AS 4970 - 2009 'Protection of trees on development sites'
A consulting Arborist takes 4 1/2 years of training which include 2 years of Diploma education to become qualified to competent standard of Level 5 in this field that allows expert advice to be given in accordance to the above standard.
With highly trained and qualified experience the consulting arborist is able to take more time in assessing the
Tree's Encroachment Area
(buildings, service lines, pathways, roads, development sites),
Health, Structure, Origin, Height and Width, Tree Root Protection (TPZ).
General Required Amenity Pruning
After a quick Visual Tree Assessment (VTA) a Condition Report is then process able and can be presented on one page and the same day (This can only be done for a single tree, will also determine the ability of the tree and its habit for the urban growth).
(*Note if an indigenous tree is determined through the origin status a request for the tree to be placed under the protection of Heritage List Protection this provides a higher evaluation of the property or land calculated area of property. Most people ignore this recommendation as council or government overlays are suggested automatic listings and profits of evaluation maybe be given to the wrong parties involved (Councils, Government, Developers, Sellers). Property evaluations must include a vegetation status which includes origin and habit, with out this assessment compromises to carbon emissions and the Useful Life Expectancy (ULE); 0 to 5 years causes death or removal these would clash with urban development planning presenting a requirement of three (3) tree replacements for one (1) tree removal)
Assessment for developments
After a Condition Report further assessments can be requested either by the Consulting Arborist or by the Tree Owner, Developer or Governing Body supplying permission for work required or development within the immediate area of the tree. These are considered Risk Assessments using data sequences that require a Risk Matrix (this measures the value of risk through consequence of targets causing injury or death within the target zone. Targets and target zones are rated through high or low value of static (buildings) mobile (pedestrians or vehicles) or immobile (roads, paths, drains).
Once determining a Risk Assessment further Specialist Advice can be applied this may consider the use of computerized data information known as the Tomograph (Digitized picture view of the consistency of wood and/or existing decay and extent of decay using around 12 or more sound devices around the effected area of the trunk or just generally around the Diameter at Brest Height (DBH) 1.4 m from the tree base. A Resistograph is then provided to enable the analysis of the resistance of wood and/or existing decay in the affected area using a 4" drill bit with a maximum depth of 35 cm, providing analysis of 4 or more test drills normally at compass reading positions.
A Maintenance Report may then be applied to this Risk Assessment as a recommendation and review or can be given separately to provided the work required following data information from the Risk Assessment and Specialist Advice and provide the skill level required for the maintenance of work required using AS 4373 - 2007 "Amenity Tree Pruning" no less than Level III.
Generally a Risk Assessment and Specialist Advice may not be given if through the VTA observes obvious damage or severity of cause of injury or death is immediate a Maintenance Report can be given right away for work required to be given a permit to commence)
All of these assessments will then be a guide-lines for recommendations that the Consulting Arborist is able to consider what should be required and what must be required of the Commercial Arborist when practicable or as soon as practicable (or known as the Project Arborist)
For an analysis of more than two (2) trees aTree Survey can be requested by the Tree Owner, Developer or Governing Body supplying permission for work required or development within the immediate area of the tree.
Further assessments may be needed or requested by either the Tree Owner, Developer, or Governing Body supplying permission for work required or development within the immediate area of the tree which is given through the above standards and calculated as the Structural Tree Zone (SRZ) or Critical Tree Zone (CRZ), this area determines the immediate area for tree protection which then allows the calculated standard for Tree Root Protection (TPZ), this then is considered the encroachment area is no less than 10%.
After a Tree Survey, an Impact on Development Statement is required. This will give the guidelines for the encroachment areas the tree will have on the development, according to AS 4970 - 2009 any encroachment that exceeds 10% has significant concern for the protection of the tree. TPZ are measured and the percentage of encroachment is recorded, with a brief review of action.
Final report is called the Tree Maintenanace Report that will included the work carried out by a Project Arborist(Commercial Arborist) qualified with no less than Certificate Level III who has the competent standards to carry out works required according to AS 4373 - 2007 'Amenity of Trees. The consulting arborist will then given written guidelines for recommendations such as:
- Ground protection
- Protective Fencing
- Amenity pruning
- Further Specialist Advice
- Or removal with a recommendation for replacement or relocation
Removals will be the first work carried out by the Project Arborist who will then mark the stumps after the tree has been removed. The Developer will then contact the Consulting Arborist as request by the Consulting Arborist to inspect that the trees have been safely removed and that only natural elements of urban life has given the tree existence, as decay and hollows could causes soil contamination or show signs of termite pests that would need further treatment of a larger area. Once approved the Amenity Pruning can then proceed carried out by the Project Arborist. Another inspection is then carried out before the Developer can commence excavation and construction. Recommendations for continued inspections need to be addressed by the Consulting Arborist having the Developer request contact for further required works or in cases of damage of trees from development stages, storms or fires.
Further Assessments and Contributions
Councils' and Shires' will have what they call planning overlays on site planning. These will included:
- Heritage Overlays
- Aboriginal conservation
Works required will need a Tree Permit, an assessment carried out by a Consulting Arborist who will establish the origin and species of the tree or trees. Health, structure, pest and disease are also recorded recommending that a Project Arborist (Commercial Arborist) will carry out the recommendations according to AS 4373 2007 'Amenity Pruning' Some councils do not require a Tree Permit.
Contracts and Tenders the Consulting Arborist is also qualified to write contracts and tenders for Project Arborists required by Councils, Commercial Companies or investors. Contract and Tenders are written approvals for extensions of works carried out over a period of time this includes statements and proof of:
- Cover Letter
- Business profile
- Previous work history
- Current work history
- Cost and pricing (proven break down of employees and equipment)
- Employee qualification
- OHS establishment
- Environmental planning and protection strategies
- Sub contracting
The Consulting Arborist will piece the contract or tender together proving the Arborist company requiring the contract or tender has the available information to submit to the provider.
Court witness a Consulting Arborist can also become a witness to any developing disputes between councils and developers. The Consulting Arborist will then provide qualifications of recommendations through the assessments practices to allow the courts or VCAT to make a decision over the development.
Without proper consultation, guidelines for safe practices and regulated standards will continue seeing populations of trees like the ones viewed on Cranbourne, Victoria, AU 27.02.2010 (18:04:53) all due to urban planning and development that is not yet properly regulated