The best way to  find the  best tree for the best spot is to  speak to an expert who is knowledgeable in the characteristics and habits of trees and shrubs. However, there are several questions to start the decision making:

How much space is there?

When selecting your tree, it is important to consider both the size of the canopy, as well as the size of the roots.  The roots are generally 1/3 of the size of the leaves. So, in a small planting space, choose a tree based on the size to which the roots will develop. If the roots are unhealthy or crowded, the rest of the tree will also be unhealthy.

What is the purpose of the tree?

Trees and shrubs can be planted for to provide shade, to be ornamental, to grow fruit or to attract wildlife. Ornamental trees and shrubs are a great choice when adding a feature to your yard or when you want to add a bit of height and flow to a flower garden.

How much shade will the tree to provide?

Trees are a great way to add shade to a hot yard.
50-70' tall = Lots of shade
30-50' tall = less shade
15-30' tall

 = dappled shade and sun