828 resultados para timber
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In this paper we have assessed the availability of land and the potential for biomass production in India to meet various demands for biomass, including modern bioenergy. This is estimated by considering the various demands on land and its suitability. The biomass production potential of energy plantations is assessed for different agroecological zones. The total woody biomass production is estimated to be 321 Mt, based on biomass productivity in the range 2 to 17 t/ha/yr for the different agro-ecological zones and considering the conservative estimate of 43 Mha land availability for biomass production. A surplus of 231 Mt of biomass (after meeting the increased demand for fuelwood and timber by the year 2010) is estimated to be available for energy, which has an electricity generation potential of 231 TWh. As a first step, only the feasible physical potential of biomass production is assessed, along with an analysis of barriers. The potential costs and benefits of biomass production strategy are not analysed. (C) 1999 Elsevier Science Ltd. All rights reserved.
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Land-use changes influence local biodiversity directly, and also cumulatively, contribute to regional and global changes in natural systems and quality of life. Consequent to these, direct impacts on the natural resources that support the health and integrity of living beings are evident in recent times. The Western Ghats being one of the global biodiversity hotspots, is reeling under a tremendous pressure from human induced changes in terms of developmental projects like hydel or thermal power plants, big dams, mining activities, unplanned agricultural practices,monoculture plantations, illegal timber logging, etc. This has led to the once contiguous forest habitats to be fragmented in patches, which in turn has led to the shrinkage of original habitat for the wildlife, change in the hydrological regime of the catchment, decreased inflow in streams,human-animal conflicts, etc. Under such circumstances, a proper management practice is called for requiring suitable biological indicators to show the impact of these changes, set priority regions and in developing models for conservation planning. Amphibians are regarded as one of the best biological indicators due to their sensitivity to even the slightest changes in the environment and hence they could be used as surrogates in conservation and management practices. They are the predominating vertebrates with a high degree of endemism (78%) in Western Ghats. The present study is an attempt to bring in the impacts of various land-uses on anuran distribution in three river basins. Sampling was carried out for amphibians during all seasons of 2003-2006 in basins of Sharavathi, Aghanashini and Bedthi. There are as many as 46 species in the region, one of which is new to science and nearly 59% of them are endemic to the Western Ghats. They belong to nine families, Dicroglossidae being represented by 14 species,followed by Rhacophoridae (9 species) and Ranidae (5 species). Species richness is high in Sharavathi river basin, with 36 species, followed by Bedthi 33 and Aghanashini 27. The impact of land-use changes, was investigated in the upper catchment of Sharavathi river basin. Species diversity indices, relative abundance values, percentage endemics gave clear indication of differences in each sub-catchment. Karl Pearson’s correlation coefficient (r) was calculated between species richness, endemics, environmental descriptors, land-use classes and fragmentation metrics. Principal component analysis was performed to depict the influence of these variables. Results show that sub-catchments with lesser percentage of forest, low canopy cover, higher amount of agricultural area, low rainfall have low species richness, less endemic species and abundant non-endemic species, whereas endemism, species richness and abundance of endemic species are more in the sub-catchments with high tree density, endemic trees, canopy cover, rainfall and lower amount of agriculture fields. This analysis aided in prioritising regions in the Sharavathi river basin for further conservation measures.
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There is a large interest in biofuels in India as a substitute to petroleum-based fuels, with a purpose of enhancing energy security and promoting rural development. India has announced an ambitious target of substituting 20% of fossil fuel consumption by biodiesel and bioethanol by 2017. India has announced a national biofuel policy and launched a large program to promote biofuel production, particularly on wastelands: its implications need to be studied intensively considering the fact that India is a large developing country with high population density and large rural population depending upon land for their livelihood. Another factor is that Indian economy is experiencing high growth rate, which may lead to enhanced demand for food, livestock products, timber, paper, etc., with implications for land use. Studies have shown that area under agriculture and forest has nearly stabilized over the past 2-3 decades. This paper presents an assessment of the implications of projected large-scale biofuel production on land available for food production, water, biodiversity, rural development and GHG emissions. The assessment will be largely focused on first generation biofuel crops, since the Indian program is currently dominated by these crops. Technological and policy options required for promoting sustainable biofuel production will be discussed. (C) 2010 Elsevier Ltd. All rights reserved.
