1-yaralla street camphor laurels revised issue b 4 11 14.docx

Yaralla Street, Concord West

Proposed removal and replacement of

camphor laurel street trees

Statement of Environmental Effects

Statement of Heritage Impact

& Aboricultural Report

ISSUE B: 4 November 2014

City of Canada Bay

Prepared by

LandArc Pty Limited Landscape, Environmental and Heritage Consultants

2 Edwin Avenue Avalon NSW 2107

T: 0411 215 721

www.landarc.com.au

YARALLA STREET STATEMENTS OF ENVIRONMENTAL EFFECTS + HERITAGE IMPACT 2 City of Canada Bay ISSUE B (4 November 2014) LandArc Pty Limited

CONTROLLED DOCUMENT

DRAFT ISSUE B: 4 November 2014

Statement of Environmental Effects

Statement of Heritage Impact

Arboricultural Report

Proposed removal and replacement of camphor laurels in

Yaralla Street, Concord West

Prepared by:

L A N D A R C

Landscape, Environmental and Heritage Consultants

2 Edwin Avenue Avalon NSW 2107 W: www.landarc.com.au

E: [email protected]

T: 0411 215 721

http://www.landarc.com.au/mailto:[email protected]


Contents

PART 1: REPORT 6

Proposed removal and replacement of heritage trees:

Camphor laurels Yaralla Street, Concord West

1.0 Introduction 6

Overview 6

Objectives 8

Report format 8

Camphor laurel (Cinnamomum camphora) 9

Historic context and management realities 9

Tree management policy 10

Tree preservation order policy 10

Asset management policy 10

Managing heritage trees whole-of-life-cycle approach 10

2.0 Physical Description & Arboricultural Report 11

Yaralla Street location and site description 11

Land uses and heritage significance 11

Description of road reserve and plantation 13

Landscape character statement 13

Site investigation 14

Tree management history 16

Typical patterns of growth in mature camphor laurels 16

Historic pollarding of street trees 18

Recent pruning history and management 18

Alignment pruning for adjacent powerlines and properties 19

Tree assessment 19

Summary of key findings 23

3.0 Heritage Significance 24

Overview 24

Legislative framework 24

Local Heritage Significance 24

Heritage Conservation Areas 25

Heritage items 25

Historic development 25

Street trees heritage significance 28

Development consent 28


Camphor laurels Inter-war period plantation (c.1930) 28

Why is heritage significance threatened? 31

Key processes affecting integrity and intactness 31

4.0 Minimising Heritage Impacts 32

Management realities 32

Current intervention strategies to minimise damage 32

How can we manage change in this context? 33

Key recommendations 33

A. Phased replacement strategy 33

B. Suitable replacement tree species 33

C. Structural soils and deep root barrier 33

D. Aerial bundling and cabling (ABC) 34

Proposed phasing strategy for tree replacements 34

Selection criteria heritage landscapes 35

Minimising the impact of replacement tree species 37

Recommended tree species 37

Is brush box a suitable option for replacement planting? 38

Tree sourcing, soil preparation and establishment 39

Sourcing appropriate trees nursery procurement 39

Site preparation, asset protection and establishment 39

Minimising impacts and maximising benefits 40

References 41

Appendix (list of nursery suppliers and stock availability) 46

List of Figures:

FIGURE 1: Location Plan & Heritage Context Yaralla Street 12

FIGURE 2: Yaralla Street Heritage item (521) 12

FIGURE 3: Yaralla Street Landscape context 14

FIGURE 4: Location of camphor laurels (Items D1-D13) and brush box 16

FIGURE 5: Camphor laurels Yaralla Street (1943) 27

FIGURE 6: Camphor laurels Yaralla Street (2012) 27

List of Tables:

