Many a branch is made to scale (5)
I believe the answer is:
climb
'to scale' is the definition.
(I've seen this before)
'many a branch' is the wordplay.
'many' becomes 'c' (C is the Roman numeral for 100).
'a branch' becomes 'limb' (I've seen this before).
'c'+'limb'='CLIMB'
'is made' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for climb that I've seen before include "Get higher" , "Ascend - ascent" , "Move upwards, ascend" , "Deadened" , "improve one's social status" .)