Table 6.

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.

TreatmentYearTotal 1997–98Percentage reduction
PriorAfter treatment
Cherrybark oak
Within crown (2–4 m high)
Control2.00 a2.22 a1.82 a4.04 a
Treated1.60 a1.06 b0.82 b1.88 b53
At base of tree (10 cm above ground line)
Control4.63 a5.86 a5.74 a11.60 a
Treated4.21 a3.19 b1.89 b  5.08 b56
Within crown (2–4 m high)
Control1.75 a1.85 a0.99 a2.84 a
Treated1.29 a1.52 b0.88 a2.40 a15
At base of tree (10 cm above ground line)
Control2.91 a1.83 a1.76 a3.59 a
Treated2.01 a1.21 b1.34 a2.55 b29
  • Pairs of values followed by the same lowercase letter are not significantly different at the P ≤ 0.05 level.