I found this great article on starting paulownia (Paulownina tomentosa) seedlings in Tubex Tree Shelters.
Paulownia, as many know, is an incredibly fast growing tree (as in 10-12 feet in 4 months!) that produces wood valued for a wide range of products.
If you have an interest in growing paulownia, I highly recommend joining the American Paulownia Association. The organization is a great resource to learn about sources of seed and planting stock, best growing practices, and to share camaraderie with other growers.