I am going through a steady stock of apple root-stock for grafting, and almost as many other fruit and nut tree (saplings) as I can I can finagle. At $8.00 to $20.00 per-each, it doesn't take long for me to hit my limit.
Tree seeds tolerate winter sowing and cold stratification very well. I buy the deepest storage totes I can, with at least the sides in translucent plastic. I cut in holes for drainage, and make divider to quarter the tote for four different kinds of seed.
I mix up soil of one part each granite chicken scratch, pine bark mulch, and peat moss. I may also too dress with peat if I am planting very small seeds.
This year I will plant out; spring blooming (H vernalis), fall blooming (H virginiana) witch hazel, pawpaw, sassafras, apple (antonovka), hazel nut, pecan, chinkapin, a wild plum, and others I am not thinking of.
I expect to move all (save pawpaw) into cells some time this summer. Pawpaw will have to wait till it goes dormant.