TABLE 1 Inventory of street trees in road carriageway 15

TABLE 2 Schedule of camphor laurel street trees 20

TABLE 3 Schedule of heritage items Yaralla Street, Concord West 26

TABLE 4 Phasing strategy: replacement of camphor laurels 35

TABLE A1 Heritage significance of camphor laurels (SHR criteria) 59


PART 2: ANNEXURES 47

SCHEDULE 1 Statement of Environmental Effects 48

Introduction 48

What is a Statement of Environmental Effects? 48

How identified 49

Camphor laurels current status 49

Current impacts retaining the status quo 49

Intervention strategies 50

Tree removal and replacement options 50

How would phased removal and replacement affect key values? 50

Proposed tree removal and replacement strategy 51

Steps taken to protect the environment or to lessen expected harm 52

Visual and aesthetic character 52

Heritage 53

Economic 54

Environmental 54

SCHEDULE 2 Statement of Heritage Impact 56

What is a Statement of Heritage Impact? 56

Summary of Heritage Significance 57

Heritage items 57

Heritage significance of street tree plantation 57

Current issues and impacts caused by the camphor laurels 58

Proposed tree removal and replacement strategy 60

Positive Benefits of Proposal 60

Potential Detrimental Impacts 61

Recommendations: Minimising Heritage Impacts 61

Phased tree replacement strategy 62

Sourcing appropriate trees nursery procurement 62

Site preliminaries 63

Site preparation, asset protection and establishment 63

Aerial bundling and cabling (ABC) option 64


PART 1:

1.0 Introduction

Overview

The following report is the fourth in a series of six reports (including an

Arboricultural Report and Statements of Environmental Effects and Heritage

Impact) for the City of Canada Bay. These reports aim to examine the heritage

significance of six street tree plantations of camphor laurels (Cinnamomum

camphora), to assess potential impacts of proposed actions and to review options

to mitigate any negative impacts with respect to these trees in the following priority

locations.

1. Tranmere Street, Drummoyne;

2. Wrights Road, Drummoyne;

3. Tavistock Street, Drummoyne;

4. Yaralla Street, Concord West;

5. Burwood Rd, Concord (Crane St - Duke Ave);

6. Renwick Street, Drummoyne.

Many of these camphor laurels are located within Heritage Conservation Areas (i.e.

development consent is required) including:

a) Bourketown Conservation Area;

b) Drummoyne Park Conservation Area;

c) Drummoyne Avenue East Conservation Area;

d) Marlborough and Tavistock Streets Conservation Area; and

e) Birkenhead and Dawson Estates Conservation Area.

Three of the plantations within the road reserves are scheduled as heritage items

in Councils LEP including:

a) Wrights Road, Drummoyne (item 510);

b) Burwood Rd, Concord (Crane St - Duke Ave) (Item 56); and

c) Yaralla Street, Concord West (Item 521).

The six reports aim to assist Council in assessing Development Applications for

proposed phased removal and replacement of camphor laurels in these locations.

The camphor laurel is a significant historic and thematic component of many of the


streetscapes of Sydneys metropolitan area, including the City of Canada Bay.

Councils asset management data base identifies over 400 mature camphor laurels

planted as public street trees. These trees represent an ageing population dating

from the Inter-war period (c.1915-1940).

Street trees are an important community asset providing environmental, health,

social and economic benefits. These trees are important contextual elements

defining the landscape setting, aesthetic and visual character of our urban

streetscapes. In cities around the world street trees are recognised for their

valuable contribution to health, wellbeing and liveability.

The camphor laurel (Cinnamomum camphora) however poses many challenges for

heritage conservation and management within this highly urbanised context. This

species is now widely considered an undesirable street tree due to its vigorous and

robust growth habit, invasive root system and status as an environmental weed. A

number of local government areas, including some within the Sydney metropolitan

area, have declared the camphor laurel a noxious weed species. Others have

provided exemptions under existing Tree Preservation Orders (e.g. Woollahra

Council exempts camphor laurels up to ten metres in height). The Council of the

City of Canada Bay is seeking to review the whole-of-life-cycle successional

management of this ageing population of camphor laurel street trees, particularly

within the broader context of environmental, social and economic sustainability.

LandArc has been commissioned by the City of Canada Bay to prepare separate

reports examining the proposed staged removal and replacement of mature

camphor laurels (Cinnamomum camphora) in these locations. This report refers

only to the camphor laurel street trees in Yaralla Street, Concord West.

