TAPER AND ASSORTMENT OF WOOD FOR Eucalyptus grandis Hill ex Maiden, IN THE SOUTHEAST REGION OF RIO GRANDE DO SUL

No presente trabalho, foi estudada a forma de tronco do Eucalyptus grandis Hill ex Maiden, com base em 261 \ue1rvores cubadas, cobrindo di\ue2metros entre 8,0 cm e 74,0 cm ao n\uedvel do dap (di\ue2metro \ue0 altura do peito) originadas de florestas de propriedade da Aracruz Celulose S. A., localizadas em hortos florestais da Depress\ue3o Central e do Escudo Sul-Riograndense, no Rio Grande do Sul, para a determina\ue7\ue3o de volume e forma\ue7\ue3o de sortimentos de madeira em duas classes: serraria, compreendendo toras com di\ue2metro na ponta fina superior a 25,0 cm com casca e com comprimentos de 5,60 metros, 4,20 metros e 2,80 metros, priorizando a forma\ue7\ue3o de sortimentos com o maior comprimento; ind\ufastria, para troncos ou por\ue7\uf5es destes com di\ue2metros entre 8,0 cm e 25,0 cm com casca. O polin\uf4mio do quinto grau, tendo como vari\ue1vel dependente os di\ue2metros relativos (di/d) e independente as alturas relativas (hi/h), foi selecionado para descrever a forma, com estratifica\ue7\ue3o dos dados em tr\ueas classes de di\ue2metro \ue0 altura do peito: di\ue2metro at\ue9 20,0 cm; entre 20,0 cm e 30,0 cm e maiores que 30,0 cm, com coeficientes de determina\ue7\ue3o superiores a 0,97 e erro padr\ue3o da estimativa inferior a 6,2 %, permitindo estimar o volume absoluto e relativo dos sortimentos por integra\ue7\ue3o da fun\ue7\ue3o de forma. O ajuste do modelo para o conjunto de \ue1rvores cobrindo toda a amplitude de di\ue2metros gerou um coeficiente de determina\ue7\ue3o igual \ue0 0,98 e erro padr\ue3o da estimativa igual a 6,54 % permitindo tamb\ue9m selecionar o modelo para ajuste da forma e obten\ue7\ue3o dos sortimentos.This study had the objective of studing the stem shape of Eucalyptus grandis Hill ex Maiden, based on 261 trees, with diameters at breast height (DBH) ranging from 8 cm to 74 cm, originated from Aracruz Celulose S. A. forests, located at Depress\ue3o Central and Escudo Sul-Riograndense, in Rio Grande do Sul state, to determine the volume and assortment of wood in two classes: timber (logs with 25 cm of minimum diameter, with bark, and lengths of 5,6; 4,2 and 2,8 m, prioritizing the higher length assortments formation) and industry (stems or portions of stem with diameters between 8 and 25 cm with bark). The fiftieth degree polynomial, having as dependent variable the relative diameters (di/d) and independent variable the relative heights (hi/h) was selected to describe the shape, with data stratification in three diameter classes (DBH): diameter until 20 cm; between 20 and 30 cm and larger than 30 cm, with coefficient of determination higher than 0,97 and standard error of the estimation lower than 6,2 %, allowing to estimate the relative and absolute volume of the assortments through integration of form function. The model adjustment for the trees complex covering all the diameters breadth generated a coefficient of determination equal to 0,98 and a standard error of the estimation equal to 6,54%, also allowing to select the model to describe the shape and assortment prediction

