Natural regeneration of fern communities after removal of Pinus elliottii in southern Brazil

Abstract

Abstract The state of Pinus cultivation in southern Brazil, from the perspective of potential environmental damage, is controversial. Little is known about naturally regenerated forests after clear-cutting Pinus, particularly regarding ferns, forest structure, and soil composition. This study evaluated differences in fern community structure, forest attributes, and soil properties in a regeneration area 15 years after P. elliottii removal, compared to an Araucaria Forest in the Canela National Forest, Brazil. A 1-hectare plot was divided into 100 m2 subplots, with 12 units randomly selected at each site. In each subplot, all fern species were recorded, and their coverage was measured. Forest and soil parameters were also collected. In the Pinus removal area, forest regeneration shows a fern community with lower species richness, greater floristic homogeneity, and a simplified structure compared to the reference area. Tree species structure differs between sites, with a high density of Pinus and absence of Araucaria angustifolia in the regeneration area. These trees are taller, form a more closed canopy, and create thicker leaf litter. The soil at the regeneration site has lower nutritional quality, greater acidity, and higher aluminum concentration compared to the natural forest. Assisted regeneration is recommended to accelerate and improvide forest recovery.