Planting a new tree is best done in the dormant season (late fall, or early spring). This allows the tree to focus its production on its root system rather than its canopy. A healthy tree will have strong healthy roots, so keep this in mind while planning to plant a tree this fall.
Transport your new tree with care. The new tree is a living, delicate organism. If you transport it with care the tree will have a better shot at a successful planting. Its root system is already compromised by being removed from its original growing spot. You want to place the tree in its new home so it can grow what roots it lost in the transplant process.
You should locate underground utilities pipes and wires prior to digging. You want to plant your new tree will as little hassle as possible, breaking a water main or pipe will only make more work for yourself.
Break up the soil around were you want the new tree to take root. By doing this you provide a suitable habitat for the roots where they can expand, collect water and take in oxygen.
Dig a wide hole, but not too deep. The top of the root system grows rapidly. If you plant the tree too deep it makes it hard for these roots to obtain oxygen.
Remove all containers, wrappings, and wires surrounding your new tree. You do not want any foreign objects hindering the new root system from taking root.
You should lift the new tree by the ball of the tree near the roots, not by the trunk of the tree to prevent damage.
Have someone help you by looking at your tree once you place it in the hole. You should look at it from all angles to make sure the tree is sitting straight. If it is not, you may have to even out the hole and make adjustments until you have it as straight as you can make it. Once you start to put the dirt back in the hole this can be a difficult task, so do it ahead of time.
You should add the soil back into the hole around the roots slowly. Water down the soil down every few inches you fill in. By doing this you take out large air pockets which could cause the roots to dry out. You want the roots to receive oxygen, but large gaps in soil are bad for the health of your tree. A thin layer of mulch can be added to protect the tree from cold temperatures, and surrounding vegetation.
You should consider your location and local activities around your new tree before staking it. Not all trees need to be staked. If it will protect the tree from wind damage, pets, or lawnmowers then you should consider staking the tree.
Care for the tree after planted to ensure a successful full grown tree. Make it sure it gets adequate water, and sunlight depending on the species.
Most trees will outlast the humans that plant them. It is best give them a healthy start to a long life. They will see your family grow, and be home to lots of wildlife. The work you put into planting your tree will have a lifetime of rewards.