Resumo As relações morfométricas referem-se ao espaço que uma árvore precisa para se desenvolver e auxiliam nas práticas de manejo da floresta. Diante disso, o estudo objetivou ajustar modelos entre as relações morfométricas e a quantidade de pinhas de sítios florestais de Araucaria angustifolia (Bertol.) Kuntze localizados em Lages, Bom Jardim da Serra e Painel, Santa Catarina. A amostragem voltou-se para as árvores femininas produtoras de pinhas, sendo mensuradas as variáveis circunferência a 1,30 metros da superfície do solo, altura total, número de pinhas, altura de inserção de copa e os quatro raios de copa. Posteriormente, foram calculados o diâmetro a 1,30 metros da superfície do solo, o comprimento de copa, a área de copa, a proporção de copa, o diâmetro de copa, índice de abrangência, índice de saliência, grau de esbeltez, formal de copa e o número potencial de árvores por hectare para cada área de copa. Com o conjunto de dados, foram calculadas as estatísticas descritivas de cada variável e realizada a análise da correlação de Pearson, que possibilitou a modelagem da quantidade de pinhas em função das variáveis morfométricas com maior correlação. Os resíduos dos modelos ajustados foram submetidos aos testes de normalidade, homogeneidade das variâncias e interdependência de erros, sendo utilizados os modelos lineares generalizados. A média de produção de pinhas e das variáveis dendromorfométricas mais elevadas foram encontradas no sítio florestal de Lages. As variáveis independentes diâmetro, proporção de copa, comprimento de copa e diâmetro de copa apresentaram correlação de 0,23, 0,15, 0,18 e 0,20%, respectivamente. Os resultados dos modelos mostraram que a quantidade de pinhas tem maior relação com o diâmetro e variáveis de copa, indicando que o manejo florestal deve proporcionar espaço lateral para o bom desenvolvimento das copas, pois auxilia na produção de pinhas e na redução da competição.

Abstract Morphometric relationships refer to the space that a tree needs to develop and they assist in forest management practices. Therefore, this study aimed to fit models between these morphometric relationships and the number of pine cones from Araucaria angustifolia (Bertol.) Kuntze forest sites located in Lages, Bom Jardim da Serra and Painel, in Santa Catarina state. The sampling focused on cone-producing female trees, then it measured the variable circumference at 1.30 meters from the soil surface, total height, number of pine cones, crown insertion height, and four crown rays. Subsequently, the variable diameter at 1.30 meters from the soil surface, canopy length, crown area, canopy ratio, crown diameter, range Index, salience index, slenderness rate, crown formal, and a potential number of trees per hectare for each crown area were calculated. Along with the data set, the descriptive statistics of each variable were calculated and Pearson's correlation analysis was performed, which made it possible to model the number of pine cones as a function of the morphometric variables with the highest correlation. The residuals of the fitted models were subjected to tests of normality, homogeneity of variances, and interdependence of errors, using generalized linear models. The means of production of cones and of the highest dendro-morphometric variables were found in the forest site of Lages. The independent diameter variables at breast height, crown proportion, crown length and crown diameter showed a correlation of 0.23, 0.15, 0.18, 0.20%, respectively. The model results showed that the number of pine cones is more related to the diameter and crown variables, indicating that forest management should provide lateral space for the good development of crowns because it assists the production of pine cones and the reduction of competition.

SUMMARY: The understanding of the succession process is a fundamental condition in defining strategies for the conservation and sustainable use of forest ecosystems. Therefore, we aimed at testing which ecological factors affect short-term successional changes in the upper-montane forests of the “Planalto Sul Catarinense” Region, Brazil. We evaluated the influence of propagules source, soil seed bank, edaphic and topographic variables, nucleating elements and natural regeneration floristic-structural composition on demographic rates of tree-shrub regenerating component in three disturbed open vegetation areas at São Joaquim National Park. We inventoried the regenerative component in 2014, 2015 and 2016, within one 20x100 m transect in each area. Afterwards, demographic rates were determined for each period. The influence of explicative variables on demographic rates of the regenerating component was tested through the Generalized Least Square (GLS) model. We found an increment in both individuals and richness over time. When analyzing the influence of the explanatory variables on the speed of the successional process, we observed that only the floristic-structural composition of the natural regeneration was determinant. We conclude that the speed of the represented succession is, to a large extent, a feature related to the phase of the successional trajectory in which the vegetation is found.

