In the forest reserves of southeastern Nigeria, the indigenous woodland is being progressively cleared and replaced by teak and gmelina plantations. The present study has investigated the risk of transmission of yellow fever in one such reserve by assessing the abundance of Aedes (Stegomyia) and other potential vector mosquitoes, using ovitraps and crepuscular human-bait collections. Ae. africanus was found abundant at ground level throughout the reserve and in the camp at its center. In the cleared areas, the resulting slash and debris provided breeding places such as tree holes for high populations of Ae. aegypti and Ae. africanus. Since at the time of tree-planting the local population cultivate crops in these cleared areas for 2-3 years, this makes for a high degree of man-vector contact. On the other hand, once the plantations have grown they are very poor sources of these mosquitoes, and thus they prove a means of environmental abatement of such disease vectors.