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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Assessment of Control Charts for Evaluating Dynamic Accuracy of Forest Growth Models

Cristan, Richard Raymond 01 December 2010 (has links)
The purpose of this study was to determine if control charts are an effective tool to identify trends in forest growth and yield model accuracy. Accurate forest growth and yield models are important for projecting future forest composition. However, environmental factors have the potential to make forest growth models created from historic data inaccurate. Control charts in this study determine if forest growth predictions fall within confidence limits established for historic growth at a number of points in time. Two data sets were used in this study: the first was a Continuous Forest Inventory (CFI) from three tracts at the University of Tennessee Cumberland Research Station and the second data set was Forest Inventory and Analysis data collected by the U.S. Forest Service. The CFI plots represented a stand level data set measured every 5 years from 1962-1977 and revisited for a re-measurement in 2009. The FIA plots were a regional data with subsets of plots measured annually from 1999-2008. The FIA data set was limited to plots of the oak/hickory forest type from Tennessee, Alabama, and Georgia. Two forest growth and yield models were used to predict growth: (1) WinYield and (2) Forest Vegetation Simulator (FVS). The two different data sets were used with both FVS and WinYield to evaluate control charts using different models ad at different spatial and temporal scales. The data sets were also subset by site index, stand age, stocking percent, aspect, and species composition to determine if control charts could identify changes in model accuracy for forests subjected to different growing conditions. The CFI and FIA data had short growth predictions and control charts indicated that there were no trends affecting accuracy. The CFI data also had a long growth prediction of 32 years and the control charts found that the predictions using WinYield and FVS were inaccurate, indicating that there may be a trend causing inaccuracy in the model.
82

Further development and adaptation of large area forest inventories and remote sensing applications to comprehensive data providers for international processes / Weiterentwicklung und Anpassung von Grossräumigen Waldinventuren und Fernerkundunglichen Anwendungen zu Umfassenden Datenquellen für Internationale Prozesse

Fischer, Christoph 10 October 2011 (has links)
No description available.
83

New adaptive plot designs for sampling rare and clustered populations / Neue Ansätze für adaptive Stichprobenverfahren zur Erfassung von seltenen und räumlich geklumpten Populationen

Yang, Haijun 28 November 2011 (has links)
No description available.
84

Regionalization of Variables of Sample Based Forest Inventories at the District Level / Regionalisierung von Variablen forstlicher Stichprobeninventuren auf Betriebsebene

Nieschulze, Jens 14 February 2003 (has links)
No description available.
85

Kazlų Rūdos mokomosios miškų urėdijos Jūrės girininkijos miškų pokyčių lyginamoji analizė / Comparative dynamics in Jūrė’s forest district analysis of Kazlų Rūda Training Forest Enterprise

