Spectroradiometer data (350 – 2500 nm) were acquired in late summer 1999 over various forest sites in Appomattox Buckingham State Forest, Virginia, to assess the spectral differentiability among six major forestry tree species, loblolly pine (Pinus taeda), Virginia pine (Pinus virginiana), shortleaf pine (Pinus echinata), scarlet oak (Quercus coccinea), white oak (Quercus alba), and yellow poplar (Liriodendron tulipifera). Data were smoothed using both moving (9-point) and static (10 nm average) filters and curve shape was determined using first and second differences of resultant data sets. Stepwise discriminant analysis decreased the number of independent variables to those significant for spectral discrimination at -level of 0.0025. Canonical discriminant analysis and a normal discriminant analysis were performed on the data sets to test separability between and within taxonomic groups. The hardwood and pine groups were shown to be highly differentiable with a 100% cross-validation accuracy. The three pines were less differentiable, with cross-validation results varying from 61.64% to 84.25%, while spectral separability among the three hardwood species showed more promise, with classification accuracies ranging from 78.36% to 92.54%. The second difference of the 9-point weighted average filter was the most effective data set, with accuracies ranging from 84.25% to 100.00% for the separability tests. Overall, variables needed for spectral discrimination were well distributed across the 350 nm to 2500 nm spectral range, indicating the usefulness of the whole wavelength range for discriminating between taxonomic groups and among species. Derivative analysis was shown to be effective for between and within group spectral discrimination, given that the data were smoothed first. Given the caveat of the limited species diversity examined, results of this study indicate that leaf-on hyperspectral remotely sensed data will likely afford spectral discrimination between hardwoods and softwoods, while discrimination within taxonomic groups might be more problematic. / Master of Science

