Performance of 19-year-old provenances of Liquidambar styraciflua in Paraguaçu Paulista, São Paulo

The genetic variation in the growth of seven 19-year-old Liquidambar styraciflua provenances was studied in Paraguaçu Paulista, São Paulo State, Brazil. The trial was established in a complete randomized block design with seven provenances, four replications and twelve-tree square plots. Significant differences among provenances were detected for diameter at breast height, height and volume, indicating the possibility of increasing timber yield through selection of the most productive provenances. Genetic correlations between growth traits were high and statistically significant. The provenance from Finca las Victorias, Guatemala had the best and the provenance from Franklin, Virginia, United States the poorest performance for all traits. A growth comparison of Pinus caribaea var. bahamensis with the best provenance at the same site indicated that the potential of L. styraciflua for silviculture in the region of Paraguaçu Paulista is high.

Emprego da reflectometria por domínio do tempo na determinação da umidade de madeiras comerciais

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Emprego de ferramentas numéricas na avaliação do módulo de elasticidade em vigas roliças de madeira

Vigas são elementos estruturais encontrados na maioria das construções civis. Dentre os materiais de engenharia, destaca-se a madeira, por ter resistência mecânica satisfatória aliada a baixa densidade. A madeira roliça apresenta-se como boa solução na confecção de vigas, uma vez que não precisa ser processada, como é o caso da madeira serrada. O projeto de elementos estruturais de madeira requer o conhecimento de suas propriedades físicas e mecânicas, obtidas segundo as premissas de documentos normativos. Em se tratando da madeira roliça, os documentos normativos nacionais que tratam da determinação das propriedades de resistência e rigidez estão vigentes há mais de vinte anos sem revisão técnica. De forma geral, tanto as normas nacionais como as internacionais idealizam geometria troncocônica para as peças roliças de madeira, implicando equações simplificadas incapazes de prever a influência das irregularidades da forma na determinação do módulo de elasticidade longitudinal. Este trabalho objetiva avaliar a influência das irregularidades da geometria em peças roliças de madeira Corymbia citriodora e Pinus caribaea no cálculo do módulo de elasticidade longitudinal. Para tanto, utilizou-se do ensaio de flexão estática a três pontos, considerando também um modelo matemático simplificado, assumindo seção circular constante para a forma do elemento. As irregularidades das peças são consideradas nos modelos numéricos, constituídos de elementos finitos de barra e tridimensionais. Os resultados encontrados revelam equivalência estatística entre os módulos de elasticidade para ambas as formas de cálculo, indicando ser plausível a consideração de seção circular constante para as peças de madeira aqui avaliadas.

Fuel manipulation with herbicide treatments to reduce fire hazard in young pine (Pinus elliottii × P. caribaea) plantations in south-east Queensland, Australia

Wildfire represents a major risk to pine plantations. This risk is particularly great for young plantations (generally less than 10 m in height) where prescribed fire cannot be used to manipulate fuel biomass, and where flammable grasses are abundant in the understorey. We report results from a replicated field experiment designed to determine the effects of two rates of glyphosate (450 g L–1) application, two extents of application (inter-row only and inter-row and row) with applications being applied once or twice, on understorey fine fuel biomass, fuel structure and composition in south-east Queensland, Australia. Two herbicide applications (~9 months apart) were more effective than a once-off treatment for reducing standing biomass, grass continuity, grass height, percentage grass dry weight and the density of shrubs. In addition, the 6-L ha–1 rate of application was more effective than the 3-L ha–1 rate of application in periodically reducing grass continuity and shrub density in the inter-rows and in reducing standing biomass in the tree rows, and application in the inter-rows and rows significantly reduced shrub density relative to the inter-row-only application. Herbicide treatment in the inter-rows and rows is likely to be useful for managing fuels before prescribed fire in young pine plantations because such treatment minimised tree scorch height during prescribed burns. Further, herbicide treatments had no adverse effects on plantation trees, and in some cases tree growth was enhanced by treatments. However, the effectiveness of herbicide treatments in reducing the risk of tree damage or mortality under wildfire conditions remains untested.

Carcterização da influência da velocidade de corte, pressão e granulometria de lixa no lixamento plano do Pinus elliottii

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ganho esperado na seleção de progenies de Pinus elliottii var. elliottii em idade precoce para produção de madeira

Pós-graduação em Agronomia - FEIS

Performance of seven hardwood species underplanted to Pinus elliottii in south-east Queensland

Seven hardwood species were tested as underplants under Pinus elliottii plantations on the coastal lowlands of south-east Queensland. The species tested were: Flindersia brayleyana (F. Muell) (Queensland maple), F. australis (R. Br.), (crow's ash), Swietenia macrophylla (King) (American mahogany), Grevillea robusta (A. cunn) (southern silky oak), Elaeocarpus grandis (F. Muell) (silver quandong), F. ifflaiana (F. Meull) (Cairns hickory) and Ceratopetalum apetalum (D. Don) (coachwood). Most species (except E. grandis) established successfully but slowly. Underplants suffered 9-16% mortality during thinning of the overstorey. By 2004 when aged c. 38 years, four underplanted species; F. brayleyana, S. macrophylla, F. ifflaiana and E. grandis, had attained predominant heights of 20 m and mean diameter at breast height of 25 cm or better. The presence of underplants increased total site productivity by up to 23% and did not have any detrimental effect on the development of the overwood.This experiment has demonstrated that some rainforest species will survive and grow healthily as underplants in exotic pine plantations plus produce small merchantable logs within a 38 year rotation. The results also indicated the importance of correct species selection if an underplanting option is to be pursued as some species have been a complete failure (notably G. robusta).

