Geostatistical behavior of dendrometric variables of Eucalyptus benthamii for forest management purpose

The aim of this study was to investigate the behavior of dendrometric variables of a commercial plantation of Eucalyptus benthamii Maiden et Cambage planted on an Inceptisol soil in Brazil for management purposes, based on geostatistic metrics and ordinary punctual kriging. A sampling grid of 70 x 70 m spaced over a 20 ha block was established in the municipality of Bocaina do Sul, in the state of Santa Catarina. Each sampling point was a circular plot of 10 m radius, where diameter at breast height (dbh), total height (h) of the first 15 trees and the 5 thickest trees were measured and the volume (v) of each tree was calculated by the Smalian method. The variables v, dbh, h and the dominant height (hdom) of each plot were subjected to geostatistical analysis based on semivariograma to detect the spatial dependence to these dendrometric variables. Only h and hdom presented satisfactory adjustment to the experimental semivariogram, with the spherical model better representing the spatial variation of these characteristics. Through kriging it was possible to estimate with high precision the variables hdom and h (r(2) = 0.97, S-yx = +/- 0.04; r(2) = 0.55, S-yx = +/- 0.21, respectively), in forest sites not sampled (validation data), thus providing subsidies for forest management purposes. Nevertheless, for dbh and v, it is recommended to conduct a higher sample intensity in order to identify spatial continuity.