Influência dos métodos de desbrota no crescimento do eucalipto

Abstract

Sprouting management in eucalyptus stands under coppice control is crucial for the growth and productivity of commercial trunks. In this context, early sprouting management stands out as a practice capable of optimizing the use of growth resources by the remaining plants. The objective of this work was to evaluate the influence of early sprouting management in eucalyptus stumps on the growth of the dominant shoot (commercial trunk), compared to the traditional late management, after the fourth year of growth, in a stand managed under coppice control at the Federal Institute of Minas Gerais (IFMG), São João Evangelista Campus. The study was conducted in a seedbed of a Eucalyptus grandis × Eucalyptus urophylla hybrid, established in a silvopastoral system, consisting of four rows of triple eucalyptus trees, spaced 3 × 2 m within the rows and 30 m between rows. The experiment was established in a randomized complete block design (RCBD), with four blocks and two treatments: T1 – early sprouting management with a manual digger; and T2 – late sprouting management with a sickle. Growth assessments were performed at 58 months of age, using the variables total height (H), diameter at breast height (DBH), height/diameter ratio (H/DBH), basal area per hectare (BAH), average individual volume (AIV), and volume per hectare (VHA). The data were subjected to analysis of variance and mean comparison tests (F-test and Tukey's test, at 5% significance), using spreadsheets and the R software. The results showed that, at 58 months of age, the variables total height (H) and height/diameter ratio (H/DBH) were statistically superior in plants managed through early pruning. Statistical analyses applied to the other variables (diameter at 1.3 m from the ground, basal area per hectare, average individual volume, and volume per hectare) indicated no significant differences between treatments. Despite this, the consistency of the percentage gains observed in early pruning compared to late pruning characterizes a technically relevant silvicultural pattern, indicating that the early removal of excess shoots has a positive effect on the growth of dominant stems, highlighting the 9.4% increase in basal area per hectare and the 9.0% increase in volume per hectare. These results represent a relevant technical contribution by demonstrating that anticipating the removal of excess shoots establishes a silvicultural pattern favorable to the growth of dominant stems in stands managed by coppicing.