Rosilei Aparecida Garcia

Effects of region, soil, land use, and terrain type on fuelwood properties of five tree/shrub species in the Sahelian and Sudanian ecozones of Mali.

Abstract• ContextThere is little information about inter- and intra-specific variation in fuelwood properties of trees/shrubs in West Africa.• AimsWe studied variation in fuelwood properties of Balanites aegyptiaca, Combretum glutinosum, Guiera senegalensis, Piliostigma reticulatum, and Zizyphus mauritiana in the Sahelian and Sudanian ecozones of Mali.• MethodsTrees were sampled on different soil (sandy, sandy/loam, or rocky), land use (parkland agroforest or woodland), and terrain (flat, temporarily flooded, or hill slope) types in five regions extending from the drier eastern to the more humid western parts of Mali. Basic density, volatile matter, fixed carbon, ash content, moisture content, gross calorific value, and fuel value index were measured for each tree and adjusted for tree age.• ResultsAll fuelwood properties differed significantly among species, but there were significant species by region interactions. Most fuelwood properties of four species differed significantly among regions. Soil and/or land use type had significant effects on a few fuelwood properties of four species.• ConclusionIn general, fuelwood production is recommended in all regions for G. senegalensis, in drier regions for B. aegyptiaca and C. glutinosum, in more humid regions for Z. mauritiana, and on rocky soils for all species. Fuelwood production of P. reticulatum is not recommended.

Surface roughness of heat treated Eucalyptus grandis wood

This study aimed to evaluate surface roughness of heat treated Eucalyptus grandis wood after peripheral planning and sanding performed in directions to the grain and against the grain. For machining tests, workpieces were collected from two different regions in the radial direction, as follows: internal, nearby the pit; external, nearby the bark. Heat treatment was carried out by heating samples at a maximum temperature of 190oC, with total treatment duration of 390 minutes. Heat treated and control samples underwent peripheral planning and sanding tests. The quality of machined surfaces was assessed by means of roughness average (Ra) measurements across and along the grain orientation. Results indicated significant differences in surface roughness as a function of machining feed direction, sandpaper grit size, and heat treatment. Surface roughness has not shown any difference in the radial direction.

Correlações da altura e diâmetro com tensões de crescimento em árvores de Corymbia citriodora e Eucalyptus urophylla

The multiple-use of planted forests by the forest products industrial sector has been increased gradually. Today, eucalyptus wood is used for nobler applications. However, some limitations, such as the presence of growth stresses, are responsible for great losses in the sector. Growth stresses generate cracks in the tops of logs and boards followed by warping. In this context, the objectives of the present work were to evaluate the growth stresses in individual Corymbia citriodora and Eucalyptus urophylla with different diameter and height classes, by the longitudinal residual strain (LRS) nondestructive method, around the trees circumference. The average longitudinal residual strain, associated to the Corymbia citriodora and Eucalyptus urophylla growth stresses, were 0.106 and 0.092 mm, respectively. For Corymbia citriodora, the diameter at breast height (DBH) had a negative significant correlation with the LRS, while the height did not show a significant correlation. For Eucalyptus urophylla, a negative significant correlation between LRS and both variables, DBH and height, was observed. Indeed, growth stresses were lower for greater DBH and heights.

Color stability of weathered heat-treated teak wood

This study investigated the color stability in a heat treatment of teak wood (Tectona grandis) exposed to ultraviolet radiation under accelerated aging conditions. Nine trees from three different spacing levels were used. Samples of 150 mm x 75 mm x 20 mm were prepared and divided into two groups: heartwood and sapwood. Two levels of heat treatment (180 and 200°C) were used. The color was measured every 42 hours with a portable spectrophotometer using the CIE-Lab system. Accelerated aging was performed in a QUV/Spray chamber. The total cycle of exposure to ultraviolet radiation was of 168 hours at 340 nm. Tree planting spacing had no effect on color change after ultraviolet radiation. Untreated sapwood had greater color change than untreated heartwood. However, after heat treatment, sapwood showed high color stability, especially at a temperature of 180°C.

Variation in growth, wood density and carbon concentration in five tree and shrub species in Niger

There is little information about variation in growth, wood density and carbon concentration in native tree and shrub species in Africa. This information is needed to make realistic projections about carbon sequestration of different species in different environments. Farmers manage natural regeneration of many native species in the drylands of Niger, so there is interest in carbon sequestration potential of the species. The objectives of this study were to determine: (1) if tree height, stem diameter, mean ring width, wood density and carbon concentration differ among five tree and shrub species (Combretum glutinosum, Combretum micranthum, Combretum nigricans, Guiera senegalensis, Piliostigma reticulatum) in Niger; (2) if variation within species is affected by land use type (parkland agroforests, woodlands), soil type (sandy, rocky), terrain type (temporarily flooded, flat, hill slope) and mean annual rainfall; and (3) if growth variables, wood density and carbon concentration are correlated in the five species. Environmental variables did not have strong effects on growth and wood variables of the species, and some effects differed among species. Height across species increased with mean annual rainfall. Stem diameter and mean ring width across species were greater in parkland agroforests than in woodlands. Carbon concentration was positively correlated with growth variables of four species, but was not correlated with wood density in most species. Correlations between wood density and growth differed in sign among some species. We conclude that above-ground carbon sequestration per tree probably increases with mean annual rainfall and is greater in parkland agroforests than in woodlands.

