# A farmer removes a complete ring of bark (including the phloem) from around the trunk of an apple tree. Explain what happens to the sugars produced in the leaves after this ring of bark is removed.

> Cambridge International IGCSE Biology (0610) — 8.4 Translocation · Explain · 4 marks

> When a ring of bark is removed from a tree trunk, all the phloem tissue at that point is destroyed. The xylem tissue beneath remains intact.

## Mark scheme (4 marks)

1. Sugars (sucrose) cannot be transported downwards past the ring because the phloem has been removed
2. Sugars accumulate / build up above the ring (in the leaves or stem above the cut)
3. Roots (and other sinks below the ring) are no longer supplied with sugars
4. The roots eventually die because they cannot respire or grow without a supply of sugars

## Key terms

- [phloem](https://www.gradenine.co.uk/glossary/phloem)

## Related

- [Revision notes for Cambridge International IGCSE Biology (0610)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-farmer-removes-a-complete-ring-c51e8c91) · Published by Druglandscape Ltd.