But gradually, farmers expanded their activities: they have planted street trees to improve the neighborhood environment and for 
(they; have planted; street trees; to improve the neighborhood environment) Context(they have planted,List([50, 67))):(they; have planted street trees to improve; the neighborhood environment)
they have planted,List([50, 67))
they they
have planted have planted street trees to improve
street trees to improve the neighborhood environment
the neighborhood environment