I've seen a lot of tires used for raised beds. One fella had a fountain style strawberry bed like you've described made from tractor tire and smaller.
Thinking about how I used veggie oil instead of stain on my cutting board, I guess there might be some concern about the stain in using it as a garden bed, but the stain would also help to preserve the wood, and would probably be less likely to be harmful than say railroad ties, and I've seen those used a LOT for raised beds. My parents' garden growing up was all raised beds. Most of our food came from there, and there ain't nothin' wrong with me. And another thing, most of our food came from there, and there ain't nothin' wrong with me.
Thinking about how I used veggie oil instead of stain on my cutting board, I guess there might be some concern about the stain in using it as a garden bed, but the stain would also help to preserve the wood, and would probably be less likely to be harmful than say railroad ties, and I've seen those used a LOT for raised beds. My parents' garden growing up was all raised beds. Most of our food came from there, and there ain't nothin' wrong with me. And another thing, most of our food came from there, and there ain't nothin' wrong with me.