First, the site in your yard may be different and would require a different tree species. The tree you plant at home will probably be larger and will have a root ball usually wrapped in burlap. You would use a shovel to dig a hole three times larger than the root ball and one and a half times as deep to plant your tree in. In the forest, you will use a dibble bar which makes a thin straight hole about a foot deep in the soil to gently and slide the delicate roots of the tree seedling in very snugly. It is very important to plant the seedling correctly.
Bent roots can make the tree more likely to be blown down years into the future.
The leaves take in carbon dioxide from the air, light from the sun for energy and combine it with water and nutrients from the soil and make sugar for the tree to grow. In the process, oxygen is made and some of the water is transpired into the air. This is very important in the water cycle. Stem or trunk - supports the tree. All growth takes place here, water and nutrients are carried up and down the tree so it will grow.