Reduction cut. All photos courtesy of the author.

Merriam-Webster Dictionary defines malpractice as “a dereliction of professional duty or a failure to exercise an ordinary degree of professional skill or learning by one rendering professional services, which results in injury, loss, or damage.” Across professions, malpractice generally includes four key elements:

• Duty: The professional owed a duty of care.
• Breach: The professional failed to meet the accepted standard.
• Causation: That failure directly caused harm.

Conduct structural pruning to manage codominant stems, improve leader dominance and reduce risk from long, slender branches.

Damages: Actual harm or loss occurred.
Unfortunately, pruning malpractice is someth ing I encounter far too often in cities across the United States. Trees are routinely subjected to improper practices such as lion-tailing, excessive interior thinning, outright topping and ignoring structural conditions, including large branches originating from the bottom 10 feet of the tree.

What is most concerning is that these practices are not limited to untrained individuals. In most cases, pruning malpractice is not rooted in malicious intent or a lack of effort, but in unclear, incomplete or poorly written pruning prescriptions that leave excessive interpretation to the production arborist.

Why standards alone aren’t enough
The ANSI A300 Pruning Standard was revised in 2023. While much of the technical content remained unchanged, several revisions were especially significant:

• The consolidation of all 10 A300 parts into one cohesive document that is periodically revised.
• The primary benefit of consolidation is ensuring practitioners are working from the most current standard.
• The explicit prohibition of mastication as pruning (tree shredding by heavy equipment).
• Few arborists would argue in favor of indiscriminately grinding a tree with heavy equipment.
• The shift from the rigid “25% rule” to objective-based pruning.
• Objective-based pruning allows arborists to remove the amount of foliage necessary to achieve the stated objective. Tree species, vigor, health and pruning interval determine the appropriate pruning dose – without creating a technical violation of an arbitrary percentage. More important, prescribing the number of pruning cuts provides a more quantitative and repeatable instruction than estimating canopy percentage removed.
• Clarification that the scheduling of monitoring and maintenance is the responsibility of the client – a term that should appear in proposal terms and conditions.

The requirement that monitoring and maintenance be addressed is found in Clause 4.7.3 (General) and applies to the entire A300 standard.

Yet despite these improvements, tree architecture in many communities has not meaningfully improved. Why?

Author’s hand used to estimate branch diameter.

Using A300 to write specifications
Most pruning proposals and contracts include language such as, “All work shall be performed according to ANSI A300 Tree Care Standards.” This tells the production arborist almost nothing about what pruning is to be performed! When I review pruning specifications, I frequently encounter outdated and vague terminology, “Class I, II, and III pruning” – listed as objectives. Even when definitions are attached, these terms remain open to interpretation by the production arborist.

Another example is language such as “selectively thin the interior for improved sail.” Most pruning on mature trees should occur at the outer crown. Removing live branches from the interior crown leads directly to lion-tailing and long-term structural problems.

To illustrate the issue, imagine a doctor instructing a nurse to “selectively administer medications as you see fit – we’ve worked together for a long time, you know what I mean.” That would clearly constitute malpractice. Without specific dosages, medication types and protocols, an unreasonable burden is placed on the nurse. The same is true in arboriculture.

The A300 standards are performance standards, not work specifications. They require the arborist to describe what the finished product should achieve, i.e., the objective. But they do not replace the need for clear, specific pruning instructions. This gap is exactly what the Prescription Pruning Qualification (PPQ) is designed to bridge – taking pruning prescriptions from paper to tree crown.

Prescription Pruning Qualification helmet sticker.

Writing specifications that meet the A300 Standard
The A300–2023 Standard provides a sample pruning specification form (page 25), and TCIA offers a digital A300 platform with interactive assessments, animations, videos and quizzes in both English and Spanish. When pruning specifications follow the A300 pruning-process flowchart (page 12), the result is a defensible document with clarity and measurable objectives.

At a minimum, a pruning specification that meets the A300 standard must include:

Exact location of the tree(s) to be pruned.

• Pruning objective(s), such as:
• Reducing crown or branches.
• Raising the crown.
• Developing or improving structure.
• Providing clearance.
• Improving tree health.
• Mitigating risk.
• Enhancing views.

Pruning system, including:

• Natural.
• Pollarding.
• Topiary.
• Espalier.
• Pleaching.

