Thesis (M.S.)--Oregon State University, 2004. / Typescript (photocopy). Includes bibliographical references (leaves 113-118). Also available on the World Wide Web.

Thesis (MScBosb)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (Ph. D.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains ix, 126 p. : ill. (some col.), col. map. Vita. Includes abstract. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Thesis (Ph. D.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 199-218).

Thesis (M.S.)--Auburn University, 2004. / Abstract. Includes bibliographical references.

Submitted by Natália da Silva Lima null (nataliadslima@gmail.com) on 2018-03-27T16:35:58Z No. of bitstreams: 1 Natalia Lima_versao_completa.pdf: 1987635 bytes, checksum: 362b53fdf9f1432de196e26249ec4371 (MD5) / Approved for entry into archive by Maria Lucia Martins Frederico null (mlucia@fca.unesp.br) on 2018-03-27T17:22:09Z (GMT) No. of bitstreams: 1 lima_ns__me_botfca.pdf: 1987635 bytes, checksum: 362b53fdf9f1432de196e26249ec4371 (MD5) / Made available in DSpace on 2018-03-27T17:22:09Z (GMT). No. of bitstreams: 1 lima_ns__me_botfca.pdf: 1987635 bytes, checksum: 362b53fdf9f1432de196e26249ec4371 (MD5) Previous issue date: 2018-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A elevada produtividade do eucalipto ocasiona a necessidade do domínio de técnicas e ferramentas precisas acerca dos povoamentos florestais, como o inventário florestal, procedimento fundamental para o monitoramento da produção que permite o conhecimento do máximo potencial das florestas, além disso, é essencial para o planejamento de atividades de corte, colheita e suprimento de madeira. As técnicas convencionais para o levantamento da produção florestal utilizam-se de métodos tradicionais de estatística (estatística clássica), considerando apenas a adoção de valores médios para a tomada de decisões, não explorando as correlações espaciais que possam existir entre as parcelas amostrais. Então, um tipo de interpolador geoestatístico que permite definir a estrutura de dependência espacial dos dados é a krigagem, que juntamente com a metodologia de amostras virtuais, pode-se tornar uma alternativa viável para obtenção de um variograma com modelagem aceitável. Desta forma, o objetivo geral deste estudo foi empregar a metodologia de amostras virtuais no planejamento da malha amostral do inventário florestal, a fim de possibilitar a determinação de um número de parcelas que possam ser estabelecidas na área para obtenção de produtividade, sem que haja perda de precisão ou aumento de custos. A área de estudo abrange uma área plantada de 287,66 ha, pertencente a empresa Eucatex S/A, localizada em Itatinga, no estado de São Paulo. Os dados dendrométricos de volume (m³.ha-1) foram obtidos por meio de inventários realizados pela própria empresa, utilizando-se 32 parcelas retangulares permanentes, para os inventários florestais contínuos (IFC) e 32 parcelas retangulares permanentes mais 66 temporárias, para o inventário pré-corte (IPC). Os seguintes passos foram realizados com os dados de IFC para espacialização dos dados originais, no programa ArcGIS: aplicação de uma estatística univariada sobre a variável volume/ha; geração do variograma experimental; ajuste do variograma; validação do modelo teórico; aplicação da krigagem; geração de mapas de produtividade ano a ano. Posteriormente, 47 amostras virtuais foram inseridas na malha amostral dos inventários contínuos, considerando apenas as parcelas permanentes (32 parcelas), sendo que 10 parcelas foram selecionadas previamente para a validação externa; a análise geoestatistica se deu com as amostras virtuais mais as amostras permanentes restantes, totalizando 69 parcelas. Comparando-se os métodos, observou-se pela validação cruzada que o erro médio e a correlação entre valores observados e estimados melhoraram adicionando-se amostras virtuais, possibilitando um melhor ajuste do variograma e obtenção de estimativas favoráveis. A comprovação da eficácia da metodologia de inserção das amostras, chamada de validação externa, deu-se pelo cálculo da média do erro médio, que foi igual a 6,8% em volume, em relação ao inventário real. Desta forma, a técnica de inserção de amostras virtuais pode ser utilizada, mostrando-se satisfatória para o planejamento da próxima malha para posteriores análises geoestatísticas, em plantios equiâneos. / The high productivity of eucalyptus trees makes it necessary to master accurate techniques and tools for forest, such as the forest inventory, a fundamental procedure for monitoring production that allows the knowledge of the maximum potential of forests, and is essential for planning of harvesting and supply of timber. Conventional techniques for surveying forest production use traditional statistical methods (classical statistics), considering only the adoption of average values for decision making, not exploring the spatial correlations that may exist between the sample plots. So, a kind of geostatistical interpolator that allows defining the structure of spatial dependence of data is kriging, which together with the methodology of virtual samples, can become a viable alternative to obtain a variogram with acceptable modeling. In this way, the aim of this study was to use the methodology of virtual samples in the planning of the sampling of the forest inventory, in order to allow the determination of a number of parcels that can be established in the area to obtain productivity, without losing accuracy or increasing costs. The study area covers a planted area of 287.66 ha, belonging to Eucatex S / A, located in Itatinga, in the state of São Paulo. The volume dendrometric data (m³.ha-1) were obtained through inventories carried out by the company and were estimated in 32 permanent rectangular plots for continuous forest inventories (CFI) and 32 permanent rectangular plots plus 66 temporary plots for the pre-cut inventory (PCI). The following steps were performed with the CFI data for spatialization of the original data in the ArcGIS program: application of an univariate statistic on the variable volume. ha-1; generation of the experimental variogram; variogram adjustment; validation of the theoretical model; application of kriging; generation of productivity maps year by year. Subsequently, 47 virtual samples were inserted into the sampling network of continuous inventories, considering only the permanent plots (32 plots), 10 plots were previously selected for external validation; the geostatistical analysis occurred with the virtual samples plus the remaining permanent samples, totaling 69 plots. Comparing the methods, it was observed through cross-validation that the mean error and the correlation between observed and estimated values were improved by adding the virtual samples, allowing better adjustment of the variogram and obtaining favorable estimates. The validity of the methodology of insertion of the samples, called external validation, was verified by means of the average error, which was 6.8% in volume, in relation to the original forest inventory. In this way, the technique of insertion of virtual samples can be used, proving to be satisfactory for the planning of the next mesh for later geostatistical analysis, in plantations that have the same age. / CAPES: 1582107

