Basic Tree Risk Assessment Form

— Trunk —

— Crown and Branches —

— Roots and Root Collar —

Unbalanced crown  LCR ______%

Dead twigs/branches ______% overall Max. dia. ________

Broken/Hangers Number __________ Max. dia. ________

Over-extended branches 

Pruning history

Crown cleaned   

Reduced   

Flush cuts 

Thinned 

Topped 

Other

Raised 

Lion-tailed 

Cracks ________________________________ Lightning damage 

Codominant  ______________________________ Included bark 

Weak aachments  _________________ Cavity/Nest hole ____% circ.

Previous branch failures  _____________ Similar branches present 

Dead/Missing bark Cankers/Galls/Burls  Sapwood damage/decay 

Conks  Heartwood decay ______________________

Response growth

Client _______________________________________________________________ Date___________________ Time_________________

Address/Tree locaon _________________________________________________________ Tree no. ____________ Sheet _____ of _____

Tree species _________________________________________ dbh_____________ Height ___________ Crown spread dia. ____________

Assessor(s) __________________________________________ Tools used______________________________ Time frame_____________

Target Assessment

Target number

Target descripon Target protecon

Praccal to

move target?

Restricon

praccal?

Target within

drip line

Target within

1 x Ht.

Target within

1.5 x Ht.

History of failures _____________________________________________________________ Topography Flat Slope _________% Aspect _____

Site changes None  Grade change  Site clearing Changed soil hydrology Root cuts Describe _____________________________________

Soil condions Limited volume Saturated Shallow  Compacted Pavement over roots ______% Describe __________________________

Prevailing wind direcon______ Common weather Strong winds  Ice Snow  Heavy rain Describe______________________________

Tree Health and Species Prole

Vigor Low  Normal  High  Foliage None (seasonal) None (dead) Normal _____% Chloroc _____% Necroc _____%

Pests/Bioc_________________________________________________ Abioc _______________________________________________________

Species failure prole Branches Trunk  Roots Describe

____________________________________________________________________

Load Factors

Wind exposure Protected Paral Full  Wind funneling  ________________________ Relave crown size Small Medium Large

Crown density Sparse Normal Dense Interior branches Few  Normal Dense Vines/Mistletoe/Moss  _____________________

Recent or expected change in load factors

________________________________________________________________________________________

Tree Defects and Condions Aecng the Likelihood of Failure

Occupancy

rate

1–rare

2 – occasional

3 – frequent

4 – constant

Basic Tree Risk Assessment Form

Page 1 of 2

Site Factors

Target zone

Condion(s) of concern

Load on defect N/A  Minor  Moderate  Signicant 

Likelihood of failure Improbable  Possible  Probable  Imminent 

Load on defect N/A  Minor  Moderate  Signicant 

Likelihood of failure Improbable  Possible  Probable  Imminent 

Part Size Fall Distance

Load on defect N/A  Minor  Moderate  Signicant 

Likelihood of failure Improbable  Possible  Probable  Imminent 

Dead/Missing bark  Abnormal bark texture/color 

Codominant stems  Included bark  Cracks 

Sapwood damage/decay  Cankers/Galls/Burls  Sap ooze 

Lightning damage  Heartwood decay  Conks/Mushrooms 

Cavity/Nest hole _____ % circ. Depth _______ Poor taper 

Lean

_____

° Corrected?

__________________________________

Response growth

Condion(s) of concern

Part Size Fall Distance

Collar buried/Not visible  Depth________ Stem girdling 

Dead  Decay  Conks/Mushrooms 

Ooze  Cavity  _____% circ.

Cracks  Cut/Damaged roots Distance from trunk _______

Root plate liing  Soil weakness 

Response growth

Condion(s) of concern

Load on defect N/A  Minor  Moderate  Signicant 

Likelihood of failure Improbable  Possible  Probable  Imminent 

Part Size Fall Distance

Part Size

Fall Distance

Target

(Target number

or descripon)

Tree part

Condion(s)

of concern

Risk

rang

(from

Matrix 2)

Matrix 1. Likelihood matrix.

Likelihood

of Failure

Likelihood of Impact

Very low Low Medium High

Imminent Unlikely Somewhat likely Likely Very likely

Probable Unlikely Unlikely Somewhat likely Likely

Possible Unlikely Unlikely Unlikely Somewhat likely

Improbable Unlikely Unlikely Unlikely Unlikely

Failure

Impact

Failure & Impact

(from Matrix 1)

Likelihood

Improbable

Imminent

Possible

Very low

Unlikely

Negligible

Medium

Likely

Signicant

Probable

Low

Somewhat

Minor

High

Very likely

Severe

Consequences

Likelihood of

Failure & Impact

Consequences of Failure

N e g l i g i b l e Minor Signicant Severe

Very likely Low Moderate High Extreme

Likely Low Moderate High High

Somewhat likely Low Low Moderate Moderate

Unlikely Low Low Low Low

Data Final  Preliminary Advanced assessment needed No Yes-Type/Reason ________________________________________________

Inspecon limitaons None Visibility Access Vines Root collar buried Describe ___________________________________________

Notes, explanaons, descripons

1.__________________________________________________________________________________ Residual risk ________

2.__________________________________________________________________________________ Residual risk ________

3.__________________________________________________________________________________ Residual risk ________

4.__________________________________________________________________________________ Residual risk ________

Overall tree risk rang Low  Moderate  High  Extreme 

Overall residual risk

None  Low  Moderate  High  Extreme  Recommended inspecon interval __________________

is datasheet was produced by the International Society of Arboriculture (ISA) — 2017

North

Page 2 of 2

Matrix 2. Risk rating matrix.

Risk Categorizaon

Migaon opons