Basal area increment model of araucaria trees in uneven aged forest

Abstract

The present study aimed to develop a mathematical model to describe annual periodic percentage increment in basal area of Araucaria angustifolia trees with data collected from increment cores extracted radially from the trunk at breast height of 109 trees distributed in a large diameter range. Dendrometric and morphometric attributes were tested by multiple linear regressions as independent variables and their interactions with dummy variables as descriptors of social position class. The model explains 80% of total variation of the periodic annual percentage increment in basal area with formal crown and height/diameter relationship for trees of all social positions, as well as length and crown proportion of dominant trees described by the dummy variable. Morphometric variables, especially those that characterize the crown size, are indicated for development of individual tree growth models of Araucaria angustifolia.