Influence of sample unit size and shape on spatial structure dependence in four forest formations in the State of São Paulo, Brazil

Abstract

The size and shape of sampling units have a large influence on the perception of spatial autocorrelation. Thus, the choice of an appropriate scale for the study of spatial processes is extremely important, because the spatial dynamics can be considered as significant, insignificant or irrelevant depending on the scale used, or the relationship between variables may be obscured or distorted. The aim of this work was to study the structure of spatial continuity, by model-based geostatistical,analyzing the influence of sample unit size and shape . For this study, four permanent plots of 320 x 320 m were divided into grids using square plots of 5 x 5 m, 10 x 10 m and 20 x 20 m, and rectangular plots of 10 x 20 m, 10 x 30 m, 10 x 40 m, 10 x 50 m and 5 x 80 m. Basal area and biomass were determined for each plot. The influence of size and shape of the plot on the perception of the structure of spatial continuity was clear. However, the rectangular plots of 10 x 40m were able to identify the variability of the forest, and the plots of 20 x 20m were the best to describe the structure of spatial continuity.