Report Types Recommended by the Institute of Australian Consulting Arboriculturists (IACA) - Discussion Paper June 2015

Members of the Institute of Australian Consulting Arboriculturists (IACA) provide written reports for their clients in the public and private sectors.  IACA members do not undertake tree pruning/removal work.

It is currently acknowledged that a more concise description and naming of the types of “Arborist Reports” should be developed to ensure that those who commission, read and assess such reports (sometimes one and the same), understand the purpose of the report.  

IACA members have developed a discussion paper which details a number of different types of arboricultural reports for different purposes. 

The aim of this Report Types document is to outline the minimum acceptable content for each report type to provide more uniformity in reports submitted.

Terminology is taken from AS4970, 2009 Protection of Trees on Development Sites and AS4373, 2007 Pruning of Amenity Trees.

Additionally, individual Councils’ “Guidelines for Preparation of Arborist’s Reports” should be referred to where applicable.  In some instances these documents may need to be qualified or amended to reflect the report titles below.

It is assumed that tree assessment and reporting is undertaken by suitably qualified (AQF Level 5 minimum) Arboriculturists (Consulting Arborists).

The report types are as follows:

  • Preliminary Tree Assessment (pre DA)
  • Arboricultural Impact Assessment (for DA)
  • Root Mapping Report
  • Development Tree Management Plan or Arboricultural Impact Management Plan
  • 5 Tree Protection Certification (during construction)
  • Tree Risk Assessment
  • Tree Assessment Report for Removal or Pruning Application
  • Tree Valuation Report
  • Tree / Landscape Maintenance and Management Report
  • Statement of Evidence
  • Others (e.g. pre-purchase tree comment)

Type 1: Preliminary Tree Assessment (Pre-Development Application)

  • Provides base arboricultural data to guide the layout of the development to maximise retention of trees with high retention value.
  • Tree Schedule to include: Tree No., Species, Common Name, DBH, Height, Spread, Vigour, Condition, ULE (or other categorisation rating), Significance, “Retainability” value, Tree Protection Zones (TPZ), Structural Root Zones (SRZ) radii and relevant comments relating to tree protection legislation for the site.
  • Includes numbering of trees and may include tagging on site based upon and verifying the Detail Survey of trees on and within 5m of the subject site. e Trees on adjoining properties must be assessed if construction is likely to be within structural rootzone or a major TPZ encroachment. If an existing tree numbering system exists this system should be used.
  • Includes a Tree Location Plan showing Tree Number, TPZ and Retention value. Tree Location Plan should preferably be in dwg format for coordination with the project architect, landscape architect and engineers.
  • Site photographs can be useful to detail streetscape / landscape character or specific tree characteristics.
  • Reports should contain the Tree Location Plan, Tree Schedule and a brief explanation of TPZ / SRZ encroachments (as per AS4970,2009) to allow for tree retention.
  • No construction impacts are reviewed at this time.

Type 2: Arboricultural Impact Assessment (AIA) (for DA)

  • The AIA should follow and incorporate the data from the Preliminary Tree Assessment.
  • Should accompany the Development Application (DA) to be lodged with the Consent Authority providing an accurate, concise assessment of likely tree retention.
  • Should reflect all construction (cut, compacted fill, trenching) reflected in the lodged DA drawings. Reports must list the Revision number of assessed drawings.
  • Should assess impact of building, infrastructure, stormwater drainage, landscape construction on the site trees. If the required drawings are unavailable, generic recommendations should be provided with notation that additional tree loss may result due to works beyond the building footprint. Recommendations to avoid further tree loss by using tree sensitive measures should be included.
  • In the case of a subdivision DA the AIA should reflect any driveway/infrastructure/building platform construction. If indicative building platforms are indicated for the proposed lots this additional tree loss should be included.
  • Trees on adjoining properties must be assessed if construction proposed within TPZs.
  • Tree Schedule to include data from the Preliminary Tree Assessment plus those trees to be retained, removed or transplanted.
  • Includes a Tree Protection Plan (drawing) clearly indicating trees retained, removed or transplanted with site-specific tree protection recommendations. The tree protection recommendations noted on the TPP should complement those contained in the body of the report. Tree Protection Plan should preferably be in dwg format for use by the project architect.
  • Site photographs can be useful to detail streetscape / landscape character or specific tree characteristics.
  • Any generic or background information should be included as Appendices. Only actual referenced material should be included.
  • The AIA may need to be updated for the Construction Certificate (more detailed) documentation.