Propriedades físicas dos lenhos juvenil e adulto de Pinus elliottii Engelm var. elliottii e de Eucalyptus grandis Hill ex Maiden

The juvenile wood presents great difference in its anatomical and physical properties in relation to the mature wood. That heterogeneity of the wood causes a series of upset for the processing industry. The present research had as objective the study of the physical properties of the juvenile and mature wood of Pinus elliottii Engelm var. elliottii, with 25 years of age and of Eucalyptus grandis Hill ex Maiden, with 30 years of age, coming from the Experimental Station of Itapetininga and State Forest of Santa Barbara, belonging to the Forest Institute of the state of São Paulo. From both species there were taken from radial boards, specimens with dimensions of 20x30x50 mm, for the determination of density, swelling and swelling coefficient of the juvenile and mature wood. The results of the species showed that the mature compared with the juvenile wood presented: (1) an increase in the values of the basic density, at 0% and at 12% of moisture content and of the volumetric, radial and tangential swelling at 12% moisture content and maximum coefficient of radial and tangential swelling; (2) a reduction in the values of longitudinal swelling at 12% and maximum and of the longitudinal swelling coefficient.

Physical and chemical changes in juvenile and mature woods of Pinus elliottii var. elliottii by thermal modification

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nutrients cycling aspects in stands of Pinus-elliottii engelm var elliottii under differents resining intensities .1. litter fall

Litter production was measured for two years (november 1986 to october 1988) in a 29 year -old Pinus elliottii var. elliottii stand in differents resin treatments. Needle production comprised 9 to 93% of total litter fall, while the other categories (branches, barks, seeds and cones) were not significant. Maximum litterfall occurred in march to may 1987 (autumn) and the minimum was in august 1988 (winter) for all treatments and the control. No relationship appeared between annual litterfall and environmental factors, although there was a tendence to exhibit two periods of production: one in summer and other in winter. The results showed that in two years of resin extraction was not sufficient in interfering the litter fall and consequently the productivity.

Nutrient cycling aspects in stands of Pinus-elliottii engelm var elliottii under differents resining intensities .2. nutrients contents in litter

Annual and monthly quantities of nutrients wich returned to the soil through litter fall in Pinus elliottii Engelm. var. elliottii stand were estimated durint a two years period, in Experimental Station of Mogi-Guacu, SP. From the trees of the stand was extracted oleoresin according two differents techniques and control. The annual average of nutrients that returned to the soil was 72.2 Kg/ha, in following order: N > Ca > K > Mg > P. No relationship appeared between nutrient concentrations plus quantities when they were compared with oleoresin yields treatments and control. The differences in annual quantities were possibly due to climatic factors. The soil profile showed short concentrations in nutrient contents. Thus, the forest may be suffering by nutrient deficiences.

Delimitação entre os lenhos juvenil e adulto de pinus elliottii engelm

Trees produce different types of woody tissue during growth. The xylem produced in the first years until a certain cambial age is called juvenile wood and has different physical, mechanical, chemical and anatomical characteristics from that produced later, when the cambial cells have matured. Thus, prior knowledge of the quality of the wood is of fundamental importance for choosing the best use of the material. This work aimed at using data from length of the tracheid and wood density to define the age transition from juvenile to mature wood. For this, three Pinus elliottii var. elliottii trees, aged 35 years, were collected at the Itapetininga Experimental Station, located in the state of São Paulo, Brazil. From each tree, disks of about 5 cm thick were obtained 0.05 m above the ground and used to determine the radial density by the gamma ray attenuation method and to measure the length of the tracheids. The results obtained by linear regression analysis showed that juvenile wood is limited to the first seven years of tree growth and the formation of mature wood occurs after twenty years. For the mature wood, there are significant differences among the averages obtained from the tracheid length and wood density.

Comparative study of the life cycle assessment of particleboards made of residues from sugarcane bagasse (Saccharum spp.) and pine wood shavings (Pinus elliottii)

This paper presents a research on the environmental impacts of particleboards produced from wastes, based on a comparative Life Cycle Assessment study. The particleboards were manufactured in laboratorial scale from the following residues: sugarcane bagasse (Saccharum spp.) and pine wood shavings (Pinus elliottii). The study was developed following the methodological guidelines of ISO 14040. The functional unit adopted was the m2 of the particleboards produced and the impacts were evaluated by the Environmental Development of Industrial Products method. The results indicated that pine particleboard present the highest environmental impact potential. Our findings suggested that the factors that mostly aggravated the environmental impacts were: the distance between the raw materials and the production site, and formaldehyde emissions (FE). The first is related to the combustion of fossil fuel during the acquisition of raw material, which achieved the values of 2185.94 g/m2 for consumption of non-renewable resources for pine particleboard and 893.53 g/m2 for bagasse particleboard. The second is related to the use of urea-formaldehyde resin, responsible for the FE into the air during production. The FE is accountable for the contamination of approximately 7,800,000.00 m3 of air per m2 of particleboard produced, and was the factor with the greatest impact in human toxicity potential. © 2013 Elsevier Ltd. All rights reserved.