Maintenance of the Economic Performance of Eucalyptus in Competition With Weeds

The aim of this study was to evaluate the growth of the hybrid clone Eucalyptus grandis × Eucalyptus urophylla submitted to competition with weeds and determine the period prior to economic loss (PPEL). The experiment was carried out in Ulianópolis, Pará State, Brazil, and consisted of the treatments continuous control and no control of weeds. Weed management was carried out by integrating both mechanical and chemical control. Stem base diameter, height, canopy diameter of eucalyptus plants were measured on the 16th month after planting. Wood volume was estimated by means of a volumetric equation. The treatments continuous control and no control of weeds were compared using the Hotelling’s T2 test and the parameters for PPEL calculation were defined from volume estimation. The treatment continuous control promoted significant gains in eucalyptus growth. PPEL tended to be reduced by 3.8287 and 0.2393 units with the increase of a unit in the price of wood and the increase of planting yield, respectively. For different eucalyptus wood prices, the calculated PPEL ranged from 40 to 161 days of coexistence with weeds.