I'm sure people have considered the possibility of growing briar in the U.S., especially during WWII when the war stopped briar harvesting in most of the traditional places. Apparently, it is a fussy plant that grows well in a few places and resists being farmed/forested. The closest U.S. plant that actually works well as tobacco pipe material is Mountain Laurel. Perhaps because it doesn't have the striking visual grain of briar, it was used during World War Ii, and rare carvers actually still use it, but it is not harvested much commercially. The only carver I know who uses Mountain Laurel on a regular basis, and does not sell online, is Jerry Perry of Colfax, N.C. He sells his pipes at the N.C. State Fair Village of Yesteryear in October, and at the TAPS pipe show at the Fairgrounds in April. I think briar takes years to become developed enough to make good pipe material, and it is fussy and only grows in specific climate and soil conditions. Harvesting it is heavy labor, not a retirement business for old guys.