That scar is an artifact of a process called grafting, or fusing two separate pieces of wood into a new tree. From citrus to ...

It is a popular method for grafting fruit trees, especially in cases where the scion wood is smaller than the rootstock. Choose a scion plant with a diameter of 1/4 to 1/2 inch and a rootstock ...

Some ornamental trees and plants, including Japanese magnolias, Japanese maples and camellias, also are grafted. Grafting is somewhat ... There’s some loss at every step of the process.” ...