Do you mean white pine? It's not 1/2". Looks like at least 3/4". Tongue & groove on 1/2" lumber is not practical for much of anything. He has a pretty nice shop, so he could have easily milled it himself. I don't recognize the license plate on the car, pic 58, to have a clue as to where they are. I'm not knowledgeable of siding or similar exterior lumbers for northern climates.
Sonny