3.2 Effect of girdling on NSC in leaves and bark
Mean NSC concentration of leaf tissues collected pre-girdling (Fig. 2a) and post-girdling (Fig. 2b) was around 170-200 mg g-1DW with a range of 140-280 mg NSC g-1 DW. The ratios of Ss to St shifted slightly from 1:1.5 at pre-girdling to 1:1.9 at post-girdling. Girdling caused a significant decline (p <0.01) in Ss of leaves, compared to pre-girdling, at the base (74.24 mg g-1 DW ± 6.71 to 64.35 mg g-1 DW ± 7.17; ±1 Standard Deviation) and top crown positions (72.61 mg g-1 DW ± 8.42 to 62.87 mg g-1 DW ± 9.83) (Fig. 2a, b). Concentrations of St differed significantly (p >0.001) between leaves from the base and top crown positions at pre-girdling (Fig. 2a), but not at post-girdling (Fig. 2b).
Bark generally contained less total NSC than leaves (<150 mg g-1 DW), largely due to a smaller pool of St (Fig. 2c, d). Prior to girdling, pools of St and Ss in bark from the base and the top of the stem did not differ (Fig. 2c). However, girdling reduced St below the girdle by 23% (base: 57.92 mg g-1 DW ± 6.76; top: 74.89 mg g-1 DW ± 2.97) and Ss by nearly 50% (base: 25.84 mg g-1 DW ± 6.71; top: 48.90 mg g-1 DW ± 14.14) compared to above the girdle (Fig. 2d). Overall, the ratio of Ss:St shifted from 1:1.4 at pre-girdling to 1:2.3 at post-girdling. Similar to leaves, girdling had a much stronger effect on the pool of Ss compared to St in bark tissue. Notably, bark below the girdle contained the lowest concentrations of both Ss and St (Fig. 2d).