Orientador: Adriano Wagner Ballarin / Banca: José Raimundo de Souza Passos / Banca: Luiz Antonio Targa / Resumo: A qualificação da madeira para uso estrutural é feita com base na sua resistência característica à compressão paralela às fibras. A partir de valores individuais de resistência à compressão paralela de corpos de prova de uma amostra representativa do lote de madeira, a resistência característica é avaliada com estimador específico, proposto pela NBR 7190 (ABNT, 1997). Com o valor da resistência característica, o lote de madeira é classificado em classes de resistência (três classes distintas para madeiras de coníferas e quatro classes distintas para madeira de folhosas) que variam de 20 MPa a 60 MPa. Lotes de madeira com maior valor de resistência característica levam, na maioria das vezes, à otimização dos projetos estruturais. O objetivo principal deste trabalho foi avaliar a eficiência de vários estimadores da resistência característica de lotes de madeira de distintas procedências, gêneses e idades das árvores, com base em suas aplicações em amostras de diferentes tamanhos amostrais. Para o estudo foram utilizados lotes de resultados de resistência mecânica da madeira de diversos conjuntos de dados, abrangendo resistências à compressão paralela às fibras e resistências ao cisalhamento de madeiras nativas e de reflorestamento, coníferas e folhosas. Com uso do software estatístico SAS, para cada lote sortearam-se repetidamente amostras, variando-se os tamanhos amostrais e, a partir dos valores de resistência dos indivíduos de cada amostra foram calculadas as resistências características dos lotes. Tomando-se a resistência característica do lote (aqui assumido como população) como referencial, foi avaliada comparativamente a eficiência de cada estimador, com base no erro quadrático médio e no desvio da estimativa. 2 Os resultados mostraram que o estimador... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In Brazil, lumber classification for structural purposes is based on its characteristic strength in compression parallel to grain. From individual values of strength in compression parallel obtained from specimens of a sample, characteristic strength is evaluated with a particular estimator proposed by the standard NBR 7190 - Design of wood structures (ABNT, 1997) for general usage (all the mechanical properties). With this characteristic strength, lumber lot is classified into classes of strength (three different classes of coniferous woods and four different classes for hardwood) ranging from 20 MPa to 60 MPa. Lumber lots with higher characteristic strength leads, in general, to a design optimization. The main objective of this study was to evaluate the efficiency of several estimators of characteristic strength of lumber lots with distinct origin, genesis and ages, based on their application in samples with different size. Lots of results of strength in compression and in shear parallel to grain of conifers and hardwood from native and reforested plantation were used. Using SAS - Statistical Analysis System - specimens were randomly sampled from each lot - varying sample size from 6 to 42 specimens - from which the characteristic strength of the lot was calculated each time based on the estimators. Taking as referential the characteristic strength of the full lot (assumed as the population), comparative efficiency of the estimators were analyzed based on MSE (mean squared error) and deviation of the estimation. Results showed that the estimator proposed by NBR 7190(ABNT, 1997) was not the more efficient in all cases. For compression and shear parallel to grain, best estimations of characteristic strength were obtained with the estimator that uses lots central tendency and dispersion parameters in its formulation... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:24:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-30Bitstream added on 2014-06-13T20:12:51Z : No. of bitstreams: 1 pinheiro_w_me_botfca.pdf: 658938 bytes, checksum: 2247a7143a27e9125566971195d85ee7 (MD5) / A qualificação da madeira para uso estrutural é feita com base na sua resistência característica à compressão paralela às fibras. A partir de valores individuais de resistência à compressão paralela de corpos de prova de uma amostra representativa do lote de madeira, a resistência característica é avaliada com estimador específico, proposto pela NBR 7190 (ABNT, 1997). Com o valor da resistência característica, o lote de madeira é classificado em classes de resistência (três classes distintas para madeiras de coníferas e quatro classes distintas para madeira de folhosas) que variam de 20 MPa a 60 MPa. Lotes de madeira com maior valor de resistência característica levam, na maioria das vezes, à otimização dos projetos estruturais. O objetivo principal deste trabalho foi avaliar a eficiência de vários estimadores da resistência característica de lotes de madeira de distintas procedências, gêneses e idades das árvores, com base em suas aplicações em amostras de diferentes tamanhos amostrais. Para o estudo foram utilizados lotes de resultados de resistência mecânica da madeira de diversos conjuntos de dados, abrangendo resistências à compressão paralela às fibras e resistências ao cisalhamento de madeiras nativas e de reflorestamento, coníferas e folhosas. Com uso do software estatístico SAS, para cada lote sortearam-se repetidamente amostras, variando-se os tamanhos amostrais e, a partir dos valores de resistência dos indivíduos de cada amostra foram calculadas as resistências características dos lotes. Tomando-se a resistência característica do lote (aqui assumido como população) como referencial, foi avaliada comparativamente a eficiência de cada estimador, com base no erro quadrático médio e no desvio da estimativa. 2 Os resultados mostraram que o estimador... / In Brazil, lumber classification for structural purposes is based on its characteristic strength in compression parallel to grain. From individual values of strength in compression parallel obtained from specimens of a sample, characteristic strength is evaluated with a particular estimator proposed by the standard NBR 7190 - Design of wood structures (ABNT, 1997) for general usage (all the mechanical properties). With this characteristic strength, lumber lot is classified into classes of strength (three different classes of coniferous woods and four different classes for hardwood) ranging from 20 MPa to 60 MPa. Lumber lots with higher characteristic strength leads, in general, to a design optimization. The main objective of this study was to evaluate the efficiency of several estimators of characteristic strength of lumber lots with distinct origin, genesis and ages, based on their application in samples with different size. Lots of results of strength in compression and in shear parallel to grain of conifers and hardwood from native and reforested plantation were used. Using SAS - Statistical Analysis System - specimens were randomly sampled from each lot - varying sample size from 6 to 42 specimens - from which the characteristic strength of the lot was calculated each time based on the estimators. Taking as referential the characteristic strength of the full lot (assumed as the population), comparative efficiency of the estimators were analyzed based on MSE (mean squared error) and deviation of the estimation. Results showed that the estimator proposed by NBR 7190(ABNT, 1997) was not the more efficient in all cases. For compression and shear parallel to grain, best estimations of characteristic strength were obtained with the estimator that uses lots central tendency and dispersion parameters in its formulation... (Complete abstract click electronic access below)

