899 resultados para Eucalyptus citriodora
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In 2010, the Brazilian forest sector is represented by about 30,000 companies producing US$ 21 billion annually and account for approximately 5% of the gross domestic product (GDP) in the country. The sanding process is highly demanded in various stages of industrialization of the wood, when there is a need for a better quality surface finishing. The objective of this work was to analyze the influence of cutting speed and sandpaper granulometry on both the surface finishing of pieces of Eucalyptus grandis processed through tubular sanding and on the sanding efforts (force and power of sanding). Four cutting speeds were used (19.5, 22.7, 26 and 28.1 m/s), one advance speed (16 m/min) and three sets of sandpaper (80-100, 80-120 and 100-120) being one for chipping and another for finishing, respectively. A central data acquisition system was set up to capture the variables (cutting power, acoustic emission and vibration) in real time. The cutting force was obtained indirectly, through a frequency inverter. The roughness of the parts was measured by a roughness meter before and after sanding. The highest cutting speed used (28.1 m/s) consumed more power and generated more acoustic emission among the four speeds tested. Regarding the vibration, the lower cutting speed (19.5 m/ s) generated the highest vibration in the sander machine. It is concluded that the range of 100-120 sandpapers resulted in values of average roughness (Ra) lower than the other sets of sandpaper used, as it resulted in better surface finishing.
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Pós-graduação em Agronomia (Produção Vegetal) - FCAV
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Can hydrogen peroxide and quercetin improve production of Eucalyptus grandis x Eucalyptus urophylla?
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Vegetative propagation is considered the best choice for the rapid multiplication of plant species, however, rooting may still present difficulties. Substances, such as auxins, phenolic compounds and hydrogen peroxide, are recognized as able to improve this process. The aim of the present work was to determine if hydrogen peroxide in combination with quercetin or indole butyric acid, can modify some characteristics related to rooting and development in cuttings of Eucalyptus grandis x Eucalyptus urophylla. Cuttings were periodically evaluated at 30, 60 and 90 days according to the following criteria: height, diameter and survival percentage. After planting (90 days), a destructive evaluation was performed to determine rooting percentage, average size and number of roots. Polyamines content and polyamine oxidase activity, as biochemical markers of plant development, were determined. No statistically significant differences in height, diameter, survival and rooting percentage, root length and number of roots per cuttings were found. Treatments induced a decrease in putrescine levels and polyamine oxidase activity in roots. For absence of positive responses, the use of these substances as a treatment to improve cutting production is economically unviable.
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The objective of this study was evaluate the effects of retification® temperatures and times on thickness variation from Eucalyptus grandis timber. Boards from logs of 30-year-old Eucalyptus grandis trees, from São Paulo Forest Institute in Santa Barbara, Brazil, were thermally modified at 180ºC for 2.5 hours, at 200ºC for 3.0 hours and 200ºC for 4.0 hours. The results showed that: (1) the thermally modified wood at 200°C by 3.0 to 4.0 hours showed increased thickness between 0.698 mm and 0.874 mm due to the internal cracks, (2) the thermally modified wood at 180°C by 2.5 hours has a decreased from 0,177 mm in thickness and the absences of internal cracks.
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O objetivo deste estudo é obter um modelo matemático logístico que representa a vaporização de toras de Eucalyptus grandis, em função do diâmetro e do tempo de permanência das toras no tratamento térmico a vapor. Para tanto, foram coletadas toras nas classes diamétricas de 25 a 40 cm de três árvores de E. grandis provenientes do Horto Florestal de Mandurí, SP. Em cada uma das toras foram inseridos três termopares, com profundidades distintas, 1/3 do raio; 2/3 do raio e o terceiro, próximo ao seu centro. Posteriormente, as toras foram vaporizadas a 85ºC e 100% de umidade relativa, até que o último termopar atingisse uma temperatura de 80ºC. Um Datalogger CR10 registrou as temperaturas, no interior do material, durante o tratamento térmico. Conclui-se que o modelo matemático logístico foi bem ajustado, obtido no tratamento térmico com vapor, levando em consideração as três classes de diâmetro e a profundidade máxima de 50 mm de raio, o modelo gerado, apresenta-se uma viabilidade técnica na aplicação do processo de aquecimento de toras com vapor, promovendo um consumo ideal de energia.
