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Araucaria angustifolia is an endangered species with more than 97% of its natural populations extinct. Logging of the species in the few remaining natural populations is highly restricted, though not readily accepted by farmers and logging companies. Consequently, political pressures have emerged for a return to logging of the species. Assessing the sustainability of such logging requires studies of a range of impacts on the remaining populations, including their genetic viability. We investigated the effect of selective logging on genetic diversity, intrapopulation spatial genetic structure (SGS), effective population size (Ne), and pollen and seed dispersal in three A. angustifolia permanent sample blocks established in a remnant of Araucaria Forest in Brazil. In these sample blocks, three logging intensities were applied (LI: 18.4, 31.4, and 32.3% of trees). Microsatellite analysis was performed for all adult and juvenile trees pre- and post-logging saplings. After selective logging, the greatest loss of alleles and the greatest decrease in Ne were observed from the highest LI. Logging increased SGS, while the distance and patterns of pollen and seed dispersal were different for both pre- and post-logging scenarios, with pollen dispersed over greater distances than seed. Pollen dispersal distance post-logging and seed dispersal distance pre- and post-logging decreased with the increased distance between parents. After logging, Ne reduced from 27.7 (LI = 31.4%) to 28.8 (LI = 18.4%) and 39.5% (LI = 32.3%), and some alleles were lost. Despite this, the loss of these alleles may be compensated for in subsequent generations, considering that logging resulted in changes such as an increase in the rate and distance of pollen immigration. Under the conditions evaluated in this study, selective logging of A. angustifolia is not adequate. To achieve truly sustainable forest logging, new rules that combine higher minimum DBH, lower logging intensity, and longer cutting cycles must be adopted. Furthermore, extensive genetic studies must be performed before logging any individual from a natural population.

O objetivo desta pesquisa foi avaliar o efeito da idade no ajuste de funções de afilamento e na evolução do sortimento em árvores masculinas e femininas em plantios de Araucaria angustifolia. Foram amostradas 60 árvores da espécie em um plantio localizado no município de Laranjeiras do Sul, Paraná. Ajustou-se o polinômio de quinto grau para o total de dados, estratificando-os em classes de idade. Foi analisada a evolução do afilamento e do sortimento das árvores com a idade. Os resultados mostraram uma leve vantagem no uso de equações ajustadas por classes de idade e uma melhoria significativa na forma do tronco com o aumento da idade. As árvores femininas (0,9975 m3) apresentaram crescimento mais elevado que as masculinas (0,9384 m3) aos 30 anos. Volumes para os sortimentos mais nobres são produzidos somente a partir da classe de idade 11 a 15 anos. The objective of this research was to evaluate the effect of age on adjust taper functions and evolution of the assortment of male and female trees of Araucaria angustifolia stands. Sixty trees were sampled in a plantation located in the municipality of Laranjeiras do Sul, Paraná state, Brazil. The fifth degree polynomials were adjusted to the whole data set, and they were stratified into age classes. The evolution of the tapering and assortment of trees was analyzed with age. The results showed a slight advantage in the use of equations adjusted for age classes and a significant improvement in the stem form with increasing age. The female trees presented higher growth (0.9975 m3) than the male trees (0.9384 m3) at 30 years of age. Volumes for the noblest assortments are produced only when the stand reaches the age class of 11 to 15 years.

The aim of this study was to assess and model the evolution of the hypsometric relationship in Araucaria angustifolia plantations grown in the 1940's and 1960's in the Irati National Forest, in the mid-south region of Paraná state, Brazil. Using the complete stem analysis method, it was possible to reconstitute the past annual growth of the diameter at 1.3 m (d) and of the total height (h) of a sample of 30 trees, selected so as to cover diametric and age variability. Eleven discs were removed from each tree at 0.1 and 1.3 m and at 15, 25, 35,..., 95% of the total height. Eleven models traditionally used in hypsometric relationships were tested, two of which were considered generic because they involved the age variable. The models were selected based on the Adjusted Coefficient of Determination (R²Adj), Standard Estimate Error (Syx), absolute (m) and relative (%), and on the graphic distribution of residues in percentage. In the models tested by age, no tendencies were observed and erros (Syx) remained below 14.6%, except for ages 5 and 11. However, the coefficients of determination were low, ranging from 0.29 to 0.55. The Curtis generic model (1970), selected to represent the h/d curve for all ages, also presented a satisfactory performance (R²Adj = 0.87 and Syx = 16%), with results similar to those obtained for the models in each age. As age increases, the h/d curve shifts to the right and changes level, remaining steep at the younger ages and more stable and flat as the population nears the end of its cycle. Nesta pesquisa, objetivou-se avaliar e modelar a evolução da relação hipsométrica em plantios de Araucaria angustifolia, estabelecidos nas décadas de 40 a 60 na Floresta Nacional de Irati, região Centro-Sul do Paraná. Com o método de análise de tronco completa foi feita a reconstituição do crescimento anual passado do diâmetro a 1,3m do solo (d) e da altura total (h) de uma amostra com 30 árvores, selecionadas de forma a cobrir a variabilidade diamétrica e de idade. De cada árvore, foram retirados 11 discos nas alturas 0,1 e 1,3 m e nas alturas de 15, 25, 35,..., 95% da altura total. Foram testados 11 modelos tradicionalmente usados para relações hipsométricas, sendo dois deles denominados de genéricos, porque envolvem a variável idade. Os modelos foram selecionados com base no Coeficiente de Determinação Ajustado (R²Adj), Erro Padrão de Estimativa (Syx) absoluto (m) e relativo (%) e na distribuição gráfica dos resíduos em percentagem. Os modelos testados por idade se mostraram sem tendências, com erros (Syx ) inferiores a 14,6%, exceto para as idades 5 e 11 anos, no entanto, os coeficientes de determinação foram baixos, variando de 0,29 a 0,55. O modelo genérico de Curtis (1970), selecionado para representar a curva h/d em todas as idades, também apresentou um bom desempenho (R²Adj = 0,87 e Syx = 16%) e com resultados similares àqueles obtidos com os modelos em cada idade. Com o avanço da idade, a curva h/d se desloca para a direita e muda de patamar, sendo íngreme nas idades mais jovens, tornando-se mais estável e aplainada quando o povoamento tende para o final de seu ciclo.