The most desirable oak seedlings have a fibrous root system and a stem at least 3/8 inch in diameter 1 inch above the root collar. Discard smaller diameter seedlings because they are less likely to survive and grow rapidly. Planting large seedlings will reduce the total number needed to insure a successful planting. Choose seedlings from a seed source known to thrive in your area and use seedlings from genetically superior stock when available.