Planting longer cuttings is like planting instant trees. Within a month after they start growing you will have branches and leaves.
You have to decide how you want to use these cuttings. I will explain how to make big trees first.
Prepare the holes for them in October if you can. Make them a foot deep and 2 inches in diameter. Cover the holes do they dont' get ice or snow. When you get your trees, scratch the lower 8 inches or so with a dull knife until you see green. If you see tan, you are scratching too deep. Now dust rooting hormone all over that area and in the bottom of the cutting. Put the cutting in the hole and add good potting soil and tamp it. Add also a bamboo cane driven deep in the ground parallel to the cutting and tape them together. This prevents the cutting to sway with the wind. Failure to plant the cuttings this way may result in some of your trees dying within 2 weeks or so because their roots are not able to find the nutrients they need. The trees should now grow and within a few days they will have plenty of leaves and grow about 10 ft. every year.
On the other hand, you want to be able to make plenty of cuttings, you have to start by tilling a long narrow area about 4 to 6 inches deep to plant these. Make a trench with a hoe a couple of inches deep on the entire area tilled. Start scratching the cuttings from one end to the other so you can see green. Again, if you see tan, you are scratching too deep. Don't touch the buds which grow every 1.5 inches. When done, dust the entire cutting with a rooting hormone and carefully put it in the trench you made previously. Continue adding cuttings until you fill the entire trench. Cuttings can now be completely covered with soil. Water the tilled area thorougly. The cuttings you just planted have a bud every 1.5 inches and that bud can grow, only we are not that lucky, not all the buds will grow, but if only one grows out of 8, you will have a tree every foot which will be just about the right distance to make long cuttings or/and plenty of cuttings. Water these during the winter if it does not snow or rain. They will start growing when the temperatures and the light are just right for them.
The best cuttings are the ones from a one-year-old-tree. Remember that. Also remember that if you don't cut your cuttings down to at least 12 inches from the ground every year, you will have 2-year old trees which don't make good cuttings.
I have harvested cuttings from my trees every year starting as soon as the last leaf falls off the trees in November, until late March before the trees show any sign of life.