A characterisation of Pinus pinaster Aiton. (Maritime Pine) woody biomass and ashes is presented in this study. Physical, thermal and chemical analysis, including density, moisture content, calorific ...value, proximate and ultimate analysis, were carried out. The fuel Energy Density (Ed) and the Fuelwood Value Index (FVI) were assessed by ranking the fuelwood quality. Furthermore, the determination of the ash metal elementals was performed. The results from this study indicated, for Pinus pinaster biomass tree components, carbon content ranging from 46.5 to 49.3%, nitrogen content from 0.13 to 1.18%, sulphur content from 0.056 to 0.148% and hydrogen content around 6–7%. The ash content in the tree components ranged from 0.22 to 1.92%. The average higher heating value (HHV) was higher for pine needles (21.61 MJ·kg−1). The Ed of 8.9 GJ·m−3 confirm the good potential of Pinus pinaster biomass tree components as fuel. The FVI ranked the wood stem (4658) and top (2861.8) as a better fuelwood and pine needles (394.2) as inferior quality. The chemical composition of the ashes revealed that the elemental contents are below the national and most European countries legislation guidelines for the employment of ash as a fertiliser.
The introduction of new species in forest management must be undertaken with a degree of care, to help prevent the spread of invasive species. However, new species with higher profitability are ...needed to increase forest products value and the resilience of rural populations. Paulownia tomentosa has an extremely fast growth. The objective and novelty of this work was to study the potential use of young Paulownia trees grown in Portugal by using heat treatment to improve its properties, thereby allowing higher value applications of the wood. The average chemical composition of untreated and heat-treated wood was determined. The extractive content was determined by successive Soxhlet extraction with dichloromethane (DCM), ethanol and water as solvents. The composition of lipophilic extracts was performed by injection in GC-MS with mass detection. Insoluble and soluble lignin, holocellulose and α-cellulose were also determined. Physical (density and water absorption and dimensional stability) and mechanical properties (bending strength and bending stiffness) and termite resistance was also determined. Results showed that extractive content increased in all solvents, lignin and α-cellulose also increased and hemicelluloses decreased. Compounds derived from the thermal degradation of lignin were found in heat-treated wood extractions. Dimensional stability improved but there was a decrease in mechanical properties. Resistance against termites was better for untreated wood than for heat-treated wood, possibly due to the thermal degradation of some toxic extractives.
Shrubs growing in former burnt areas play two diametrically opposed roles. On the one hand, they protect the soil against erosion, promote rainwater infiltration, carbon sequestration and support ...animal life. On the other hand, after the shrubs’ density reaches a particular size for the canopy to touch and the shrubs’ biomass accumulates more than 10 Mg ha−1, they create the necessary conditions for severe wild fires to occur and spread. The creation of a methodology suitable to identify former burnt areas and to track shrubs’ regrowth within these areas in a regular and a multi temporal basis would be beneficial. The combined use of geographical information systems (GIS) and remote sensing (RS) supported by dedicated land survey and field work for data collection has been identified as a suitable method to manage these tasks. The free access to Sentinel images constitutes a valuable tool for updating the GIS project and for the monitoring of regular shrubs’ accumulated biomass. Sentinel 2 VIS-NIR images are suitable to classify rural areas (overall accuracy = 79.6% and Cohen’s K = 0.754) and to create normalized difference vegetation index (NDVI) images to be used in association to allometric equations for the shrubs’ biomass estimation (R2 = 0.8984, p-value < 0.05 and RMSE = 4.46 Mg ha−1). Five to six years after a forest fire occurrence, almost all the former burnt area is covered by shrubs. Up to 10 years after a fire, the accumulated shrubs’ biomass surpasses 14 Mg ha−1. The results described in this paper demonstrate that Northwest Portugal presents larger shrubland areas and greater shrub biomass accumulation (average 18.3 Mg ha−1) than the Northeast (average 7.7 Mg ha−1) of the country.
