VARIÁVEIS AMBIENTAIS, DINÂMICA E BIOMASSA EM FRAGMENTO DA FLORESTA OMBRÓFILA MISTA

Abstract

This work aims to characterize the floristic composition and dynamics of the arboreal component of a forest fragment with Araucaria in Guarapuava – PR and to evaluate the influence of environmental variables on the annual average increase in biomass (IMABio). A survey of the vegetation and the environmental variables, chemical and physical quality indexes of the soil, lightness and canopy cover. Were sampled in 50 plots for evaluation of the tree component, all live trees with a circumference ≥ 15,7 cm in height of 1,30 m of the ground. To evaluate the environmental variables, 15 permanent plots of 10x10 m divided into three treatments, (TA) subplots with an above average IMABio, (TB) subplots with an IMABio below the mean and (TM) subplots with an IMABio around the mean. It is possible to affirm that the fragment has a high diversity and a low dominance, with high distribution of the species, Matayba elaeagnoides (Miguel-pintado), had the highest value of importance, followed by Lithraea molleoides (Aroeira-branca), Ilex paraguariensis (Erva-mate). The admission rate was 1,72% per year and the mortality rate was 1,17% per year, the IMABio was 2,361 kg ano-1. General biomass was estimated at 99,6 and 126,8 Mg ha-1 in 2007 and 2017, respectively. The soil physical quality indicators showed an influence on the productivity of forest biomass, influence of resistance to soil penetration, soil density and porosity. The components that presented the greatest correlation positive with IMABio are soil moisture and porosity in the macropores domain, the most limiting components being the presence of potential acidity and resistance to soil penetration. It concludes that the fragment has high diversity and that the IMABio suffers the influence of the studied environmental variables.