Phytosociological survey in Brazilian forest genetic reserve of Cacador

A phytosociological survey was carried out in the Forest Genetic Reserve of Cacador, which belongs to the Brazilian Agriculture Research Corporation - EMBRAPA. The Genetic Reserve comprises an area of 1120 ha and has been managed by the Agricultural Research and Extension Corporation of the State of Santa Catarina (EPAGRI). A restricted random sampling by plots, with units of 2500 m(2) (100 x 25 m) was used, allocating 40 plots to stands containing Araucaria angustifolia. All trees with diameter greater than or equal to 20 cm at breast height were measured. Frequency, density, dominance, soil coverage, and importance value were evaluated. The most important species indicated by these parameters were Araucaria angustifolia, Ocotea porosa, Cupania vernalis, Matayba eleagnoides, Mollinedia elegans, Ocotea pulchella, Ilex paraguariensis and Prunus brasiliensis. In spite of the very high mean basal area (35.84 m(2) ha(-1)), mean density (222 trees ha(-1)) and mean volume outside bark (531.14 m(3) ha-(1)) for A. angustifolia it was found that understory had low commercial value and a very low natural regeneration rate in the priority species for in situ conservation: A. angustifolia, Cedrela fissilis, I. paraguariensis, Mimosa scabrella, P. brasiliensis and O. porosa. Simpson's index has shown in this case a low floristic diversity of species however, as was expected, the highest levels of abundance, dominance and frequency were found for Araucaria angustifolia.