These terms are important factors for choosing the right tree for the intended space, planting and training the tree, and managing the overall tree size and shape.

Excurrent Tree Form: A tree form that develops when the central leader outgrows the lateral branches forming a narrow, cone-shaped form with a clearly defined central trunk. The regulation of the form is by an actively growing apical bud (meristem). This is common for most gymnosperms.

Decurrent Tree Form: A tree or shrub form that develops when there is weak apical dominance resulting in a rounded or spreading tree crown. This is common in most angiosperms.