Growth of Araucaria angustifolia, Cedrela fissilis and Ocotea porosa in different locations within the Araucaria forest in the southern Brazil

Abstract

This research investigated and characterized growth of Araucaria angustifolia (Bert.) O. Ktze, Cedrela fissilis Velloso and Ocotea porosa (Nees & C. Mart.) Barroso in Araucaria Forest in sites located within three States of southern Brazil, each one presenting different conservation stages. We evaluate diametric growth based on partial stem analysis using core samples from 30 trees by species at each study site (totalizing 480 trees), collected proportionally to the diametric distribution.The samples were collectedfor each species in six locations: Irati and São João do Triunfo, in Parana State, Três Barras, Chapecó and Caçador, in Santa Catarina State and São Francisco de Paula in Rio Grande do Sul State. The oldest trees were observed in Caçador (A. angustifolia, 588 years old and O. porosa, 322 years old) and Irati (C. fissilis, 231 years old). The youngest ones were A. angustifolia in Chapecó (33 years), O. porosa in Três Barras (26 years) and C. fissilis in São João do Triunfo (20 years). The largest average diameters for A. angustifolia and C. fissilis were found in Caçador (75 and 44.1 cm, respectively) and for O. porosa (54.5 cm) in São João do Triunfo. The age and the diametric classes of the trees affect growth, independent of the forest stock condition. Although differences in diameter growth of the three species have been attributed to variations in environmental conditions, it is suspected a greater influence of forest structure since similar climatic groups have showed distinct growth rates. Successional stages of the forest should also be considered when evaluating growth rhythm of the same species in different sites.