Dinâmica e Estratégias para a Projeção da Estrutura Diamétrica em Floresta Ombrófila Mista no Planalto Norte Catarinense

Abstract

The research had as object to analyze dynamics in the period from 2004 to 2016 involving the floristic, horizontal structure, increment, mortality, ingrowth and the diametric structure. Data clustering strategies were also tested for the prognoses of the diametric structure with the "Movement Ratio" method in a Mixed Ombrophylous Forest located in the National Forest of Três barras-SC. In this fragment, 26 permanent plots (one hectare each), subdivided into 520 secondary plots (500 m²) were installed in 2004, these plots were remediated in 2009 and 2016. All trees with DBH ≥ 10 cm were numbered, measured and identified. Floristic analysis, horizontal and dynamic structure were performed from the first measurement. By means of the clustering analysis, the stratification of the secondary plots was realized. The evaluation of prognoses was performed using the Kolmogorov-Smirnov Test (K-S) and Reynolds Index (RI). Prognosis was performed for the entire forest using the interval of seven and twelve years. Using the temporal amplitude of seven years, the projection was realized for three scenarios: with all the species of the forest; for groups formed through multivariate analysis; and for Araucaria and hardwood species. In 2004, were found 713.85 trees ha-1, in 2009, 703.85 trees.ha-1, and in the year 2016, 664.65 trees were recorded, divided into 113 tree species, 67 genera and 39 botanical families. During the monitoring years, the number of trees per hectare decreased, however, the number of family, genera and botanical species increased. Just over 50% of the importance value found for the entire forest in the year 2016, were represented by only seven species, among them Araucaria angustifolia, Ocotea porosa and Matayba elaeagnoides. During the twelve years of monitoring, the forest presented an average increment of 0.22 cm.year-1, and an increase of 7.84% in the basal area. The annual ingrowth rate was 2.01% and the mortality rate was 2.68%. The cluster analysis resulted in three groups of plots, different from each other in terms of basal area and number of individuals. The two projections were not adhered by the K-S test, and in the shortest period, the number of trees projected by diametric class is closer to the real value. According to the statistical tests, the projections improved when the prognosis was performed for the groups of homogeneous plots and for the Araucaria and hardwood species.