Phytosociology of natural regeneration as a subsidy for restoration in post-harvest areas of Pinus sp. in the Mixed and Dense Ombrophilous Forest

Abstract The objective of this study was to evaluate the natural regeneration in permanent preservation areas (PPA) in forest restoration process after Pinus sp. harvest through the survey of phytosociological parameters.. The study was carried out in the PPA, associated with springs and rivers in two areas with different post-harvest ages of Pinus sp., being inserted in Mixed Ombrophilous Forest (MOF - 7 years old) and Dense Ombrophilous Forest in transition (DOF/MOF - 12 years old) both in the Santa Catarina state. Nineteen rectangular plots with dimensions of 25 m x 4 m (100 m2) were allocated at random in each one of the areas, for the floristic-structural evaluation of the tree-shrub regenerative component. In the DOF in transition, 913 regenerating individuals of tree and shrub species were sampled, belonging to 90 species, 60 genera and 30 botanical families. The species with the highest importance value were Cupania vernalis (8.71%), followed by Bernardia pulchella (5.93%), Aureliana wettsteiniana (5.25%). At MOF, an area undergoing restoration in less time, 782 regenerating individuals of tree and shrub species were sampled, belonging to 62 species, 21 botanical families and 30 genera. The species with the highest importance value were Myrsine coriacea (10.06%), Solanum variabile (9.79%), Myrsine lorentziana (7.08%). Shannon’s diversity indexes were H’ = 3.76 for DOF in transition and H’ = 3.24 for MOF, and showed a high diversity of species, whereas the Pielou equability index obtained J = 0.81 for DOF in transition and J = 0.77 for MOF, showing high uniformity in the distribution of individuals in the species for the two areas. The diametric distribution of the individuals showed an “inverted J” pattern for both phytophysiognomies, behavior expected in native forests. The NMDS (Non-metric multidimensional scaling) presented a stress value of 9.81% indicating suitability of the ordering and allowing inferences to be made with reliability. Through the NMDS ordering, it was observed the formation of two distinct floristic-structural groups, associated with MOF phytophysiognomies and MOF/DOF transition. All plots inserted in MOF areas are grouped to the right in the ordering, while most plots inserted in the MOF/DOF transition area are grouped to the left of the ordering. The tree-shrub regenerative component evaluated in post-harvest areas of Pinus sp. at both phytophysiognomies has a great diversity of species with great importance for forest formation, being a favorable environment for the conservation of species and essential to guarantee the succession of the forest and the restoration resilience.