INDIVIDUAL TREE GROWTH MODEL FOR Nectandra megapotamica (Spreng.) Mez

Abstract

Sustainable forest management requires knowledge of forest stock and future growth of forests. In the forest sector growth models are used to predict the growth of trees, stands or forests. In heterogeneous uneven-aged forests of Rio Grande do Sul, models on an individual tree basis are appropriate. The present work was established to contribute to the formulation of growth models for one species of the seasonal deciduous forests of Rio Grande do Sul: Nectandra megapotamica. Sampling was realized in the district of Vale Vêneto, near Santa Maria in the years of 1994 and 1997. Vegetation was classified into different successional stages and within these permanent sample plots (uap) were installed. In every sample plot the trees with diameter at breast height above 5 cm were identified, numerated and measured. Additionally, the sociological position and site parameters were estimated. In every uap individual basal area increment, basal area per ha and basal area larger (BAL), as competition indexes, were calculated. Then growth equations were established by using the ‘stepwise’ procedure. The general formulation of the model is: Increment (g/year) = f (dimension, competition, site). The best model for Nectandra megapotamica is: ICA = 0,002084 + 0,000001039 x DBH² - 0,0003498 x Degradation - 0,000375 x Sociological position - 0,00000904 x Soil stonyty - 0,0000103 x BAL.