Modelagem do diâmetro da copa de dois clones de Eucalyptus urograndis sob três espaçamentos em Rio Largo, Alagoas.

Abstract

The growth of eucalyptus plantations is evident across a significant portion of the national territory, with the northeastern region having one of the smallest cultivated areas. Within this context, studies on the development of this species contribute to the region's viability. This study aims to define an equation model that best fits the crown diameter for two hybrid clones of Eucalyptus grandis and Eucalyptus urophylla - I144 and VE41 - cultivated under three different tree spacing conditions (3m x 2m, 3m x 3m, 3m x 4m) and at 55 months of age in an experimental area at the Campus of Engineering and Agricultural Sciences of the Federal University of Alagoas, Rio Largo, Alagoas, involving three randomized blocks in monoculture with or without fertilization. Forest inventories were conducted over various periods, and the Pearson correlation coefficient was used to select relevant independent variables. These variables underwent transformations and were analyzed through the SAS OnDemand for Academics software to identify the most suitable equation, separating trunk diameter and age into different models for comparison. The adjusted equations exhibited highly significant F and t values, proving adequate for crown diameter estimations. The equations were simple in application, with trunk diameter and age as predictors, implying reduced susceptibility to errors. Concerning crown projection surfaces, it was observed that larger spacings facilitated greater crown growth, proportional to increased available space. The comparison between I144 and VE41 clones displayed a slight difference in both crown diameter over time and in relation to trunk diameter.