Type 3: Root Mapping Report

  • Undertaken when construction proposed within the structural root zone (SRZ) or where warranted a major encroachment into the TPZ or where additional information is required to justify tree retention.
  • Mapping is to be non-destructive (e.g. hand excavation, air knife, ground penetrating radar) and undertaken at the proposed line of construction.
  • Report should include a scaled plan and section drawing of the trench showing chainage, depth and diameter of roots.
  • Trench should be to the full depth and at the alignment of the proposed construction or to bedrock /compacted subsoil.
  • Root Mapping Report may be appended to an AIA or form part of a tree management Plan.

Type 4: Development Tree Management Plan (TMP)

  • A TMP provides tree protection and management recommendations for the proposed construction.
  • A TMP should be site-specific and reflect the Construction Certificate (CC) drawings.
  • The tree protection recommendations contained in the AIA may need to be amended to reflect the CC drawings.
  • The recommendation should be concise and should illustrate Figures from AS4970, 2009 wherever possible.
  • Should include a drawing illustrating the tree location and areas for particular tree protection measures.

 Type 5: Tree Protection Certification (during works)

  • Prepared to meet the relevant Conditions of Consent of the DA.
  • A complete set of Conditions of Consent and the approved plans should be sought from the Applicant prior to engagement as tree protection conditions are often in different parts of the Consent.
  • Should include certification on tree protection fencing, tree removal / pruning/ transplanting, other tree protection site works or as specified.
  • Certification reports should be required at the critical construction stages (demolition, bulk earthworks, ground floor, at completion of building works and prior to Occupation Certificate).
  • Certification reports should be short concise documents with reference to approved plans and documents of relevance.

Type 6: Tree Risk Assessment

  • A specific assessment of the risks associated with a single tree or group of trees. Tree risk assessment is not tree risk management.
  • A recognised Tree Risk Assessment method (e.g. TRAQ (ISA) or QTRA (M. Ellison) should be used.
  • The assessor should be qualified in the use of the method used.
  • The Target/s, Tree Part/s and Probability of Failure must be clearly defined in producing a Risk of Harm or Tree Risk Rating
  • The scope of the risk assessment is to be clearly stated.
  • The Level of inspection (visual, basic or advanced) is to be stated.
  • Mitigation options should be concise and tree or tree group specific.
  • Works prioritisation should be included.
  • Reassessment frequency should be stated.
  • Site photographs can be useful for record keeping.

Type 7: Arborist Report to Accompany a Tree Preservation Order (TPO) Application

  • Acknowledge the relevant TPO aims, objectives, definitions and exemptions and relevant clauses of the LEP or DCP.
  • State clearly the tree owners concerns and sought works.
  • Provide an objective, balanced assessment based upon likelihood of failure, likely damage to structures or injury and impact upon landscape character of the site and locality. Also the health and condition of the tree in arboricultural terms.
  • If the hydraulic service disruptions or structural damage is believed to be caused by the tree ensure accurate evidence is obtained and appended to the report.
  • Pruning options should to be considered to avoid tree removal.
  • If internal trunk or limb defect is the sole concern then a detailed Tree Risk Assessment (see above) will be required rather than a VTA type of assessment.

Type 8: Tree Valuation Report

  • To assess the monetary amenity value of a tree or group of trees for the purposes of compensation or valuation.
  • Should be based upon the Draft Australia Standard (EV-018-00-01) or other recognized Tree Valuation Formula.
  • Should include site photographs.
  • Should only be undertaken by suitably qualified users of these recognised methods.

Type 9: Tree / Landscape Maintenance and Management Report

  • Can be unrelated to development works.
  • For on-going arboricultural maintenance of existing trees or newly planted trees.
  • Should describe the existing condition and vigour of the assessed trees to allow a benchmark for comparison. Photographic record can be useful with date indicated.
  • Should describe current maintenance practices and detail areas for improvement and schedule for such works.
  • Report should provide concise detail of recommended products and services (e.g. soil type and supplier).
  • Should reference AS4373 Pruning of Amenity Trees and AQF Level 3 qualification being the minimum for pruning.

Type 10: Statement of Evidence

  • An expert and expert’s report are to comply with the requirements of Division 2 of Pt 31 of the Uniform Civil Procedure Rules 2005 and the Expert Witness Code of Conduct (Schedule 7). This document is to be provided by the client’s solicitor.
  • The overriding role of the expert is to assist the Court.
  • Only material within one’s area of expertise should be addressed.
  • Reports should address concisely the “Letter of Brief” or the relevant Contentions in the matter.
  • Report formats will vary from Court to Court. Ensure you understand the reporting requirements prior to engagement.
  • Separating fact from opinion is essential for all legal reporting.

Type 11: Other

  • (A) Pre-purchase Tree Report. This report needs to relate to the relevant tree protection legislation relating to the property.


IACA members can be contacted on the IACA website


IACA Executive

June, 2015