In order to evaluate the regeneration of a forest remnant, we installed 256 2 x 2 m plots for measuring forest species individuals with height ≥ 30 cm and stem diameter ≤ 1 cm. Horizontal structure was evaluated and calculated by the Shannon (H') diversity index and the Pielou (J) evenness index. We performed clustering analysis by the agglomerative and divisive hierarchical method (the variable was the number of individuals); and used the Principal Component Analysis to verify the species distribution. We sampled 3021 individuals, distributed in 26 families and 51 species (H' = 2.78 and J = 0.66). Allophylus edulis had the highest values of absolute frequency (63.3) and absolute density (5186 ind.ha-1), while Ligustrum lucidum presented greater dissimilarity. The analysis showed the presence of regeneration mechanisms, and evidenced biological invasion problem.