Modelagem Biométrica e Fitossociologia de Pteridófitas Arborescentes em Floresta Ombrófila Mista

Abstract

In the state of Paraná, there are thirteen species of tree ferns, among them Dicksonia sellowiana (Pres.) Hook, and ciateáceas Alsophila setosa Kaulf, Cyathea phalerata Mart. and Cyathea corcovadensis (Raddi) Domin. The objective with this study perform biometric and phytosociologic characterization of tree ferns in a fragment of Araucaria Forest in Irati National Forest. We evaluated 25 sample units of 500 m² each, were evaluated systematically distributed in permanent plots of 25 ha installed in 2002 Irati National Forest in a fragment of Mixed Rain Forest without intervention approximately 70 years. Were measured and identified all tree ferns up to 1.3m high, taking measurements of the CBH with tape measure and full height with telescopic ruler. Collection of botanical material was performed and tumbled in the Herbarium Universidade Estadual do Centro-Oeste, Campus Irati. It was performed nondestructive cubed by Smalian. For modeling were adjusted 15 hypsometric models for D. sellowiana and 16 volumetric models for A. setosa and D. sellowiana. Phytosociology, were calculated dominance, density and frequency in absolute and relative values, and the importance value index. Were measured in 1831 individuals of the four species and 1682 A. setosa, 26 C. phalerata, 3 C. corcovadensis and 120 of D. sellowiana, with DBH ranging between 6.5 and 60.2 cm and total height ranging from 1.3 and 8.7 m. To A. setosa there is not hypsometric relationship and the chosen volumetric model estimated 50.5 m³/ha and D. sellowiana there is a weak hypsometric relationship and its total volume was estimated at 22.21 m³/ha and trade volume 10.5 m³/ha. In phytosociology A. setosa had the highest VI (93,46), the highest density (1345.6 individuals/ha) and one of the higher frequencies. D. sellowiana had the third highest dominance (5,98 m²/ha). The hypsometric model was adequate to estimates for D. sellowiana and volumetric models were effective for estimates for both species. A. setosa and D. sellowiana stood out in phytosociology, but C. phalerata and C. corcovadensis did not stand out in phytosociology.