Influence of the stump diameter and height on the growth and vigor of eucalyptus sprouts

ABSTRACT Forest stands managed with the coppicing technique tend to display a decreased production in subsequent rotations, demanding high stump sprouting rates, so that the planting succeeds. This study aimed to assess the vigour of eucalyptus sprouts on the basis of stumps diameter and height. The number of sprouts and height of the highest sprout were assessed regarding the stumps diameter, providing the following treatments: stumps smaller than 12 cm in diameter; from 12 to 15 cm; from 15.1 to 18 cm; and larger than 18 cm. The number of sprouts was also assessed as a function of the cutting height of the stumps, providing the following treatments: stumps near the ground and at 5, 10 and 15 cm above the ground. The diameter of the stumps did not influence the amount of sprouts, but exerted influence on the height of the highest sprout after 120 and 150 days of resprouting. The stump height had a great influence on the number of sprouts, indicating that, despite reducing the volume of timber harvested, the highest stumps provided expressive gains in the stand regeneration. The cutting height and stumps diameter influence the sprouting vigour of eucalyptus clones managed by the coppicing system.