Protecting the earth, driver perhaps in leafy area (9)
I believe the answer is:
greenwood
'leafy area' is the definition.
(archaic term for a forest)
'protecting the earth driver perhaps' is the wordplay.
'protecting the earth' becomes 'green' (eco-friendly).
'driver perhaps' becomes 'wood' (driver is a kind of wood).
'green'+'wood'='GREENWOOD'
'in' is the link.
(Other definitions for greenwood that I've seen before include "unspoiled countryside" , "territory for outlaws" , "Under the -- Tree (Thomas Hardy)" .)