mearnsii seedlings per metre squared. Over-sowing with E. curvula did, however, significantly suppress the wattle re-growth. In the thatching trial the early harvested plots showed lower numbers of A. mearnsii per metre squared than the late harvest plots, as they were covered with a thick layer of thatch soon after the A. mearnsii was cleared which suppressed the A. mearnsii re-growth. Although E. curvula is able to produce a high biomass and suppress the A. meansii seedlings, it has a detrimental effect on the biodiversity of the area. Therefore, in conservation areas, where biodiversity is of great importance the planted plugs (at 30 cm spacing) or seed bearing hay must be used in preference to sowing E. curvula , although it must be remembered that greater follow up control is likely to be needed with planted plugs or seed bearing hay. The area must be planted or thatched as soon as possible after clear felling to provide competition for the A. mearnsii seedlings.
Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Alleycropping is an agroforestry technology of planting crops between rows of trees, preferable legumes to promote an interaction among them with positive benefits in terms of improving soil fertility and hence good crop yields. The technology has been tested with a variety of trees/shrubs species in association with crops (alleycropping) or with grasses (alleygrazing), sometimes with encouraging results and sometimes not, in a wide range of environmental conditions around the world. Research in alleycropping started in late 1970s and sinc~ then many publications have been released. However, little or nothing has been reported about this technology using black wattle and the fever tree, two nitrogen-fixing trees common in South Africa and reported as fast-growing species which produce a considerable amount of biomass within a short period of time. Due to that fact, a two-year trial was established in 2003 at the Ukulinga research farm, Pietermaritzburg, South Africa to evaluate the potential of the two tree species under alleycropping with maize and cowpeas as joint intercrops, under alleycropping with pumpkin, and under alleygrazing with Eragrostis curvula and with Panicum maximum. The trial assessed the crop yields and the biomass production from all the components, and their fodder digestibility using Neutral Detergent Fibre (NDF) and Acid Detergent Fibre (ADF) determinations. Additionally the changes in tree grovlth vaa."'i.ables (difu~eter, total height, total \lollhl1e and biomass) were mortitored to produce regression equations to predict those variables, one from another, using regression analysis. The diameter was taken at ground level (dgl) and at the height of 1.3 m, normally called diameter at breast height (dbh). The results showed that tree growth and biomass production were better in black wattle alleycropping than in association with the fever tree. The average dgl of black wattle after 12 months was 48mm and the average dbh was 36mlll. Over the same period the total tree height was about 406cm. A tree pruning was done to one-year old black wattle in the whole trial and the prunings produced about 5.6t/ha of fresh foliage biomass in the association with maize and cowpea and 4.5t/ha in the association with pumpkin. In alleygrazing the growth variables were similar to those obtained in alleycropping but the biomass production was considerably different. The prunings produced about 7.66t/ha of fresh foliage biomass. The dry matter biomass from the prunings was 1.96t/ha, 1.58t/ha and 2.68t/ha in the association with maize and cowpeas, pumpkin and E. curvula respectively. The dry matter was obtained from 4days- oven-dried samples and it was 35% of the fresh foliage biomass and 60% of the fresh woody biomass. The fever tree did not grow significantly during the study period and due to that fact, the species was discarded from the study. Similarly, because after several endeavours using different seed lots, P. maximum had germinated very unevenly, and this grass was excluded from the experimentation. Values ofNDF and ADF less than 35% are considered good, between 35% and 60% fair and poor if greater than 50%. Using is classification the NDF and ADF values from this study were good in pumpkin (30.5% and 29.9%) and cowpeas (36.5% and 46.9%) biomass, fair in E. curvula (41.9% and 39.9%) and maize stover (53.6% and 42.1%) and poor in black wattle (76.58% and 68.1%) foliage. If black wattle is to be used as fodder, it must be mixed with highly digestible fodder like P. maximum, Digitaria sp., and other legume plants, to increase animal intake and to avoid any risk of it becoming an animal hazard due to tannin effects. The regression equations produced linear relationships between dgl and age, and biomass and dbh. The other interactions were not linear. The best equations were obtained in the interaction between dgl and age (dgl= 4.8*Age -7.03; R2 =0.86; SE= 6.6), dgl and height (h= -0.03dg12 + 10.5dgl - 21.25; R2= 0.96, SE= 42.9, h= height), biomass and dbh (lny = 2.409*lndbh; R2=0.99, SE=O.O, Y= tree foliage biomass). During the study, monkeys, cattle, birds and bushbucks posed a threat to the success of the study due to damage they caused to the crops. It was possible to keep the damage below the critical levels, although at high cost.
Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Acacia mearnsii (black wattle) is an important South African commercial forestry species, providing a source of high quality raw material (fibre) for both the domestic and international pulp and paper industries. Compared with many Pinus and Eucalyptus species, there has been very little research into the wood and pulping properties of black wattle. The ability to assess pulp yield in a non-destructive manner, using near infrared (NIR) spectroscopy, is vital from a tree improvement perspective. Destructive sampling and analysis, results in the loss of the genotype, while also being very expensive and time consuming. In order to assess some of the important characteristics that make the species desirable from a fibre perspective, this study investigates growth characteristics, wood density and pulp yield of ten trees grown on each of three different sites namely, Bloemendal, Glen Echo and Phoenix, and from each of three different age classes being 7- , 9- and 11-years-old. In total, 90 trees were sampled for this stage of the study. In general, physical characteristics such as utilisable height and diameter at breast height of the trees differed between sites and increased with age, this age effect trend was not reflected in the pulp yield or wood density results. Pulp yield measurements ranged from 52.61 to 59.91% across all sites and age classes, which, when compared to the pulp yield from many other forestry species, is relatively high. Laboratory pulp yield data was used in conjunction with NIR spectra obtained from the same wood samples to calibrate a NIR spectrophotometer to predict pulp yield. Thirty 11- year-old trees were then chosen from the Bloemendal site and sampled extensively to investigate the within-tree variation in pulp yield. The NIR model developed was used to measure the pulp yield from the numerous samples taken from within the trees. In general, pulp yield decreased from pith to bark and from the base of the tree to about 20% of the tree height and then decreased towards the top of the tree. The within-tree variation data for pulp yield was analysed to identify the best position for non-destructive sampling, and a model was then developed to predict whole tree pulp yield based on this sample, which was taken at 1.4 m up the tree. The analyses of small samples of wood meal, using near infrared spectroscopy, enabled the prediction of whole tree pulp yield.
Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2009.

Leaf area index (LAI) is an important variable in models that attempt to simulate carbon, nutrient, water and energy fluxes for forest ecosystems. LAI can be measured either directly (destructive sampling) or by using indirect techniques that involve estimation of LAI from light penetration through canopies. Destructive sampling techniques are laborious, expensive and can only be carried out for small plots. Although indirect techniques are non-destructive and less time consuming, they assume a random foliage distribution that rarely occurs in nature. Thus a technique is required that would allow for rapid estimation of LAI at the stand level. A means of getting this information is via remotely sensed measurements of reflected energy with an airborne or satellite-based sensor. Such information on an important plant species such as Acacia mearnsii (Black Wattle) is vital as it provides an insight into its water use. Landsat ETM+ images covering four study sites In KwaZulu-Natal midlands encompassing pure stands of Acacia mearnsii were processed to obtain four types of vegetation indices (VIs). The indices included: normalized difference vegetation index (NDVI), ratio vegetation index (RVI), transformed vegetation index (TVI) and vegetation index 3 (VB). Ground based measurements of LAI were made using destructive sampling (actual LAI) and LAI-2000 optical instrument, (plant area index, PAl). Specific leafarea (SLA) and leaf area (LA) were measured in the field for the entire sample stands to estimate their LAI values. The relationships between the various VIs and SLA, actual LAI and PAl values measured by LAI-2000 were evaluated using correlation and regression statistical analyses. Results showed that the overall mean SLA value of Acacia mearnsii was 8.28 m2kg-1 SLA showed strong correlations with NDVI (r=0.71, pThesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

Black wattle (Acacia mearnsii) is one of South Africa's leading commercial exotic species comprising nearly seven percent of South African forestry plantations. The planting of black wattle has become increasingly popular, initially for its high quality tannin content and in more recent times, for its wood and wood products. The industry also provides jobs for more than 36 000 people. Despite the commercial value of black wattle, if left unmanaged, it is one of South Africa's top invader species that aggressively colonise and rapidly out-competes indigenous vegetation. Thus, both plant breeders and environmentalists alike are faced with an interesting paradox of balancing the commercial significance of black wattle on the one hand with increasing environmental concern on the other. At the Institute for Commercial Forestry Research (ICFR), black wattle breeding programmes are being designed and implemented in order to reduce invasiveness whilst still maintaining product quality. One way of minimising invasiveness is to decrease fertility through the introduction of semi-sterility; while at the same