Abstract: 1. In the bark of tapped trees, the thickness of the conducting phloem is less than 1 mm. Hence the conducting sieve tubes do not necessarily be cut off at the usual cutting depth required. The suggestion of conserving the conducting phloem during tapping is desirable and practicable. 2. Although the sieve tubes are not cut off directly during tapping, the outer part of the sieve tube layer at/near the gapping cut will be collapsed as a result of the damaging effect from tapping. This has revealed the actual process of the destruction in the sieve tubes during tapping.