Annual xylem ring increment (mm) for the year prior to treatment and for 2 years after treatment with paclobutrazol in March 1997 using the soil drench method for cherrybark oak and sweetgum growing in Louisiana, with total reduction expressed as a percentage of untreated controls.
| Treatment | Year | Total 1997–98 | Percentage reduction | ||
|---|---|---|---|---|---|
| Prior | After treatment | ||||
| 1996 | 1997 | 1998 | |||
| Cherrybark oak | |||||
| Within crown (2–4 m high) | |||||
| Control | 2.00 a | 2.22 a | 1.82 a | 4.04 a | |
| Treated | 1.60 a | 1.06 b | 0.82 b | 1.88 b | 53 |
| At base of tree (10 cm above ground line) | |||||
| Control | 4.63 a | 5.86 a | 5.74 a | 11.60 a | |
| Treated | 4.21 a | 3.19 b | 1.89 b | 5.08 b | 56 |
| Sweetgum | |||||
| Within crown (2–4 m high) | |||||
| Control | 1.75 a | 1.85 a | 0.99 a | 2.84 a | |
| Treated | 1.29 a | 1.52 b | 0.88 a | 2.40 a | 15 |
| At base of tree (10 cm above ground line) | |||||
| Control | 2.91 a | 1.83 a | 1.76 a | 3.59 a | |
| Treated | 2.01 a | 1.21 b | 1.34 a | 2.55 b | 29 |
Pairs of values followed by the same lowercase letter are not significantly different at the P ≤ 0.05 level.