Post made of timber found around Loch Lomond, primarily (7)
I believe the answer is:
bollard
'post' is the definition.
(I know that bollard is a type of post)
'timber found around loch lomond primarily' is the wordplay.
'timber' becomes 'board' (board is a kind of timber).
'found around' means one lot of letters goes inside another.
'primarily' suggests taking the first letters.
The initial letters of 'loch lomond' is 'll'.
'board' going around 'll' is 'BOLLARD'.
'made of' acts as a link.
(Other definitions for bollard that I've seen before include "Strong post" , "Mooring post - traffic restriction device" , "Short post barring traffic" , "Thick post for mooring" , "Roadside post" .)