FITTING AND SELECTING TRADITIONAL MODELS FOR TREE'S HEIGHT TIME SERIES DATA

A medi\ue7\ue3o da altura das \ue1rvores \ue9 de extrema import\ue2ncia para o planejamento da produ\ue7\ue3o florestal. Geralmente, \ue9 realizada por meio de amostragens por causa do tamanho das popula\ue7\uf5es e das pr\uf3prias \ue1rvores. Medi\ue7\uf5es ao longo do tempo formam s\ue9ries de dados temporais que implicam em certos problemas para o ajuste de equa\ue7\uf5es que descrevam sua evolu\ue7\ue3o. Muitos modelos de equa\ue7\uf5es foram desenvolvidos com essa finalidade, sendo que neste trabalho s\ue3o utilizados modelos lineares, logar\uedtmicos, n\ue3o-lineares lineariz\ue1veis e n\ue3o-lineariz\ue1veis para descrever a altura ao longo do tempo. As estat\uedsticas utilizadas para compara\ue7\ue3o entre modelos s\ue3o o coeficiente de determina\ue7\ue3o (R2), a estat\uedstica Cp de Mallows, o crit\ue9rio de informa\ue7\ue3o de Akaike (Akaike's information criterion \u2013 AIC), o quadrado m\ue9dio dos res\uedduos (QMres) e a an\ue1lise gr\ue1fica de res\uedduos. O objetivo deste trabalho foi desenvolver um exemplo de ajustamento de equa\ue7\uf5es de crescimento para altura, verificar quais se adaptam melhor aos dados populacionais e determinar que crit\ue9rios de sele\ue7\ue3o, entre os utilizados, t\ueam mais rela\ue7\ue3o com o verdadeiro melhor modelo. Para tanto, foi utilizada uma amostra de 64 \ue1rvores, provenientes de uma popula\ue7\ue3o de 531 \ue1rvores de Pinus elliottii Engelm. Nesse caso, as estat\uedsticas da amostra s\ue3o comparadas com as estat\uedsticas da popula\ue7\ue3o, demonstrando qual modelo descreve melhor os dados da popula\ue7\ue3o. A qualidade do ajuste dos dados da popula\ue7\ue3o aos estimados por cada modelo foi avaliada pelo teste Qui-Quadrado e an\ue1lise gr\ue1fica dos res\uedduos. O uso do crit\ue9rio de Akaike (AIC) mostrou-se adequado na sele\ue7\ue3o de modelos para os dados utilizados. As duas melhores equa\ue7\uf5es foram a equa\ue7\ue3o h = b0 + b1.t + b2.t5 e o modelo de Chapman-Richards, que n\ue3o apresentaram diferen\ue7as significativas entre si para os crit\ue9rios analizados. Nesse sentido, o crit\ue9rio de Akaike, calculado para os dados amostrais, mostrou-se eficiente como crit\ue9rio de sele\ue7\ue3o de equa\ue7\uf5es para descrever a altura das \ue1rvores ao longo do tempo, para a popula\ue7\ue3o utilizada neste estudo. A generabilidade, calculada pelo teste Qui-Quadrado em rela\ue7\ue3o \ue0 popula\ue7\ue3o, n\ue3o mostrou diferen\ue7a significativa entre os modelos 3 e 9. A sele\ue7\ue3o final, usando-se os crit\ue9rios qualitativos de liga\ue7\ue3o do modelo com o processo estudado, sua interpretabilidade e compreensibilidade, determinou a escolha do modelo de Chapman-Richards como o melhor para descrever o crescimento em altura das \ue1rvores estudadas.Mesuring trees' height is very importance for planning forest production. Usually, it is accomplished through samplings due to the size of the populations and the size of the trees themselves. Measurements along time form a time series data with some problems for the adjustment of equations to describe its growth. Several models were developed with that purpose. The equations used in this paper were linear, logarithmic, and non-linear models. The statistics used for comparison of those models were the determination coefficient (R2), Cp of Mallows, Akaike's information criterion (AIC), Schwarz's Bayesian criterion (SBC/BIC), squared mean of residues and the graphic analysis of residues. The objective of this work was to develop an example of adjustment of growth equations for height, to demonstrate which one adapts better to the population data and to determine which selection criteria have more relationship with the better true model. To do so, a sample of 64 trees was used, submitted to the trunk analysis, from a population of 531 trees of Pinus elliottii Engelm. The statistics of the sample were compared to the statistics of the population, demonstrating which model describes better the data of the population. Quality of the adjustment to the population's data of each model was evaluated through the Chi-square test and graphic analysis of residues. The Akaike's information criterion (AIC) was appropriated to select models for the data. The two better equations were h=b0 + b1.t + b2.t5 and Chapman-Richards' growth model, which showed no significant differences for the chosen criteria in this study. In this sense, the Akaike's information criterion (AIC) calculated to the sample data showed efficiency as an equations' selection criterion to describe the height of the trees along the time for the population used in this study. The generability, calculated by Qui-square test, in relation to the population, didn't show significant difference between models 3 and 9. Final selection, using the qualitative criteria of connection of the model to the studied process, its interpretability and comprehensibility, determined the choice of the Chapman-Richards' model as the best to describe the height growth for the studied trees

