We'd to go round a lake in woodland (5)
I believe the answer is:
weald
'woodland' is the definition.
(thesaurus)
'we'd to go round a lake' is the wordplay.
'to go round' is an insertion indicator.
'lake' becomes 'L' (geographical abbreviation).
'a'+'l'='al'
'wed' enclosing 'al' is 'WEALD'.
'in' acts as a link.
(Other definitions for weald that I've seen before include "District between N. & S. Downs" , "ancient woodland" , "The ___, area between the North and South Downs" , "Area of SE England" , "area of woodland" .)