In an initial research proposal of December 1969, the scientists of the Coniferous Forest Biome (CFB), an ecosystem study centered in the Pacific Northwest and part of the larger International Biological Programme (IBP), expressed optimism that computer simulations and systems modeling could transform empirical knowledge of the carbon, water, and nutrient flows turned into viable forest management practice. The CFB's strategy aimed to use projections of the computer simulations and data from field study to constantly check and direct each other, resulting in a flexible, refined, and accurate understanding of forest ecosystems, as well as a reliable guide to forest management. To what extent did the CFB's research program, centered on a total system model, complete its cycle of field study, modeling, and validation? Despite the innovative strategies of the CFB modelers, ecosystem modeling lost its preeminent status among the goals of the CFB, due to different interpretations of the purpose and philosophy of ecosystem modeling and the practical limitations of administering a large research program. Instead, small field-based studies during the CFB yielded a number of ground-breaking discoveries. Although they diverged from the modeling objectives, these areas of fieldwork emerged from questions the forest's functions and cycling processes that the modeling efforts of the CFB required. Focusing on the work of CFB participants from Oregon State University and the USDA Forest Service in the H. J. Andrews Experimental Forest, this thesis addresses the relationship between the marginalization of the modeling objectives and the rising centrality of field-based forest studies in the CFB from 1969 to 1980. Given the ongoing legacy of CFB research at the Andrews Long-Term Ecological Research (LTER) site and the later implications of CFB findings in debates over forest policy and management, this thesis also seeks to evaluate the Coniferous Forest Biome as a whole and discuss the role of modeling and field work within large ecological research endeavors more generally. / Graduation date: 2006

The West has lost up to 60% of its historic aspen stands over the last century, probably as a result of the successional tendency of aspen to be replaced by coniferous species in the absence of periodic fires. One of several major impacts of this change is the loss of understory forage as conifer canopy cover increases. I measured understory biomass in aspen stands ranging from 0% to 81 % absolute conifer cover in the canopy Ill and found that understory production declines exponentially as conifers replace aspen. I also did an economic analysis to determine the value of the forage that is not being produced by aspen sites due to a presence of coniferous species within the tree canopy. Study results indicate significant losses in forage, marketable through the sale of livestock, and losses in revenue generated through grazing fees for the USDA Forest Service.

