According to North Carolina State University at Raleigh, planting a tree via a branch, also known as stem cutting, is a very common method used to grow trees. It can be more difficult to root the branch, however. Stem cuttings need to have their leaves and flowers trimmed and must be kept in high humidity.
Stem cutting is more difficult than planting a seed due to the requirements the branch needs in order to root. Branches will need high humidity, which can be achieved by covering the pot with a bottomless milk carton or by placing the pot in a plastic bag.
Stem cuttings work best if the branch is from the current or most recent season's growth. Older branches may not root. Any buds or flowers should be removed so that the branch can use all of its energy in forming roots. Leaves from the lower third of the branch should also be removed. Large leaves can be trimmed down in order to conserve water. As with all plants, the time it takes before the branch roots varies from species to species. Newly rooted branches should not be placed directly into the landscape. North Carolina State University at Raleigh recommends allowing them to grow and stabilize before transplanting.