time leaving product yield and quality unaffected. A method of achieving semi-sterility is by the induction of autopolyploidy that results in unviable gametes. Autopolyploidy, tetraploidy, is induced chemically through doubling of the chromosomes of diploids. These induced tetraploids may then be crossed with diploids to produce triploids. Thus, an effective method to identify polyploids at the seedling stage would greatly facilitate the success of the abovementioned breeding programmes in the black wattle industry. Polyploidy in plants is often associated with physiological and biochemical changes that become apparent as gigantism of organs which include fruits, flowers and leaves. Polyploidy is also associated with an increase in the number of organelles such as the number of stomatal chloroplasts and nucleoli, as well as an increased production of some proteins and pigments such as chlorophyll. These ploidy-related manifestations are often utilised in breeding programmes to increase the size and quality of plant products as well as a tool to discriminate between polyploids and diploids. Two putative diagnostic procedures to differentiate between diploid and tetraploid black wattle were developed in this investigation. The study focused on the discriminating power of stomatal chloroplast numbers and arrangements as well as the chlorophyll content in the two different ploids. A number of associated experiments were initially conducted to establish the optimal conditions for chlorophyll content analyses such as the type of leaf material and storage conditions. Stomatal chloroplast frequencies were determined in diploid and tetraploid black wattle and comprised three lines per ploidy level with five plants per line. A thin epidermal layer from the abaxial surface of a pinnule was stripped, stained, mounted and 15 stomatal guard cells per plant were viewed at 40X magnification. The mean number of chloroplasts per cell in diploids (9.89 ± 0.222) was found to be statistically different (p < 0.001) to that of tetraploids (22.43 ± 0.222) with no overlapping of the mean chloroplast values between the two ploidy levels. The ratio of diploid and tetraploid stomatal chloroplast numbers was roughly 1:2. An analysis of the least significant difference (LSD) was performed and indicated significant differences between plants within lines, between lines of different ploids (LSD =0.6266), as well as between the different ploids (LSD =0.2802). Furthermore, stomatal chloroplasts spatial arrangements were distinctly different in diploids and tetraploids. In diploids, chloroplasts were clustered into two regions, each towards the extreme ends of the kidney shaped stomatal cells. In the tetraploids, no clustering of chloroplasts could be identified, with an even distribution around the convex curvature/perimeter of the cells. There are a number of factors that influence chlorophyll content and degradation, which are either environmental or genetic in nature. Environmental factors that were considered are sample age and sample storage conditions. Genetic factors include genetic composition and, specifically, the number of sets of chromosomes, that is, the ploidy. Chlorophyll content was investigated by chemically extracting chlorophyll from leaf material and obtaining absorbance spectra with a PerkinElmer UV/vis spectrometer for wavelengths from 400 nm to 700 nm. Chlorophyll absorbance spectra were generated in terms of leaves stored prior to chlorophyll extraction, leaves of different ages, trees of different ages and ploidy. The effects of storage of leaves on chlorophyll content were determined in five non-identical two year-old nursery diploid black wattle genotypes. Fifteen leaf samples from each genotype were either oven dried and then stored for one week or one month at room temperature, or frozen for one week or one month at -4 °C, before chlorophyll was extracted and absorbance spectra determined. Chlorophyll absorbance values of chlorophyll extracted from leaf material on the day of collection (day-0) was used as the control. An analysis of variance (ANOVA) revealed that the chlorophyll absorbance values of the different storage treatments were all significantly lower than the chlorophyll absorbance values of the control (p < 0.001). Assessment of the mean chlorophyll absorbance (TĀ), sum of the three peak absorbance values at three wavelengths, namely, 433 nm, 456 nm and 663 nm, revealed significant differences (p < 0.001) from the control (TĀ = 1.275) for all treatments. Dried leaves that were stored for seven days (TĀ = 1.132) resulted in the least amount of chlorophyll degradation followed by 28 day ice storage (TĀ = 1.114), seven day ice storage (TĀ = 1.103) and lastly 28 day dried storage (TĀ = 1.093). An analysis of least significant differences (LSD) revealed that chlorophyll absorbance values within lines and between wavelengths were significantly different (LSD = 0.005). Furthermore, LSD analysis revealed significant differences between all treatments (LSD =0.003) which also supported the ANOVA findings. Chlorophyll absorbance values within dried and frozen treatments were compared with respect to storage time periods of one week and one month. It was noted that whilst all treatments decreased from the control (day-0), dried samples responded differently to storage periods as compared to frozen samples. Chlorophyll absorbance values of dried material decreased steadily over time from control to seven-day storage to one-month storage, whereas, in