Mate I am really wary about "green" because of the sap/oil = creosote residue. I have seen/eaten a fair bit of food grilled over vine cuttings & pruned branches but always after they have sat for bit.Olive cuttings are just brilliant but they need to dry a bit ,just my 2 bobs worth you understand .
I really like apple & similiar for gentler smokes. I had a girlfriend from orchard country back in the day,apple,peach,cherry,plum it was lovely to BBQ with if you picked it out of the pile a few months after it was cut. Sat in the sun for a few months.Lamb chops & snags unbeatable.
I watched Italians smoke salami here over grape,olive,fruit wood but they always used wood that had been sitting for a few months. I follow their lead .They have never steered me wrong. Hope this helps!