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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 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]