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Bonding a fibre reinforced polymer (FRP) composite or metallic plate to the soffit of a reinforced concrete (RC), timber or metallic beam can significantly increase its strength and other aspects of structural performance. These hybrid beams are often found to fail due to premature debonding of the plate from the original beam in a brittle manner. This has led to the development of many analytical solutions over the last two decades to quantify the interfacial shear and normal stresses between the adherends. The adherends are subjected to axial, bending and shear deformations. However, most analytical solutions have neglected the influence of shear deformation of the adherends. For the few solutions which consider this effect in an approximate manner, their applicability is limited to one or two specific load cases. This paper presents a general analytical solution for the interfacial stresses in plated beams under an arbitrary loading with the shear deformation of the adherends duly considered. The shear stress distribution is assumed to be parabolic through the depth of the adherends in predicting the interfacial shear stress and Timoshenko's beam theory is adopted in predicting interfacial normal stress to account for the shear deformation. The solution is applicable to a beam of arbitrary prismatic cross-section bonded symmetrically or asymmetrically with a thin or thick plate, both having linear elastic material properties. The effect of shear deformation is illustrated through an example beam. The influence of material and geometric parameters of the adherends and adhesive on the interfacial stress concentrations at the plate end is discussed. (C) 2011 Elsevier Ltd. All rights reserved.
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The study follows an approach to estimate phytomass using recent techniques of remote sensing and digital photogrammetry. It involved tree inventory of forest plantations in Bhakra forest range of Nainital district. Panchromatic stereo dataset of Cartosat-1 was evaluated for mean stand height retrieval. Texture analysis and tree-tops detection analyses were done on Quick-Bird PAN data. The composite texture image of mean, variance and contrast with a 5x5 pixel window was found best to separate tree crowns for assessment of crown areas. Tree tops count obtained by local maxima filtering was found to be 83.4 % efficient with an RMSE+/-13 for 35 sample plots. The predicted phytomass ranged from 27.01 to 35.08 t/ha in the case of Eucalyptus sp. while in the case of Tectona grandis from 26.52 to 156 t/ha. The correlation between observed and predicted phytomass in Eucalyptus sp. was 0.468 with an RMSE of 5.12. However, the phytomass predicted in Tectona grandis was fairly strong with R-2=0.65 and RMSE of 9.89 as there was no undergrowth and the crowns were clearly visible. Results of the study show the potential of Cartosat-1 derived DSM and Quick-Bird texture image for the estimation of stand height, stem diameter, tree count and phytomass of important timber species.
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[EUS]Enirio-Aralarreko mendietako basoek ez dute XVIII. mendera arte ustiapen gogorrik jasango. Ordura arte Batasunetako biztanleek behar zuten egurra soilik ateratzen zuten, ia ustiapen industrialik gabe. XVIII. mendean, beheko aldeko hariztiak agortu zirenean, Enirio-Aralarreko pagoak hasi ziren ustiatzen ikatza, itsasontziak edo arma-kajoiak egiteko. Aldi berean, ordura arte “tokian tokiko” abeltzaintza izan zena, erdi trashumantzia bihurtu zen: kostaldeko eta inguruko artaldeak Enirio-Aralar mendietan hasi ziren uda ematen. Aipatutako bi faktoreek –basoaren ustiapenak eta kanpoko artaldeen etorrerak–, batik bat XVIII. mendearen bukaeran eta XIX. mendearen hasieran, Enirio-Aralarreko basoaren atzerakada eragin zuten. XIX eta XX. mendeetan zehar deforestazioa areagotu egin zen, bertako mendiei gaur egun ezagutzen dugun itxura eman arte.
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[ES] A fin de garantizar el aprovechamiento deun recurso renovable como la madera, en un momento de retroceso forestal y escasez de materiales, los habitantes de la provincia de Guipúzcoa, ante lo exiguo de su territorio, arbitraron un sistema que permitió combinar las necesidades y demandas de actividades tan dispares como la ganadería, el consumo doméstico, la siderurgia o la construcción naval. El presente artículo pretende analizar el origen, desarrollo y desaparición de los trasmochos guiados y describir su técnica en el territorio guipuzcoano. A falta de mayores evidencias, parece que la técnica del trasmochado o desmochado guiado inició su andadura en la Baja Edad Media, aunque hasta las primeras décadas del siglo XVI no existen datos documentales de su utilización en territorio guipuzcoano. Su generalización en todo el territorio guipuzcoano no parece producirse definitivamente hasta finales del siglo XVII, aunque para entonces se venía aplicando en la costa y el sector oriental de la reclamaciones de las autoridades reales y territoriales, la obligación de dejar horca y pendón se encontró con la oposición de carboneros y ferrones, quienes trasmochaban los árboles pero sin guiarlos, perjudicando de ese modo a las autoridades e intereses de la Marina Real. Precisamente el incumplimiento de las ordenanzas fue lo que provocó la aparición de dos modelos, con usos diferenciados: trasmochos sin guiar y trasmochos guiados. A lo largo del siglo XIX dicha técnica se fue perdiendo, coincidiendo con la paulatina desaparición de la construcción naval en madera.
