Effect of container type on root ball attributes of ‘Florida Flame’ red maple harvested from eight #15 container types.
| Container type | % trees graded as cull at #3 container positionz | % trees with roots >5 mm diameter over root collar within #3 container dimensions | Diameter of five largest roots at #3 container position (mm)y | % of five largest roots at #3 container positiony in the top half of #15 root ball that ascended |
|---|---|---|---|---|
| APx | 40 abw | 20 bc | 12.5 abc | 2 b |
| CR | 40 ab | 20 bc | 12.7 ab | 2 b |
| FN | 40 ab | 50 abc | 6.4 d | 7 b |
| JP | 30 b | 10 c | 5.7 d | 0 b |
| RB | 80 a | 20 bc | 11.8 abc | 2 b |
| RT | 60 ab | 80 a | 8.0 bcd | 16 a |
| SP | 40 ab | 60 ab | 7.8 cd | 0 b |
| SS | 70 ab | 40 abc | 13.5 a | 4 b |
↵z Based on roots in the top 5 cm of root ball according to Florida Grades and Standards for Nursery Plants (Anonymous 2015); a cull occurs when there is one (or more) root greater than one-tenth the trunk diameter in the top half of the root ball growing more than one-third around the root ball. Trees in #3 and #15 containers for 7 and 9 months, respectively.
↵y Roots measured at the position of the #3 container, before descending, circling, kinking, ascending, or growing straight into #15 substrate; only ascending roots were significant. Ascended = grew up or around at >45 degree angle to horizontal; descended = grew down or around at >45 degree angle to horizontal; circling = grew around, down, or up at <45 degree angle to horizontal; kinked = grew back toward the trunk after striking container wall. There was no difference among types in the bottom half of the root balls.
↵x See Table 1 for descriptions.
↵w Means in a column with a different letter are statistically different at P < 0.05; n = 10 averaged across root pruning treatment due to insignificant interaction (P > 0.22).