Glossary of Tree Service Terms

The American National Standards Institute A300 series — the industry-accepted standards for tree care operations in the United States, covering pruning, cabling, preservation, and more. Following A300 is the benchmark of professional practice. See also: Industry Standards.

The American National Standard for Arboricultural Operations — Safety Requirements. Published by the Tree Care Industry Association (TCIA), Z133 covers safety requirements for climbing, rigging, aerial lift operations, and chipper safety.

A professional who possesses the technical competence to provide for or supervise the management of trees and other woody plants. Many professional arborists are certified by the International Society of Arboriculture (ISA). See: Hiring & Training.

The art, science, and practice of tree cultivation and management. It involves a wide range of activities, including planting, pruning, fertilising, monitoring for pests and diseases, and removing trees when necessary.

A vehicle-mounted device used to position workers at elevated work sites. In tree care, aerial lifts (bucket trucks) are used for pruning, removal, and utility line clearance. All aerial lift operators must be trained per ANSI A92 standards.

The swollen area at the base of a branch where it meets the trunk. This area contains specialised tissues that help the tree seal wounds. Proper pruning cuts are made just outside the branch collar to preserve these tissues and promote wound closure.

The point where a branch attaches to the trunk or to another branch. Branch unions can be strong (U-shaped) or weak (V-shaped, often with included bark). Weak unions are a primary target for cabling and bracing.

An aerial lift truck used to position workers at height. Also called a cherry picker or aerial device. Essential for utility line clearance work and large-scale commercial tree care. See: Equipment Guide.

The tissue that forms around a wound on a tree, gradually covering and sealing the damaged area. Proper pruning technique — cutting just outside the branch collar — maximises callus formation and reduces decay.

The upper layer of foliage in a tree, formed by the branches and leaves. Canopy management — through pruning, thinning, and elevation — is one of the core services of a professional tree care company.

A machine used to reduce tree branches and brush into wood chips. Available in drum and disc configurations, with capacities from 4″ to 18″+. See: Equipment Guide.

The harness worn by a tree climber, connecting them to the climbing rope and providing support during aerial work. Must meet ANSI Z133 requirements and be inspected before each use.

The entirety of a tree’s branches, twigs, and leaves. Crown management services include crown cleaning, crown thinning, crown raising, and crown reduction.

Dead branches within a tree’s crown. Deadwood removal (crown cleaning) is one of the most common tree care services, improving aesthetics, reducing hazard, and promoting tree health.

The area on the ground where cut material is expected to fall during tree work. Establishing and securing a drop zone is a critical safety step in every tree removal and pruning operation.

A written document provided to a potential customer outlining the scope of work, materials, and price for a tree care job. A professional estimate should include a detailed description of all work to be performed, payment terms, and liability limitations. See: Estimating Guide.

In arboriculture, the use of air or water tools to expose tree roots without damaging them. Used for root assessment, soil aeration, and installation of root barriers.

The area that could be affected if a tree or tree part falls. Calculating the fall zone is a critical step in planning any tree removal. The fall zone radius is typically 1.5x the height of the tree.

The process of cutting down a standing tree. Directional felling — controlling the direction a tree falls — requires specific training and is one of the most hazardous operations in tree care.

A root that grows around the base of a tree’s trunk, gradually constricting the flow of water and nutrients. Girdling roots are a leading cause of tree decline in urban environments and are often visible as a flattened area at the base of the trunk.

The team members who work on the ground during tree operations, responsible for securing the work zone, handling ropes and rigging, processing brush, and communicating with the climber. See: Hiring & Training.

A tree with structural defects that make it likely to fail, and which is located where failure could cause property damage or personal injury. Hazard tree assessment is a specialised service requiring ISA training.

The uncut wood between the back cut and the face notch during directional felling. The hinge controls the direction of fall and must be of uniform thickness and positioned correctly for safe, predictable felling.

Bark that becomes trapped between two co-dominant stems or between a branch and the trunk, forming a weak union. Included bark is a major structural defect and a primary indicator of cabling or removal need.

The leading professional organisation for arborists worldwide. ISA administers the Certified Arborist programme, publishes best management practices, and advocates for the tree care profession. See: Industry Standards.

A written document completed before each tree care job that identifies specific hazards and the controls in place to mitigate them. Required by OSHA for high-hazard operations and a critical component of any safety programme. See: JHA Template.

A type of climbing rope with a braided outer sheath (mantle) protecting an inner core (kern). Kernmantle ropes are the standard for tree climbing due to their strength, flexibility, and resistance to abrasion.

The angle at which a tree grows relative to vertical. A significant lean — especially combined with root damage or decay — dramatically increases the risk of failure and must be assessed before any work begins.

The process of removing branches from a felled tree. Also called “bucking” when referring to cutting the trunk into sections.

The application of organic material (often wood chips) to the soil surface around a tree. Proper mulching — 2–4 inches deep, not touching the trunk — conserves moisture, moderates soil temperature, and suppresses weeds.

The V-shaped cut made on the side of a tree facing the intended direction of fall during directional felling. The notch must be cut to the correct depth (typically 1/4 of the tree’s diameter) and angle (70° open-face or traditional 45°) for safe felling.

Equipment worn to minimise exposure to hazards. For tree care, mandatory PPE includes: hard hat (ANSI Z89.1 Class E), chainsaw chaps (ASTM F1897), cut-resistant gloves, eye protection, hearing protection, and steel-toed boots. See: Safety Guide.

The selective removal of specific parts of a tree — branches, buds, or roots — to improve structure, health, safety, or aesthetics. All pruning should follow ANSI A300 Part 1 standards.

The use of ropes, blocks, and other hardware to control the descent of cut tree parts. Proper rigging technique is essential for working in confined spaces and protecting property. See: Safety & Compliance.

The widening of the trunk at the base where it meets the root system. The root flare should always be visible above the soil line. Buried root flares are a leading cause of tree decline and are often the result of improper planting or soil accumulation.

A detailed written description of all work to be performed on a tree care job. A clear scope of work protects both the contractor and the customer and is the foundation of a professional estimate. See: Estimate Template.

The mechanical removal of a tree stump using a rotating cutting wheel. Stump grinders remove the stump to 6–12 inches below grade. Full stump removal (excavation) is a separate, more expensive service.

The leading trade association for tree care companies in the United States. TCIA publishes ANSI Z133, administers the company accreditation programme, and advocates for the industry at the federal and state level. See: Industry Standards.

The indiscriminate cutting of tree branches to stubs or lateral branches that are not large enough to assume the terminal role. Topping is explicitly prohibited under ANSI A300 Part 1 and is considered an unacceptable pruning practice by all major arboricultural organisations.

Tree pruning or removal work performed in proximity to energised electrical lines. Requires specific OSHA training (29 CFR 1910.269), utility company authorisation, and specialised equipment. Typically pays 40–60% more per hour than standard residential work.

A written document authorising tree care work to be performed. A signed work order is essential for every job and should include: scope of work, price, payment terms, liability limitations, and customer signature. See: Work Order Template.

Material produced by a chipper from tree branches and brush. Wood chips have value as mulch and are increasingly used as biomass fuel. Many tree service companies offer free chip delivery as a marketing tool.