Is someone marketing something called that? His book, Four Season Harvest, doesn't mention one - the big star of that book is the Gothic hoophouse. But he's written other books and does collaborate with dealers on garden product design.
-O

I've read his books. Never heard of his A-frame,but he did have
a hoophouse set on tracks which he would move to different garden
beds on a rotational basis to decrease the usual greenhouse pest
problems.

Swanz

Last time I was at his place on Cape Rosier, it was late winter, maybe two years ago. He had an A frame with single layer plastic over it, with wiggle wire on the ends. One of his minions was closing it up for the night as I stood there. He said it was an experiment in overwintering some tender perenial stuff. I think he had rosemary or something of similar tenderness in there. It was made of 1" square tubing, which he said he used because it was at hand, left over from some earlier experiment. It was an equalateral triangle, 8' on a side and maybe 40' long. I don't know if he's done any more with it.

Dan

I'm in the midst of reading his 4 Seasons Gardening. He does mention a "temporary A-Frame" in there. He's talking about peas on a trellis and suggests putting plastic over th trellis and anchoring the ends to make an A-shaped temporary cover.
By the way, I appreciated the tribute in the first poster's handle to Aldo Leopold, a great and early American naturalist.

The A frame is something he came up with b/c he had leftover lengths of square galvanized tubing. He says in one of his video's "why must a greenhouse be round?", and proceeded to build an A frame plastic covered house. He overwintered his leeks in there to make them easier to harvest. Each side was made of a 9' piece of square tubing and was set over a small stub sticking out of the ground, plastic attached with wiggle wire.

He also uses an A-frame over the compost pile in winter to keep it from freezing solidly. The outside few inches will freeze now and then but the rest stays thawed.