ISA Municipal Specialist cheat sheet

Program authority derives from the municipal charter or code; confirm whether the tree program sits under public works, parks, or a standalone forestry division before drafting plans.

A written urban forest management plan typically covers 5-10 years and links inventory data, canopy goals, staffing, and budget to adopted council priorities.

Canopy cover targets are set as percentages by land use (e.g., residential, commercial, park) rather than one citywide number, because achievable cover differs by zoning density.

Chain of custody for program accountability: council adopts plan → department sets work plan → supervisor assigns crews → annual report measures progress against baseline metrics.

Common performance metrics: trees planted vs. removed ratio, pruning cycle length, percent of inventory inspected, response time to hazard calls, and canopy change per decade.

Municipal arborist certification (ISA) and state pesticide/applicator licenses are the typical credential requirements written into job classifications for tree crew leaders.

Emergency response annexes should pre-identify priority routes (hospitals, evacuation corridors, power substations) for storm debris clearance before the event occurs.

Interdepartmental coordination is required with public works (streets, utilities), planning/zoning, risk management, and emergency management; document roles in a memorandum of understanding.

Inventory types: complete (100% of public trees, high accuracy, high cost), sample (statistically valid estimates via stratified random plots), and partial/priority (hazard or high-use areas only).

Minimum data fields for a management inventory: unique tree ID, species, DBH, condition rating, location (GPS or address), site type, and maintenance recommendation.

DBH is measured at 4.5 ft (1.37 m) above ground on the uphill side; trees on slopes or with swellings use the standard adjustment rules for measurement height.

Condition rating scales are typically 5-class (excellent to dead/dying) or a numeric 0-100; whatever scale is used must be defined in writing so ratings are repeatable across inspectors.

i-Tree Eco and i-Tree Streets quantify ecosystem services (carbon storage, stormwater interception, energy savings); input requirements include species, DBH, condition, and local climate/ pollution data.

Stratified sampling precision is reported as a standard error or confidence interval; a common target is ±10% at 95% confidence for citywide estimates.

Benefit-cost ratio (BCR) = total annual benefits ÷ total annual costs; values above 1.0 indicate the program returns more in services than it costs.

Canopy cover is measured from aerial or satellite imagery using classified land-cover rasters; change detection requires consistent imagery season and resolution between years.

Street tree ordinance elements typically include: definitions, jurisdiction over public trees, permit requirements, prohibited species, planting spacing standards, and penalties.

Tree protection ordinance provisions regulate removal on private property via permits, replacement ratios, and mitigation fees; thresholds are usually set by DBH or by heritage/specimen status.

Heritage, landmark, or specimen tree designation usually requires a documented nomination, an assessment by the municipal arborist, and a public hearing before a board or council.

Replacement requirements are often expressed as caliper-inches replaced per caliper-inch removed (e.g., 1:1 or 2:1) or as a fee-in-lieu schedule tied to appraised value.

Tree appraisal for removal or damage claims commonly uses the trunk formula method (CTLA/ISA guidance): value based on species rating, condition, location, and replacement cost.

Clearance and sight-distance standards (e.g., 8 ft over sidewalks, 14-16 ft over streets) are usually codified in the street tree or vegetation management ordinance and must be cited in permits.

Enforcement mechanisms include stop-work orders, citations, civil penalties, permit denial, and required restoration; due-process notice and appeal rights must be written into the code.

Ordinance updates require legal review, stakeholder input, planning commission or council action, and a public comment period; effective dates and grandfathering clauses must be explicit.

Species selection criteria: USDA hardiness zone match, soil pH and drainage tolerance, mature size vs. available growing space, pest/disease resistance, and native or regionally adapted status.

Diversity rule of thumb (the 10-20-30 guideline): no more than 10% of one species, 20% of one genus, 30% of one family in the planting stock to limit catastrophic loss.

Nursery stock standards: ANSI Z60.1 governs root ball size, caliper, branching, and quality; specify it in purchase contracts to avoid substandard stock.

Planting hole width should be at least 2-3 times the root ball diameter; depth is set so the root flare sits at or slightly above grade, never buried.

Bare-root planting is limited to dormant season; container and B&B stock can be planted across a wider window but require irrigation through the first two growing seasons.

Establishment period is typically 2-3 years post-planting, during which supplemental irrigation, mulch maintenance, and structural pruning are scheduled.

Mulch rings should be 2-4 inches deep, kept away from the trunk, and extended to the drip line where feasible; mulch volcanoes are a defect to correct.

