I live in Maine and grew up here.

Field across the road used to be a blueberry field, and one of Wyman's huge freezer facilities is a few miles down the road, along a now discontinued rail line.

Now its a high school. Ahh, goodbye nice friendly traffic pattern, I miss you.

That said, I don't think they've actually stopped burning blueberry fields, every so often I hear someone talk about it. It doesn't seem to be a lost art, just a lesser practiced ones. The kind of wild blueberries we have up here (not those fat ugly tasteless ones other states grow) seem to require it from time to time.