Ed first went in back door made of sequoia (7)
I believe the answer is:
redwood
'sequoia' is the definition.
('redwood' can be a synonym of 'sequoia')
'ed first went in back door' is the wordplay.
'first' suggests taking the first letters.
'in' is an insertion indicator.
'back' is a reversal indicator.
The first letter of 'went' is 'w'.
'door' in reverse letter order is 'rood'.
'ed'+'w'='edw'
'edw' going within 'rood' is 'REDWOOD'.
'made of' acts as a link.
(Other definitions for redwood that I've seen before include "former Tory minister" , "Sequoia tree" , "Californian conifer" , "Giant tree of California" , "big in California?" .)