1. The effects of seasonal inundation on the biology of fishes on floodplains of large Amazonian rivers are well studied. However, the small seasonal changes in headwater streams are generally ...considered to have little effect on fish assemblages. 2. In this study, we analysed seasonal changes in the species composition and abundance of fish in small Amazonian forest streams. We sampled fish with hand and seine nets in headwater streams in a 10 000 ha terra-firme forest reserve near Manaus, Brazil. Each stream was surveyed at the end of the 2005 dry season, at the beginning of the 2006 rainy season and at the beginning of the 2006 dry season, by means of a standardized sampling effort. 3. The numbers of individuals and species caught were higher in the dry season, but rarefaction analyses indicated that greater species numbers could have been due simply to the larger number of individuals caught. 4. Between the dry and rainy season, the direction of changes in species composition in multivariate space varied among sites, especially for quantitative (abundance) data. However, the observed variation among sites was the less than expected if the directions of change were random. 5. Fish assemblages in the second dry season were more similar to those in the previous dry season than expected if changes in species composition among seasons were random. This indicates that a general seasonal pattern in fish assemblages can be detected, despite the existence of some erratic site-specific changes. 6. Most of the species that showed large seasonal variations in density occupy temporary ponds during the rainy season, when much of the valley is inundated and pond networks form adjacent to streams. Short-duration lateral migrations to these ponds may play an important role in the seasonal fish-assemblage dynamics in Amazonian headwater streams. 7. Our results contrast with previous studies on small Amazonian streams, which have found little seasonal change in fish assemblages, and highlight the importance of the abundance of common species as an indicator of general fish assemblage structure in biological monitoring programmes.
Paulownia wood has raised high attention due to its rapid growth and fire resistance. The number of plantations in Portugal has been growing, and new exploitation methods are needed. This study ...intends to determine the properties of particleboards made with very young Paulownia trees from Portuguese plantations. Single layer particleboards were produced with 3-year-old Paulownia trees using different processing parameters and different board composition in order to determine the best properties for use in dry environments. The standard particleboard was produced at 180 °C and a 36.3 kg/cm
pressure for 6 min using 40 g of raw material with 10% urea-formaldehyde resin. Higher particle size lead to lower-density particleboards, while higher resin contents lead to higher density of the boards. Density has a major effect on board properties with higher densities improving mechanical properties such as bending strength, modulus of elasticity (MOE) and internal bond, lower water absorption but higher thickness swelling and thermal conductivity. Particleboards meeting the requirements for dry environment according to NP EN 312 standard, could be produced with young Paulownia wood with acceptable mechanical and thermal conductivity properties with density around 0.65 g/cm
and a thermal conductivity of 0.115 W/mK.
RESUMO O artigo analisa o processo de formação do espaço cívico na cidade de Natal entre 1902 e 1922. Procura compreender o papel central dos historiadores locais e do Instituto Histórico e ...Geográfico do Rio Grande do Norte na construção de uma memória pública republicana por meio do agenciamento de artefatos, da ressignificação de locais públicos e da prática dos rituais cívicos. A pesquisa visa compreender como a nomeação e renomeação de ruas e logradouros, a criação de praças, o entalhamento e a instalação de estátuas, bustos, lápides, hermas e quadros, a identificação de “sítios históricos” e o estabelecimento de espaços edificados para abrigar relíquias e “objetos históricos” colecionados, bem como as celebrações históricas de personagens e de acontecimentos dignos de nota foram importantes na construção de uma identidade coletiva na qual a consciência histórica deveria ter um lugar relevante.
ABSTRACT This article analyzes the formation process of civic space in Natal between 1902 and 1922. We seek to comprehend the central role of local historians and of Instituto Histórico e Geográfico do Rio Grande do Norte (Historical and Geographical Institute of Rio Grande do Norte) in the construction of a public republican memory through the assemblage of artifacts, the attribution of new meanings to public sites and the practice of civic rituals. This research aims to understand how the practice of naming and renaming streets and public parks, creating squares, the carving and installation of statues, busts, tombstones, hermas and paintings, the identification of “historical sites” and the construction of places built to house collected relics and “historical objects”, as well as for the historical celebration of noteworthy characters and events that were important when constructing a collective identity in which the historical consciousness should have a critical role.
With the increase of forest fires in Portugal in recent decades, a significant part of woodlands is being converted into shrubland areas.
: From an ecological point of view, woodlands and shrublands ...play an essential role, as they not only prevent soil erosion and desertification, but also contribute to soil protection, habitat preservation and restoration, and also increased biodiversity for carbon sequestration. Concerning the shrublands, the assessment of their biomass is essential for evaluating the fuel load and forest fire behavior and also beneficial for obtaining estimates of carbon and biomass for energy use.
: In this study, we collected data about the potential shrub biomass accumulation along fifteen years in former burnt areas within North Portugal.
: The achieved results showed that for a post-fire period ranging from one to 15 years, the accumulated shrubs' biomass ranged from 0.12 up to 28.88 Mg ha
. The model developed to estimate the shrub biomass using the time after a fire (age) as a predictor variable presented a high adjustment to data (
-value of the F statistic <0.01 and R
= 0.89), allowing estimating shrub biomass regeneration within former burnt areas with an RMSE of 3.31 Mg ha
.
: This paper provides practical information on the availability and assessment of shrub biomass in North Portugal, highlighting the suitability of shrubs as potential sources of biomass.
