Maybe a Forest defender's heard, one providing the score (8)
I believe the answer is:
arranger
'one providing the score' is the definition.
(I know that arrangers provide musical scores)
'maybe a forest defender's heard' is the wordplay.
'maybe' becomes 'a' (I can't justify this - if you can you should give a lot more credence to this answer).
'a forest defender' becomes 'ranger' (forest rangers look after a forest).
'heard' indicates a 'sounds like' (homophone) clue.
'ranger' sounds like 'rranger'.
'a'+'rranger'='ARRANGER'
Can you help me to learn more?
(Other definitions for arranger that I've seen before include "One who organises" , "Orchestrator" , "One who adapts music" , "Rare gran (anag.)" , "One adapting a piece of music" .)