Dumčienė, Violeta 16 August 2007 (has links)
Magistro darbe tiriama miško našumas ir jo pokyčiai, girininkijos ūkinės veiklos įtakoje. Darbo objektas – Kazlų Rūdos mokomosios miškų urėdijos Jūrės girininkijos miškai. Darbo tikslas – įvertinti miškų pokyčius ir ūkinės veiklos efektyvumą Jūrės girininkijos miškuose, panaudojant sklypinės ir atrankinės miškų inventorizacijų duomenis. Darbo metodai – panaudoti atrankinės miškų inventorizacijos, taksacinių rodiklių analizės ir medynų našumo balanso metodai. Vertinant medynų našumą ir jo pasikeitimus, atlikta įvairiapusė medynų analizė, gauti duomenys palyginti su miškotvarkos duomenimis. Įvertintas naudmenų pasikeitimas, iškirstas tūris ir kt. rodikliai. Įvertinta kokį poveikį našumo pasikeitimams turėjo girininkijos ūkinė veikla. Darbo rezultatai. Atlikus tyrimus, gauti rezultatai: Jūrės girininkijos miškuose didėja pušynų ir juodalksnynų plotai, kas rodo tikslingą medynų rūšinės sudėties formavimą Nbl, Lbl bei pelkinėse augavietėse. Vyraujantys vidutinio amžiaus ir pribręstantys medynai, mažos apimties pagrindiniai kirtimai lemia aukštą tūrio prieaugio kaupimą, didėjantį medynų amžių, skalsumą, didelius medyno tūrius. Pagal atrankinės miškų inventorizacijos duomenis nustatytas vidutinis 3,4 m3/ha per metus tūrio prieaugio kaupimas, intensyvus vidutinio tūrio didėjimas, kai tuo tarpu pagal miškotvarkos duomenis nustatytas tik 10 m3/ha tūrio pokytis per 14 metų. / The object of Master‘s study is forest yield and its changes under growth and silviculture measures in Jūrė‘s forest district of Kazlų Rūda Training Forest. Enterprise the purpose of the work is to estimate changes of forest and forest yield as well as efficiency of silviculture activities in Jure’s forest district. Analysis of there changes was made using data of standwise inventory and inventory by sampling method. Following work methods were used in this study: forest inventory by sampling method, analysis of stand parameters changes, method of stand yield balance. Following analysis of stand yields and its changes was made using data of inventory by sampling method. Obtained results were compared with data of standwise inventory forest. There were estimated changes of forestland categories, distribution by forest types felled volume and other parameters. The impact of forestry activities on changes of forest stand yield was evaluated too. Research results showed increasing of area pine and black alder forest types in Jūrė’s forest district. This results show purposive formation of stands’ species composition in Nbl, Lbl site. Prevailing in Jūrė’s forest district medium and mature age stands determine high grass increment, stands age, grown up stock volume. According to the results of sampling inventory by method there is defined grow annual increment increasing by 3,4 m3/ha over a year intense average stock volume increase. Meanwhile standwise forest inventory data... [to full text]
86

Neparametrinio kNN metodo taikymo miškų inventorizacijoje tyrimai / Investigation of the application of non – parametric kNN method for forest inventory

Jonikavičius, Donatas 16 August 2007 (has links)
Magistro darbe yra nagrinėjamos neparametrinio knn (k-nearest neighbor) metodo taikymo galimybės Lietuvos sąlygomis vertinant tradicinius miško taksacinius rodiklius bet kokiame šalies teritorijos taške. Darbo objektas – Dubravos miškų urėdijos Dubravos miškas. Darbo tikslas – įvertinti neparametrinio knn (k-nearest neighbor) metodo taikymo Lietuvos miškų inventorizacijose galimybes. Darbo rezultatai. Nustatyta, kad taksacinių rodiklių įvertinimo knn metodu tikslumas kyla didinant apskaitos vienetų, išmatuotų vietovėje, skaičių. Pagrindiniai knn metodo parametrai, kuriais gauti geriausi rezultatai, buvo: 10 artimiausių kaimynų (k reikšmė), atvirkščiai proporcingo atstumo schema, nusakant kiekvieno iš artimiausių kaimynų svertus. Papildomos pagalbinės informacijos – tradicinės sklypinės miškų inventorizacijos metu nustatytų medynų taksacinių rodiklių – panaudojimas kartu su kosminiais Spot Xi vaizdais padidina taksacinių rodiklių įvertinimo tikslumą. Pritaikius optimalų knn metodo taikymo taktikos variantą, mažiausios pasiektos taksacinių rodiklių nustatymo vidutinės kvadratinės paklaidos sudarė 27% medyno vidutinio skersmens, 20% vidutinio aukščio, 40% skerspločių sumos, 35% vidutinio amžiaus, 43% tūrio viename ha, 33% spygliuočių procento rodiklio. Pasitelkus 1999 metų Spot Xi kosminius vaizdus, 1986 apskaitos bareliuose išmatuotas pagrindines medynų taksacines charakteristikas bei 1988 metų sklypinės miškotvarkos duomenis, knn metodu nustatyti pagrindinių taksacinių... [toliau žr. visą tekstą] / The research is dealing with investigations of non-parametric knn (k-nearest neighbor) method for estimation of standard forest characteristics at any point of an area under Lithuanian conditions. Study object: Dubrava forest, managed by Dubrava experimental forest enterprise. Objectives: to assess the usability of non-parametric knn (k-nearest neighbor) method in Lithuanian forests inventory. Results. The increase in number of sample plots with known field information was found to improve the estimation accuracy. The most important parameters for use of knn methods were the following: 10 nearest neighbors (value of k), inverse distance weighted scheme for defining the weights of selected neighbors. Integrating of additional auxiliary information – characteristics of forest compartments, estimated during the conventional stand-wise inventory – to be used together with Spot Xi images improved the overall accuracy of estimations. The lowest achieved root mean square errors were 27% of the average value of all plots within the study area for mean diameter, 20% for mean height, 40% for basal area, 35% for mean age, 43% for volume per 1ha and 33% for the percent of coniferous species in stand tree species composition, when the optimal knn tactics were applied. Spot Xi images from the year 1999, main forest characteristics from 1986 field measured sample plots and data of conventional stand-wise forest inventory from the year 1988 were utilized to estimate using knn method the... [to full text]
87

