Application
This unit of competency describes the skills and knowledge required to dismantle trees in close proximity to structures and other assets and in difficult or hazardous circumstances using a specialised range of methods, tools, equipment and materials and requiring the application of extensive arboricultural knowledge.
The unit applies to individuals who work in arboriculture under broad direction and take responsibility for their own work. They use discretion and judgement in the selection, allocation and use of available resources and for solving problems.
The arboriculture industry requires that all tree dismantling work is undertaken according to preferred industry practices (as outlined in the Companion Volume).
Legislation, regulations and by-laws relating to the treatment and removal of trees apply in some states and territories.
Elements and Performance Criteria
Elements | Performance Criteria |
1. Prepare for tree removal | 1.1 Determine access to site and confirm approval for works to commence 1.2 Confirm site preparations, including notification of stakeholders 1.3 Undertake a site-specific job safety analysis (JSA), and record and implement site-specific control measures according to workplace safety procedures 1.4 Inspect tree to identify structural defects and appropriate removal methods 1.5 Determine a dismantling strategy identifying potential drop or lowering zones and providing safety zones for load, tools and equipment 1.6 Review dismantling strategy with work crew and adjust according to feedback 1.7 Protect property and vegetation assets in the work zone from potential damage 1.8 Confirm availability of emergency response resources and safety procedures 1.9 Select and prepare tools, equipment and machinery and conduct pre-operation and safety checks 1.10 Select, check and use personal protective equipment |
2. Design and prepare rigging system | 2.1 Design rigging system according to dismantling strategy 2.2 Select appropriate anchor and attachment points 2.3 Estimate force applied to tree structure and to rigging equipment during planned rigging operations 2.4 Design rigging system to allow for load, impact of force and structural integrity of tree 2.5 Consider breaking strength, working load limits and safety factor of equipment in use 2.6 Discuss and confirm rigging system with work team 2.7 Select rigging equipment, inspect for defects, and repair, replace or remove from service damaged components according to workplace safety procedures 2.8 Assemble and configure rigging equipment into selected rigging system and install at anchor point |
3. Implement dismantling of trees | 3.1 Coordinate and sequence work with work team during operations using communication methods agreed with work team for site environment 3.2 Access tree crown safely according to dismantling strategy and workplace safety procedures 3.3 Select and apply rigging or dismantling techniques in correct sequence to dismantle tree according to determined dismantling strategy 3.4 Plan each cut and install rigging equipment according to rigging system design and manufacturer instructions 3.5 Check rigging assembly is correctly installed and safe to use prior to performing cut 3.6 Accurately apply a selection of cuts to achieve directional felling and controlled rigging and dismantling of the tree crown and trunk 3.7 Perform cuts from a safe and secure work position using industry standard cutting techniques 3.8 Monitor and adjust dismantling process as required to maintain a safe and efficient workflow 3.9 Dismantle tree by sections into drop zone according to industry standards |
4. Complete tree removal activities | 4.1 Clean, check, maintain and store tools and equipment according to workplace procedures 4.2 Maintain records according to workplace procedures 4.3 Report completion of tree removal to stakeholder |
Evidence of Performance
An individual demonstrating competency must satisfy all of the elements and performance criteria in this unit.
There must be evidence that the individual has completely dismantled at least 2 trees in close proximity to structures or other assets. For each tree, the individual must have planned, communicated, prepared, conducted and completed each step of the dismantling process in the correct sequence within a timeframe expected by industry.
Each tree must be a minimum of 15 metres in height and have a minimum canopy spread of 10 metres. There must be a drop zone of no more than 4 square metres available with no access within the remaining drip line of the tree representing structures or other assets to be protected.
There must also be evidence that for each tree the individual has:
controlled the process from start to finish
devised a plan, communicated the plan and executed the plan
selected and implemented an appropriate rigging strategy and sequence including:
balancing and lifting of lateral branches
negative rigging of timber and heads
dismantled the tree safely and without damage to assets including:
selected appropriate tree components and attached rope correctly
made accurate and appropriate cuts from safe working positions
maintained constant communication with work team
There must also be evidence that the individual has:
identified workplace health, safety and environmental hazard and risks and implemented controls for the site, including:
conducted and completed a job safety analysis (JSA) or safe work method statement (SWMS)
prepared and used personal protective equipment
protected site and environmental assets
controlled vehicular and foot traffic, including erected signage, barriers, and warning devices
identified above and below ground services
identified site and tree hazards and risks, and adjusted work method or implemented control measures
assessed size, characteristics and defects of tree and determined dismantling strategy
confirmed access to emergency response resources and procedures
selected, prepared, checked and used tools and equipment for rigging and dismantling work, including:
identified working load limits of equipment components
configured compatible equipment components into appropriate rigging systems
identified force that will be applied to components in configured system during planned rigging operations
estimated mass of load and ensured force applied during rigging operations did not exceed working load limit of equipment
adjusted rigging systems as required to limit force applied to rigging system and tree structure
cleaned, inspected, maintained and stored tools and equipment according to workplace procedures
installed rigging equipment to industry standards including selected and tied the following knots:
bowline
bowline on a bight
clove hitch and two half hitches
cows hitch
Flemish bend
girth hitch
half hitch pre knot
marlinspike hitch
round turn and two half hitches
rolling hitch
running bowline
sheet bend
slippery sheet bend
timber hitch
twin bowline bend
zeppelin bend
used at least one of the following methods to safely access the tree according to dismantling method and strategy:
climbing technique
elevated work platform (EWP)
dismantled trees using rigging techniques to ensure no damage to assets, using all of the following methods:
cut and drop into designated drop zone
cut and lower using rigging and devices
step cut, hold and throw
directional felling techniques
tip lowering, butt lowering, lifting and balancing
negative rigging techniques for leaders and vertical timber
the use of multiple anchor points
floating anchor rigging (simple floating anchor or highline)
running anchor rigging ('cradle' rigging or speed line)
made accurate cuts according to industry standards, including:
making cuts from a safe and secure work position
selecting appropriate cuts for the desired outcome
accurately cutting scarfs, step cuts and back cuts.