RESUMEN: Se busca evaluar los factores ecológicos que afectan los cambios sucesionales en los bosques de la alta montaña de la región "Planalto Sul Catarinense", Brasil. Se analizó la influencia de la fuente de propágulos, banco de semillas del suelo, variables edáficas y topográficas, elementos nucleadores y composición florístico-estructural de la regeneración natural en las tasas demográficas del componente de regeneración de árboles y arbustos en tres áreas de vegetación abierta perturbada en el Parque Nacional Nacional de São Joaquim. Se inventarió el componente regenerativo en 2014, 2015 y 2016, dentro de un transecto de 20x100 m en cada área. Entonces, se determinó las tasas demográficas para cada período. La influencia de las variables explicativas en las tasas demográficas del componente de regeneración se evaluó mediante el modelo de mínimos cuadrados generalizados (GLS). Se encontró un incremento tanto en los individuos como en la riqueza a lo largo del tiempo. Al analizar la influencia de las variables explicativas sobre la velocidad del proceso sucesorio, se observó que solo la composición florístico-estructural de la regeneración natural fue determinante. Por lo tanto, se puede inferir que la velocidad de sucesión representa una característica inherente a la fase sucesional de la vegetación. Se concluye que el proceso de sucesión se desarrolló de forma diferente entre áreas, con el pastizal presentando un proceso de invasión leñosa.

Resumo O presente estudo visou avaliar a organização funcional de espécies arbóreas em um remanescente de Floresta Ombrófila Mista Alto-Montana no município de Urubici, SC. A hipótese de que as espécies avaliadas apresentam elevada heterogeneidade funcional e que é espacialmente estruturada em função da distância da borda do remanescente foi testada. Para a determinação das espécies mais abundantes do fragmento, foi alocada uma transecção (20 x 100 m) perpendicular à borda do fragmento, em que foram amostradas as árvores com diâmetro a altura do peito (DAP) ≥ 5 cm. Para as espécies mais abundantes, foram caracterizados os seus traços funcionais: densidade da madeira (DM), área foliar (AF), área foliar específica (AFE) e altura máxima potencial (Hmax). Foram determinados os valores médios dos traços ponderados para a comunidade (CWM) e a diversidade funcional (RaoQ). Os dados foram analisados por meio de uma Análise de Componentes Principais (PCA) e por meio de correlograma de Mantel. Enquanto o eixo 1 da PCA sintetizou um gradiente funcional relacionado com a Hmax e AFE, o eixo 2 indicou uma variação relacionada com a DM e a AF. Além disso, observou-se estruturação espacial dos traços foliares (AF e AFE) e da diversidade funcional. Na borda, que é o ambiente onde a vegetação está mais exposta à geada, foi observada menor diversidade funcional, com a predominância de espécies com folhas pequenas. Assim, foi possível concluir que as espécies estudadas não são funcionalmente homogêneas e que a organização funcional é espacialmente estruturada em função da distância da borda.

Abstract We aimed to evaluate the functional organization of tree species in an Upper-Montane Araucaria Forest remnant, in the municipality of Urubici, Santa Catarina state. We tested the following hypothesis: the species present a high functional heterogeneity that is spatially structured as a function of the remnant edge distance. To determine the most abundant tree species, we plotted a 20 x 100 m transect, perpendicular to the fragment edge, where all trees with diameter at breast height (dbh) ≥ 5 cm were sampled. For the most abundant species, the functional traits were characterized: wood density (DM), leaf area (AF), specific leaf area (AFE) and maximum potential height (Hmax). The community weight mean values of functional traits (CWM) and functional diversity (RaoQ) were determined. The data were analyzed by Principal Component Analysis (PCA) and by Mantel Correlogram. While PCA axis 1 summarized a functional gradient related to Hmax and AFE, axis 2 indicated a variation related to DM and AF. Moreover, the edge distance significantly influenced the leaf traits and the functional diversity. At the edge, which is the environment where the vegetation is most exposed to frost, lower functional diversity was observed, with the predominance of species with small leaves. We concluded that the studied species are not functionally homogeneous and that the functional organization is spatially structured according to the edge distance.