Variation in growth, wood stiffness and density, and correlations between growth and wood stiffness and density in five tree and shrub species in the Sahelian and Sudanian ecozones of Mali

Key messageMost effects of environmental variables on growth, wood stiffness, specific stiffness and density, and correlations between growth and wood stiffness, specific stiffness and density were not consistent among species.AbstractWood stiffness is a key functional trait of woody plants, but variation in wood stiffness has not been studied in native tree and shrub species in Africa. We investigated variation in growth (height, stem diameter, height/diameter ratio, ring width), wood stiffness (dynamic modulus of elasticity in longitudinal and tangential axes), specific wood stiffness (dynamic modulus of elasticity divided by air-dry density) and air-dry density of Balanites aegyptiaca, Combretum glutinosum, Guiera senegalensis, Piliostigma reticulatum and Ziziphus mauritiana related to region, land use type, soil type, terrain type, latitude, longitude, elevation and mean annual rainfall, and correlations of growth with wood stiffness, specific wood stiffness and wood density in the Sahelian and Sudanian ecozones of Mali. Growth variables, wood stiffness and wood density differed significantly among some of the species, but specific wood stiffness did not differ significantly among any of the species. There were few consistent effects of the environmental variables on growth and wood variables of the five species. Geographical coordinates generally had stronger effects than mean annual rainfall on growth and wood variables of the species. Positive correlations between growth and wood density were significant in three of the species. Correlations between height and wood stiffness and/or specific wood stiffness differed in sign among some of the species. Results illustrate that different species may respond differently to environmental factors in the Sahelian and Sudanian ecozones of West Africa.

Efeito da termorretificação nas propriedades físicas e químicas da madeira de Pinus caribaea

Conduziu-se este estudo, com o objetivo de avaliar o efeito da termorretificacao nas propriedades fisicas (densidade aparente, teor de umidade de equilibrio, perda de massa, contracao e inchamento lineares e volumetricos) e na composicao quimica da madeira normal (lado oposto) e de compressao de Pinus caribaea Morelet. Amostras de 25 x 25 x 50 mm foram termorretificadas sob duas temperaturas: 200 e 220 oC. Os resultados indicaram uma reducao no teor de umidade de equilibrio e nos inchamentos e contracoes apos a termorretificacao, independente do tipo de lenho. A madeira de compressao apresentou maior inchamento longitudinal que a madeira normal, entretanto, apos a termorretificacao, as melhorias foram similares entre os dois tipos de lenho. As madeiras termorretificadas a 200 e 220 oC apresentaram perdas de massa de 9,94 e 21,03 %, respectivamente. A termorretificacao promoveu um aumento relativo no teor de lignina e uma reducao nos teores de holocelulose e α-celulose, indicando a ocorrencia de degradacao termica desses componentes.

Variation and correlations in traits of Prosopis africana and Balanites aegyptiaca in the West African Sahel: implications for tree domestication programs.

ABSTRACT Rural communities in the West African Sahel use Prosopis africana and Balanites aegyptiaca for construction wood, fuel and other needs. Provenance/progeny tests were established at one site in Niger, and evaluated after 11 (growth, survival) and 13 years (wood basic density, calorific value). Based on analysis of variance, growth and wood density varied significantly among provenances and families of P. africana only. For both species, linear regressions demonstrated that provenances from drier zones of the Sahel grew faster than those from more humid zones. P. africana provenances from drier zones also had denser wood and higher survival. In contrast, wood calorific value of both species was generally higher in provenances from more humid zones. Larger trees of both species tended to have denser wood and higher calorific value, but density and calorific value were not significantly correlated. Results suggest that selecting faster growing trees could indirectly increase both wood density and calorific value.

Qualidade de adesão de juntas coladas de diferentes espécies comerciais de madeira

Neste estudo, objetivou-se determinar o efeito da densidade da madeira, do tipo de adesivo e da pressao de colagem na resistencia ao cisalhamento de juntas coladas de quatorze especies comerciais de madeira. As madeiras foram classificadas em tres classes de densidade (Classe 1: menor que 0,55 g cm-3; Classe 2: entre 0,55 e 0,75 g cm-3; e Classe 3: maior que 0,75 g cm-3) e as juntas foram coladas com dois adesivos: acetato de polivinila (PVA) e ureia-formaldeido (UF), sob duas diferentes pressoes de colagem: 6 e 12 kgf cm-2. As juntas coladas com o adesivo PVA apresentaram maior resistencia ao cisalhamento que aquelas coladas com o adesivo UF. Quanto a porcentagem de falha na madeira, o adesivo PVA tambem obteve o melhor desempenho, entretanto, somente as madeiras das Classes 1 e 2 atingiram os valores requeridos pela norma ASTM 3110. As especies de madeira da Classe 3, coladas com UF, nao atingiram os valores de resistencia da madeira solida. A pressao de colagem de 12 kgf cm-2 foi mais eficiente para as madeiras da Classe 3, tanto para a resistencia ao cisalhamento quanto para a porcentagem de falha na madeira.

Correlações dendroclimatológicas do Eucalyptus grandis Hill ex Maiden na região de Rio Claro, RJ

The commercial forests plantation contributes decisively to generate socio-economic and environmental benefits, providing sustainability at the forest-based industries. The Eucalyptus grandis Hill ex Maiden stand out as one of the most cultivated species for reforestation in Brazil. The objective of this study was to determine the relationship between precipitation and wood production for 23-year old Eucalyptus grandis from a commercial plantation in Rio Claro, Rio de Janeiro state, Brazil. The annual increment of wood was determined by the X-ray densitometry, which provides a detailed wood density profile in radial direction for each sample. One year of the tree life was considered because this the period for the formation of two consecutive latewood rings formation, which corresponds to two high density peaks. The results showed a positive correlation between precipitation data and annual increment of wood, revealing the dendroclimatology potential of this species in this region.