Sacred nuts in trees (6)
I believe the answer is:
cedars
'trees' is the definition.
(cedar is a kind of tree)
'sacred nuts' is the wordplay.
'nuts' indicates an anagram (nuts can mean crazy).
'sacred' with letters rearranged gives 'CEDARS'.
'in' is the link.
(Other definitions for cedars that I've seen before include "Sacred (anag) -- trees" , "(Lebanese?) trees" , "Strangely sacred trees" , "Trees with perfumed wood" , "Fragrant trees of the Lebanon" .)