Miško išteklių dinamikos tyrimas / Forest outcomes dynamic analysis

Dubickas, Rytis 14 January 2009 (has links)
Darbo objektas – Mažeikių miškų urėdijos Mažeikių girininkijos miškai. Darbo tikslas - įvertinti miškų kokybinius ir kiekybinius pokyčius ir jų priežastis Mažeikų miškų masyve 1982 – 2006 metais, panaudojant sklypinės inventorizacijos duomenis. Darbo metodai - panaudoti sklypinės miškų inventorizacijos, taksacinių rodiklių analizės metodai. Vertinant medynų našumą ir jo pasikeitimus, atlikta įvairiapusė medynų analizė, gauti duomenys palyginti su ankstesnių inventorizacijų duomenimis. Įvertintas naudmenų pasikeitimas, miškų taksaciniai ir kt. rodikliai. Įvertinta kokį poveikį miško našumo pasikeitimams turėjo girininkijos ūkinė veikla. Darbo rezultatai. Atlikus tyrimus, gauti rezultatai: Mažeikių girininkijos miškuose didėja eglynų ir beržynų plotai. Tokie medynai dabar vyrauja Lcs, Lbl, Ncs augavietėse. Vyraujantys pusamžiai ir bręstantys medynai, mažos apimties pagrindiniai kirtimai lemia didelį tūrio prieaugio kaupimą. Per analizuojamą laikotarpį padidėjo medynų tūris 1 ha ( dabar 217 m³/ ha ). Pagal sklypinės miškų inventorizacijos duomenis nustatytas vidutinis tūrio prieaugio kaupimas 6,86 m3/ha per metus. / The object of Master's study is forest yield and its changes under growth and forest measures in Mažeikiai forest district of Mažeikiai Training Forest. Enterprise. The purpose of the work is to estimate changes of forest and forest yield as well as efficiency of silviculture activities in Mažeikiai forest district. Analysis of there changes was made using data of standwise inventory. Following work methods were used in this study: forest inventory by standwise inventory method, analysis of stand parameters changes, method of stand yield balance. Following analysis of stand yields and its changes was made using data of inventory by sampling method. Obtained results were compared with data of standvvise inventory forest. There were estimated changes of forestland categories, distribution by forest types felled volume and other parameters. The impact of forestry activities on changes of forest stand yield was evaluated too. Research results showed increasing of area pine and black alder forest types in Mažeikiai forest district. This results show purposive formation of stands' species composition in Lcs, Lbl, Ncs sites. Prevailing in Mažeikiai forest district young, medium and mature age stands determine high grass increment, stands age, grown up stock volume. According to the results of sampling inventory by method there is defined grow annual increment increasing by 6,86 m3/ha over a year intense average stock volume increase.
88

Modelos de afilamento do tronco de Araucaria angustifolia (Bertol.) Kuntze, no Oeste do Estado de Santa Catarina / Models of tapering of the stem of Araucaria Angustifolia (Bertol.) Kuntze, in the west of the state of Santa Catarina

