Dinâmica e prognose do crescimento em um fragmento de floresta ombrófila mista no sul do Paraná

Abstract

The present study aims to enrich the scientific and technical knowledge on a Mixed Araucaria Forest fragment and, for that reason, this study was divided into five chapters with specific goals. The first chapter describes the general aspects of this research. The second chapter analyzes and compares the changes in floristic, phytosociological and structure, as well as mortality and recruitment. The third chapter evaluate the changes in species growth, botanical families and of the forest as a whole, relating them with the meteorological variables in the region. The fourth chapter tested accuracy of diameter projections, using the transition matrix and movement ratio models in different temporal amplitudes and diameter class intervals. The fifth and last chapter simulates the growth in number of trees and basal area inside the forest as a whole, botanical families and species with the greater importance value, using movement ratio model. For this pourpose the used data proceeded from a continuous inventory conducted in a Mixed Araucaria Forest fragment with three permanent sample plots of 1 ha each and one permanent plot of 0.5 ha, subdivided in 350 subunits with 100 m2 and 3.5 ha of sampled area, which were measured annually ever in July since 1995 up to 2011, in the Experimental Station Rudi Arno Seitz, in the São João do Triunfo, Paraná. All trees with diameter at breast height equal or greater than 10.0 cm (DBH ≥ 10.0 cm) were identified and measured, and during remeasurements all recruited and dead trees were counted until the year 2011. The results showed that that fragment had high floristic diversity and has changed little over the years. The Lauraceae and Myrtaceae had greater diversity and representation in this forest as well as the species Araucaria angustifolia, Nectandra grandiflora, Ilex paraguariensis and Matayba elaeagnoides. The diameter distribution presented the decrescent form, typical behavior of allaged and mixed forests. The average recruitment rate was higher than the mortality rate in this fragment. The mean periodic diameter increment of the forest presented an average of 0.22 cm.ano-1, but the increment values vary in relation to species. The growth rate of the forest and for each species changed over the years, maintaining a gradual growth, apogee and after senescence, even when one observes the same diameter classes over the years. The results of diametric projections indicated that the movement ratio model with temporal amplitudes of 2 years and diameter class intervals of 10 cm are the most recommended to the realization of the prognosis of the number of trees. In the future, the forest as a whole will grow considerably in basal area, but not in number of trees, confirming the maturation of this Mixed Araucaria Forest fragment.