BobbyLane
Imperial Masterpiece
Ok so what you mean is you expect the roots in the smaller pot to escape the drainage holes and carry on growing. Its called the escape method, but is usually done on the ground. The immediate benefit is the outer pot creates more humidity around the tree. On one of my recently severed layers, that didnt have much root, ive buried its pot in one of my balcony troughs which are full of soil, to raise the general humidity.The purpose of the larger pot is to encourage faster trunk growth, similar to ground growing. It also looks nice, and I had the pot just lying around. Drainage/percolation does not seem to be an issue.