Quantifying and modeling processes involved in the global carbon cycle is important to evaluate the temporal and spatial variability of these processes and understand the effect of this variability on future response to changing climate and land use patterns. Biomass accumulation and Net Primary Productivity (NPP) are large components of ecosystem carbon exchange with the atmosphere and thus are the focus of many modeling efforts. When scaling estimates of NPP temporally from days to years and spatially from square meters to landscapes and regions the spatial coherence of these processes through time must be taken into account. Spatial coherence is the degree to which pairs of sites across space are synchronous (i.e., correlated) through time with respect to a given process or variable. In this thesis I determined the spatial coherence of a major component of NPP, tree bole productivity (NPP[subscript B]), and examine how it influences scaling and our ability to predict NPP and forecast change of this flux. In Chapter 2 I developed and tested a method modeling radial tree increment growth from sub-sampled trees and estimating annual site-level biomass accumulation that allows quantification of the uncertainty in these estimates. Results demonstrated that a simple model using the mean and standard deviation of growth increments underestimated bole biomass increment in all three age classes examined by 1% at the largest sample sizes and up to 15% at the smallest sample sizes. The long term average NPP[subscript B] and inter-annual variability were also underestimated by as much as 10% and 22%, respectively. Stratification of trees by size in sampling and modeling methods increased accuracy and precision of estimates markedly. The precision of both models was sufficient to detect patterns of inter-annual variability. To estimate bole biomass accumulation with acceptable levels of accuracy and precision our results suggest sampling at least 64 trees per site, although one site required a sample size of more than 100 trees. In Chapter 3 I compared year to year variability of NPP for tree boles (NPP[subscript B]) for two adjacent small watersheds (second-growth and old-growth) in the western Cascades of Oregon using the methods developed in Chapter 2. Spatial coherence of NPP[subscript B] within and between watersheds was assessed using multivariate analysis techniques. NPP[subscript B] was found to be less coherent between watersheds than within watersheds, indicating decreased spatial coherence with differences in age class and increased spatial scale. However, a larger degree of spatial coherence existed within the old-growth watershed compared to the second-growth watershed, which may be a result of the smaller degree of variation in environmental characteristics in the former watershed. Within a watershed, potential annual direct incident radiation and heat load were more strongly associated with the variation of NPP[subscript B] than climate. Climatic factors correlated with the temporal variation of annual NPP[subscript B] varied between the two watersheds. Results suggest that inter-annual variability and spatial coherence of forest productivity is a result of both internal (e.g., environment and stand dynamics) and external (climate) factors. An unexpected conclusion was that spatial coherence was not consistent and changed through time. Therefore, the coherence of sites over time is not a simple relationship. Instead the patterns of spatial coherence exhibit complex behaviors that have implications for scaling estimates of productivity. This result also indicates that a correlation coefficient alone may not capture the complexity of change through time across space. In Chapter 4 I estimated year to year variation of NPP[subscript B] for eleven sites of varying age, elevation, moisture, and species composition in the Western Cascades of Oregon. Spatial coherence of tree growth within sites and NPP[subscript B] between sites was assessed using Pearson's product-moment correlation coefficient (r). Results suggest that spatial coherence is highly variable between sites (r=-O.18 to 0.92). The second-growth sites exhibited the greatest temporal variability of annual NPP[subscript B] due to the large accumulation of biomass during stand initiation, but old-growth sites exhibited the greatest variation of coherence of NPP[subscript B] between sites. In some years all sites behaved similarly, but for other years some sites were synchronous while others were not. As growth of individual trees and NPP[subscript B] at the site scale increased, inter-annual variability of those variables increased. Climate in part affected annual NPP[subscript B], but intrinsic factors and spatial proximity also affected the coherence between sites in this landscape. / Graduation date: 2006

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