Jacket in front of recess in a tree? (6)
I believe the answer is:
anorak
'jacket' is the definition.
(anorak is a kind of jacket)
'front of recess in a tree?' is the wordplay.
'front of' indicates taking the first letters.
'in' is an insertion indicator.
'a' becomes 'an'.
'tree?' becomes 'oak' (oak is a type of tree).
The first letter of 'recess' is 'r'.
'an'+'oak'='anoak'
'r' put into 'anoak' is 'ANORAK'.
'in' is the link.
(Other definitions for anorak that I've seen before include "Parka, windcheater" , "Coat (for the boringly obsessive?)" , "Raincoat" , "Jacket for obsessives?" , "geek" .)