Estudo da dependência espacial de características dendrométricas para Eucalyptus grandis

Abstract

The knowledge of spatial continuity structure of dendrometric characteristics is crucial in forest inventory, management and planning. The inclusion of spatial continuity effect in inventory analysis provides stable and safe results that can be used in forest management and planning. This paper evaluated the structure of spatial continuity of four dendrometric characteristics obtained by two sampling procedures. Data were collected in 987 hectares of Eucalyptus grandis, located in the south of São Paulo State. Two sampling procedures were used, systematic grading and unencumbered systematic. For each plot from the two samples, the following dendrometric characteristics were measured: volume, quadratic average diameter, basal area and average height of the dominant trees. For each one of these characteristics, anisotropic and isotropic semi variogrammes were built, in order to evaluate the spatial continuity structure. The semi variogrammes were built using the moment estimator method. The main authorized functions were adjusted to the experimental semi variogrammes, by The Minimum Square Method. The behavior of the spatial continuity was evaluated through the degree of spatial dependence and of the assigned semi variogrammes for the four characteristics, in the appraised sampling methods, respectively. All appraised characteristics presented spatially structured, independently of the appraised sampling procedure. The continuity structure of the four characteristics was isotropic, i.e., the variance among pairs of points depends on the separation vector h. Therefore, unidirectional semi variogrammes can be built for all appraised characteristics. The results suggest that, in forest inventory, the spatial component should be considered, i.e., plots should not be treated separately.