All tree dismantling work is required to be performed according to preferred industry practices (as outlined in the Companion Volume).
Evidence of Knowledge
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:
anatomy and physiology of tree species and tree removal strategies
weather conditions and impact on planning and dismantling procedures, including the effect of wind direction and speed
site and tree hazards that might be encountered, including:
identification and evaluation of structural defects in trees
above and below ground services and effect on tree removal procedures
selection of tree removal methods for trees in close proximity to structures and other assets
methods for accessing trees for dismantling, including:
climbing techniques
elevated work platform (EWP) for tree removal
handling and using ropes for rigging and dismantling trees, including:
selecting, tying, dressing, setting and finishing arborist knots for rigging and dismantling trees
common problems and hazards with rigging and their potential consequences and solutions
dismantling techniques, including:
cut and drop
cut and lower
step cuts
directional felling
rigging techniques, including:
butt lowering, tip lowering and balancing
negative rigging techniques for leaders and trunk sections
floating anchor techniques (highlines and floating anchors)
running anchor techniques (cradle rigging and speed lines)
applying friction at the point of cut
rigging equipment selection configuration and use for tree dismantling work, including:
friction devices
pulleys, blocks, connectors and other hardware
dead-eye slings, loopie slings and whoopie slings
ropes for rigging and dismantling (tag or pulling lines)
configuration of equipment into rigging systems
impact of force, breaking strength, safety factors and cycles to failure
safe working limits on rigging and lowering equipment
calculation and estimation of tree dimensions and forces in rigging, including:
density of tree sections
methods of estimating mass of tree sections
estimation of force magnitude and direction applied during rigging operations
tree structural limitations and defects and impact on rigging and dismantling operations
ensuring force applied does not exceed working load limit of equipment components
mass dampening effect of rigging systems
methods of minimising environmental impact
preferred industry practices (as outlined in the Companion Volume) relating to dismantling of trees
legislation, regulations and local government laws governing tree removal, including:
permits and approvals
stakeholder notifications
site safety controls, including:
first aid and rescue personnel
equipment and procedures applicable to tree work
barriers and traffic control
signage and warning devices
responsibility for protecting property and assets in work areas and methods to prevent damage
considerations in developing a tree dismantling process, including:
drop zones
lowering zones
locating tools and equipment
communication requirements for tree dismantling work, including:
communicating with clients, residents and authorities
communicating with team members
coordinating and scheduling work teams
effective communication strategies during tree removal work, including the impact of:
noise
environmental conditions
communications resources
visibility
tools, equipment and resources required for dismantling trees, including:
safe use and operation
care and maintenance
cleaning and storing
inspecting equipment for signs of defects, including:
defective ropes and equipment
legal responsibility for maintaining equipment
tagging, replacing and reporting defective equipment
workplace record keeping and reporting procedures.
Assessment Conditions
Assessment of the skills in this unit of competency must take place under the following conditions:
physical conditions:
the two trees to be dismantled as stipulated in the performance evidence requirements
resources, equipment and materials:
rigging equipment
height access equipment (climbing equipment or EWP)
personal protective equipment
chainsaws
first aid and emergency response equipment
traffic management kit and signage
specifications:
workplace procedures and instructions related to dismantling trees
legislation, regulations, codes of practice and preferred industry practices (as outlined in the Companion Volume) relating to dismantling work
relationships:
work team.
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.
Foundation Skills
Skill | Description |
Writing | Accurately complete organisational documents, including job safety analysis and records, using clear language, grammar and industry terminology |
Oral communication | Clearly explain detailed information using language, tone and pace appropriate to work team when discussing rigging systems and communicating during dismantling work |
Numeracy | Interpret numerical information and calculate volume, weight and dimension of tree components when estimating the forces on rigging equipment |
Sectors
Arboriculture (ARB)