Tree on borders of Surrey appeared full of gold (8)
I believe the answer is:
sycamore
'tree' is the definition.
(sycamore is a kind of tree)
'borders of surrey appeared full of gold' is the wordplay.
'borders of' means to remove the middle letters.
'appeared' becomes 'came' (I've seen this before).
'full of' is an insertion indicator.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'surrey' with its centre removed is 'sy'.
'came' placed around 'or' is 'camore'.
'sy'+'camore'='SYCAMORE'
'on' is the link.
(Other definitions for sycamore that I've seen before include "Tree with two-winged fruit" , "Great maple tree" , "Wood" , "Ray comes (anag) - tree" , "Tree for the odd Rose Macy" .)