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Royal Visit. The Vice President of Ecuador in the Galápagos. The Galápagos Marine Resources Reserve. The Charles Darwin Foundation Endowment Fund. Repatriation of Captive-bred Land Iguanas. The 1987 Flamingo Census. Experimental Plantations to Provide Building Timber. Visitors and Events at the Charles Darwin Research Station.
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A conservação dos ecossistemas e dos recursos ambientais neles inclusos é uma condição básica e essencial para o desenvolvimento sustentado de uma dada região. A degradação faz com que a possibilidade dele retornar ao seu estado original seja ínfima pois, sua dinâmica de restauração não seria a mesma do que antes foi sua colonização. A recuperação de áreas degradadas é dificultada devido à complexidade estrutural dos ecossistemas, exemplo das restingas ambientes sujeitos as condições bastante adversas (altas temperaturas, períodos de seca, vento constante, alta salinidade e escassez de nutrientes), por isso demandam de alta tecnologia para o desenvolvimento e produção de mudas, além de alto custo associado. O objetivo deste estudo é a criação de uma proposta para uso socioeconômico das áreas degradadas por plantios de cocos, em formações vegetais de restinga, município de Caravelas, e criar um modelo para que essas áreas sejam mais produtivas economicamente, a médio e longo prazo, a partir da geração de trabalho e renda e, conseqüentemente, inclusão social voltada para o uso sustentável de espécies nativas de restinga, através do extrativismo, considerando-se o potencial e a vocação natural do ecossistema de restinga. Nesse contexto, as categorias de análise desta tese basearam-se nos conflitos e vulnerabilidade socioambiental, etnobotânica, fitofisionomias, bens e serviços associados, tecnologia social, desenvolvimento local, gestão costeira, sustentabilidade ambiental e democrática, produtos florestais não madeiráveis e inclusão social. Os procedimentos metodológicos utilizados neste estudo foram apresentados em cada capítulo desta tese, estando inserido em pesquisas qualitativas (técnicas de observação participante e análise do discurso coletivo) associada aos levantamentos bibliográficos (dados secundários) e as pesquisas quantitativas, por entrevistas semiestruturadas. Os resultados deste estudo subsidiaram a formação de uma rede interativa para implantação de empreendimentos sustentáveis no processo produtivo local, no que se refere à utilização de espécies nativas de restingas com reflorestamento de áreas degradadas por plantios de coco, para fins de geração de trabalho e renda com base no movimento de tecnologia social.
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107 pag.
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This monograph on the ecology of Atlantic white cedar wetlands is one of a series of U.S. Fish and Wildlife Service profiles of important freshwater wetland ecosystems of the United States. The purpose of the profile is to describe the extent, components, functioning, history, and treatment of these wetlands. It is intended to provide a useful reference to relevant scientific information and a synthesis of the available literature. The world range of Atlantic white cedar (Chamaecyparis thyoides) is limited to a ribbon of freshwater wetlands within 200 km of the Atlantic and Gulf coasts of the United States, extending from mid-Maine to mid-Florida and Mississippi. Often in inaccessible sites and difficult to traverse, cedar wetlands contain distinctive suites of plant species. Highly valued as commercial timber since the early days of European colonization of the continent, the cedar and its habitat are rapidly disappearing. This profile describes the Atlantic white cedar and the bogs and swamps it dominates or codominates throughout its range, discussing interrelationships with other habitats, putative origins and migration patterns, substrate biogeochemistry, associated plant and animal species (with attention to those that are rare, endangered, or threatened regionally or nationally), and impacts of both natural and anthropogenic disturbance. Research needs for each area are outlined. Chapters are devoted to the practices and problems of harvest and management, and to an examination of a large preserve recently acquired by the USFWS, the Alligator River National Wildlife Refuge in North Carolina.