Ciarnoschi, Lucas Dalmolin 22 February 2016 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2017-12-08T11:26:22Z No. of bitstreams: 1 PGEF16MA058.pdf: 2613075 bytes, checksum: 6818848cc42688c9ae9c287f102d82f5 (MD5) / Made available in DSpace on 2017-12-08T11:26:22Z (GMT). No. of bitstreams: 1 PGEF16MA058.pdf: 2613075 bytes, checksum: 6818848cc42688c9ae9c287f102d82f5 (MD5) Previous issue date: 2016-02-22 / FUMDES / This work aimed to evaluate nineteen tapering models divided into five groups as the framework for the estimation of the profile, relative height and volume on a planted forest of Araucaria angustifolia (Bertol.) Kuntze. The settlements are located in the West of the State of Santa Catarina, deployed in the 1970 and 1980. The trees were divided into classes of diameter and height, by means of this stratification divided the data into two groups being 70% used for adjustment and 30% used for validation of the equations. In the adjustment of the models the best statistics were for the model described by Bi (2000), showing how R²aj. 0,9852, Standard Error of Estimate Relative (%) value of Syx 6,95% and Akaike information criterion (AIC) 964.5 value. Based on the graphical analysis of waste, statistics of the deviation (D), Sum of the square of the relative error (SQER) and residue in percentage (RP), it was found that for the estimation of the diameter along the stem form equations variable obtained the best settings, and the equation of Lee et al. (2003), obtained from value D 6,8361, SRRP 0,0796 end RP 0,3338. To estimate the heights in different diameters equation that best estimated Heights was the equation developed by Kozak (1988), as the value of D 0,1471, SRRQ 0,1457 and RP 4,9396. To estimate the volumes of mergers the equation that stood out was described by Lee et al. (2003), so variable, showing value of D 0,0004, SRRQ 0,2318 and RP 0,0028. Therefore, the estimates of the diameters, heights and the group volume of the equations that best stood out were those of variable shape and equation which best presented the results of estimates for the variables was the equation proposed by Lee et al. (2003). The Chi-square test (χ ²) all the equations were able to perform estimates. To do so, were generated a graph and a table of assortment which can figure out the percentage of each product generated and also the absolute volume of wood in each diameter class / Este trabalho teve como objetivo avaliar dezenove modelos de afilamento divididos em cinco grupos quanto a estrutura, para à estimativa do perfil, altura relativa e volume em uma floresta plantada de Araucaria angustifolia (Bertol.) Kuntze. Os povoamentos estão localizados na região Oeste do estado de Santa Catarina, implantados nas décadas de 1970 e 1980. As árvores foram divididas em classes de diâmetro e de altura, por meio desta estratificação dividiu-se os dados em dois grupos sendo 70% utilizado para o ajuste e 30% utilizados para a validação das equações. No ajuste dos modelos as melhores estatísticas foram para o modelo descrito por Bi (2000), apresentando como R²aj. 0,9852, Erro Padrão da Estimativa Relativo (Syx%) o valor de 6,95% e Critério de Informação Akaike (AIC) o valor de 964,5. Com base na análise gráfica dos resíduos, na estatística do Desvio (D), Soma do Quadrado do Erro Relativo (SQER) e Resíduo em porcentagem (RP), verificou-se que para a estimativa dos diâmetros ao longo do fuste as equações de forma variável obtiveram os melhores ajustes, sendo que a equação de Lee et al. (2003), obteve valor de D de -0,0796, SQER 6,8361 e RP de -0,3338. Para estimativa das alturas em diferentes diâmetros a equação que melhor estimou as alturas foi a equação desenvolvida por Kozak (1988), tendo como valor de D -0,1471, SQER 0,1457 e RP -4,9396. Para estimativa dos volumes dos troncos a equação que se destacou foi a descrita por Lee et al. (2003), de forma variável, apresentando valor de D 0,0004, SQER 0,0028 e RP 0,2318. Portanto, para as estimativas dos diâmetros, alturas e volume o grupo das equações que melhor se destacaram foram as de forma variável e a equação que melhor apresentou os resultados de estimativas para as variáveis foi a equação proposta por Lee et al. (2003). No teste de qui-quadrado (χ²) todas as equações mostraram-se aptas a realizar as estimativas. Para tanto, foram gerados um gráfico e uma tabela de sortimento os quais pode-se perceber a porcentagem de cada produto gerado e também o volume absoluto de madeira em cada classe de diâmetro
89

Derivation of forest productivity and structure attributes from remote sensing imaging technology

