Trees and The Land
I thoroughly recommend The Land: an occasional magazine about land rights (rights here in the widest sense), whose current issue is devoted to trees and forests. Some articles can be found on their website, but for the bulk of it you need to pay £5, or, better still, support it with a modest £18 subscription for five issues.
I post a scan of the short editorial:
Those who might be impatient for a future issue on grass could meanwhile acquire a copy of Graham Harvey's The Forgiveness of Nature: the story of grass, which is also fascinating. All of his books repay reading.