Average twig growth after four consecutive years of slow-release N application and PBZ application in Year 1.
Species | Nitrogen rate (kg N/100 m2) | PBZ (g a.i./cm dbh) | Average twig growth (cm) after each annual N application | |||
---|---|---|---|---|---|---|
Year 1 | Year 2 | Year 3 | Year 4 | |||
Bur oak | 0 | 0 | 6.2 | 6.8az | 9.3 | 8.2 |
0.96 | 0 | 8.4 | 11.9b | 9.4 | 7.9 | |
2.88 | 0 | 7.2 | 8.8b | 10.9 | 10.5 | |
Bur oak | 0 | 1.2 | 9.5 | 7.9 | 8.4 | 6.8 |
0.96 | 1.2 | 5.9 | 8.9 | 10.3 | 7.2 | |
2.88 | 1.2 | 9.3 | 8.9 | 9.1 | 10.0 | |
White oak | 0 | 0 | 9.2 | 10.4 | 12.6 | 13.7 |
0.96 | 0 | 7.7 | 13.4 | 13.4 | 10.4 | |
2.88 | 0 | 7.8 | 9.9 | 10.5 | 10.5 |
↵z Values in the same column for the same species and treatment combination followed by different letters were significantly different at P ≤ 0.05.