Bendrą šalies miškų sanitarinę būklę ženkliai veikia paprastosios pušies ir paprastosios eglės formuojamų grynų arba mišrių medynų sveikatingumas, kadangi šios dvi spygliuočių rūšys užima daugiau nei pusę (56,1 %) šalies medynų ploto. Nors per paskutinį dešimtmetį pušynų plotas padidėjo 9,7 tūkst. ha, tačiau šalies eglynų plotas per tą patį laikotarpį sumažėjo 16,2 tūkst. ha. Kaip viena iš galimų paprastosios eglės formuojamų medynų mažėjimą sukeliančių priežasčių gali būti įvardytas gamtinių veiksnių sukeliamų pažeidimų eglynuose skaičiaus didėjimas. Šių veiksnių įtaka Lietuvos spygliuočių būklei bei kaitos tendencijos įgyja nemažai svarbos besikeičiančio klimato sąlygomis. Šio baigiamojo magistro darbo tikslas – pagal miškų monitoringo duomenis nustatyti biotinių ir abiotinių medžių pažeidimų kaitos pokyčių tendencijas šalies eglynuose ir pušynuose bei įvertinti galimą klimato kaitos įtaką spygliuočių pažeidžiamumui. Pagal miškų monitoringo duomenis nustatytas gamtinių veiksnių pažeidimų skaičius paprastosios eglės ir paprastosios pušies formuojamuose medynuose leido įvertinti šių medžių rūšių pažeidžiamumo kaitą 1989-2013 metų laikotarpiu. Pažeidimų gausos kitimo vertinimui naudota koreliacinė analizė, o vizualiai identifikuojamų pažeidimų poveikis medžio būklei įvertintas paskaičiavus skirtumus tarp pažeidimo požymius turinčių ir jų neturinčių medžių vidutinės lajos defoliacijos. Taip pat analizuotas ir medžių pažeidimų pasiskirstymas pagal tam tikras klimato sąlygas... [toliau žr. visą tekstą] / The condition of coniferous tree species is the main cause of all country forest health because of high proportion of coniferous stands in a country forests. These species cover more than half (56,1 %) of forest land. The area of Scots pine stands expanded by 9700 ha over the last ten years while the area of Norway spruce reduced by 16200 ha during the same period. Damages of biotic and abiotic factors may be called as the one of main cause of this reduction in spruce stands. Moreover the influence of the state of coniferous tree species by these factors increases under the climate change. The aim of this Master thesis is to establish the extent of biotic and abiotic damages and its changes in coniferous stands in Lithuania according to the forest monitoring data and to evaluate the possible influence of climate change to vulnerability of these tree species. According to forest monitoring data the number of biotic and abiotic damages in Norway spruce and Scots pine stands helped to evaluate the tendency of vulnerability of these tree species during the 1989-2013. Moreover, the correlation analysis revealed the changes in the extent of trees’ damages and the influence of visually identifiable damages on the condition of tree has been determined by subtracting the average overgrowth’s defoliation of undamaged trees from damaged trees. Also the distribution of tree damages in different climatic regions in a country was analysed to evaluate the impact of climate change in... [to full text]

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Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.

abstract: Accurate characterization of forest canopy cover from satellite imagery hinges on the development of a model that considers the level of detail achieved by field methods. With the improved precision of both optical sensors and various spatial techniques, models built to extract forest structure attributes have become increasingly robust, yet many still fail to address some of the most important characteristics of a forest stand's intricate make-up. The objective of this study, therefore, was to address canopy cover from the ground, up. To assess canopy cover in the field, a vertical densitometer was used to acquire a total of 2,160 percent-cover readings from 30 randomly located triangular plots within a 6.94 km2 study area in the central highlands of the Bradshaw Ranger District, Prescott National Forest, Arizona. Categorized by species with the largest overall percentage of cover observations (Pinus ponderosa, Populus tremuloides, and Quercus gambelii), three datasets were created to assess the predictability of coniferous, deciduous, and mixed (coniferous and deciduous) canopies. Landsat-TM 5 imagery was processed using six spectral enhancement algorithms (PCA, TCT, NDVI, EVI, RVI, SAVI) and three local windows (3x3, 5x5, 7x7) to extract and assess the various ways in which these data were expressed in the imagery, and from those expressions, develop a model that predicted percent-cover for the entire study area. Generally, modeled cover estimates exceeded actual cover, over predicting percent-cover by a margin of 9-13%. Models predicted percent-cover more accurately when treated with a 3x3 local window than those treated with 5x5 and 7x7 local windows. In addition, the performance of models defined by the principal components of three vegetation indices (NDVI, EVI, RVI) were superior to those defined by the principal components of all four (NDVI, EVI, RVI, SAVI), as well as the principal and tasseled cap components of all multispectral bands (bands 123457). Models designed to predict mixed and coniferous percent-cover were more accurate than deciduous models. / Dissertation/Thesis / M.A. Geography 2012

京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第20038号 / 地環博第154号 / 新制||地環||31(附属図書館) / 33134 / 京都大学大学院地球環境学舎環境マネジメント専攻 / (主査)教授 梶井 克純, 准教授 真常 仁志, 准教授 田中 周平 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM