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Elements and Performance Criteria
Performance Evidence
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 finishdevised a plan, communicated the plan and executed the planselected and implemented an appropriate rigging strategy and sequence including:balancing and lifting of lateral branches negative rigging of timber and headsdismantled the tree safely and without damage to assets including:selected appropriate tree components and attached rope correctlymade accurate and appropriate cuts from safe working positionsmaintained constant communication with work teamThere 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 equipmentprotected site and environmental assets controlled vehicular and foot traffic, including erected signage, barriers, and warning devicesidentified above and below ground services identified site and tree hazards and risks, and adjusted work method or implemented control measuresassessed size, characteristics and defects of tree and determined dismantling strategyconfirmed 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 componentsconfigured compatible equipment components into appropriate rigging systemsidentified force that will be applied to components in configured system during planned rigging operationsestimated 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 structurecleaned, inspected, maintained and stored tools and equipment according to workplace proceduresinstalled rigging equipment to industry standards including selected and tied the following knots:bowlinebowline on a bightclove hitch and two half hitchescows hitchFlemish bendgirth hitchhalf hitch pre knotmarlinspike hitchround turn and two half hitchesrolling hitchrunning bowlinesheet bendslippery sheet bendtimber hitchtwin bowline bendzeppelin bendused at least one of the following methods to safely access the tree according to dismantling method and strategy:climbing techniqueelevated 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 zonecut and lower using rigging and devicesstep cut, hold and throwdirectional felling techniquestip lowering, butt lowering, lifting and balancingnegative rigging techniques for leaders and vertical timberthe use of multiple anchor pointsfloating 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 positionselecting appropriate cuts for the desired outcomeaccurately 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).
Knowledge Evidence
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 strategiesweather conditions and impact on planning and dismantling procedures, including the effect of wind direction and speedsite and tree hazards that might be encountered, including:identification and evaluation of structural defects in treesabove and below ground services and effect on tree removal proceduresselection of tree removal methods for trees in close proximity to structures and other assetsmethods for accessing trees for dismantling, including:climbing techniqueselevated work platform (EWP) for tree removalhandling and using ropes for rigging and dismantling trees, including:selecting, tying, dressing, setting and finishing arborist knots for rigging and dismantling treescommon problems and hazards with rigging and their potential consequences and solutionsdismantling techniques, including:cut and dropcut and lowerstep cutsdirectional fellingrigging techniques, including:butt lowering, tip lowering and balancingnegative rigging techniques for leaders and trunk sectionsfloating anchor techniques (highlines and floating anchors)running anchor techniques (cradle rigging and speed lines)applying friction at the point of cutrigging equipment selection configuration and use for tree dismantling work, including:friction devicespulleys, blocks, connectors and other hardwaredead-eye slings, loopie slings and whoopie slingsropes for rigging and dismantling (tag or pulling lines)configuration of equipment into rigging systemsimpact of force, breaking strength, safety factors and cycles to failuresafe working limits on rigging and lowering equipmentcalculation and estimation of tree dimensions and forces in rigging, including:density of tree sectionsmethods of estimating mass of tree sectionsestimation of force magnitude and direction applied during rigging operationstree structural limitations and defects and impact on rigging and dismantling operationsensuring force applied does not exceed working load limit of equipment componentsmass dampening effect of rigging systemsmethods of minimising environmental impactpreferred industry practices (as outlined in the Companion Volume) relating to dismantling of treeslegislation, regulations and local government laws governing tree removal, including:permits and approvalsstakeholder notifications site safety controls, including:first aid and rescue personnelequipment and procedures applicable to tree workbarriers and traffic controlsignage and warning devicesresponsibility for protecting property and assets in work areas and methods to prevent damageconsiderations in developing a tree dismantling process, including:drop zoneslowering zoneslocating tools and equipmentcommunication requirements for tree dismantling work, including:communicating with clients, residents and authoritiescommunicating with team memberscoordinating and scheduling work teamseffective communication strategies during tree removal work, including the impact of:noiseenvironmental conditionscommunications resourcesvisibilitytools, equipment and resources required for dismantling trees, including:safe use and operationcare and maintenancecleaning and storinginspecting equipment for signs of defects, including:defective ropes and equipmentlegal responsibility for maintaining equipmenttagging, replacing and reporting defective equipmentworkplace record keeping and reporting procedures.