Nível de dano econômico para formigas-cortadeiras em função do índice de produtividade florestal de eucaliptais em uma região de Mata Atlântica / Economic damage level for leaf-cutting ants in function of the productivity index of eucalyptus plantations in an Atlantic Forest region

ABSTRACT

The production and quality of eucalyptus plantations have been studied in areas with different densities of ant nests, being important to estimate losses caused by leaf-cutting ants. The effects of leaf-cutting ant on wood production in differents productivity sites were studied in eucalyptus plantations in the region of Atlantic Forest, Minas Gerais State, Brazil from 2003 to 2006. Data of plots of the continuous forest inventory and data of leaf-cutting ant monitoring in eucalyptus plantations were obtained. Each unitary increment in the area of Atta spp. nests per hectare reduced the wood production of the eucalyptus forest between 0.04 and 0.13 m³.ha-1, resulting in a level of economic damage for leaf-cutting ants between 13.4 and 39.2 m².ha-1, in this region. Moreover, this study innovated when using indices of forest productivity (site index) that promote better adjustment of the models and produce estimate more accurate of the level of economic damage for leaf-cutting ants in cultivated forests, allowing to conclude that the increase of the total area of ant nests reduces the wooden volume of eucalyptus, proportionally to the productive potential of the forest.