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One of the important techniques to assist a tree improvement program is the grafting, which is used for the propagation of selected trees. The objective of this study was to evaluate the survival rate using a modified method of lateral grafting on Eucalyptus dunnii, Eucalyptus urophylla and a hybrid of Eucalyptus urophylla x Eucalyptus grandis. The work was conducted by the research teams of Eucatex and Palmasola companies, in September of 2011, and 589 grafts were made. The survival rate of the grafts was evaluated 180 days after grafting. Survival grafts rates were: 74% for E. dunnii, 55% for E. urophylla and 62% for the hybrid E. urophylla x E. grandis. These survival rates were higher than those currently obtained by the conventional method of eucalypt grafting. Thus, the method seems promising to assist in forest tree improvement programs, but further studies are still necessary to refine this grafting approach.
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The research objective was to study the genetic diversity of morphological traits in Eucalyptus grandis progenies growing under paclobutrazol regulator effects. The progeny trail was set up through design of randomized blocks. The morphological changes occurred before and during the plant flowering were analyzed. The estimation of genetic parameters were for plant height and stem diameter. The paclobutrazol have caused changes on plant development being strong by the beginning and becoming lightening through the evaluations. The coefficients of variation have shown there is higher genetic diversity within than among progenies for the studied traits. Therefore, it can have high efficiency on selection within progenies in the Eucalyptus grandis breeding program.
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Genus Atta includes some of the most important Formicidae leaf cutter ants which cause extensive damage to the eucalyptus plantations. Atta sexdens rubropilosa Forel, one of the chief pests in Brazilian reforestation, can restrict and reduce forest productivity by its intense and constant leaf-cutting activities on plants at all stages. Therefore, the demand for new products to control A. sexdens rubropilosa indicates the study of the utilization of the dry powder formulation of diatomaceous earth (DE) against this pest in the eucalyptus cultivars. The study was conducted using 120 colonies of A. sexdens rubropilosa in Eucalyptus grandis Hill ex. Maiden x Eucalyptus urophylla Blake (Myrtaceae) (urograndis) stand. The randomized block experimental design was used with six treatments (1, 10, 25, and 50 g/m2 of DE, 6.0 g/m2 sulfluramid bait per square meter of loose soil, and the control) with five replications, each with four colonies of this ant. Diatomaceous earth was applied to the active A. sexdens rubropilosa ant holes, and the sulfluramid bait was applied in bulk in a localized manner. The control efficacy of A. sexdens rubropilosa with DE was low, showing values similar to that of the control, and, for this reason, it cannot be used to control this ant. The bait with sulfluramid showed higher efficacy than those of the other treatments.
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The bronze bug is an invasive Australian pest that has reached eucalypt production areas worldwide in <10 years. The fi rst record in South America was in 2005 in Argentina. Collaboration in the region towards a unifi ed strategy for the management of the bronze bug started soon after the dispersal of the pest into Brazil and Uruguay was confi rmed. Here, we present the main achievements of this collaboration in four main topics: 1) biology of the pest, 2) monitoring, 3) biological control, and 4) cooperative networks. Two mass rearing procedures have been implemented in the region with relative success, allowing basic biological studies on the pest. Continuous monitoring in the region for >5 years has provided a reasonable knowledge on seasonal patterns of T. peregrinus. Biological control strategies developed include the use of local natural enemies of T. peregrinus, the development of biopesticides, and the introduction of Cleruchoides noackae, an egg parasitoid of T. peregrinus from Australia. We review the main achievements in each country. Finally, a regional network of institutions, researchers, and students has strengthened in the region, providing a solid background for future collaboration.
Biological control of the bronze bug, Thaumastocoris peregrinus, in eucalyptus plantations in Brazil
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The bronze bug Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae) was detected in Brazil in 2008 and infested >180 000 ha of eucalyptus plantations in 2011. The bronze bug can cause a reduction of 10–15% in wood productivity after 2 years of heavy infestation. Although there is not an effective control method known, biological control is the main control strategy studied. An exotic egg parasitoid, Cleruchoides noackae (Hymenoptera: Mymaridae), was imported from Australia in 2012, reared in a laboratory and released in three Brazilian regions. Parasitoids were recovered at release points after 20–30 d. In 2013, preliminary evaluations demonstrated parasitoid establishment in these areas, and the parasitoid was recovered in adjacent areas after 1 year of release. Bioassays confi rmed egg parasitism of 15–20% by C. noackae. Other native natural enemies were studied. We found green lacewing Chrysoperla externa and predatory bugs Supputius cincticeps and Atopozelus opsimus preying on nymphs and/or adults of T. peregrinus. Another promising possibility is entomopathogenic fungi. Commercial formulations of Beauveria bassiana were tested with success in lab and fi eld conditions. Fusarium proliferatum and Paecilomyces cateniannulatus caused mortality of T. peregrinus in natural epizooties. After 5 years of research, it is possible to develop an integrated pest management system (IPM) for eucalyptus plantations based on biocontrol strategy for bronze bug.