Detailed pruning specifications describing the work to be performed.
Additional information, as needed.

When A300 terminology is used correctly, it calibrates the Prescriber (sales arborist), the Producer (production arborist) and the client – ensuring everyone is speaking the same language.

Introducing Prescription Pruning Qualification (PPQ)
Prescription Pruning Qualification is a Florida ISA Chapter credential and a three-day, in-depth program designed to improve pruning communication, accuracy and outcomes.

Day 1: Prescribers and Producers attend together. Producers are not required to be ISA Certified Arborists, and they complete their training at the end of Day 1, receiving a certificate of completion (no exam).

Days 2-3: Prescribers (ISA Certified Arborists required) focus on developing pruning prescriptions through classroom instruction, outdoor exercises and real-world examples.

Day 3 concludes with a review and
multiple-choice exam. Those who pass earn the PPQ credential.

Conditions of concern: Aligning the customer and the tree
A key component of PPQ is identifying Conditions of Concern (COC). Customers contact tree care companies because they already have concerns – often related to light, safety or appearance.

The Prescriber’s role is to integrate the customer’s concerns with the tree’s conditions. For example:

• Customer COC – More sunlight on the lawn and a better-looking tree.
• Tree COC – Clustered large aspect-ratio branches, suppressed leader, excessive upright growth, unbalanced crown.

From this, the Prescriber may develop multiple objectives:

Improve leader vigor (structure).
Balance crown density (appearance).
Create 8 feet of trunk clearance.

These real-world exercises are central to PPQ training.

Removal cut.

Going beyond A300: The five additional PPQ elements
PPQ builds on the A300 Standard by adding five critical elements that dramatically reduce decision-making in the tree.

1. Pruning-cut number or range. Providing a cut number or range immediately communicates the scope of work, while cut size further clarifies intent. A300 Section 5.5.1 states that pruning cuts should be the smallest diameter and fewest number required to meet the objective.
2. Pruning-cut size or range (e.g., 1-2 inches).
3. Pruning-cut size. A simple field tool for estimating cut size is your hand; for example, my index finger measures approximately 5 inches and my thumb about 3 inches.
4. Pruning-cut type (reduction, removal, heading). Cut types – reduction, removal and heading – are clearly defined in A300, yet those definitions are not always consistently understood between Prescribers and Producers. PPQ ensures alignment.
5. Pruning-cut location.
6. Cut location is communicated using the branch-order concept, borrowed from botany and road mapping, which simplifies identifying exactly which branches to prune. Branch orientation is also considered; research has shown that flattening lateral branch growth improves tree architecture and can assist when deciding which branches to cut.
7. Part type to remove (dead or alive).
8. PPQ also clarifies whether the branch to be removed is dead or alive.

Additional prescription elements
Additional elements of a complete pruning prescription include:

• Limitations: Clear boundaries for Producers (e.g., make no removal cuts on first order branches).
• Additional instructions (e.g., remove more from larger branches than smaller branches).
• Additional cuts for appearance: Allowing experienced Producers limited discretion (e.g., up to 15 additional cuts under ¾-inch diameter to fine-tune balance).

PPQ also addresses tree architecture, pruning response, heartwood presence and pruning intervals – all essential considerations when writing effective prescriptions.

While this article focuses on single-tree prescriptions, the same principles scale to dozens or hundreds of trees across species and age classes.

Conclusion
Prescription Pruning Qualification complements the ANSI A300 Standard by bringing clarity to pruning objectives and training Producers to think more critically in the tree. When implemented within an organization, PPQ strengthens communication between Prescribers, Producers and clients – leading to safer work practices, consistent outcomes, improved efficiency and greater value.

Ultimately, pruning malpractice is best prevented through education, deliberate training and a shared commitment to professional standards. Well-written pruning prescriptions reduce liability, improve production efficiency and raise the standard of care in professional tree management.

Kristoffer Rasmussen is a CTSP, CLQ, ISA Urban Forest Professional, Florida ISA Chapter Prescription Pruning Coordinator, TCIA Accreditation Auditor and Loss Control Specialist, and serves on the TCI Magazine editorial advisory committee. If you’re interested in learning more about PPQ, please contact Kristoffer Rasmussen at
krasmussen@tcia.org.