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Com a chegada dos europeus ao Brasil, inicia-se a intensa exploração dos recursos da Mata Atlântica, direcionados primeiramente para uso da coroa e, posteriormente, para os assentamentos populacionais da colônia. As informações sobre o uso de madeiras na época do Brasil-colônia de Portugal (1630-1822) são escassas e se encontram dispersas. Dessa forma, o objetivo deste trabalho foi realizar uma referência cruzada utilizando três diferentes tipos de culturas materiais: documentos históricos, artefatos e paisagem. Tendo como foco as senzalas da Fazenda Ponte Alta no estado do Rio de Janeiro/RJ, relacionou-se os dados históricos sobre o uso de madeiras de construção no período colonial com o conhecimento científico atual sobre a flora de Mata Atlântica, identificando as espécies utilizadas no passado e sua ocorrência nos fragmentos florestais remanescentes. Para tal, foram visitadas bibliotecas nacionais e internacionais; analisadas amostras das madeiras da estrutura das senzalas e realizado um inventário fitossociológico nos fragmentos florestais remanescentes. Como um dos principais resultados, destaca-se o expressivo número de espécies madeireiras da Mata Atlântica que eram utilizadas nas construções do Brasil-colônia. E que a preferência de uso de determinados táxons pertencentes à Leguminosae, Sapotaceae e Lauraceae, reflete a disponibilidade e abundância dessas famílias no Bioma. Das espécies identificadas nas estruturas das senzalas, 68% foram citadas nos documentos históricos como sendo utilizadas em construções no período colonial e 37% dessas, também foram amostradas no inventário fitossociológico realizado. Constatou-se que as espécies utilizadas para construção no Brasilcolônia apresentavam, na maioria, boa qualidade e alta resistência o que lhes conferia uma multiplicidade de uso. Essa demanda, certamente, tem reflexos diretos na distribuição geográfica, no tamanho populacional e no status de conservação atual das espécies. Os resultados indicam, também, que os construtores do período, principais atores da história, detinham o conhecimento necessário à utilização das florestas locais. Assim, os dados obtidos nos diferentes materiais analisados se mostraram complementares e com interação entre si, agregando informação e veracidade aos argumentos inicialmente postulados
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[EN] The intense industrial activity that took place over the past century resulted in large contaminated áreas. This is an important risk to human health and environmental safety. Recent biotechnological techniques for bioremediation include phytoremediation, which uses plants to remove or stabilize contaminants in soils. In our study we choose birch (Betula alba) as the preferred species to remedy mining soils, due to it produces a large biomass and can accumulate high levels of toxic elements in its tissues. The aim of this study was (i) to determine the possibility of using this species in reforestation and/or remediation of mining soils (ii) to elucidate the potential of tocopherol levels as indicators of heavy metal pollution. Trees growing in mining soils with high concentrations of Zn, Cd and Pb were sampled and the metal content in various organs and in tree rings was analyzed. α-tocoferol levels were also analyzed as an indicator of stress. The results showed a different distribution of metals in plant tissues. Zn and Cd had a higher accumulation in leaves, whereas Pb was stored in the timber. In addition, the metal content in tree rings was higher in older rings, leading to a conclusion that older tissues present a detoxification strategy. Furthermore, we saw how the presence of α- tocoferol on branches can be an indicator of metal stress in plants and it can be also used as a monitoring factor.
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Aquatic agricultural systems (AAS) are diverse production and livelihood systems where families cultivate a range of crops, raise livestock, farm or catch fish, gather fruits and other tree crops, and harness natural resources such as timber, reeds, and wildlife. Aquatic agricultural systems occur along freshwater floodplains, coastal deltas, and inshore marine waters, and are characterized by dependence on seasonal changes in productivity, driven by seasonal variation in rainfall, river flow, and/or coastal and marine processes. Despite this natural productivity, the farming, fishing, and herding communities who live in these systems are among the poorest and most vulnerable in their countries and regions. This report provides an overview of the scale and scope of development challenges in coastal aquatic agricultural systems, their significance for poor and vulnerable communities, and the opportunities for partnership and investment that support efforts of these communities to secure resilient livelihoods in the face of multiple risks.