Raw materials from the forest (4)
I believe the answer is:
ores
'raw materials' is the definition.
(I've seen this in another clue)
'from the forest' is the wordplay.
'from' indicates the answer is hidden within the clue.
'ORES' is hidden within 'forest'.
(Other definitions for ores that I've seen before include "Mineral deposits" , "Metal-bearing minerals" , "Bauxite, haematite etc" , "Rocks or minerals containing metals" , "Sources of metal" .)