Land that's on fire (6)
I believe the answer is:
alight
This clue is a double definition.
'land' is the first definition.
(I know that alight is a more specific form of the action land)
'on fire' is the second definition.
(synonyms)
'that's' is the link.
(Other definitions for alight that I've seen before include "Settle; on fire" , "Dismount" , "Come to rest, settle" , "Ignited; get off" , "Land; on fire" .)