Tree Biology
11%of exam
PhysiologyAnatomyCODITRoots
Identification + Selection
9%of exam
Soil Management
7%of exam
Installation + Establishment
9%of exam
PlantingRoot FlareMulchEstablishment
Pruning
14%of exam
Diagnosis + Treatment
9%of exam
SymptomsSignsAbioticIPM
Trees + Construction
9%of exam
TPZRootsCompactionProtection
Tree Risk
11%of exam
Safe Work Practices
15%of exam
Z133PPEElectricalJob Briefing
Urban Forestry
6%of exam
BenefitsInventoryOrdinancesManagement Plan
Quick Facts
- Questions
- 200 MCQ
- Pretest
- 20 unscored
- Time
- 3.5 hours
- Pass
- 76%
- Eligibility
- 3 years
- Experience year
- 1,795 hours
- Validity
- 3 years
- Renewal
- 30 CEUs
- First attempt
- $335/$419
CODIT Walls
Vertical, inward, radial, barrier
W1: verticalW2: inwardW3: radialW4: strongest
Xylem vs Phloem
Xylem
- Water/minerals
- Mostly upward
- Wood tissue
Phloem
- Sugars
- Source-to-sink
- Inner bark
Water up; sugars move
Tree Biology
- Xylem
- Water upward
- Phloem
- Sugars source-to-sink
- Cambium
- New vascular tissue
- Cork cambium
- Outer bark
- Apical meristem
- Length growth
- Lateral meristem
- Diameter growth
- Stomata
- Gas exchange
- Transpiration
- Water vapor loss
- Photosynthesis
- Sugar production
- Respiration
- Energy release
CODIT + Roots
- CODIT
- Decay compartmentalization
- Wall 1
- Vertical plugging
- Wall 2
- Inward resistance
- Wall 3
- Radial resistance
- Wall 4
- Strong barrier zone
- Root flare
- Visible trunk base
- Absorbing roots
- Shallow, widespread
- Mycorrhizae
- Root-fungus partnership
Selection Picker
- Cold climate→Hardiness match
- Narrow site→Small mature form
- Overhead wires→Low-growing species
- Salt exposure→Salt-tolerant species
- Wet soil→Flood-tolerant species
- Known invasive→Do not plant
- Poor diversity→Different genus
- Paved site→Urban-tolerant species
Identification + Selection
- Simple leaf
- One blade
- Compound leaf
- Multiple leaflets
- Opposite
- Paired nodes
- Alternate
- Staggered nodes
- Whorled
- Three-plus nodes
- Gymnosperm
- Naked seed
- Angiosperm
- Enclosed seed
- Hardiness
- Climate match
- Mature size
- Space match
- Invasive
- Avoid planting
Soil Picker
- Need nutrients→Soil test
- Standing water→Drainage correction
- High compaction→Air excavation
- Low organic matter→Compost topdress
- High pH chlorosis→Micronutrient plan
- Exposed roots→Mulch protection
Soils
- Texture
- Sand/silt/clay ratio
- Structure
- Aggregate arrangement
- Bulk density
- Compaction indicator
- Porosity
- Air-water space
- Field capacity
- Held water
- Wilting point
- Unavailable water
- pH
- Nutrient availability
- Organic matter
- Biology plus structure
- Chlorosis
- Yellowing leaves
- Mulch
- Moderates soil
Planting Rule
Flare visible; mulch never touches
Flare at gradeWide holeRemove twineNo volcano
Planting + Establishment
- Root flare
- At finished grade
- Hole width
- Two-three times ball
- Hole depth
- No deeper than ball
- Burlap
- Remove synthetic material
- Wire basket
- Remove top portion
- Twine
- Remove from trunk
- Mulch depth
- Two-four inches
- Mulch volcano
- Avoid trunk contact
- Staking
- Only when needed
- Establishment
- Monitor water stress
Removal vs Reduction
Removal
- At origin
- Outside collar
- Branch gone
Reduction
- To lateral
- Keeps branch
- Controls length
Origin vs lateral
Pruning Picker
- Dead branches→Clean
- Clear sidewalk→Raise
- Reduce spread→Reduction cuts
- Crowded crown→Thin selectively
- Young co-dominants→Structural pruning
- Storm-topped crown→Restore
- Large limb removal→Three-cut method
- Need lateral leader→One-third rule
Pruning Cuts
- Removal cut
- At branch origin
- Reduction cut
- To suitable lateral
- Heading cut
- Internodal or weak lateral
- Branch collar
- Do not injure
- Branch bark ridge
- Cut placement marker
- Stub cut
- Too far out
- Flush cut
- Damages collar
- Three-cut method
- Prevents bark tear
- One-third rule
- Reduction lateral size
- Topping
- Unacceptable practice
Flush Cut vs Stub
Flush cut
- Cuts collar
- Damages defense
- Too close
Stub cut
- Leaves stub
- Poor closure
- Too far
Collar cut vs stub
Pruning Objectives
- Clean
- Remove dead/diseased
- Thin
- Reduce crown density
- Raise
- Provide clearance
- Reduce
- Decrease height/spread
- Restore
- Improve damaged structure
- Structural
- Develop strong form
- Mature dose
- Limit live removal
- Lion-tailing
- Interior stripping
Diagnosis Flow
Host, normal, symptom, sign, pattern
Identify hostDefine normalFind signsRead pattern
Sign vs Symptom
Sign
- Pathogen evidence
- Insect frass
- Fruiting body
Symptom
- Plant response
- Wilt
- Chlorosis
Evidence vs response
Diagnosis Picker
- Fungal fruiting bodies→Disease sign
- Uniform site decline→Abiotic suspect
- Species-specific pattern→Biotic suspect
- Interveinal yellowing→Chlorosis workup