ABSTRACT: The natural regeneration process is essential for forest maintenance since it is critical for establishing new tree individuals. This study aimed to improve the understanding of the regenerative component dynamics of Araucaria Forests in Southern Brazil. We investigated the effects of climate, light, tree component structure and anthropogenic disturbance on tree species regeneration. Regenerating communities from six different fragments in forest remnants of the “Planalto Sul Catarinense” region was evaluated in permanent plots two years after the first inventory. The following demographic rates were determined: recruitment, mortality, net change in the number of individuals and the changes to both upper and lower height classes. The following variables were measured in each fragment: altitude, climatic variables, light environment, tree component density and cattle presence. Association between dynamics rates, regenerating species abundance and explanatory variables was verified by the fourth-corner and RLQ methods. A total of 4,379 and 5,268 individuals were sampled for the first and second inventories, respectively, with recruitment rate (21 % yr−1) higher than mortality rate (13 % yr−1). The dynamics pattern of the fragment with greater presence of cattle stood out for the intense height increase of regenerating species caused by the presence of fast growth and light-demanding species. Natural regeneration of forest remnants under study is facing a structuring process. The main conclusions of this study were: i) climate and altitude play a relevant role in defining floristic identity and ii) chronic disturbances may influence the definition of ecological strategies.

SUMMARY: This study aimed at analyzing the dynamics of tree components in a forest adjacent to the Barra Grande Hydroelectric Power Plant reservoir, in the southern Brazilian Atlantic Forest, located in the municipality of Capão Alto. In 2013, this area was previously inventoried and divided into three sectors according to the distance from the reservoir: lower sector (in contact with the reservoir), intermediate sector (a slope area following the first sector) and upper sector (near the slope top). Fifty plots were allocated in the sectors, where all tree individuals with DBH (diameter at breast height) higher than or equal to 5 cm were inventoried (identified and measured at the circumference). In 2017 the surviving individuals were measured again, the dead ones were registered and the recruits (those with DBH reaching 5 cm) were included into the survey. Dynamics rates in number of individuals and basal area were calculated. The tree community under study has shown species richness stability, though also structural development, which is typical of areas that are facing a self-thinning process. The higher density populations of each sector have shown a similar structural dynamics pattern. There were no differences in the demographic rates among sectors, indicating that, approximately 12 years after the reservoir filling, the forest dynamics has not been influenced by the reservoir but by ecological factors dependent on density, such as competition.

RESUMEN: El objetivo del estudio fue analizar la dinámica del componente arbóreo en un bosque adyacente al reservorio de la Usina Hidroeléctrica (UHE) Barra Grande en Capão Alto, Mata Atlántica del sur de Brasil. En el año 2013, se hizo un inventario en el área, y se dividió en tres sitios con diferentes distancias del embalse: sector inferior, en contacto con el embalse; sector intermedio, área de ladera tras el primer sector, y sector superior, cerca de la cima. Fueron espaciadas 50 parcelas en los sitios, donde todos los individuos arbóreos con clase diamétrica (DAP) igual o mayor a 5 cm fueron inventariados (se identificaron y se midieron sus circunferencias). En 2017, los individuos sobrevivientes fueron remedidos, los individuos muertos registrados, y los de reclutamiento (aquellos que alcanzaron 5 cm de DAP), agregados al estudio. Se calcularon las tasas de dinámica en número de individuos y en área basal. La comunidad presentó estabilidad en la riqueza de especies y desarrollo estructural, típico de áreas que se encuentran en proceso de autorraleo. Las poblaciones de mayor densidad y de cada sector presentaron patrón de dinámica estructural similar. No se observaron diferencias en las tasas demográficas entre los sitios, por lo tanto, se concluye que, aproximadamente 12 años después del llenado del embalse, el mismo no está influenciando la dinámica del bosque adyacente, siendo esta más influenciada por factores ecológicos dependientes de la densidad, como la competencia.