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The present study aimed to elaborate Density Management Diagrams (DMD) for Eucalyptus grandis W. Hill. ex Maiden stands including the dominant height. Data were obtained from permanent plots installed in the Centro Oriental Riograndense region and the Porto Alegre Metropolitan area, both located in the state of Rio Grande do Sul. The models to describe the relationships between average volume, number of trees per hectare, mean diameter, and dominant height were assessed by the statistical criteria of coefficient of determination (R²), standard error of the estimate in percentage (Syx%), and graphical analysis of residuals. The developed DMD allows for a better control of stocks in the management of stands due to the strong relationship of dominant height with stand development site and forest yield. [ABSTRACT FROM AUTHOR]

Understanding how climate affects tree growth is crucial for assessing climate change impacts on forests. Furthermore, trees in more competitive environments appear to respond to climate differently than trees in less competitive environments. An important tool for investigating the growth-environment relationships is tree ring dating. This study aimed to characterize the climatic factors that affect Pinus taeda growth in southern Brazil in two distinct stand types: open growth trees and competing trees. We hypothesized that competing trees present more vulnerable responses to climate variability than open growth trees. Thus, we used increment borers to access long-term growth through tree rings. Pearson’s correlation was applied to compare radial growth with monthly and annual climatic data. The chronologies generated for the two environments present similar year-to-year growth patterns. However, competing trees are more sensitive under limiting climate conditions than open growth trees. Water availability during the current spring/summer was the primary climate constraint for P. taeda growth in the region, followed by high temperatures during the summer, probably due to photosynthetic restrictions. The paper provides additional information on climatic factors that contribute to growth models and reports an important research field, considering planning forest management in the future. [ABSTRACT FROM AUTHOR]

The growth of individual trees can be simulated by multiplying a function that describes the potential by another modifier, the "modifying-potential". Modeling of the potential function for trees growing without competition determines the limit of optimum growth to species, while a modifying function sets the decrease component taking in consideration the influence of environmental factors. Thus, the aim of the study was to adjust the modifier function to describe the periodic increment in the basal area of Araucaria angustifolia trees in sites with Araucaria Forest in southern Brazil. For this, we sampled 397 individual trees. Dendrometric and morphometric variables, competition indices and increment in diameter with the chronology of widths of the growth ring were measured. Periodic increment in basal area was described by a logarithmic function that explained 57% of variance and correlated with the diameter at the beginning of the period, height, variable of crown size and competition indices. Results indicate that the modifier function can be used accurately to explain changes in growth and spatial and temporal structure of the species in the Araucaria Forest. El crecimiento de los árboles individuales se puede simular multiplicando una función que describe su potencial por otra modificadora "potencial-modificadora". El modelado de la función potencial para árboles creciendo sin competencia determina el límite de crecimiento óptimo para una especie, mientras que la función modificadora establece el componente de descenso teniendo en cuenta la influencia de factores ambientales. Así, el objetivo del estudio fue ajustar la función modificadora para describir el incremento periódico en el área basal de árboles de Araucaria angustifolia en sitios de bosques con araucaria en el sur de Brasil. Para eso, se tomaron muestras de 397 árboles individuales y se midieron sus variables dendrométricas, morfométricas, sus índices de competencia y su incremento en diámetro con la cronología de los anchos de anillos de crecimiento. El incremento periódico en el área basal fue descripto por una función logarítmica que explicó el 57% de la varianza y se correlaciona con el diámetro al inicio del periodo, altura, variable de dimensión de la copa y el índice de la competencia. Los resultados indican que se puede utilizar la función modificadora con precisión para explicar los cambios en el crecimiento, en la estructura espacial y temporal de la especie en el bosque de araucaria. [ABSTRACT FROM AUTHOR]

Reliable biomass data are very important in the evaluation of ecosystems, and help in understanding the contribution of forests in climate change. Variables that describe the size of the tree, like diameter and height are directly associated with biomass, which allows the use of regression models to estimate this element. Therefore, this study aimed to estimate by regression models, the biomass of different compartments of natural regeneration of trees of a Pinus taeda L. stand. The data were obtained through direct destructive method, using 100 randomly selected trees in the understory of a stand of Pinus taeda. We analyzed three arithmetical models, three logarithmic and two models developed by Stepwise process. Logarithmic equations developed by Stepwise procedure showed the best estimates of total and stems biomass. However, for needles and twigs compartments the best adjust was observed with Husch model and for root biomass Berkhout model proved to be the most suitable. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop the density management diagram of Araucaria Uneven Aged Forest, located in Lages city, SC. Plots with predominance of Araucaria angustifolia (Bertol.) Kuntze trees growing under high competition were sampled in order to determine the basal area per hectare, the number of trees per hectare, mean basal area diameter, volume per hectare, dominant height and average height, applying the point density method proposed by Spurr (1962). The Reineke (1933) model was adjusted and had recalculated the intercept value to set the maximum density line. The average trading volume in the sample point was estimated with adjustment of Schumacher and Hall (1933) model modified. All models were evaluated for their adjustment statistics, accuracy and graphical analysis of residuals. Slope coefficient of the Reineke (1933) model was -1.5192, confirming the Law of -3/2 power of self-thinning. Management dendrograms developed for basal area, commercial volume in function of the number of trees per hectare and average diameter of basal area, can assist in forest operations, optimizing production according to the condition of the site and growth characteristics of the species. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop the density management diagram of Araucaria Uneven Aged Forest, located in Lages city, SC. Plots with predominance of Araucaria angustifolia (Bertol.) Kuntze trees growing under high competition were sampled in order to determine the basal area per hectare, the number of trees per hectare, mean basal area diameter, volume per hectare, dominant height and average height, applying the point density method proposed by Spurr (1962). The Reineke (1933) model was adjusted and had recalculated the intercept value to set the maximum density line. The average trading volume in the sample point was estimated with adjustment of Schumacher and Hall (1933) model modified. All models were evaluated for their adjustment statistics, accuracy and graphical analysis of residuals. Slope coefficient of the Reineke (1933) model was -1.5192, confirming the Law of -3/2 power of self-thinning. Management dendrograms developed for basal area, commercial volume in function of the number of trees per hectare and average diameter of basal area, can assist in forest operations, optimizing production according to the condition of the site and growth characteristics of the species. [ABSTRACT FROM AUTHOR]

The present study aimed to develop a mathematical model to describe annual periodic percentage increment in basal area of Araucaria angustifolia trees with data collected from increment cores extracted radially from the trunk at breast height of 109 trees distributed in a large diameter range. Dendrometric and morphometric attributes were tested by multiple linear regressions as independent variables and their interactions with dummy variables as descriptors of social position class. The model explains 80% of total variation of the periodic annual percentage increment in basal area with formal crown and height/diameter relationship for trees of all social positions, as well as length and crown proportion of dominant trees described by the dummy variable. Morphometric variables, especially those that characterize the crown size, are indicated for development of individual tree growth models of Araucaria angustifolia. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate precision and accuracy in estimating horizontal projection crown area of trees of Araucaria Angustifolia in different social positions. We sampled 294 trees in the forest and classified them according to their position in sociological position as dominant, codominant and dominated. In each tree it was measured the diameter at breast height, total height and eight crown radius following the cardinal points direction. The horizontal projection area of the crown was calculated by the average of the respective radius numbers evaluated in the crown (methods): eight, four and two. Statistical differences between among methods were verified by variance analysis with factorial arrangement, considering two factors, methods of crown area and the social position occupied by trees. The results indicated that although there was no significant difference between the mean area of crown projection when measured eight and four radius, the graphical analysis revealed tendency to overestimate the area calculated with four and two radius in irregular crown, often identified in codominant and dominated trees. Furthermore, in relation to symmetrical crowns, determining the area of horizontal projection crown with four radius can be used without loss of accuracy. [ABSTRACT FROM AUTHOR]

Operational research (OR) is a powerful tool for decision-making in optimizing forestry production planning. Thus, the objective of this study is to use the OR to solve forest regulation problems in a natural forest of Araucaria angustifolia (Bertol) Kuntze. The proposal for better management regime for the forest consisted in the elaboration of two OR problems using integer linear programming (ILP). I - the first aiming to maximize income for each regime; and the II - second aiming to define the best management alternative for three values of the De Liocourt q quotient of 1.1; 1.3 and 1.5, residual basal areas of 10.0, 12.0 and 14.0 m².ha-1 and cutting cycles of 20, 25 and 30 years, creating thus 27 management scenarios. Despite the application of cutting cycles of 20, 25 and 30 years, the management alternative that best uses the resources and maximizes the income for this area of 84 ha, in the municipality of Lages, SC, is "q" = 1.3 with residual basal area of 12 m².ha-1 for all cutting cycles. The removal of these trees in the forest will contribute to the maintenance of a future diametric structure, natural regeneration, species conservation and tree increment rate, as well as the maintenance of resources of the forest ecosystem. [ABSTRACT FROM AUTHOR]