Natural regeneration of Pinus spp. around seed production areas and orchards

Abstract This study aims at determining the establishment potential of the main species of the Pinus genus planted in Brazil and broaden the knowledge on the conditions that facilitate the invasion. The density of regenerants neighboring pine stands planted with 35 populations of Pinus spp. (P. caribaea (var. bahamensis and var. caribaea), P. elliottii, P. kesiya, P. merkussi, P. oocarpa, P. patula, P. pseudstrobus, P. strobus, P. taeda, and P. tecunomanii) was evaluated in three locations in the state of São Paulo. The vegetal covers neighboring the pine stands were evaluated regarding native vegetation occupation, open area, and eucalypts plantation. The census of regenerants was conducted up to 100 m away from the pine stand edges; samples were collected over an area divided into four 25m-wide transects. In each transect, the regenerants were quantified and classified into three size classes: sprouts (≤ 0.3 m), seedlings (≥ 0.3 m ≤ 1.0 m), and trees (> 1.0 m). The results indicate that Pinus elliottii is the species with the greatest invasion potential in the studied areas since it adapts to different environments. Areas without established vegetation favored regeneration, indicating the effect of the environment on regeneration occurrence. The number of regenerants increased near the seed source but decreased significantly between 50 and 100 m away, despite the directional effect of the prevailing winds and the long-distance dispersal capacity of the genus.