Certified Arborists Offering Landscaping Services

Certified arborists who offer landscaping services occupy a specific professional category that bridges tree science and property aesthetics. This page defines what that credential means in practice, explains how arborist-led landscaping work differs from general landscape contracting, identifies the property situations where certified expertise is most relevant, and outlines how property owners and project managers can determine when arborist involvement is necessary versus optional. Understanding these distinctions matters because credential requirements, liability exposures, and service outcomes differ significantly depending on which professional type is engaged.

Definition and scope

A certified arborist is an individual who has passed a competency examination administered by the International Society of Arboriculture (ISA), the primary credentialing body for tree care professionals in the United States. ISA certification requires demonstrated knowledge across tree biology, diagnosis, pruning, soil science, risk assessment, and safe work practices, plus ongoing continuing education units to maintain active status. As of the ISA's published data, more than 27,000 ISA Certified Arborists hold active credentials in the United States.

When a certified arborist also offers landscaping services, the scope of work typically extends beyond isolated tree care to include tree selection and placement within designed landscapes, integration of woody plants with shrub and groundcover schemes, tree health assessment as part of broader site planning, and post-installation maintenance. This differs from a licensed landscape architect, who focuses on spatial design and hardscape, and from a general landscaper, who primarily handles mowing, planting beds, and irrigation without formal tree science training. A full breakdown of these credential distinctions is covered at arborist vs landscaper service distinctions.

The scope of arborist-provided landscaping services generally falls into three categories:

• Tree-integrated landscape design — selecting species appropriate to site conditions, placing trees to meet functional goals (shade, screening, stormwater), and coordinating root zones with underground utilities and structures.
• Health and maintenance programming — developing multi-year pruning cycles, soil amendment schedules, and deep root fertilization plans tied to landscape performance objectives.
• Risk-informed removal and replacement — removing trees that represent structural hazards or landscape design conflicts, followed by species-appropriate replanting through tree planting and landscape design protocols.

How it works

When a certified arborist engages a landscaping project, the process typically begins with a site inventory. Every existing tree is assessed for species, structural condition, root zone extent, and compatibility with planned improvements. This inventory forms the basis for decisions about preservation, removal, or relocation.

Following the inventory, the arborist applies ISA-published best management practices — including the ISA Best Management Practices: Tree Pruning and ISA Best Management Practices: Trees and Turf documents — to develop a work scope. Pruning specifications reference ANSI A300 standards, the tree care industry's primary technical standard published by the American National Standards Institute (ANSI). ANSI A300 Part 1 governs pruning; Part 2 covers soil management; Part 9 covers tree risk assessment. These standards are not legally binding in most jurisdictions, but they define the professional baseline against which arborist work is measured in liability disputes.

Work execution involves equipment selection based on tree size and site access, worker safety compliance under OSHA's tree care safety standards (primarily 29 CFR 1910.269 and ANSI Z133), and debris management through wood chip mulch recycling or hauling.

Certified arborist vs. unlicensed tree contractor — key distinctions:

Factor ISA Certified Arborist Unlicensed Tree Contractor

Credential basis ISA exam + CEUs None required (varies by state)

Pruning standard ANSI A300 No formal requirement

Diagnostic capability Formal training in disease and pest ID Limited or none

Liability in disputes Credential provides defensible standard No standard to reference

Typical service breadth Tree science + landscape integration Labor tasks only

State licensing requirements for tree service contractors vary — tree service licensing requirements in the US provides a state-by-state breakdown of what credentials are legally required versus voluntary.

Common scenarios

Certified arborist involvement in landscaping projects is most common in four situations:

• New construction landscapes — Builders and landscape architects retain arborists to identify which existing trees can survive grading, utility installation, and soil compaction through tree preservation during construction protocols.
• Mature urban or suburban properties — Properties with trees 30 or more years old require professional assessment before any significant landscape renovation to avoid inadvertent root damage or destabilization.
• Post-storm landscape restoration — After major wind or ice events, storm damage tree service assessment by a certified arborist determines which storm-damaged trees are structurally salvageable and which require removal before landscape replanting begins.
• Commercial or municipal properties — Office parks, HOA common areas, and municipal streetscapes routinely specify ISA certification in procurement documents because of insurance requirements and public safety liability. Commercial tree service landscaping and municipal tree service landscaping pages detail these procurement contexts further.

Decision boundaries

Not every tree-related landscaping task requires a certified arborist. The decision boundary depends on risk level, tree size, and the complexity of the diagnostic requirement.

Tasks that typically require or strongly benefit from certified arborist involvement:

• Tree risk assessment on trees near structures or high-use areas

Tasks that a qualified general landscaper can typically handle without arborist oversight:

The critical distinction is that general landscapers operate on aesthetic and horticultural training, while certified arborists operate on a structural and biological science foundation. When a landscaping decision could affect the long-term structural integrity or survival of a tree, the credential boundary becomes a liability boundary. Tree service provider evaluation criteria provides a structured framework for matching project requirements to the appropriate credential level.

References

• BLS Occupational Outlook: Grounds Maintenance Workers

The law belongs to the people. Georgia v. Public.Resource.Org, 590 U.S. (2020)