First and second entering woodland (8)
I believe the answer is:
foremost
'first' is the definition.
('foremost' can be a synonym of 'first')
'second entering woodland' is the wordplay.
'second' becomes 'mo' (both are short periods of time).
'entering' means one lot of letters goes inside another.
'woodland' becomes 'forest' ('forest' can be a synonym of 'woodland').
'mo' going into 'forest' is 'FOREMOST'.
'and' is the link.
(Other definitions for foremost that I've seen before include "top" , "First in rank" , "'Leading, best (8)'" , "premier" , "First in time, place or importance" .)