The poem, on the page, doesn't seem to really follow any pre-set pattern of any kind. The stanzas range from one to three lines a piece, and the line lengths run the gamut from four to thirteen syllables. No particular stress pattern, either (i.e., we're not in, say, iambic pentameter, à la Shakespeare). So this poem plays relatively fast and loose with its own construction, though not hugely so. It's free, but not wildly so.
Now about that "pastoral" part. Pastoral poems are typically defined as poems that are about the beauty of the natural world, and certainly this poem would fall squarely into that category, don't you agree? It's a little bit of a strange pastoral, though, which is why we think it's so intriguing. First of all, there's a fair amount of darkness in there – all of that drunkenness (5), fractured-ness (also line 5), helplessness (11), burning-down-ness (13-14, 17)…you get where we're going. This is not about fluffy bunnies. It's a pretty edgy beauty, when it comes right down to it.