This unit of competency describes the skills and knowledge required to examine and assess tree health, structure, age, taxonomy, risk, amenity value and significance, and compile a tree assessment report.

The unit applies to individuals who work in arboriculture and analyse information and exercise judgement to complete a range of advanced skilled activities and demonstrate deep knowledge in a specific technical area. They have accountability for the work of others and analyse, design and communicate solutions to a range of complex problems.

Legislation, regulations and by-laws relating to the treatment and removal of trees apply in some states and territories.

An individual demonstrating competency must satisfy all of the elements and performance criteria in this unit.

There must be evidence that the individual has examined and assessed at least two different trees, including:

identified scope and purpose of assessment from client brief

selected, checked and used personal protective equipment

located tree and documented position

identified and recorded tree species and determined implication on brief

assessed and considered tree health and impact on brief

estimated age of tree, tree parts and defects

determined and recorded tree dimensions, which must include:

tree height

tree spread

diameter-at-breast-height (DBH)

trunk circumference

diameter at base

investigated, assessed and recorded the following indicators of value:

habitat and ecological significance

historical and cultural significance

statutory controls

selected and compared amenity tree for at least 2 different valuation methods

collected unit values and data required by the valuation method selected

calculated and recorded amenity value of at least 2 different trees

compared results of different valuation methods and accounted for differences

considered and communicated value of trees captured for valuation

inspected tree for visual indicators of likely failure of tree or tree parts

assessed relationship of tree to potential targets

assessed likely impact of wind loading on potential for failure

used basic diagnostic tools to confirm presence and extent of hazards

assessed hazards and determined likelihood of failure

selected tree risk assessment methods and determined their limitations

determined target of concern and occupation rate

determined tree components of concern and their likelihood of failure

determined likelihood of impact and consequence of tree failure on target

calculated and documented determinations and level of risk

provided client with benchmarks and context for risk assessment

determined and documented potential risk mitigation controls and estimated residual risk

recommended timeframes for implementation of risk mitigation controls and follow-up inspections

considered risk against value of tree

produced a tree risk assessment report.

An individual must be able to demonstrate the knowledge required to perform the tasks outlined in the elements and performance criteria of this unit. This includes knowledge of:

areas to address in a client brief and developing the scope of assessment, including:

purpose of assessment

owner/client and address

who requested the assessment

reasons for assessments to be requested

client risk thresholds

data capture procedures

requirements for assessment

tree assessment and measuring equipment

trees and surveying their location on a site, including:

methods for locating trees on devices, drawings, plans or aerial images

techniques to position tree on site from boundaries and structures

tree identification, biology and physiology

assessing tree health, including:

signs and symptoms of disease

methods of detecting decay and structural defects in trees

use of basic diagnostic tools

testing equipment to detect decay, disease and scope of tree problems

factors affecting the likelihood of tree failure

use of diagnostic tools

computations and estimating tree dimensions and their relevance to tree assessment, including:

tree height and spread

trunk circumference

DBH

diameter at ground level

assessing structure and symmetry of the canopy, including:

symmetrical and asymmetrical canopy structure and consequences on tree stability and health

trunk inclination and calculating the lean

impact of wind loading on trees and tree structures

estimating and calculating wind loading

relationship and responsiveness of form of crown to surrounding trees and structures

tree age and health issues and their estimation, including:

uninodal and multinodal tree species as an indicator of age

growth increments, including bud scars, sympodial growth and flush marks

checking age estimations using documented images

valuation methods of amenity trees, including:

a range of tree valuation methods and their application

legal and statutory controls and protection of trees

indicators of habitat use

ecological value and significance

cultural value and significance

historical value and significance

preservation orders and local environmental protection laws

calculating amenity tree value of individual trees

visual tree assessment (VTA) techniques and procedures, including:

visual indications and symptoms of disease and health issues

tests and checking the extent of disease and health issues

assessment of impact of tree disease and health issues on tree safety

the purpose and use of basic diagnostic tools

methods of determining and mitigating levels of risk, including:

a range of tree risk assessment methods and their application

identification and extent of tree hazards

causes of instability, decay, damage and stress in trees

quantification and qualification of tree risk

risk benchmarks from non-arboricultural activities

controls available to mitigate risks

remedial action of tree problems

determining the consequence of risk, including:

why most likely outcomes are used and not worst case

abbreviated injury index/scale

possible targets associated with tree risk, including:

persons, property, interruptions to community activity, interruptions to services

occupation rates

tree assessment reporting procedures, including images.

Assessment of the skills in this unit of competency must take place under the following conditions:

physical conditions:

an arboriculture site with the trees stipulated in the performance evidence

resources, equipment and materials:

computer with software for word processing

digital imaging equipment

personal protective equipment

diagnostic tools, including sounding hammer, trowel, probe, cordless drill

measuring equipment for tree dimensions, locating trees on site

samples of cross-sectioned defects and diseases

field tree inspection equipment, including hand lenses, probes, binoculars, containers for sample collection

specifications:

legislation and regulations relevant to arboriculture

client brief and specifications for tree assessment task

relationships:

client.

Assessors of this unit must satisfy the requirements for assessors in applicable vocational education and training legislation, frameworks and/or standards. In particular, assessors must have:

arboriculture vocational competencies at least to the level being assessed

current arboriculture industry skills directly relevant to the unit of competency being assessed.

This section describes those language, literacy, numeracy and employment skills that are essential for performance in this unit of competency but are not explicit in the performance criteria.

Arboriculture (ARB)