Timber European found below crest (9)
I believe the answer is:
ridgepole
'timber' is the definition.
(wooden pole)
'european found below crest' is the wordplay.
'european' becomes 'pole' (someone from Poland).
'found below' says to put letters next to each other (in a down clue, some letters go below others).
'crest' becomes 'ridge' (I've seen this before).
'pole' after 'ridge' is 'RIDGEPOLE'.
(Other definitions for ridgepole that I've seen before include "Horizontal member in a long tent" , "Top strut of tent" .)