Question

which sentence is correct?
when grown in the shade of trees, coffee plants can coexist with birds, and coffee farmers can feel good about maintaining a vital natural habitat.
when grown in the shade of trees, birds can coexist with coffee plants, and coffee farmers can feel good about maintaining a vital natural habitat.

Explanation:

We analyze the subject of the phrase "When grown in the shade of trees". The subject should be the one being grown, which is coffee plants (not birds, as birds are not grown). So the first sentence has the correct subject - verb (grown - coffee plants) relationship.

Answer:

When grown in the shade of trees, coffee plants can coexist with birds, and coffee farmers can feel good about maintaining a vital natural habitat.