Cluster analysis in seasonal deciduous forest remnants/Analise de agrupamentos em remanescente de floresta estacional decidual

This study intended to analyze the presence of clusters in the vegetation of Seasonal Deciduous Forest remnants, characterized as a concave enclave, on steep sandy soil, among the region's characteristic fields. Shrub and tree specimens with CBH (circumference at breast height) [greater than or equal to] 15 cm were sampled in two size classes. In class I (CBH ≥ 30 cm) specimen sampling, we used fourteen 20 x 100 m plots, divided into sub-plots (10 x 10 m). Class II (15 [less than or equal to] CBH < 30 cm) specimens were observed in 70 sub-portions. We used the TWINSPAN program to analyze the clusters, which indicated two well-defined clusters in class I (G1 and G2) and one relatively homogenous cluster in class II (understorey). There were Trichilia claussenii, Cupania vernalis and Crysophyllum marginatum indicator species in the G1 cluster; and Luehea divaricata and Sebastiania commersoniana in the G2 cluster. Regarding to horizontal structure, these species were among the three most important ones in both clusters. In the understorey, the most important species were Actinostemon concolor, Trichilia claussenii, Trichilia elegans, Eugenia rostrifolia and Sorocea bonplandii. Since these species prevail in the tree vegetation, they are fundamental to stabilize hillsides, considering that they are adapted to steep and shallow soil areas, pointing out the Cupania vernalis and Trichilia claussenii in less modified environments and the Luehea divaricata and Sebastiania commersoniana in environments more susceptible to interference.