Tree Care Glossary & Encyclopedia

A trained professional who specializes in the care and maintenance of trees, including planting, pruning, diagnosis, and removal.

Structural support systems installed in trees to reduce the risk of failure in branches or stems with weak attachments.

A thin layer of actively dividing cells between the bark and wood of a tree that produces new growth each year.

The uppermost layer of branches and leaves of a tree, forming the crown that intercepts sunlight and rainfall.

A pruning technique that reduces the overall size of a tree's canopy by cutting branches back to suitable lateral branches.

A standard measurement of tree trunk diameter taken at 4.5 feet (1.37 meters) above ground level, used for inventory, assessment, and regulatory purposes.

The removal of dead, dying, or diseased branches from a tree's canopy to reduce hazard risk and improve appearance.

The dense, inner core of wood in a tree trunk that no longer conducts water but provides structural support.

A professional credential awarded by the International Society of Arboriculture that verifies an arborist's knowledge and competence in tree care.

The practice of applying a layer of organic or inorganic material around the base of a tree to conserve moisture, moderate soil temperature, and suppress weeds.

The selective removal of plant parts such as branches, buds, or roots to improve tree structure, health, or appearance.

The area of soil occupied by a tree's root system, typically extending well beyond the drip line of the canopy.

The outer, lighter-colored layers of wood in a tree trunk that actively conduct water and dissolved minerals from roots to leaves.

A designated area around a tree, typically defined by the drip line, that is protected from construction activity to prevent root damage.

A systematic process of evaluating a tree's structural condition and site factors to determine the likelihood and consequences of failure.