Before planting new tree assess both your needs and the existing conditions of your site.  Trees, like all garden plants, have specific light and soil requirements which can influence its health.  Trees also have specific space requirements.  Some trees spread wide and need a lot of space, such as the beech, while others, such as the birch, grow tall and narrow.  Unlike other garden plants, however, trees tend to be permanent features in the landscape so proper placement is critical.

Assess your gardens needs.  Does your garden need shade or color?  How much space do you have?  Trees need a lot of room as they mature.  Trees that are 10 at the nursery can easily reach 20 in a matter of years and may reach 50 or more at maturity.  Improperly sited trees and shrubs are a common mistake among gardeners.  Trees planted to close to a house or garden path may require frequent pruning, resulting in awkwardly shaped trees.  In many instances, transplanting becomes necessary resulting in more work than originally planned.  

If you want to create a shady spot in the garden, figure out how much shade you want.  Trees such as the thornless honey locust and the river birch provide dappled shade and create comfortable outdoor gathering spaces.  For creating deeper shade, large trees with dense foliage such as the beech and maple are useful. 

Deciduous trees, those which loose their leaves in the fall, create shade in the summer but allow sunlight through in the winter.  These trees are effective when used to increas energy efficiency.  Planted to shade a house from the summer sum, trees have a cooling effect, in the winter, trees without their leaves allow the sun to heat the home.

Trees can serve as wonderful focal points in the landscape.  In a field, a sugar maple can stand alone in the landscape a have a stunning effect.  Large trees with interesting form and year-round interest are suitable as a focal point or a specimen plant.  Trees can also be effective when used to frame views, garden art and vistas.

Flowering ornamental trees, such as the flowering crabapple, cherry and magnolia, provide stunning blooms in the spring.  These ornamental trees are generally smaller so they can be used in any size garden and closer to structures.

As an accent in the smaller garden, ornamental trees can provide the garden with some shade and add character to the landscape.  For example, the dogwood begins the season with showy flowers and red fruit.  After the dogwoods colorful fall foliage falls to the ground its bark which flakes with age becomes exposed providing the garden with interest through the winter.  A more exotic choice would be the Japanese maple.  Its striking, sculptural form and red foliage make the Japanese maple a year-round joy.  The birch trees beautiful form is a year-round feature but is most noticeable in the winter after it sheds its brilliant autumn foliage. 

All deciduous trees change color in the fall; some, however, are treasured more than others for their autumn foliage.  The sugar maple, red maple, tupelo and sumac all have brilliant fall color. 

Dont overlook features such as a plants form, colorful berries and interesting bark.  It is these features which are treasured through the winter months.  Berry producing plants also provide wildlife with food.  Both the birch and aforementioned Japanese maple, have beautiful forms and are year-round features. 

Choosing the appropriate tree for your garden requires some planning.  Trees can be difficult to transplant so planting the right tree in the right location is critical.  With some initial planning, trees which are appropriately located and planted, can last a lifetime with little or no maintenance.