I had the chance to stay on a brazil nut farm in Peru, not far from the border with Brazil.
It's amazing how the ecosystem fits right in with the trees, as you are right, you can't just plant a farm anywhere, as it probably wont fruit.
It's actually illegal to cut down or burn a brazil nut tree in brazil. Farmers usually get around this by burning all around the tree, which will usually kill it anyway.
Where I went was possibly the first Brazil Nut farm that was also a tourist destination. they were just setting up their operation, but it was really educational and a great time for us, also because we were good friends with the guide and his girlfriend!
RE: Can Brazil Nuts Prevent Rapid Amazon Deforestation?