Only cleaning equipment that climbs tropical trees (7)

'tropical trees' is the definition.
'pomelos' can be an answer for 'trees' (pomelo is a kind of tree). I'm not sure about the 'tropical' bit.

'only cleaning equipment that climbs' is the wordplay.
'only' becomes 'sole' (synonyms).
'cleaning equipment' becomes 'mop' (I can't explain this - if you can you should give a lot more credence to this answer).
'that climbs' says the letters should be written in reverse.
'sole'+'mop'='solemop'
'solemop' written backwards gives 'POMELOS'.

Can you help me to learn more?