Marshall Tree Farm

Production method and irrigation affect Root Morphology of Live Oak

Trees in the Nursery – Field Production
Michael D. Marshall and Edward F. Gilman
Journal of Environmental Horticulture 15(2):84-87. June 1997.

Trees of live oak were container-grown or field-grown to a mean trunk diameter of 3.7 inches,
transplanted into sandy soil, and established with frequent or periodic irrigation. Three years after
transplanting, trees were harvested with a 60-inch diameter tree spade. Root number and root crosssectional
area was evaluated for all roots at the periphery of the tree-spade-dug root ball. Despite
similar increases in trunk diameter, field-grown trees had greater root number and root cross-sectional
area than container-grown trees. The greater root cross-sectional area occurred in roots 0.2 to 0.8
inches (5-20 mm) in diameter at soil depths of 0 to 9.8 inches (0-25 mm) and 29.5 to 39.3 inches (75-
100 mm). Irrigation frequency after transplanting had no effect on root number in field-grown trees.
However, root number in container-grown trees was lower without frequent irrigation.