Crown area and trunk diameter relationship for tree species at a mixed-araucaria natural forest in the mid-southern Parana state, Brazil

Abstract

This paper analyzed the relationship between crown area and diameter at breast height of tree species in a Mixed-Araucaria Forest in mid-southern Parana State, Brazil. The data come from 1 hectare plot where all trees were mapped and had their crown projection drawn in the field and transferred to computer to a SIG environment to relate to DBH. In this paper, 634 individuals >10 cm DBH were used for the analysis. Trees were separated in 5 groups: General (all species), Araucaria, Imbuia, Canelas and Others. Outliers from each were properly eliminated from the correlation analysis and regression model testing. Imbuia and Araucaria were those that showed the strongest correlations. Among the models tested, the best fitting was provided by potential function (lnAC=β0+β1(lnDAP)), with the lowest standard errors of estimate and most homogeneous graphical residual distribution. It was concluded that the relationship between crown area and trunk diameter is stronger in some cases (Araucaria and Imbuia) than when a mix of species is taken into account (Canelas, Others and all species due to the different architecture of the crowns). It is possible to estimate accurately the tree crown area from its diameter when the relationship is strong.