Emanuel Arnoni Costa

Growth Dynamics of Araucaria after Management Interventions in Natural Forest

The objective of this study was to evaluate the effect of selective logging on the growth dynamics of Araucaria angustifolia in a natural forest of Rio Grande do Sul state, Brazil. Treatments were based on percentage reduction of the basal area per DBH class, namely, T0 (control) = 0%; T1 (light selective logging) = reduction of 20-30%; T2 (moderate selective logging) = reduction of 40-50%. Data were obtained prior to the management interventions and four, eight and 13 years after selective logging. Changes between treatments were assessed using the following parameters: absolute density, absolute dominance, importance value index, and growth rates. Results show that population reduction and canopy opening provided greater recruitment and higher growth rates for araucaria in the management treatments (T1 and T2) compared with those of the control treatment (T0). These results reinforce that management practices are necessary for the continuous development of araucaria in this forest formation.

INFLUÊNCIA DA POSIÇÃO SOCIAL NAS RELAÇÕES MORFOMÉTRICAS DE Araucaria angustifolia

The morphometric relations allow describing dimensions of trees without prior knowledge of the age, it help the forest planning and implementation of silvicultural treatments, especially when needs to make sustainable use of forests. For this purpose, the aim of this study was to model and comparising the morphometric relations araucaria trees in social position dominant, codominant and dominated in native forest remnant, located in Lages, SC. A total of 294 trees distributed in dbh classes were intentionally selected inside of forest. In each tree was measured dbh, total height, bole height, crown diameter by eight radius, as well as the classification of social position. Simple and multiple linear regression models were used to describe the relation h/d, the proportion of the crown and formal crown in function of diameter at breast height with simple transformation, quadratic, cubic, inverse and logarithmic form. The analysis of covariance with dummy variables were used to describe the social position and tested the parallelism and slope of regression indicating need or not of the use independent regressions. The results indicated that even with great variability in the shape and size of the crown due to growth and competition process, the morphometric relations of araucaria can be accurately estimated by regression models. The relation h/d, proportion of the crown and formal crown can be described by individual model for social position dominant, codominant and dominant, or alternatively a single model with the use of dummy variables that differentiate trees group dominated for the relation h/d and formal crown. The proportion of crown presented difference in dimensions of the trees, being necessary to use dummy variable for each social stratus or use the individual models.

HEIGHT-DIAMETER RELATIONSHIPS FOR Araucaria angustifolia (BERTOL.) KUNTZE IN SOUTHERN BRAZIL

Height-diameter relationships are used in order to make forest inventories less expensive and to assess growth and yield. This study aimed to develop height-diameter models for individual trees of Araucaria angustifolia (Bertol.) Kuntze for different locations and growth conditions in Southern Brazil. Our data include locations of at least one third of this species natural geographical distribution. We used Michailoff’s model, and compared height-diameter tendency through analytical methods. The model showed good overall precision and accuracy. Trees growing in forest conditions had a higher asymptotic height, and reached it at smaller diameters than open-grown trees. Different regions had contrasting height-diameter tendency indicating site potential, especially for natural forests. Individual tree asymptotic height was correlated with site altitude and mean annual precipitation. This study represents a source of parameters for height-diameter relationships in a large geographical span, for a species with high cultural and timber value in Southern Brazil.

Height-Diameter Models for Araucaria angustifolia (Bertol.) Kuntze in Natural Forests

The height-diameter relationship of Araucaria angustifolia trees in different sociological positions (dominant, codominant, dominated) was evaluated in a native forest in the south of Brazil, aiming to find accuracy in its estimation and its use as a component of forest description, growth and yield. The total number of trees of the three sociological positions was 657. Part of these trees of each sociological position was used to estimate the parameters of models, and the remaining for model evaluation. Thus, the objective of this work was to find the best height estimate using nonlinear models, linear with dummy variable, principal component with nonlinear regression, and principal component with mixed nonlinear regression. The criteria for accuracy of fit were adjusted coefficient of determination, root mean square error and mean error. The results showed that the fit using principal component with mixed nonlinear regression obtained consistent results and better accuracy. It showed that height growth capacity depends on the sociological position.

