GLOSSARY OF TREE CARE TERMS

A set of industry standards that guide professional tree care practices, including pruning, planting, soil care, risk assessment, and tree preservation.

A written report prepared by a qualified arborist that documents tree condition, risks, defects, health concerns, and recommended actions.

Recommended tree care methods that explain how industry standards should be applied in the field.

An expert arborist who provides professional advice, inspections, reports, and recommendations for tree health, safety, preservation, and management.

A tree care professional certified by the International Society of Arboriculture who has demonstrated knowledge of proper tree care, safety, diagnosis, and maintenance.

A structured inspection used to evaluate the likelihood of tree failure, the likelihood of impact, and the possible consequences.

An ISA qualification that trains tree care professionals to use a standardized process for assessing and documenting tree risk.

The strategic planning and maintenance of trees within city boundaries, including street trees, parks, and residential properties

An evaluation of tree canopy cover across a property, site, or urban area to understand tree coverage, shade, gaps, and long-term management needs.

The area around a tree where roots are most important for stability, water uptake, and overall tree health.

A professional evaluation of an individual tree’s crown, including foliage density, dieback, branch structure, clearance, defects, and overall crown condition.

An inspection of a tree’s health, structure, site conditions, defects, and care needs.

A comprehensive survey that records the location, species, size, and health of individual trees within a defined area

The ongoing use and updating of tree inventory data to plan pruning, removals, planting, inspections, and budgets.

The process of marking tree locations on a map or digital platform for tracking, planning, and maintenance.

The legal, physical, and environmental methods used to protect mature, valuable, or ecologically significant trees from destruction, damage, or removal

The managed area around a structure where vegetation is reduced or maintained to help slow wildfire spread.

The area around a tree where roots are most important for stability, water uptake, and overall tree health.

The amount of burnable vegetation or material in an area, including dry grass, brush, deadwood, leaves, and branches.

The area around a structure where vegetation, materials, and maintenance have the greatest effect on wildfire exposure.

The spread of burnable vegetation across the ground or canopy that can allow fire to move sideways through a site.

Low or mid-level vegetation that can carry fire from the ground into tree canopies.

Vegetation management is the systematic control, removal, or modification of plant life

The connection between ground fuels, shrubs, low branches, and tree canopies that can help fire move upward.

Wood mulch made from tree material and used to support soil health, moisture retention, and root protection.

A charcoal-like soil amendment that can help improve soil structure, moisture retention, and nutrient holding capacity.

A dead or diseased area on bark, branches, or stems that can weaken tree tissue.

Yellowing of leaves caused by issues such as nutrient deficiency, poor soil conditions, root problems, or disease.

A watering method that delivers water into the soil near the root zone instead of only wetting the surface.

Lateral roots that grow in a circular or spiral pattern around the base of a tree’s trunk rather than radiating outward.

An ecosystem-based, sustainable strategy that focuses on the long-term prevention of pests and their damage

The practice of placing organic material over soil to help retain moisture, moderate temperature, reduce weeds, and improve soil over time.

The raised line of bark that forms in the union between a branch and the trunk or parent limb.

The point where a branch connects to another branch or to the trunk.

An open hollow or void in a trunk, stem, branch, or root area.

Two or more main stems of similar size growing from the same area of the tree.

The expected severity of damage or injury if a tree or tree part fails and strikes a target.

The breakdown of wood caused by fungi or other organisms, often reducing strength over time.

A tree with defects or conditions that may create an unacceptable risk to people, property, roads, or utilities.

A structural defect in trees where bark gets trapped between two stems or branches as they grow, rather than forming strong connective wood.

A tree that grows or shifts away from a vertical position, sometimes because of root issues, soil movement, wind, or natural form.

The estimated chance that a tree or tree part will break or fall during a certain time period.

The estimated chance that a failed tree or tree part will strike a target.

Pruning that reduces weight or wind force on a branch, stem, or tree.

Wood formed by a tree to support leaning stems, heavy branches, or areas under stress.

A weakness in a tree’s form or wood that may affect stability or increase the chance of failure.

A person, structure, vehicle, road, utility, or other object that could be struck if a tree or branch fails.

A structural weakness, injury, decay, crack, poor branch attachment, or other condition that can affect tree stability.

The breaking or falling of a whole tree, trunk, stem, branch, or root system.

A branch attachment that has poor structure and may be more likely to split or fail.

The swollen area at the base of a branch where it connects to the trunk or parent limb.

The main upright stem of a tree, usually forming the dominant trunk.

Pruning that provides space around buildings, signs, sidewalks, roads, lights, or utilities.

Pruning that removes dead, broken, diseased, or weak branches from the crown.

Pruning that reduces the overall size or spread of a tree’s canopy using proper reduction cuts.

Selective pruning that removes branches to reduce crown density while keeping the tree’s natural shape.

The removal of dead branches from a tree.

Pruning that reduces weight near the end of a branch to lower stress and reduce failure potential.

A pruning cut made through a branch or stem without cutting back to a suitable lateral branch.

The ratio between the part of the tree with live foliage and the total height of the tree.

The lowest major branch intended to remain as part of the mature tree structure.

A pruning cut made outside the branch collar without damaging the collar or leaving an excessive stub.

A pruning cut that shortens a branch or stem back to a smaller lateral branch.

A pruning cut that removes an entire branch at the trunk or parent limb.

A person, structure, vehicle, road, utility, or other object that could be struck if a tree or branch fails.

A structural weakness, injury, decay, crack, poor branch attachment, or other condition that can affect tree stability.

Pruning used to improve the structure and appearance of trees that were damaged, topped, neglected, or poorly pruned.

A main limb that helps form the permanent structure of a tree’s canopy.

Pruning that improves a tree’s branch arrangement, trunk development, and long-term strength.

An arboricultural technique used to slow the growth of a competing, co-dominant stem or an overly vigorous branch.

A pruning cut that removes a branch back to its point of origin.

A tree that sheds its leaves during part of the year.

A tree with a broad, spreading canopy and multiple large limbs. Oaks often show this form.

A tree that keeps foliage throughout the year, although individual leaves or needles may still be shed over time.

A tree with one strong central trunk and smaller side branches. Redwoods often show this form.

Pruning that cuts a branch back to a lateral branch or parent limb.

Vigorous, fast-growing shoots that sprout from the base of a tree, root system, or between the main stem and leaves.

vigorous, fast-growing shoots that emerge vertically from a tree’s trunk or main branches.

The time after planting when a tree is developing new roots and needs consistent care.

The depth at which a tree is planted, with the root flare kept at or slightly above soil level.

The mass of roots and soil moved with a tree during planting or transplanting.

The area where the trunk base meets the main roots, also called the root flare or root collar.

The temporary support of a newly planted tree to help it remain stable while roots establish.

Regular watering during the early years after planting to help roots grow into the surrounding soil.

The process of placing a tree in the ground at the correct depth and location to support healthy establishment.

The process of moving a tree from one location to another while preserving enough roots for survival.