Competition indices in a eucalyptus stand in Central Brazil after thinning

Competition for resources influences growth and mortality in eucalyptus stands, but its effects are still poorlyunderstood, especially under different thinning intensities which alter stand density and growth dynamics compared to unthinned areas. Understanding these effects is essential to optimize forest production and ensure the sustainability of management systems. The objective of this study was to propose, estimate and evaluate distance-independent indices and distance-semi-independent indices in individual trees from a stand of eucalyptus trees subjected to different thinning intensities. The thinning treatments studied were: T0: control (without thinning); T25: 25% reduction in the number of individuals; T33: 33% reduction; and T50: 50% reduction. The stand was measured at 60 (before intervention), 67, 74, 81, 88 and 95 months. Competition indices were estimated considering 8 and 24 competing trees. The inclusion of sum of basal areas of 24 trees closest to the object-tree (BA24) variable in the calculation of the competition indices was also evaluated. Our results indicate that only the Basal Area of Larger Trees (BAL) index was efficient to represent the competition after thinning stands between the traditional distance-independent indices. The semi-distance-independent indices with 8 and 24 trees were not efficient to capture the effect of thinning. The inclusion of the BA24 variable resulted in accurate indices to describe the competition between trees in thinned eucalyptus stands.