- Recent herbicide→Exposure history
- Pest below threshold→Monitor
- Threshold exceeded→IPM action
- Unclear cause→Collect samples
Diagnosis + Treatment
- Identify host
- Start diagnosis
- Normal condition
- Know baseline
- Symptom
- Plant response
- Sign
- Pest evidence
- Pattern
- Distribution clue
- Biotic
- Living cause
- Abiotic
- Nonliving cause
- IPM
- Integrated controls
- Threshold
- Action trigger
- Chemical control
- Targeted last resort
Biotic vs Abiotic
Biotic
- Living cause
- Often spreads
- Signs possible
Abiotic
- Nonliving cause
- Site pattern
- No pathogen sign
Living vs environment
TPZ vs Dripline
TPZ
- Protection zone
- Managed boundary
- Site-specific
Dripline
- Canopy edge
- Rough guide
- Not enough alone
Protection vs canopy edge
Construction Protection
- TPZ
- Protected root area
- CRZ
- Critical root zone
- Fencing
- Install before work
- Trenching
- Severs roots
- Compaction
- Reduces pore space
- Grade change
- Alters root oxygen
- Fill soil
- Can suffocate roots
- Cut soil
- Removes roots
- Storage
- Keep outside TPZ
- Air excavation
- Root-safe digging
Risk Formula
Failure likelihood plus target consequences
DefectLoadTargetOccupancy
Risk vs Hazard
Hazard
- Potential harm
- Defect/source
- Condition exists
Risk
- Likelihood plus consequence
- Target dependent
- Managed level
Source vs probability
Risk Picker
- No target→Low consequence
- High occupancy→Prioritize review
- Obvious defects→Basic assessment
- Hidden decay→Advanced assessment
- Dead branch over target→Prune/remove
- Root plate movement→Restrict access
- Risk unacceptable→Mitigate promptly
- Risk acceptable→Set interval
Tree Risk
- Risk
- Likelihood plus consequence
- Target
- Person/property/activity
- Occupancy
- Target presence
- Load
- Forces on tree
- Defect
- Weakness or condition
- Decay
- Wood degradation
- Crack
- Separation in wood
- Included bark
- Weak union
- Mitigation
- Reduce risk
- Interval
- Next inspection timing
Big Domains
Safety and pruning carry 29%
Safety 15%Pruning 14%Biology 11%Risk 11%
Qualified vs Unqualified
Qualified
- Documented training
- Voltage knowledge
- Specific MAD
Unqualified
- No close work
- Ten-foot baseline
- Call utility
Training controls distance
Exam Logistics
- ISA credential
- Voluntary certification
- Exam
- Closed book
- Questions
- Four-option MCQ
- Pretest items
- Unscored, hidden
- Overall pass
- 76 percent
- Domain scores
- Weighted, not averaged
- Retake
- After failed attempt
- Recertify
- CEUs or exam
Safe Work
- ANSI Z133
- Arboricultural safety
- Job briefing
- Hazards plus plan
- PPE
- Task-specific protection
- Hard hat
- Head protection
- Eye protection
- Impact protection
- Hearing protection
- Noise reduction
- Leg protection
- Chainsaw protection
- Electrical hazard
- Maintain MAD
- Aerial rescue
- Emergency readiness
- Escape route
- Felling safety
Eligibility
- Experience path
- Three full-time years
- One year
- About 1,795 hours
- Associate path
- Degree plus two years
- Bachelor path
- Degree plus one year
- 900 training
- Plus two years
- 1,800 training
- Plus one year
- Self-employed
- Three references
- Documentation
- Dates, duties, hours
Urban Forestry
- Canopy cover
- Urban forest extent
- Inventory
- Tree data system
- DBH
- Stem diameter
- Condition
- Health/structure rating
- Diversity
- Species risk spread
- Ordinance
- Local tree rule
- Permit
- Required authorization
- Appraisal
- Tree value estimate
- Benefits
- Environmental/social/economic
- Management plan
- Goals and cycles
Common Traps
Certification vs license
ISA is voluntary ≠ Local rules still apply
Domain scores vs overall
Domains are weighted ≠ Average is misleading
Study guide vs exam
Guide helps study ≠ Exam tests body
Deep planting vs grade
Flare must show ≠ Buried flare declines
Wound paint vs CODIT
Trees compartmentalize ≠ Paint rarely helps
Topping vs reduction
Topping heads indiscriminately ≠ Reduction uses laterals
Sign vs symptom
Sign is evidence ≠ Symptom is response
TPZ vs storage area
TPZ excludes activity ≠ Storage compacts roots
No target vs high risk
Target drives consequence ≠ Defect alone insufficient
PPE vs hazard control
PPE is last layer ≠ Plan removes hazards
Last Minute
- 1.Weights: Safety 15, Pruning 14
- 2.200 MCQ; 20 unscored
- 3.Pass is 76 percent
- 4.Three years equals 1,795 hours
- 5.Renew with 30 CEUs
- 6.Xylem water; phloem sugar
- 7.CODIT wall four strongest
- 8.Root flare stays visible
- 9.No flush cuts or stubs
- 10.Reduction needs suitable lateral
- 11.Signs are pest evidence
- 12.Abiotic often sitewide pattern
- 13.Protect TPZ before construction
- 14.Risk requires target consequence
- 15.Electrical work follows MAD
- 16.Job briefing before tree work
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