Forest management should allow the sustainable use of forests. This is only possible through solid knowledge in the disciplines that forest science encompasses. The readers of New Perspectives in ...Forest Science have an excellent source of information on actual trends of forest research and knowledge about the use of forest and landscape. This book has been written by specialists focusing on the following aspects of forest science: C cycle, biomass, forest restoration, forest resources and biodiversity. The authors of this book are of different nationalities and specialties, thus providing diverse perspectives on the subject of forestry. We hope that the chapters of this book can serve both students and researchers, as excellent guides to improve their knowledge on forest science.
ABSTRACT Leaf area index (LAI) is an important parameter controlling many biological and physiological processes associated with vegetation on the Earth's surface, such as photosynthesis, ...respiration, transpiration, carbon and nutrient cycle and rainfall interception. LAI can be measured indirectly by sunfleck ceptometers in an easy and non-destructive way but this practical methodology tends to underestimated when measured by these instruments. Trying to correct this underestimation, some previous studies heave proposed the multiplication of the observed LAI value by a constant correction factor. The assumption of this work is LAI obtained from the allometric equations are not so problematic and can be used as a reference LAI to develop a new methodology to correct the ceptometer one. This new methodology indicates that the bias (the difference between the ceptometer and the reference LAI) is estimated as a function of the basal area per unit ground area and that bias is summed to the measured value. This study has proved that while the measured Pinus LAI needs a correction, there is no need for that correction for the Eucalyptus LAI. However, even for this last specie the proposed methodology gives closer estimations to the real LAI values.
RESUMO O índice de área foliar (IAF) é um parâmetro importante que controla muitos processos biológicos e fisiológicos associados à vegetação, entre as quais a fotossíntese, a respiração, a transpiração e o ciclo do carbono. O IAF pode ser medido indiretamente, de uma maneira fácil e não destrutiva, como pelo uso de ceptometros sunfleck. Contudo, esta metodologia, apesar de prática, tende a subestimar o IAF em grande parte devido à forma como as folhas se organizam nas copas, em especial o agrupamento das acículas em coníferas. Na tentativa de corrigir esta deficiência, propõe-se a multiplicação do valor de IAF medido por um fator de correção constante. Em contrapartida, assume-se que o IAF obtido a partir das equações alométricas não é tão problemático e pode ser usado como uma referência para estimar o IAF e desenvolver uma nova metodologia para corrigir as médias obtidas pelo ceptometro. Esta nova metodologia assume que o erro (a diferença entre o IAF do ceptometro e o IAF de referência) é estimado como uma função da área basal por hectare. O erro obtido deve então ser somado ao IAF do ceptometro, para se obter um valor corrigido. Este estudo mostrou ainda que, embora o IAF da Pinus necessite da aplicação desta correção, não há necessidade de aplicar no casa do IAF para a Eucalyptus. No entanto, mesmo para esta última espécie a metodologia proposta dá estimativas mais próximas dos valores reais de IAF.
Forest fires in Portugal give rise to a large amount of burnt wood, a waste, and as such with few applications. Its energy recovery can be seen to manage these residues with advantages for the ...environment and as a source of income for the populations that depend on the primary sector of the economy. Burnt pine wood was evaluated as raw material for pyrolysis. The collected biomass samples, from the maritime pine trunk, were cut to separate the burnt part (external layer) from the part not affected by the fire, giving rise to the two distinct biomass samples, raw and burnt. The lignocellulosic composition was assessed by thermogravimetry and the differences in composition arise from the fact that the raw sample is sapwood, whereas the burnt sample is mainly cambium. Biomass pyrolysis kinetics evaluated by the KAS method led to an activation energy of 192 kJ/mol for raw and 169 kJ/mol for burnt biomasses. Biomass was pyrolyzed in a fixed bed pyrex reactor for temperatures in the 673–773 K range corresponding to the maximum thermal degradation rate assessed by thermogravimetry. The burnt biomass showed lower bio-oil yields (maximum 31%), which increase with the pyrolysis temperature. Besides, burnt biomass bio-char yield was always greater than the analog produced from raw biomass over the entire temperature range. The catalyzed pyrolysis tests using carbonate catalysts (limestone, CaCO3, Na2CO3, and Li2CO3) showed improved pyrogas which are compatible with the gasification role of alkali carbonate catalysts reported in the literature.
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•Maritime pine trunks from summer fires are only burned in the outer layers.•Outer layers affected by the fire contain more lignin than the bulk trunk.•Pyrolysis of burnt biomass led to highest biochar yield and lowest bio-oil yield.•Alkali based catalysts had a positive effect on the bio-oil quality.•Biochar from burnt biomass was less graphitized than that from raw biomass.
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