Arboriculture – The art, science, technology, and business of commercial, public, and utility tree care.
Arborist – An individual engaged in the profession of arboriculture who, through experience, education, and related training, possesses the competence to provide for or supervise the management of trees and other woody plants.
Branch collar – The swollen area at the base of a branch.
Cleaning – Selective pruning to remove one or more of the following parts: dead, diseased, and/or broken branches.
Co-dominant leader – A tree that does not have a single main stem, but forms two or more main stems in the crown of the tree.
Crown – The leaves and branches of a tree measured from the lowest branch on the trunk to the top of the tree.
Espalier – The combination of pruning, supporting, and training branches to orient a plant in one plane.
Interfering branches – Crossing, rubbing, or upright branches that have the potential to damage tree structure and/or health.
Internodal cut – A cut located between lateral branches or buds.
Lateral branch – A shoot or stem growing from a parent branch or stem.
Leader – A dominant or co-dominant, upright stem.
Limb – A large, prominent branch.
Parent branch or stem – A tree trunk, limb, or prominent branch from which shoots or stems grow.
Pollarding – The maintenance of a tree by making internodal cuts to reduce the size of a young tree, followed by the annual removal of shoot growth at its point of origin.
Pruning – The selective removal of plant parts to meet specific goals and objectives.
Raising – Selective pruning to provide vertical clearance.
Reduction – Selective pruning to decrease height and/or spread.
Restoration – Selective pruning to improve the structure, form, and appearance of trees that have been severely headed, vandalized, or damaged.
Stub – An undesirable short length of a branch remaining after a break or incorrect pruning cut is made.
Thinning – Selective pruning to reduce density of live branches.
Topping – The reduction of a tree’s size using heading cuts that shorten limbs or branches back to a predetermined crown limit. Topping is not an acceptable pruning practice.
Vista Pruning – Selective pruning to allow a specific view.
Watersprouts – New stems originating from epicormic buds.