Quinn, Geoffrey 02 January 2019 (has links)
There are considerable expenditures by government and private forest industry to enhance the growth of forests and reduce time required for crop rotation. The effectiveness of some of these treatments is dependent on site productivity. In addition, as responsible stewards of the forest resource and habitat, it is important that the state of forests are actively monitored, especially in the face of a changing climate and increased rates of disturbance. This dissertation reports on the development of a method for estimating and mapping forest productivity. The Shawnigan Lake thinning and fertilization forest installation, established in 1971 by CFS, was selected as the study site largely for its rich mensuration history. Square treatment plots were 0.04ha in area and included two thinning levels (1/3 & 2/3 of the basal area), two fertilization treatments (224kg & 448kg N/ha) with repeated fertilizations and macronutrient experiments (S, P) and control plots. A sample of plots was selected for high precision ground based lidar reference surveys. In September of 2012 a multi-sensor airborne survey of SLP was conducted that collected high-density lidar (up to ~70pnts/m2) and VNIR imaging spectroscopy. A thorough empirical radiometric calibration was conducted in addition to a spatial calibration at the Victoria International Airport. A combination of area based height percentile, point density ratios and statistical moments with individual lidar tree metrics including height distribution and proximity metrics were generated. Topographic metrics were also generated from the lidar ground classified point cloud. A library of spectral indices was computed from the imaging spectrometer data, with an emphasis on those indices known to be associated with vegetation health. These metrics were summarized to the plot level for a coarse scale regression analysis. A control survey and ground based lidar was used to facilitate an individual tree based fine scale of analysis, where reference data could unambiguously be matched to airborne collected data through the projected positions. Regression analysis was conducted applying the best subset regression with exhaustive feature selection search criteria and included a critical evaluation of the resulting selected features. Models were investigated considering the data source and in combination, that is, lidar metrics were considered independent of spectroscopy as well as the converse, and lidar metrics in combination with spectral metrics. The contribution of this study is the revelation that existing area based point cloud metrics are highly correlated, potentially noisy and sensitive to variations in point density, resulting in unstable feature selection and coefficients in model building. The approach offered as an alternative is the gridded lidar treetops method, which is evidently lacking within the literature and which this study overwhelmingly advocates. Additionally, the breadth and diversity of metrics assessed, the size and quality of the reference data applied, and the fine spatial scale of analysis are unique within the research area. This study also contributes to the knowledge base, in that, productivity can be estimated by remote sensing technologies. The use of gridded generalizations of the individual tree approach reduced estimation errors for both structural and productivity attributes. At the plot-level, crown structure and crown health features best estimated productivity. This study emphasizes the dangers of empirical modeling; at the even-aged SLP installation, growth is strongly tied to structure and the extrapolation to other sites is expected to provide biased values. It is my perspective that physical lidar structural models of the dominant and co-dominant crown classes be used to augment spatially explicit tree and stand growth models. In addition, direct measures should be obtained by multi-temporal lidar surveys or as an alternative photogrammetric point clouds after an initial lidar survey to quantify growth and aid in calibrating growth models. / Graduate
90

Métodos de amostragem no levantamento da diversidade arbórea do Cerradão da Estação Ecológica de Assis. / Sampling methods used in the tree diversity survey in Cerradão at The Ecological Study Station in the city of Assis.

