This unit of competency describes the skills and knowledge required to identify and analyse aspects of tree biomechanics that affect the physical load and strength of trees, branches and anchorage in the ground. It requires the assessment of tree strength and the loads that occur, and the ability to assess factors that can weaken trees that increase the chance of failure.

The unit applies to individuals with highly specialised advanced theoretical and technical knowledge for professional work and research in arboriculture. They exercise advanced cognitive, technical and communication skills and demonstrate complete autonomy, judgement and adaptability in research and analysis for complex problems.

No licensing, legislative or certification requirements apply to this unit at the time of publication.

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

There must be evidence that the individual has analysed the structure and biodynamics of a minimum of five different trees, including performed the following:

five static load tests, and

five dynamic load analyses.

There must also be evidence that the individual has:

determined existing physical loads affecting trees

identified areas of high stress on trees and the factors that affect these areas of high stress

assessed root plate environment for damage

assessed history and effect of tree pruning operations on tree roots and stems

determined presence and extent of tree defects

assessed strength and material properties of tree structural components

determined wind environment of tree

determined surface area of structure exposed to wind

determined crown surface area exposed to wind

assessed aerodynamic drag factor of tree crown

estimated primary loads occurring in seasonal climatic events

determined wind-load of prevailing storms

determined load associated with saturated foliage

determined static load on trees for structural integrity testing as an estimate of a wind equivalent load

calibrated static load testing instruments

conducted static tests that must include:

loads to the tree

measures the trunk strength

assesses root plate anchorage

monitored loads and forces using electronic equipment

monitored trees to ensure loads are kept within safe limits to prevent damage

maintained records of all data from static tests

compared data against benchmarks from stable tree populations and prepared a report on structural integrity testing

investigated tree biomechanics using dynamic methods of analysis

reviewed complex models of tree dynamics analysis

calculated mass of branches to determine degree of open-grown form of tree

calculated vector of force on the tree

determined tree dynamic response under defined wind loads

investigated level of contribution of material properties in tree dynamics

investigated the dynamic effect of branches on frequency and damping

determined the level of contribution of form and morphology in tree dynamics

reviewed suitability of invasive and non-invasive methods of testing

evaluated and determined likelihood of structural failure

confirmed level of anchoring potential of root system and stability of tree

prepared a structural integrity report and provided to client.

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:

tree dynamics and impact of tree form and morphology

tree stability and physical loads affecting trees, particularly in high stress environments

root plate environment, including:

depth and consistency of soil

spatial limitations

site excavations and potential damage

arboricultural activity and impact on tree structure and stability, including:

pruning operations to branches and roots

presence and impact of defects on tree structure, including:

extent of decay and damage of trunk and root system

assessment of strength and material properties of structural wood

biomechanical impact of wind on tree structure, including:

seasonal wind patterns, and tree exposure

surface area and tree structure

aerodynamic drag factor of tree crown in relation to trunk diameter and extent of hollowness

estimation of primary loads occurring in seasonal climatic events

severe wind-load due to storms and extreme weather conditions

load associated with rain and snow saturated foliage

additional drag associated with saturated foliage

open-grown form of tree

testing principles for static load, including:

use and purpose of a static load on trees during structural integrity testing as an estimate of a wind equivalent load

calibrating static load testing instruments

limits of structural safety during a static testing

measurement of trunk strength

invasive and non-invasive methods of testing trees

assessment of root plate anchorage in the ground

methods and reasons for monitoring loads and forces on trees, including:

electronic monitoring

monitoring of tree to ensure loads are kept within safe limits

value and purpose of benchmarks obtained from stable tree populations

tree biomechanics studies using dynamic methods of analysis, including:

simple models of tree dynamics

complex models and finite element analyses

multimodal approaches representing dynamics of branches on trees

calculations required for structural and biomechanical assessments of trees, including:

mass of branches

vector of force on trees

tree dynamic response

wind velocity and direction

statistical analysis and interpretation of test results

dynamic effect of branch movement on tree stability and failure rate, including:

oscillation frequency

energy dissipation and damping effect of canopy structure

likelihood of structural failure

level of anchoring potential of root system

stability of tree

records and reporting procedures for analysis of structural integrity testing.

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

physical conditions:

an arboriculture work site that has the trees stipulated in the performance evidence

resources, equipment and materials:

computer with word processing software

wind environment statistics

static load test equipment

models of tree dynamics

specifications:

test equipment manuals, standard procedures and quality standards for performing load tests

sample reports for the diagnostic test methods listed in the performance criteria.

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)