Trees are sold in a variety of sizes and forms, and their prices will reflect this. Size is usually how tall trees are or the diameter of the trunk. Form of a tree or bush is how it is shaped. Maturity is how old the tree is and can also be reflected by height and trunk diameter. Function of the tree is the purpose to which the tree is serving. Please take into consideration the size, form, and function of the trees for the area you would like to enhance.
Form and Size
A basic principle of modern architecture is “form follows function.” This is a good rule to remember when selecting a tree. Selecting the right form (shape) to complement the desired function (what you want the tree to do) can significantly reduce maintenance costs and increase the tree’s value in the landscape. When making a selection about form, also consider mature tree size. Trees grow in a variety of sizes and shapes, as shown below. They can vary in height from several inches to several hundred feet. Select a form and size that will fit the planting space provided.Depending on your site restrictions, you can choose from among hundreds of combinations of form and size. You may choose a small-spreading tree in a location with overhead utility lines. You may select a narrow, columnar form to provide a screen between two buildings. You may choose large, vase-shaped trees to create an arbor over a driveway or city street. You may even determine that the site just does not have enough space for a tree of any kind.
Sizes of trees at maturity
Many people get confused about how big trees will grow. Many books don’t help as they give a size, but in the small print you find that this is the expected size after 10 years. So people unwittingly plant trees that will often outgrow the chosen site within 15 to 20 years. This may be okay in some situations. After that time, the tree has given satisfaction but the owner may wish to remove it before it becomes a problem and replace it with something different.
To clarify matters, here is a guide that is generally adopted in the trade to describe the mature size of trees in catalog descriptions of trees.
Small Tree – Grows to somewhere between 12ft and 30ft. Below this category you have the blurred area of large shrub/small tree.
Medium Tree – Grows to between 30ft and 50ft.
Large Tree – Grows in excess of 50ft. This may be a lot more than 50ft. The tallest trees in Wisconsin are over 200ft.