Post-planting inspections at 30 days, 1 year, and 2 years catch transplant shock, girdling ties, and irrigation failures before mortality occurs.

Pruning types: structural (young tree training), crown cleaning, thinning, raising, reduction, and restoration; each has a defined objective and should be specified in the work order.

ANSI A300 (Part 1) is the pruning standard; the 1/3 rule limits removal to no more than 25-33% of live crown per pruning cycle depending on species and age.

Branch collar cuts (natural target pruning) preserve the branch bark ridge and collar; flush cuts and stub cuts are defects that create decay and sprouting.

Tree risk assessment uses a matrix: likelihood of failure × likelihood of impact × consequence of failure; ISA Tree Risk Assessment Qualification (TRAQ) levels are limited, basic, advanced.

Risk categories drive response time: high-risk trees are mitigated immediately or within days, moderate within weeks to months, low scheduled in the normal cycle.

Decay and defect indicators include conks, cavities, cracks, included bark, codominant stems, and root plate disturbance; sounding and resistograph testing support but do not replace visual assessment.

Pruning cycles: high-use areas every 3-5 years, moderate-use every 5-7, low-use every 7-10; cycle length should be tied to growth rate and species.

Record keeping for risk management: document inspection date, assessor, defects found, mitigation performed, and follow-up date to support liability defense.

Critical Root Zone (CRZ) is commonly defined as a radius of 1 ft per 1 inch of DBH (or 1.5 ft per inch in some jurisdictions); the Tree Protection Zone (TPZ) is often 1.5× the CRZ.

Tree protection fencing must be installed before demolition or grading and remain in place until final landscaping; fencing is inspected and photographed at installation.

Prohibited within the TPZ: grade changes, trenching, storage of materials, equipment parking, fuel storage, and disposal of wash water or concrete.

Grade changes within the CRZ: lowering grade removes roots; raising grade suffocates roots; both require arborist review and often root pruning or aeration systems.

Root pruning must be done with clean, sharp tools and limited to 25% of the root system per season; cuts should be made at a smooth angle, not torn.

Trenching near trees should be rerouted or done by directional boring or air spading; utility corridors should be planned before tree layout in site design.

Tree protection plans are reviewed by the municipal arborist and may require a posted bond or escrow that is released only after final inspection.

Post-construction tree condition assessments compare pre- and post-construction ratings; trees that decline within a defined period may trigger replacement obligations.

Risk communication principles: state the hazard, the action being taken, the timeline, and the contact for questions; avoid technical jargon and avoid minimizing legitimate concerns.

Public notice requirements for tree removal on public property typically include posting on the tree, notice to adjacent property owners, and a hearing or comment period per code.

Engagement ladder (inform → consult → involve → collaborate → empower) should match the decision: species selection in a park may warrant collaboration; emergency removals warrant inform only.

Volunteer tree planting events require a safety briefing, tool training, and a signed waiver; minors require guardian consent per municipal risk policy.

Tree giveaway and education programs should include planting and care instructions, species appropriate to the region, and follow-up contact to measure survival.

Canopy equity analysis maps canopy cover against income, race, and heat vulnerability data; results guide planting prioritization and are communicated publicly.

Crisis communication after storm damage: pre-drafted templates, a single spokesperson, and a debris-removal hotline reduce misinformation and call volume.

Measuring outreach success uses process metrics (attendance, trees distributed) and outcome metrics (survival at 1 and 3 years, canopy change in target areas).

Budget categories: personnel and benefits, equipment and depreciation, contractual services, nursery stock, and contingency (typically 5-10% of operating budget).

Cost accounting should separate planting, pruning, removal, and inspection so cost-per-tree metrics can be calculated and compared across years and crews.

Procurement thresholds: informal quotes below a set dollar amount, formal sealed bids above it; emergency procurement requires documented justification and council approval.

Contract specifications must cite standards (ANSI A300, Z60.1, Z133 for safety), define scope, units (per tree, per DBH inch, hourly), and inspection/acceptance criteria.

Contractor qualifications to require: ISA Certified Arborist on staff, state pesticide license where applicable, insurance limits, and safety record (OSHA logs).

Crew productivity benchmarks: a trained 2-3 person crew can prune roughly 15-30 trees per day depending on size and access; use local data to set unit prices.

Volunteer management requires background checks where required by policy, role descriptions, training, supervision ratios, and recognition to sustain participation.

Staffing plans should include cross-training for storm response, certification renewal budgets, and succession planning for the municipal arborist position.