Generatation of models for the management of Araucaria forests in southern Brazil using morphometric relationships with density is still scarce. Changes in the dynamics of the shape and size of trees in the forest indicate the need to regulate the density of trees (silvicultural intervention) or self-adjustment of the species to shape structure, living space, competition, growth rate and resource use. Trees with larger crowns show higher growth rate and their size inform the vital space of growth and support management density of the forest. This information is important to support forest management and can be used to build individual tree growth models. Management models built based on the relationship between forest density and morphometric variables are powerful tools to achieve sustainable yield. Thus, the purpose of this study was to adjust equations to express the diameter, the shape of the crown in function of morphometric/dendrometric variables and to relate the dynamics of the changes in crown surface area and the number of trees per hectare with the diameter and crown surface area. Morphometric and dendrometric data were measured from individual trees in 25 permanent plots located in 84 hectares of a natural forest with predominance of Araucaria angustifolia (Bertol.) Kuntze species. The diameter at breast height, total height, crown insertion height and four crown radius were measured, including 330 trees. The data were subjected to Pearson correlation analysis and regression conditioners (normality and homogeneity of variance). All the equations proposed in the objectives were generated using generalized linear models (GLM) techniques, which showed accuracy and precision with low values of deviation and Akaike criterion. The results showed that there is interaction between crown shape, density and diameter, indicated by Pearson correlation higher than 0.9. The interactions of crown and density variables identified requirements of silvicultural interventions and the period to perform these activities according to the mean diameter of the forest or to a desired diameter. This is important information for the conservation of the Araucaria Forest structure.
O estudo teve como objetivo determinar um fator de forma artificial para Pinus taeda no município de Enéas Marques, localizado no sudoeste do Paraná. Primeiramente foi realizado o inventário florestal da área, utilizando como método de amostragem o de área fixa e o processo sistemático, instalando 15 parcelas de 600 m². Para determinar o fator de forma artificial, realizou-se a cubagem rigorosa de 16 árvores; destas, oito de diâmetro de área basal médio (dg) e oito árvores dominantes, com base no método de Smalian. Os diâmetros foram medidos a 0,10; 0,30; 0,70; 1,30 m; depois de 1,0 m em 1,0 m. Após determinou-se o fator de forma para cada árvore cubada, o qual foi obtido pela relação entre o volume rigoroso e o volume do cilindro a 1,30 m das árvores cubadas. Encontraram-se valores médios de fator de forma igual a 0,52 para árvores dg e 0,48 para árvores dominantes. O valor médio total para 16 árvores cubadas foi de 0,50 e um volume total de 168,22 m3/ha. Os resultados encontrados revelaram que árvores com menor diâmetro apresentam fator de forma maior, quando comparadas com árvores de diâmetro maior.
Crown efficiency is a relation of growth with the area tree occupies (available area efficiency). Efficiency is associated with the vertical and lateral expansion capacity of the tree and crown, increase, density and light absorption. Thus, our study aimed to evaluate crown efficiency with pine cones∙tree-1 production and dendro/morphometric variables of individual araucaria trees in three forest sites in south Brazil. In each site of each tree, dendrometric and morphometric variables were measured and increment rolls were taken at the breast height diameter level. Together with these data, the morphometric indexes, annual periodic increment in diameter of the last ten years (APId) and efficiency of the crown as a function of APId by the horizontal projection area of the crown (hpac) and number of pine cones∙tree-1 (np) by hpac were calculated. Crown efficiency was modeled as a function of the independent variables hpac, APId, crown length (cl), crown ratio (cr) and np. The accuracy of the adjustment was evaluated by the statistics of the deviance, Akaike’s information criterion and graph of the residuals. The results show that the number of pine cones∙tree-1 increases with annual periodic increment in diameter and diameter. Crown efficiency decreases with increasing hpac, cl and cr, indicating silvicultural treatments should be performed with the removal of trees of larger diameter and crown size. A higher pine cones production and efficiency correlates with forest growth, shape, competition, sociological position (stratum tree occupies) and density.
Silvicultural interventions are necessary to control the competition and to maintain the forest structure. Thus, this work aimed to know the interactions between dendro/morphometric variables to indicate density interventions in Brazilian pine Forest. Dendrometric and morphometric variables were measured from 186 individual trees of this species, which were distributed in diametric classes at three sites. With the variables were fitted models for the relationships between the degree of slenderness and the potential crown diameter as a function of the number of trees per hectare. The fit indicated that the variables showed interaction and the relationship can be described by linear function explaining between 51.9 and 99.3% of the variance between morphometry and forest density. This adjustment and information can be used to indicate the optimum density according to the amplitude of each index. The results show that the morphometric indexes and their interaction indicate the period of the interventions, having relation with the characteristics of the site, the diametric structure and the dynamics of the forest growth.
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