Romualdo Maestri

Dominant Height Model for Site Classification of Eucalyptus grandis Incorporating Climatic Variables

This study tested the effects of inserting climatic variables in Eucalyptus grandis as covariables of a dominant height model, which for site index classification is usually related to age alone. Dominant height values ranging from 1 to 12 years of age located in the Southeast region of Brazil were used, as well as data from 19 automatic meteorological stations from the area. The Chapman-Richards model was chosen to represent dominant height as a function of age. To include the environmental variables a modifier was included in the asymptote of the model. The asymptote was chosen since this parameter is responsible for the maximum value which the dominant height can reach. Of the four environmental variables most responsible for database variation, the two with the highest correlation to the mean annual increment in dominant height (mean monthly precipitation and temperature) were selected to compose the asymptote modifier. Model validation showed a gain in precision of 33% (reduction of the standard error of estimate) when climatic variables were inserted in the model. Possible applications of the method include the estimation of site capacity in regions lacking any planting history, as well as updating forest inventory data based on past climate regimes.

Dominant height projection model with the addition of environmental variables

This study investigated the behavior of climatic variables inserted as inclination modifiers of the Chapman-Richards model for estimating dominant height. Thus, 1507 data pairs from a Continuous Forestry Inventory of clonal eucalyptus stands were used. The stands are located in the States of Espirito Santo and southern Bahia. The climatic variables were inserted in the dominant height model because the model is a key variable in the whole prognosis system. The models were adjusted using 1360 data pairs, where the rest of the data was reserved for model validation. The climatic variables were selected by using the Backward model construction method. The climatic variables indicated by the Backward method and inserted in the model were: mean monthly precipitation and solar radiation. The inclusion of climatic variables in the model resulted in a precision gain of 19.8% for dominant height projection values when compared with the conventional model. The advantage of the method used in this study is the actualization of inventory data contemplating climatic history and productivity estimates in areas without prior plantation.

Estimativa do crescimento de povoamentos de Eucalyptus baseada em modelos lineares em multiníveis de efeito misto

The main purpose of this study was to apply the mixed-effects theory in modeling Eucalyptus stand growth. The database is from homogeneous stands located on Brazilian coastal region, Espirito Santo and Bahia States. We used two levels of sampling: sample units and individual trees inside of sample units. As an example, we considered the logarithm of the basal area as response variable and inverse of age, logarithm of the total height and their interaction as covariates. The parameter estimate quality of the linear model was significantly improved. Also, by modeling the heteroscedasticity and the autocorrelation (AR(1)), the log-likelyhood values were increased significantly.

Avaliação de um sistema para otimização do sortimento de Eucalyptus sp.

Normal 0 21 MicrosoftInternetExplorer4 Este trabalho teve como objetivo geral a avaliacao de uma metodologia para estimativa do volume de madeira no inventario florestal considerando o perfil de qualidade do fuste das arvores. Foi utilizado um talhao com area de 4,31 ha, plantado com Eucalyptus sp. com idade de dezesseis anos, proveniente de propagacao seminifera. O espacamento inicial utilizado no plantio foi 3 m x 3 m, sendo feito um desbaste seletivo aos 8,6 anos de idade. Foram lancadas oito parcelas circulares de 855 m². Nessas parcelas, foram medidos o diâmetro na altura de 1,30 m ( DAP ) e altura total ( HT ) das arvores, sendo os fustes das arvores com DAP maior que 28 cm classificados de acordo com classes de qualidade definidas a priori . Os fustes das arvores das oito parcelas foram submetidos ao processo de otimizacao. Apos a colheita de todas as arvores das oito parcelas, os fustes foram marcados por uma equipe treinada e passaram pelo processo de tracamento para posterior comparacao dos volumes comerciais das toras tracadas com o volume obtido pelo metodo de otimizacao. O volume e o numero de toras por classes de qualidade e sortimento, otimizado e colhido, diferiram significativamente pelo teste qui-quadrado a 5% de probabilidade. Concluiu-se, ao final, que ha necessidade de padronizacao do treinamento das equipes de colheita e inventario florestal, e a metodologia de inventario apresentada necessita de ajustes antes de sua implementacao.