ISA AM common mistakes
ISA AM · Understand the traps and how to avoid them.
Answering municipal-arboriculture scenario questions with the biology-only reasoning used for the arborist certification exam, choosing the horticulturally ideal option even when the stem specifies budget, staffing, or political constraints.
Candidates prepare from tree-care study material and carry over the habit of selecting the 'best for the tree' answer, but the AM exam tests decisions made inside a municipal program, where feasibility and liability shape the correct response.
What to do instead
Before selecting, re-read the stem for constraint cues (limited crew hours, council direction, public objection, grant conditions) and eliminate any option that ignores the stated constraint, even if it is arboriculturally superior.
Treating a public tree inventory as a one-time deliverable and choosing answers that describe a single complete census, rather than a risk-based or sample inventory followed by a cyclical re-inventory schedule.
Candidates conflate 'inventory' with 'count every tree once' and miss the program-management logic of stratified sampling, cycle length tied to risk, and updating records as work orders close.
What to do instead
Learn the trade-offs among full census, stratified sample, and risk-based partial inventory, and default to answers that build inventory into an ongoing cycle linked to work-order and budget data.
Confusing CODIT wall numbering and the sequence of compartmentalization, or assuming compartmentalization means the tree heals the wound, when the process only confines the spread of decay.
Wall terminology is easy to memorize shallowly, and everyday language about trees 'healing' leaks into answers; the exam probes whether the candidate knows which wall resists which direction of spread and that the barrier zone forms after wounding.
What to do instead
Draw the four walls from memory with the direction each resists, and state explicitly that trees seal rather than heal; practice distinguishing wall 4 and the barrier zone from the other three.
Selecting a mitigation recommendation that is disproportionate to the assessed likelihood and consequence, such as recommending removal for a low-likelihood defect on a low-target tree, or doing nothing for a high-consequence target.
Candidates focus on the defect itself and skip the target and likelihood steps, or they overcorrect out of fear of liability and default to the most severe option.
What to do instead
Work every risk question through the matrix in order: identify the target, rate likelihood of failure, rate consequence, then choose the least restrictive mitigation that brings risk to an acceptable level; justify with the matrix, not with the defect alone.
Mixing up the roles of the municipal arborist and the certified arborist in policy settings, answering as if the AM credential authorizes tree risk assessment or pest diagnosis that requires other qualifications.
The credential names overlap, and candidates assume the AM exam tests the same technical scope as the arborist certification; questions on program authority then get answered with field-technician framing.
What to do instead
Frame AM answers around program design, budget justification, ordinance administration, contractor oversight, and public communication, and defer technical determinations to the appropriately qualified professional when the stem implies that division of labor.
Ignoring the difference between tree protection during construction and tree preservation planning, giving answers that describe fencing at the dripline without addressing pre-construction planning, root-zone calculation, and enforcement.
Candidates memorize the fencing rule of thumb and stop there, missing that municipal questions test the ordinance, plan review, and inspection sequence that makes protection enforceable.
What to do instead
Build answers around the full sequence: pre-design tree survey, preservation plan, critical root zone calculation, protective fencing before demolition, and inspection authority with penalties for noncompliance.
Choosing a pest or disease response that names a pesticide or treatment before establishing identification and the municipal decision framework, or recommending chemical control where the correct answer is survey, quarantine awareness, or removal.
Field-training habits push toward treatment, and candidates underweight the regulatory and programmatic layer (reporting to authorities, delimiting surveys, public notice) that municipal exams emphasize.
What to do instead
For every pest question, answer in order: confirm identification, determine regulatory status and reporting duty, then select management (cultural, mechanical, chemical, or removal) with the least risk and clearest authority.
Writing budget and staffing answers that request new funding without quantifying workload, such as number of trees, maintenance cycles, crew hours per tree, or backlog, and without identifying an existing revenue or grant source.
Candidates treat budget questions as opinion questions and give general advocacy statements instead of the arithmetic-based justification municipal decision-makers expect.
What to do instead
Practice converting inventory and work-order data into workload and cost figures (trees per crew day, cycle length, backlog years) and tie every funding request to a measurable service level and a named funding mechanism.
Answering ordinance questions with the ANSI A300 standard as if the standard were law, or citing a standard's recommendation as a legal requirement without noting that the municipality must adopt it.
Standards and ordinances are learned together, and candidates blur the distinction between voluntary industry practice, which the municipality may reference in code, and enforceable local law.
What to do instead
State the relationship explicitly in answers: ANSI A300 and the companion Best Management Practices are voluntary standards that become enforceable only when adopted by reference in an ordinance or contract specification.
Skipping the target and occupancy analysis when evaluating a tree in a park or streetscape and instead rating risk from species, size, and visible decay alone.
Species-and-defect shortcuts are fast and feel authoritative, so candidates bypass the target step, which is precisely where municipal settings differ from woodland settings because targets are dense and occupancy varies by hour and season.
What to do instead
For every municipal risk scenario, explicitly name the target, its occupancy pattern (daily, seasonal, event-driven), and the consequence of failure before assigning a risk rating, and adjust for temporary high-occupancy events.