Fall is a good time for tree planting, taking advantage of a tree's natural growth cycle to let it get established and thrive. Use the warm soil and mild weather of early fall to help your tree develop parts of a new root system to sustain it through winter cold. Planting and watering are all that are needed until trees become dormant; fertilizer can wait till spring. Although some kinds of trees, known to be sensitive to winter damage, are best planted in the spring, fall planting gives many varieties of trees a good start on preparing for spring growth.
Choose young trees known to weather winter stress well. Previously planted large trees should be moved only by professionals, to maximize their chances of survival. Nursery-sized trees, with balled or wrapped roots, can be planted by home gardeners. A general guideline is: if you can't budge it at the nursery, you need help planting it. Dragging or other heavy handling can damage bark and roots needed to survive till spring. Further, avoid trees known for susceptibility to winter damage. In Indiana, for example, those trees can include magnolia, dogwood, flowering and fruiting cherry and plum, tulip tree, and several varieties of oak. The county extension service in your area can guide you to trees recommended for fall planting. Bare-root saplings are more often planted in the spring.
Loosen or remove the wrapping around roots. Dig a hole the same depth and twice the circumference of the tree's root ball. Loosen the soil by adding peat moss, shredded bark, organic matter or other soil amendments needed to provide good drainage for developing roots. Add water to dampen the soil mix thoroughly.
Place the tree in the hole. Replace the soil and tamp it down all the way around the tree trunk, to assure that your tree is securely seated and that the soil contains no large air pockets that could dry and kill growing roots. Provide one inch of water per week to your new tree until the ground freezes (you will resume watering at this level once the ground thaws).
Provide weather protection to maximize your young tree's survival. Build windbreaks with burlap and green stakes, or pile brush loosely around evergreens and small trees exposed to heavy wind and snow. Stake decidious trees over four feet in height to prevent wind damage. Mound wood chips or shredded bark mulch around roots, to lessen snow and ice damage.