During the war America still had imports.
From September 1939 to December 1941 America was a neutral nation, and Italy was neutral until June 1940.
A cargo ship full of briar was not a lawful target, at any time during the war. It also for Germans wouldn’t be worth a precious torpedo.
My old friend Jack used to tell about coffee rationing during WW2.
Coffee boats going towards America or returning from South America generally were not attacked by German U boats.
They were often neutral ships carrying neutral goods, designed only to carry coffee. And more importantly they weren’t worth a torpedo. After they used all their torpedoes a U boat became just a boat, and had to return to base.
But a German sub shelled a coffee boat with her deck gun in sight of the East Coast and being full of coffee beans, burned for days in full view of all the newspaper reporters.
And guess what happened?
The public ran out and emptied the shelves of unrationed coffee.
So coffee made the ration list, a pound every three weeks. And those who didn’t drink coffee bought their pound anyway. Having bought it, they drank it and developed a coffee habit, or traded it, or hoarded coffee.
Finally a wise bureaucrat in the rationing department required the merchant to open the can at the point of sale, and within weeks coffee was off the ration lists. There never really was a shortage of coffee in the first place.
With briar, after the liberation of Algeria in late 1942 and the surrender of Italy in 1943 there likely was a trickle of briar coming back in merchant ships.
Yet the domestic briar was undoubtedly cheaper. It could have been cured quickly, and kiln dried, and not aged, but for price controlled dollar pipes the makers used it.
When the war in Europe ended Pipe Lover’s Magazine was of the opinion there would be a permanent market for California and North Carolina domestic briar for lower priced pipes.
That didn’t happen.
The customers demanded Imported Briar stamped on their pipes, where it remains still today,