Oak root systems on the left were from trees that were not irrigated during nursery production. Those in the middle received irrigation only on the soil that was to become the root ball. A similar response was found when fertilizer was applied only over the soil that was to become the root ball. Those on the right received the same volume of irrigation as those in the center but water was applied to a 3 foot diameter circle around the trunk. Trees in the center had the most fine roots in the root ball.