the case of frozen material, a similar trend could not be identified. A greater decrease from the control to seven day ice storage was recorded than for the decrease from the control to 28 day ice storage. The effects of tree and leaf ages of diploid black wattle on chlorophyll content were determined. Two types of leaf flushes namely, old and new flush, were examined in relation to different tree ages; two, four, six, eight and nine year-old; in order to assess whether the choice of material impacts on chlorophyll absorbance values. Five leaf samples from each tree were collected, bagged and chlorophyll extracted within two hours of collection. These chlorophyll absorbance values were compared to young diploid seedling material as a base-value and as a control value. An analysis of variance (ANOVA), revealed significant differences between tree ages and between leaf ages (p < 0.001). An analysis of least significant differences (LSD) revealed that new flush of all tree age groups were significantly different from the control (LSD = 0.006). This was mostly true for old flush, except that of six year-old old flush which was not significantly different from the control (LSD =0.006). The chlorophyll absorbance values of both old and new flush of different age groups produced spectral graphs for which no specific trends could be ascertained. Therefore, the data from the two flush types were pooled and revealed a marked increase in chlorophyll absorbance as trees became older. Moreover, this increase was more apparent in new flush than in old flush. Interestingly, juvenile characteristics were identified in two year-old black wattle trees, where a marked increase in chlorophyll content was noted. The effects of the number of chromosome sets on chlorophyll content were assessed for diploid and tetraploid black wattle. Seedlings, bagged juveniles as well as two year-old field trees were analysed. Three genetic lines per ploidy level comprising of ten plants per line were used in the analysis. An analysis of variance (ANOVA) revealed significant increases of chlorophyll absorbance values (p < 0.001) for diploid seedlings (TĀ = 1.1086) to bagged trees (TĀ = 1.149) to field trees (TĀ = 1.224). Similar significant increases were recorded for the tetraploid seedlings (TĀ = 1.886) to bagged trees (TĀ = 1.931) to field trees (TĀ = 2.059). There were distinct differences in chlorophyll absorbance between the two levels of ploidy (LSD =0.002). Furthermore, chlorophyll absorbance within lines, between wavelengths were found not to be significant (p = 0.984), which was supported by an analysis of least significant differences (LSD = 0.004). Moreover, the ratio of diploid to tetraploid chlorophyll absorbance was roughly 2:3. Additionally, the increase of chlorophyll content from seedlings to bagged juveniles to field material of both diploid and tetraploid black wattle further supported the findings in the previous age study that there was an increase in chlorophyll content as the tree matures. Stomatal chloroplast frequencies and chlorophyll content have been identified as two methods that are able to effectively, and with ease, discern between diploid and tetraploid black wattle.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Black wattle (Acacia mearnsii), which belongs to the genus Acacia, is one of the many species of trees or hardwoods grown commercially in South Africa. Black wattle is a species indigenous to Australia and was introduced into South Africa by the van der Plank brothers in 1864. These trees are grown in South Africa because of its tannin-rich bark, the extract of which is used by the leather tanning industry. Black wattle is also grown for its timber, timber products and pulp. The introduction and cultivation history of black wattle suggests that the South African plantations contain limited genetic variation with relatedness amongst groups estimated to be high, thus implying a narrow genetic base in the South African black wattle population. In this investigation, Random Amplified Polymorphic DNA (RAPD) was used to estimate the genetic variation between seven different black wattle groups. A total number of 34 individuals obtained from different areas in South Africa were examined; Piet Retief (group 47 and 50: half-sibs), Kumbula (group 85: unrelated individuals), Howick (group 400: unrelated individuals) and an unknown area (groups 88, 89, 91: full-sibs). As this investigation was the first of its kind, a DNA isolation method as well as a PCR-RAPD protocol had to be modified. Total genomic DNA was successfully extracted using the CTAB DNA extraction method. This method removed large amounts of tannin present in the cells of the black wattle leaves and extracted high quality DNA to conduct between 50-100 RAPD reactions. The DNA purities ranged from 0.1 to 1.8, with an average of 1.46. A total of fourteen 10-mer RAPD primer sequences were randomly selected from the Operon Technologies primer list A, and tested in this investigation. Of the 14 primers used, only nine primers produced clear, single and repeatable bands. Therefore nine primers were selected for subsequent analyses. Ninety one loci that generated bands ranging from 300-3050 base pairs were produced. Seven to 13 loci per primer were generated. A total of 95.6 % of the loci were polymorphic. The overall expected mean heterozygosity (H = 0.3) obtained in this study was high in comparison to other studies conducted on acacias. The high levels of genetic variation were attributed