Trees for senior citizens? (6)
I believe the answer is:
elders
'trees for' is the definition.
'elders' can be an answer for 'trees' (I've seen this before). I am unsure of the 'for' bit.
'senior citizens?' is the wordplay.
'senior' becomes 'elder' (synonyms).
'citizens?' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'elder'+'s'='ELDERS'
Can you help me to learn more?
(Other definitions for elders that I've seen before include "Senior trees?" , "Older trees?" , "Senior members of tribe" , "Church officers and small trees" , "Better and wiser people?" .)