A IDADE DAS PLANTA\u106 5ES DE EUCALYPTUS sp. INFLUENCIANDO OS ESTOQUES DE CARBONO

The tree growth and biomass accumulation, as well as the maintenance of forest residue at the soil surface can act in the removal of carbon from the atmosphere through the cycling process of plant material. The objective was to study the influence of Eucalyptus sp. Plantations with 20, 44 and 240 months of age on the variation of carbon in soil and biomass. The carbon in the soil depth was determined by CHNS auto-analyzer and carbon in the vegetation was determined by the biomass in each forest, considering a factor of 0.45 of the dry mass. We determined the density and particle size distribution of soil. For the comparison between plantations, there was analysis of variance and comparison of means of carbon in vegetation and soil, considering the 5 % level of probability. The carbon content and stock in the soil were low, indicating that a natural feature of the category of Paleuldt, or the growth of eucalyptus forests, replacing the field native vegetation did not aggregate a significant increase in the carbon. Although, there was a significant increase carbon in aboveground biomass. It includes forest biomass and litter. So, despite the values of carbon stocks are low, it identified a greater average total in the soil compared to the stock aboveground. Furthermore, this increase aboveground (tree and litter compartments) can be considered significant between the eucalyptus plantations of different ages.O crescimento das \ue1rvores e ac\ufamulo de biomassa, bem como a manuten\ue7\ue3o do res\uedduo florestal na superf\uedcie do solo pode atuar na retirada de carbono da atmosfera gra\ue7as ao processo de ciclagem de material vegetal. O objetivo foi estudar a influ\ueancia das planta\ue7\uf5es de Eucalyptus SP. com 20, 44 e 240 meses de idade sobre a varia\ue7\ue3o de carbono no solo e na biomassa. O carbono no solo foi determinado em profundidade por meio de autoanalisador CHNS e o carbono na vegeta\ue7\ue3o foi determinado pela biomassa em cada floresta, considerando um fator de 0,45 da massa seca. Determinaram-se a densidade e a an\ue1lise granulom\ue9trica do solo. Para a compara\ue7\ue3o entre planta\ue7\uf5es, realizou-se a an\ue1lise de vari\ue2ncia e compara\ue7\ue3o de m\ue9dias do carbono na vegeta\ue7\ue3o e no solo, considerando o n\uedvel de 5 % de probabilidade. O teor e estoque de carbono no solo foram baixos, indicando ser uma caracter\uedstica natural da categoria dos Argissolos ou que o crescimento das florestas de eucalipto em substitui\ue7\ue3o \ue0 vegeta\ue7\ue3o campo nativo n\ue3o agregou um aumento significativo no carbono, apesar de ter ocorrido um aumento significativo de carbono na biomassa acima do solo, a qual inclui a biomassa florestal a\ue9rea e a serapilheira. Portanto, apesar dos baixos valores de estoque de carbono, identificou-se um maior estoque m\ue9dio total no solo quando comparado ao estoque acima do solo. Al\ue9m disso, esse aumento acima do solo (compartimentos arb\uf3reos e serapilheira) pode ser considerado significativo entre as planta\ue7\uf5es de eucalipto com diferentes idades