Graciela I. B. Muñiz

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.

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.

Avaliação das Propriedades Energéticas de Resíduos de Madeiras Tropicais com Uso da Espectroscopia NIR / Evaluation of the Energy-related Properties of Tropical Wood Waste Using NIR Spectroscopy

The aim of this study was to evaluate the energy-related potential of wood residues of four Amazonian species and calibrate the properties of wood and charcoal using the Near Infrared Spectrometry (NIRS) technique. Residue slabs of cardeiro (Scleronema micranthum Ducke), cedrinho (Scleronema sp.), louro (Ocotea sp.), and piquiarana (Caryocar villosum Pers.) wood were used. The following properties were determined: density, chemical composition, immediate chemical analysis, and superior calorific value of wood; and yield, immediate chemical analysis, calorific value, and friability of charcoal. NIR spectra were obtained and calibration models were generated for each energy property. The results indicate that residues of these forest species can be used as a renewable energy source. NIR spectroscopy has proved to be a possible tool for calibrating energy properties of wood.

Classificação de lâminas de madeira de Pinus spp. contaminadas por fungos manchadores

A busca por novas tecnologias que garantam a uniformidade da qualidade dos produtos tem se tornado constante, assim este trabalho teve como objetivo estudar a potencialidade de medidas espectroscopicas combinadas a ferramentas estatisticas para classificacao de lâminas de madeiras de Pinus spp. contaminadas por fungos manchadores. As amostras foram coletadas em processo industrial, e observou-se que algumas lâminas estavam contaminadas por fungos manchadores. Assim, utilizou-se este material para investigar a influencia dessa mancha azul em metodologias espectroscopicas e a possibilidade de discriminacao dessa contaminacao. Desse material contaminado foram capturados os espectros, na faixa de 400 a 1000 nm. Com esses dados, realizou-se uma analise exploratoria por Componentes Principais (PCA) e classificacao via SIMCA, em que se verificou a discriminacao eficiente em dois grupos, madeiras sadias e contaminadas. Observou-se que a tecnica de espectroscopia optica preenche os requisitos necessarios para uma possivel aplicacao na classificacao de lâminas no processo produtivo.

Charred shrimp shells treated with potassium fluoride used as a catalyst for the transesterification of soybean oil with methanol

A basic catalyst made of charred shrimp shells treated with potassium fluoride (KF) was employed in the transesterification reaction of soybean oil in the presence of methanol to produce methyl esters. The shells used here are wastes from freshwater shrimp farming in the western region of the state of Parana, Brazil, which are normally discarded in dumps/landfills and are a rich source of the biopolymer chitin (poly-β-1,4-N-acetyl-D-glucosamine). Charring of the shells (at 450 °C for 2 h) is aimed at partially eliminating rests of proteins and fibers, as well as acetyl groups (-CH3CO), carbon dioxide (-CO2) and water, causing the rearrangement of the chitin structure. The subsequent treatment of the shells with KF (impregnation and activation at 250 °C for 2 h) potentiated the basic sites on the catalyst surface, rendering it active in the transesterification reaction. The catalysts and shrimp shells were characterized by thermal gravimetric analysis, differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, N2 physisorption (Braunauer, Emmet and Teller) (BET), and Hammett basicity. An experimental design was created to evaluate the effect of the following variables of the transesterification reaction:temperature, catalyst weight ratio, and molar ratio of oil:alcohol. The results indicate that the treatment with KF increased the basicity of the catalyst. The highest conversion into methyl esters obtained with the experimental design was 86.3%, using an oil:alcohol molar ratio of 1:9, 3.0% (w/w) of catalyst, 85 °C, and 3 h of reaction. Leaching tests indicated that, after 10 h of refluxing in methanol, a conversion rate of 52.4% was achieved using the catalyst leached in optimized conditions. Kinetic studies showed that chemical equilibrium was established after 8 h of reaction, reaching a conversion rate of 96.7%, which reveals the potential of the catalyst to produce methyl esters (biodiesel).

Development of Chitosan Membranes as a Potential PEMFC Electrolyte

Commercial chitosan and chitosan extracted from shrimp shells are being used to design membranes to be tested as low cost electrolyte in PEM fuel cells. This study investigated the influence of the deacetylation degree (DD) and molar mass (MV) of the chitosans used in the composition of membranes on its performance regarding to proton conductivity and other properties. Preliminary results indicate that the chitosan extracted from shrimp shells generated membranes with promising properties such as proton conductivity, which demonstrated to be even a 100 times higher than those shown by commercial chitosan membranes. The significant increase in proton conductivity can be associated with the higher number and availability of amino groups (–NH2) in the chitosan produced in the laboratory, which presents higher DD and lower MV. It is believed that the properties of chitosan can be manipulated in such a way that it would be possible to obtain proton conductivity values closer to that presented by Nafion®.

A contribution to the identification of charcoal origin in Brazil III: microscopic identification of 10 Cerrado species

Brazil has one of the richest biodiversities in the world. The Brazilian savanna is a hotspot for conservation priorities and its deforestation is of global concern. Conservation in this biome is threatened by unsustainable use of forests, such as illegal logging for charcoal production. Thus, government agents need to verify whether charcoal loads follow the Document of Forestry Origin (DOF). To improve charcoal identification, our study presents the microscopic description of 10 Cerrado species and provides an identification key to aid government agents during surveillance. We analysed charcoal samples with a scanning electron microscope. The method of carbonisation simulated real conditions. We chose species with similar wood anatomy (sparse axial parenchyma and narrow rays), which increases misidentification by forest controllers because of their difficulty to identify these features. Also, paratracheal scanty, diffuse and diffuse-in-aggregates parenchyma were harder to recognise in charcoal than in wood. Other features, such as vessels, rays and abundant axial parenchyma, were easily identified. The present work can be used as a part of a charcoal anatomy database focussed on preventing deforestation in Brazil and in other countries with similar problems.

Surface wettability of Brazilian tropical wood flooring treated with He plasma

This study investigated the effect of plasma treatment on changes of surface wettability of wood flooring from two Brazilian tropical species, Hymenaea spp. (rode locus) and Tabebuia spp. (lapacho). Wood flooring samples were plasma treated at low pressure in a helium atmosphere. Energy level was set at 100 W and four glow discharge times (5, 15, 30 and 45 s) were tested. Changes in wettability were investigated by measuring apparent contact angle, droplet volume and spreading contact area. The results showed less susceptibility of lapacho wood to the plasma treatments, while reduction of apparent contact angle in rode locus wood reached up to 76% for longer discharge times. In general, discharge time of 15 s produced the same effect as discharge of 45 s on wettability, which is important for industrial applications. Visual analyses revealed increase of water droplet spreading on lapacho wood surface, even though the variation of spreading contact area was not significant. Plasma treatment is feasible to improve wettability of tropical woods. Nevertheless, these findings should be investigated further due to the intrinsic characteristics of woods from tropical species.