Landowner Factsheets indicate how large a mature tree will be by rating it from 0 - 5 circles. This rating is relative to other trees and it combines combines height of the tree with size of the trunk.
Trees with five solid circles are the largest trees.
Trees with one solid circle are the smallest trees.
Larger species are generally better timber. Smaller species are safer to plant near buildings. The mature size of the tree is important to consider when spacing seedlings. Crowded trees will have a reduced growth rate. More detail about the adult dimensions of the trees are on the sylvics page.