Supports reverting to stocking sources of wood (9)

'sources of wood' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Perhaps you can see an association between them that I don't see?

'supports reverting to stocking' is the wordplay.
'supports' becomes 'forests' (I can't justify this - if you can you should give a lot more credence to this answer).
'reverting' says the letters should be written in reverse.
'stocking' is an insertion indicator ('stock' can mean 'fill').
'to' in reverse letter order is 'ot'.
'forests' placed around 'ot' is 'FOOTRESTS'.

Can you help me to learn more?