One said to be planting tree? (5)
I believe the answer is:
cedar
'tree?' is the definition.
(cedar is a kind of tree)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for cedar that I've seen before include "Deodar" , "Raced around a great hardwood tree" , "Leaving body" , "Tree giving fragrant wood" , "Fragrant conifer" .)