Growth-site relationships in plantations ofPinus elliottii andAraucaria angustifolia in Brazil

Summary

As a basis for land classification for afforestation withPinus elliottii andAraucaria angustifolia, an investigation was made on the relations between growth and site factors in the State of Sao Paolo in Brazil. The growth of both species depends to a considerable extent on the fertility of the soil, as defined by the contents of the nutrients which were measured. Of these nutrients Ca and Mg especially seem important for growth. On the other hand, a significant part of the systematic growth variation between sites could not be explained by the systematic variation of the chemical soil factors. It appears necessary therefore, to use a soil classification as a basis for land evaluation. Certain mathematical procedures such as the fitting of curves, non-linear in their parameters, and the method of principal component analysis, have proved helpful in understanding some of the many complicated growth-site relationships.