Possible Clues:

• ___ biloba (ornamental tree with a widely used extract)
• Food supplement damaging koalas to some extent
• Spirit and energy required to maintain Kew's top tree
• Growth of goods to eat in -- passable when served up
• Italian chap procures Greek and Oriental tree
• The maidenhair tree
• Chinese ornamental tree
• Working, drop round to fell tree
• Medicinal plant
• Encouraging koala into this tree?