MODELAGEM DO ESPAÇO DE CRESCIMENTO PARA ARAUCÁRIA

This study was developed in order to model the growing space for Araucaria angustifolia (Bertol.) Kuntze trees. A total of 869 Parana pine trees were sampled in three municipalities in southern Brazil, being 175 trees with free growing of competition in the municipalities of Canoinhas (SC state) and Lages (SC state), and 694 under influence of competition in natural forest in the municipalities of Sao Francisco de Paula (RS state) and Lages (SC state). In each tree was measured diameter at breast height, total height and crown rays following the directions of the cardinal points. The crown diameter was determined by doubling the value of the average radius of the crown. Three models were fitted and evaluated the fit statistics, accuracy and residual graphical analysis, according to the municipality and growth condition. When comparing the equations, covariance analysis indicated that there is no significant difference between the level and slope of the crown diameter equations of open growth trees and under competition in different places where data were sampled. A single equation was defined to estimate the crown diameter as a function of the diameter at breast height for this species.

CARBON CONTENTS AND MODELLING OF TOTAL ORGANIC CARBON FOR Pinus taeda L. FROM NATURAL REGENERATION

Os objetivos deste trabalho foram quantificar o carbono total e dos compartimentos: raizes, fustes, galhos e aciculas, visando selecionar uma equacao estimativa do carbono orgânico total para Pinus taeda L. que se estabeleceram a partir de regeneracao natural no sub-bosque de uma floresta plantada, localizada no municipio de Tres Barras, SC. Os dados sao provenientes da selecao aleatoria de 96 individuos com diâmetro a 0,3 metros do nivel do solo, variando de 2,5 a 19 cm. Os individuos selecionados tiveram suas variaveis dimensionais (variaveis dendrometricas e morfometricas) medidas e, em seguida, foram abatidos e seus compartimentos separados, pesados e amostras retiradas e conduzidas para analise do teor de carbono. Foram testados 8 modelos tradicionais, sendo 6 aritmeticos e 2 logaritmicos e tambem um modelo desenvolvido pelo processo Stepwise, tendo o carbono orgânico total como variavel dependente e as variaveis dimensionais, como variaveis independentes. O teor de carbono total encontrado, em media, foi de 46,7% e o teste de Tukey e Cramer indicou diferencas significativas na quantidade de carbono entre os compartimentos. Em comparacao com as equacoes tradicionais testadas, a equacao ajustada por Stepwise mostrou-se mais acurada, com bom ajuste (R2aj. = 0,931) e precisao (Syx% = 18,5).

Efeito da Competição nas Relações Dimensionais de Araucária

This study aimed to describe the effect of competition in the dimensional relations of Araucaria angustifolia (Bertol.) Kuntze. Covariance analysis was used to compare tendency dimensional relationship for the group of open grown in fields and under competition in the forest. Trees growing under competition when compared to those with open grown presented, on average, regression lines with superior intercept for height, height of crown insertion point, height/diameter ratio, when evaluating the same diameter at breast height. Decreased tree competition increases the crown length and reduces height of crown insertion point. The inclusion of variable competition index in models improved fit and accuracy of dimensional relations in forest trees, which allows to use the equations fitted to estimate the crown dimensions as assistance for silvicultural activities of araucaria.

FUNÇÃO DE AFILAMENTO E SORTIMENTOS DE MADEIRA PARA Araucaria angustifolia

Taper functions allow determining size classes and volumes of trees with direct application in the planning of technical and economic forest activities. For this purpose, the aim of this study was to describe the taper of the trunk of Araucaria angustifolia (Bertol.) Kuntze in the portion between the ground level and the insertion of the crown of individuals in remnant of native forest. Also tried to fit the regression model to represent relations height/DBH, diameter at the insertion of the crown in function DBH and the development of assortment timber table. Eighty-five trees were measured their diameters and heights relatives using Hohenadl cubed method and the diameter of the insertion crown with Criterion RD 1000 instrument. The taper models were adjusted by regression analysis using polynomial of the 5 th degree, Kozak (1988), Lee et al. (2003) and Sharma and Zhang (2004). The adjusted coefficient of determination (R²aj), the standard error of estimate in percentage (Syx%) and graphical analysis between estimated values in function of observed were used statistics to evaluate the quality of fit and models precision. The model height/DBH and diameter at the insertion point of the crown evidence good fit statistical and precision, allowing its application in activities intended at planning and forest inventories. The flexibility and efficiency of Kozak (1988) model in predicting diameters and volumes until the crown insertion point favors the use and obtain timber assortments of araucaria.