Daniela Andrade Medeiros 24 February 2005 (has links)
Apesar de ocupar cerca de 25% do território nacional e abrigar, potencialmente, um terço da fauna e flora brasileira, o bioma cerrado é classificado como um “hotspot” por apresentar expressiva redução de biodiversidade. Perante este quadro, este trabalho teve por objetivo comparar os métodos de amostragem de parcelas de área fixa e de ponto quadrante em uma área com predominância da fisionomia cerradão (savana florestada) na Estação Ecológica de Assis (SP), estando inserido no projeto temático “Métodos de Inventário da Biodiversidade de Espécies Arbóreas\", do Programa BIOTA/FAPESP. A área estudada é representada por uma grade amostral sistemática que contém 64 parcelas de 90 x 10 m (900 m2), inseridas em 8 linhas distantes 100 m entre si, com 8 parcelas em cada linha. Estas foram subdivididas em 9 subparcelas de 10 x 10 m, com um intervalo de 10 m não amostrado entre as parcelas nas linhas. Os pontos quadrantes foram instalados em cada limite entre as subparcelas. Os indivíduos arbóreos com DAP maior ou igual a 4,77 cm foram inseridos nesta amostragem, sendo posteriormente identificados. Partindo-se deste delineamento amostral e, diante da ocorrência de fragmentos de cerrado strictu sensu juntamente com áreas de cerradão, simulou-se a existência de nove tamanhos de parcela, variando de 100 a 900 m2, a fim de avaliar como esses diferentes tamanhos, bem como o método do ponto quadrante, interferem no esforço amostral, na estimativa da densidade e nos índices fitossociológicos e de diversidade. Ao final do levantamento, o método de parcelas de 900 m2 incluiu 102 espécies, distribuídas em 45 famílias, enquanto que o método do ponto quadrante amostrou 71 espécies, distribuídas em 37 famílias. Os resultados encontrados em ambos os métodos quanto ao Índice de Valor de Importância apontaram as espécies Copaifera langsdorffii, Vochysia tucanorum e Ocotea corymbosa como as mais importantes; já a família Myrtaceae se destacou nestes dois métodos quanto à riqueza de espécies. A curva de esforço amostral do método do ponto quadrante incluiu um número de espécies semelhante à curva das parcelas de 200 m2, com a vantagem de apresentar maior praticidade de instalação no campo. Os valores do Índice de Diversidade de Shannon foram inferiores a outros biomas, enquanto que o Índice de Diversidade de Simpson não pôde ser o mais indicado para o cerradão estudado, por não ser sensível à ocorrência de espécies com apenas um indivíduo na parcela. Para a determinação da diversidade arbórea do cerradão da E. E. Assis, recomendou-se o uso da parcela de 400 m2. Já na estimativa da densidade, as parcelas de 700 m2 foram as mais adequadas; entretanto, devido à grande variabilidade deste parâmetro na área, sugeriu-se uma estratificação da área de amostragem. / Cerrado biome is classified as a hotspot, because it presents an expressive reduction on the biodiversity, despite of occupying around 25% of the national territory and potentially sheltering one third of the Brazilian fauna and flora. In this scenario, this work had as objective to compare the fixed area plots and the point-centered quarter sampling methods in an area with a cerradão (savanna woodland) physiognomy at the Ecological Study Station in the city of Assis (SP), which is part of the “Tree Species Biodiversity Inventory Methods”, a thematic project of BIOTA/FAPESP Program. The studied area is represented by a systematic sampling frame containing 64 plots, measuring 90 x 10 m (900 m2), inserted in 8 lines, which is 100 m away from each other, with 8 plots in each line. They were divided into 9 sub-plots measuring 10 x 10 m, with a 10-m non-sampled gap between the plots in the lines. The point-centered points were installed in each limit between the sub-plots. The arboreal individuals with DBH equal or larger than 4.77 cm were set in this sampling and identified later. From this sampling design and due to the presence of fragments of cerrado strictu sensu together with areas of cerradão, it was simulated the existence of nine size samples varying from 100 to 900 m2 aiming evaluating how these different sizes and the point-centered quarter method interfere in the sampling effort, in the density estimates, and in the phytossociological and diversity indexes. At the end of the surveying, the 900-m2-plot method included 102 species, distributed in 45 families, whereas in the center-pointed quarter method 71 species were sampled, distributed in 37 families. The results found in both methods in relation to the Importance Value Index showed Copaifera langsdorffii, Vochysia tucanorum, and Ocotea corymbosa as the most important ones; Myrtaceae family stood out on both methods in relation to species richness. The sampling effort curve of the point-center quarter method included a number of species similar to the 200-m2 plots’ curve, with an advantage of being easier to be installed in the field. The Shannon Index values were lower than in the other biomes, whereas the Simpson Index could not be the best indicated for the cerradão under study, because it was not sensitive to the presence of species with only one individual in the plot. It was recommended the use of 400-m2 plots in order to determine the tree diversity in the cerradão at the Ecological Study Station in the city of Assis. The most adequate plots to estimate the density were the 700-m2 ones. However, stratification on the sampling area was suggested due to the great variability of this parameter in the area.

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