After putting the seed in the ground the process of embryogenesis takes place.
Once the embryo germinates from its seeds or parent plant, it begins to produce leaves, stems and roots.This is the process of organogenesis. New roots grow from root meristemms and new leaves grow from shoot meristems. When cells on one side of a stem grow longer and faster than cells on the other sides, the stem will bend to the side of the slow growing cells as a result. This direct growth can occur due to response of particular stimulus such as light, gravity, water, and physical contact.
This process continues and results in growth of plant to tree.