AS 4970-2009

1 - AS 4970-2009 PROTECTION OF TREES ON DEVELOPMENT SITES
4 - PREFACE
5 - CONTENTS
6 - FOREWORD
7 - SECTION 1 SCOPE AND GENERAL
7 - 1.1 SCOPE
7 - 1.2 APPLICATION
7 - 1.3 REFERENCED DOCUMENTS
7 - 1.4 DEFINITIONS
7 - 1.4.1 Determining authority
7 - 1.4.2 Development
8 - 1.4.3 Diameter at breast height (DBH)
8 - 1.4.4 Project arborist
8 - 1.4.5 Structural root zone (SRZ)
8 - 1.4.6 Tree
8 - 1.4.7 Tree protection zone (TPZ)
8 - 1.4.8 Vigour
8 - 1.4.9 Work
9 - SECTION 2 PLANNING AND THE TREE MANAGEMENT PROCESS
9 - 2.1 TREE MANAGEMENT PROCESS
9 - 2.2 DETERMINING AUTHORITIES
10 - 2.3 PLANNING
10 - 2.3.1 Site survey
11 - 2.3.2 Preliminary tree assessment
11 - 2.3.3 Preliminary arboricultural report
12 - 2.3.4 Development design and review
12 - 2.3.5 Arboricultural impact assessment
13 - SECTION 3 DETERMINING THE PROTECTION ZONES OF THE SELECTED TREES
13 - 3.1 TREE PROTECTION ZONE (TPZ)
13 - 3.2 DETERMINING THE TPZ
13 - 3.3 VARIATIONS TO THE TPZ
13 - 3.3.1 General
13 - 3.3.2 Minor encroachment
13 - 3.3.3 Major encroachment
14 - 3.3.4 TPZ encroachment considerations
14 - 3.3.5 Structural root zone (SRZ)
15 - 3.3.6 Crown protection
17 - SECTION 4 TREE PROTECTION MEASURES
17 - 4.1 GENERAL
17 - 4.2 ACTIVITIES RESTRICTED WITHIN THE TPZ
17 - 4.3 PROTECTIVE FENCING
18 - 4.4 SIGNS
18 - 4.5 OTHER TREE PROTECTION MEASURES
18 - 4.5.1 General
19 - 4.5.2 Trunk and branch protection
19 - 4.5.3 Ground protection
20 - 4.5.4 Root protection during works within the TPZ
20 - 4.5.5 Installing underground services within TPZ
20 - 4.5.6 Scaffolding
21 - 4.6 MAINTAINING THE TPZ
21 - 4.6.1 Mulching
21 - 4.6.2 Watering
21 - 4.6.3 Weed removal
22 - SECTION 5 MONITORING AND CERTIFICATION
22 - 5.1 GENERAL
22 - 5.2 TREE PROTECTION PLAN
22 - 5.3 PRE-CONSTRUCTION
22 - 5.3.1 Tree removal and pruning
22 - 5.3.2 Installing tree protection fencing and other protection measures
22 - 5.4 CONSTRUCTION STAGE
22 - 5.4.1 General
23 - 5.4.2 Site establishment
23 - 5.4.3 Construction work
23 - 5.4.4 Landscape works
23 - 5.4.5 Practical completion
23 - 5.5 POST-CONSTRUCTION
23 - 5.5.1 Defects liability period
23 - 5.5.2 Final certification
25 - APPENDIX A - DIAMETER AT BREAST HEIGHT (DBH)
26 - APPENDIX B - POTENTIAL DAMAGE TO TREES ON DEVELOPMENT SITES
26 - B1 INTRODUCTION
26 - B2 BACKGROUND BIOLOGY
26 - B2.1 General
26 - B2.2 Leaves
26 - B2.3 Trunks and branches
26 - B2.4 Roots
28 - B3 EFFECTS OF DEVELOPMENT ON TREES
28 - B3.1 General
28 - B3.2 Crown damage
28 - B3.3 Trunk damage
28 - B3.4 Root damage
29 - B4 CONCLUSIONS
30 - APPENDIX C - TREE PROTECTION ZONE SIGN EXAMPLE
31 - APPENDIX D - ENCROACHMENT INTO TREE PROTECTION ZONE
32 - APPENDIX E - BIBLIOGRAPHY

Provides guidance on the principles for protecting trees on land subject to development.

This Standard provides guidance on the principles for protecting trees on land subject to development. It follows, in sequence, the stages of development from planning to implementation.This Standard aims to assist those concerned with trees in relation to development. Where development is to occur, the Standard provides guidance on how to decide which trees are appropriate for retention, and on the means of protecting those trees during construction work. It does not argue for or against development, or for the removal or retention of trees nor does it consider the monetary value of trees. The Standard does not apply to the establishment of new trees.

First published as AS 4970-2009.
Reconfirmed 2020. First published as AS 4970-2009. Reissued incorporating Amendment No. 1 (March 2010).