Trees are selected for different purposes.  It is important to consider the purpose a tree will fill in your landscape.  A tree may meet a variety of aesthetic objectives.  It may be selected for its flowering, fruiting, fall color, bark character, foliage texture or crown shape.  A tree can also serve functional purposes such as screening noise abatement, traffic control, wind modification, or heat control.  A shade tree is obviously selected for the shade it will provide.

Mature Size: The ultimate mature size is an important factor that too few people really consider when selecting a tree.  A young tree in a nursery is hard to imagine five, ten and fifteen years in the future.  Trees that outgrow their space in the landscape are a nightmare.  They block views, their roots raise sidewalks and driveways, and they cause concern when violent weather is predicted.

There is a tendency to select trees that grow fast and provide the most shade in the quickest amount of time.  Unfortunately many fast growing species become extremely large very quickly.  They are prime targets for the bad pruning practice of topping.  This spoils the natural shape and beauty of the tree as well as shortening the life of the tree.  Many of these speedy growers have weak wood and a disposition to develop wood rot after injuries or pruning wounds caused by topping.  They also tend to have relatively short lives, not becoming the stately trees of history.