| The objective of this research was to compare red maple (Acer
rubrum L.) root and canopy growth five years after landscape planting from
seven different container designs maintained under two irrigation regimes.
Trees planted from low profile air root pruning containers had larger trunks
five years after landscape installation than those planted from regular
air root pruning containers, wood boxes with cupric hydroxide coating, or
standard black plastic containers with cupric hydroxide coating. Despite
significant differences in root weight and amount of deflected roots among
container types when trees were planted in the landscape, root number, root
depth, and radial root distribution around the trunk were identical five
years after planting from all container types. However, frequency of irrigation
in the first 24 weeks following planting had a significant effect on root
system structure even five years later. Frequent irrigation resulted in
larger trunks, more roots, greater root cross sectional area, and a more
uniform radial root distribution. The increase in root growth on frequently
irrigated trees occurred exclusively in the top 30.5 cm (12 in) of soil.
Codominant stems four years after planting were equally common regardless
of production method and irrigation treatment. With the exception of the
low profile air root pruned container, the reduction in root defects on
the outer surface of root balls grown in containers designed to reduce defects
appeared to provide no measurable benefit to trees five months or five years
after planting into the landscape. Irrigation management after planting
had a more positive impact on landscape root growth and distribution than
container type. |