Under the provisions of Council's Environmental Planning Instruments (EPIs)

Council cannot grant consent to a development application involving a heritage

item or certain development in a conservation area without considering how the

development would impact on the heritage significance of the heritage item or of

the conservation area. In accordance with the Canada Bay Local Environmental

Plan 2013 (LEP 2013) if proposed works involve the pruning or removal of a tree

that is or forms part of a Heritage Item or is within a Heritage Conservation Area,

then development consent is required.


Objectives

Councils brief identifies the following objectives for this study:

a) Plan of the proposed trees to be retained or removed including

recommended conservation and management policies/ guidelines (i.e.

actions to prolong life and improved condition of the subject trees, if

deemed to be retained;

b) Statement of Environmental Effects for the planned removals, if proposed;

c) Statement of Heritage Impact (SOHI);

d) An Arborist Report, including an assessment of Statement of Significance

(incl. but not limited to age, condition, etc.);

e) Address questions raised by public submission during the Development

Application period;

f) Addressing options for tree(s) replacement, either partially or as a group

(e.g. a scheme for inter-planting or replanting) and assessment of planting

in adjacent streets;

g) Recommendation on other appropriate species; and

h) Recommendation for the staged removal/ replacement of trees will need to

consider grouping the trees to permit a cost-effective restoration of civil

infrastructure (i.e. grouping adjacent trees where possible).

This report aims to clearly articulate the issues and to establish a rationale for

whole-of-life-cycle management of these heritage trees. It aims to build community

engagement and a capacity for change through broader ownership of the actions,

decisions and shared responsibility.

Report format

This report is divided into Part 1: Key Report (sections 1-4) and Annexure (sections

5-6) as follows:

Part 1: Key Report

1. Introduction;

2. Physical description and arboricultural report;

3. Establishing the basis for heritage significance;

4. Review of options and recommendations for minimising heritage impact.

Annexure:

5. Statement of Environmental Effects (SEE);

6. Statement of Heritage Impact (SOHI).


Part 1: Key Report (sections 1-4) examines the physical, cultural and historic

context of these street trees, their current condition and status, arboricultural

management history, key issues and threats. This report establishes the basis for

assessing the heritage significance of these trees and issues affecting their

conservation and long term sustainability. Recommendations including measures

to mitigate potential negative impacts are provided in PART 1 (section 4.0).

ANNEXURE (Item 5): Statement of Environmental Effects (SEE) summarises the

reports findings with respect to environmental impacts of the proposal, how the

impacts have been identified and steps taken to protect the environment or to

lessen the expected harm to the environment.

ANNEXURE (Item 6): Statement of Heritage Impact (SOHI) firstly establishes why

the items are of heritage significance, secondly, what impact(s), if any, the

proposed works would have on significance, thirdly, what measures are proposed

to mitigate any potential negative impacts and finally, how effective would

alternative(s)/ options be in providing a more sympathetic solution if applicable.

Camphor laurel (Cinnamomum camphora)

Historic context and management realities

The camphor laurel (Cinnamomum camphora), a member of the Lauraceae family,

is an exotic broad-leaf evergreen tree species introduced to Australia during the

early nineteenth century. This ornamental shade tree proved extremely hardy,

robust and adaptable displaying exceptional vigour and durability under drought

conditions and resistance to insect pests and disease. During the 1920s-1940s this

tree became one of Sydneys most favoured species for street tree planting.

As the camphor laurels have matured many of the positive benefits have been

increasingly outweighed by a host of negative factors. This species has exceptional

vigour and a robust growth habit including buttressing, basal raised surface roots

and an extensive shallow root system. Many of these street trees cause significant

damage to public urban infrastructure such as road pavements, kerbs, guttering

and footpaths as well as adjoining private property (including built heritage fabric).

The associated public risk management issues tend to increase over time creating

an ongoing negative impact on local government resources. Furthermore, the

camphor laurels propensity for self-germination and establishment may lead to

competition and exclusion of other more desirable plants, particularly remnant

native species in fragmented bushland. Although considered an environmental

weed species in the City of Canada Bay, camphor laurel has not been declared a

noxious weed species under the Noxious Weeds Act 1993.


