Tree in shot taken from garrison town (5)
I believe the answer is:
alder
'tree' is the definition.
(I know that alder is a type of tree)
'shot taken from garrison town' is the wordplay.
'taken from' is a deletion indicator.
'garrison town' becomes 'Aldershot' (Aldershot is the 'home of the British Army').
'aldershot' with 'shot' taken away is 'ALDER'.
'in' is the link.
(Other definitions for alder that I've seen before include "A tree for Adler" , "Type of birch tree" , "Tree whose bark is used in tanning" , "Tree with catkins" , "North temperate tree with cone-like fruit" .)