Modeling of the height-diameter relationship in eucalyptus in integrated crop-livestock systems

Modelagem da relação altura-diâmetro de eucalipto em sistemas de integração lavoura-pecuária

Abstract

The objective of this work was to compare the height-diameter relationship, described by nonlinear biological models, in Eucalyptus benthamii in monoculture forestry and in three different integrated crop-livestock systems (ICLS): crop-forestry, livestock-forestry, and crop-livestock-forestry. The trees were evaluated during seven years after planting. Five nonlinear biological models were fitted to evaluate the height-diameter relationship, and Gompertz’s model was selected to describe the data, although all models described satisfactorily the height-diameter relationship of the trees in the ICLS. The analysis of the data showed that there is no similarity between monoculture forestry and the ICLS as to the height-diameter relationship. In addition, the height-diameter relationship in E. benthamii changes between the different ICLS. Particularly, two systems with cattle provide the same values of maximum growth rate, asymptote, and inflection point of diameter at breast height. Furthermore, with the integration of cattle into the tree component, the produced trees show lower asymptotic heights, with larger diameters when the average tree heights of the ICLS are equal.

Index terms:
Eucalyptus benthamii ; agroforestry systems; agrosilvopastoral; biological models; Gompertz; nonlinear models