to mating systems, dissortative mating and geographic distribution. The statistical packages POPGENE and ARLEQUIN were used to analyse the RAPD fingerprints. The genetic measures, Nei's diversity and Shannon's Information Index, showed that there was greater diversity exhibited (Nei's gene diversity = 32.09 % and Shannon's = 48.31 %), in the whole population than in each of the groups (with average of Nei's gene diversity = 20.33 % and Shannon's = 34.64 %). With regards to individual group analyses, low levels of genetic variation was obtained in group 400 (unrelated), from the Howick region, and group 85 (unrelated), from the Kumbula region, (mean 0.14 and 0.17 respectively). The low genetic values were attributed to limited gene exchange occurring in these two areas, bottlenecks and selection pressures. Groups 88, 89 and 91, from the unknown region (full-sib groups), were the most variable in comparison to the other groups, with means of (0.27,0.24 and 0.18 respectively). These high genetic variation values could be due to the fact that gene migration could have occurred between these groups and others in the area. It is thought that most acacias are insect-pollinated and this could have lead to gene migration between groups or populations, thereby explaining the high mean values. The gene flow obtained for the seven groups (FST = 0.174) indicated that great genetic differentiation existed in this population of black wattle studied. This value is higher in comparison to other woody species; however it is similar to other acacia species. UPGMA cluster analysis using Nei's unbiased genetic distance, revealed four distinct clusters of groups corresponding to the distribution areas represented in this study. The Howick (group 400: unrelated) and Kumbula (group 85: unrelated) were more closely related to each other than to the other groups, since both these groups are from Natal. The Piet Retief groups (groups 47 and 50: half-sibs), branched-off together, indicating that they are distinct from the other groups. The pairwise analysis of identity showed that the relationship between the group from Howick (group 400: unrelated) and all the other groups from the other regions was the lowest, ranging from 64 % to 79 %. The relationship between all the groups beside the group from Howick (group 400: unrelated) was reasonably high, ranging from 78 % to 90 %. This distance displayed by group 400 (unrelated) from Howick in relation to the groups, is attributed to the fact that it is frost resistant and the other groups not. Genetic variation was also detected and partitioned, between and within groups, by Analysis of Molecular Variance (AMQVA). Majority of the variation existed within groups (82.65 %) but significant differentiation was recorded between groups (17.44 %). This high level of within group differentiation may be explained by many aspects, such as the species breeding system, genetic drift or genetic isolation of groups or populations. The application of RAPD fingerprinting in black wattle has provided a more in depth understanding of the genetic variation residing in the South African population. The results achieved implementing this technique has shown that significant genetic variation exists within the black wattle population in South Africa. The results obtained in this study are also important since it is contrary to the expectation that the black wattle population in South Africa has low genetic variation. This knowledge is of great value to genetically discriminate between individuals or groups, to improve the selection of superior genotypes and allowing improved quality control in breeding programmes and seed orchard management.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

In South Africa, invasive black wattle trees (Acacia mearnsii D. Wild) are a major threat to ecosystem functionality causing widespread social, economic and environmental degradation. It is important that environmental managers are provided with rapid, regular and accurate information on the location of invasive black wattle trees to coordinate removal efforts. This study investigated the potential of an automated image classification algorithm to accurately identify black wattle (A. mearnsii De Wild.) trees using imaging spectroscopy. Hyperspectral data acquired by the EO-1 Hyperion sensor was used to identify black wattle trees in two study areas near Greytown, KwaZulu-Natal, South Africa. Image classifications were performed by the classification algorithm to identify black wattle trees using general and age specific spectral signatures (three to five years, seven to nine years, eleven to thirteen years). Results showed that using the general spectral signature an overall accuracy of 86.25% (user’s accuracy: 72.50%) and 84.50% (user’s accuracy: 69%) was achieved for study area one and study area two respectively. Using age specific spectral signatures, black wattle trees between three to five years of age were mapped with an overall accuracy of 62% (user’s accuracy: 24%) and 74.50% (user’s accuracy: 49%) for study area one and study area two respectively. The low user’s accuracies for the age specific classifications could be attributed to the use of relatively low resolution satellite imagery and not the efficacy of the classification algorithm. It was concluded that the classification algorithm could be used to identify black wattle trees using imaging spectroscopy with a high degree of accuracy.
Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.