Some could help a man to climb a tree (5)
I believe the answer is:
maple
'a tree' is the definition.
(maple is a kind of tree)
'some could help a man to climb' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'to climb' shows that the letters should be reversed in order (I've seen 'climbs' mean this).
'elpam' can be found hidden inside 'could help a man'.
'elpam' in reverse letter order is 'MAPLE'.
(Other definitions for maple that I've seen before include "Tree providing syrup" , "Its leaf is the emblem of 8 down" , "Tree; sauce" , "Tree with winged seeds" , "Hard light-coloured wood used for furniture" .)