Tree Management Policy

Tree preservation order policy

The City of Canada Bay Tree Preservation Order Policy (2006) identifies camphor

laurel (Cinnamomum camphora) as one of a number of targeted exotic tree

species which should be replaced with a more suitable native species. Exemptions

to the Tree Preservation Order may apply for camphor laurels however the City of

Canada Bay Development Control Plan (DCP) Item 3.8 Preservation of trees and

vegetation states that if the tree is or forms part of a Heritage item or is within a

Heritage Conservation Area, then development consent is required. For further

information on exemptions refer to Councils Tree Preservation Order Policy.

Asset management policy

The importance of conserving significant streetscapes is outlined in City of Canada

Bay Asset Management Policy 2010. Council must ensure that public assets are

managed in a way which is acceptable to the community in terms of financial

burden, safety, quality, impact on the environment, meeting needs and Councils

ability to fund those works (City of Canada Bay, 2010, p.7). The DCP highlights

the need for a coordinated approach to assessment and management of trees and

identifies criteria where a permit or development consent for removal of tree(s) may

be granted including the following:

The tree is a poor specimen and is in decline or inappropriate for the

location;

The tree has caused significant structural damage and supporting

documentation is provided;

It can be demonstrated that there is an ongoing problem with the tree and

no other course of action will rectify the problem (DCP, p.37).

A more detailed discussion of Councils tree policy and issues is contained in the

Tranmere Street report (Report No.1 of 6).

Managing heritage trees a whole-of-life-cycle approach

Tree removal and replacement programs, particularly with regard to heritage trees,

involve considerable change for a community. Trees, like all living things, are

subject to life-cycle processes. The City of Canada Bay has the responsibility of

managing these complex issues and developing a sustainable tree management

strategy. To ensure continuity and renewal it is important to establish a whole-of-

life-cycle planning and management approach.


2.0 Physical Description &

Aboricultural Report

Yaralla Street location and site description

Yaralla Street lies between Queen Street and Nullawarra Avenue. The avenue of

mature camphor laurels (Cinnamomum camphora) is located between Concord

Road (eastern boundary) and Queen Street (western boundary). See Figure 1:

Location Plan and Heritage Context. This portion of Yaralla Street is approximately

310 metres in length and has an east-west alignment. Intersections occur at

Concord Road, Mackenzie Street, Consett Street and Queen Street. Warbrick Park

is located at the eastern end of the study area, between Concord Road and

Mackenzie Street.

In comparison to the streets reviewed in Drummoyne (see camphor laurel reports

for Tranmere Street, Wrights Road and Tavistock Street), Yaralla Street, Concord

West is distinctive in having street trees planted within the carriageway (i.e. road

pavement rather than public verge). In addition, this sites soils are derived from

Wianamatta Group shales rather than Hawkesbury sandstone. Typically, the soils

on the lower slopes and flats are comprised of relatively deep yellow podzolic soils

overlying red and brown podzolic soils of low fertility and poor drainage. Soil

profiles range from brownish-black friable loam to clay loam (topsoil A1 horizon,

pH 5.5-7.0) to hard-setting brown clay loam and strongly pedal, mottled brown clay

(subsoil B horizon, pH 4.5-6.5) (Sydney Soil Landscape Series Map Sheet

9130 4th Ed.). The soil profiles within the road carriageway are highly compacted.

Mean annual rainfall (Concord Golf Club) is 1135.5mm. Rainfall can be extremely

variable (e.g. rainfall recorded to end of June 2014 is only 275.6mm) (Bureau of

Meteorology, 2014). These physical factors are important in selecting replacement

tree species (see discussion in 4.0 Minimising Heritage Impacts).

Land uses and heritage significance

Land use is a mix of low density and medium density residential (zoned R2 and R3

respectively, LEP 2013). Warbrick Park is zoned public recreation (RE1, LEP

2013). This portion of Yaralla Street retains a number of early free-standing Inter-

war period houses. Many of these houses however have been significantly

modified, impacting upon overall homogeneity and consistency of scale and

materials. Yaralla Street retains a mature and predominantly single species avenue

of camphor laurels (Cinnamomum camphora) dating from the Inter-war period.


FIGURE 1: Location plan & heritage context

Base Map Source: LEP 2013 Heritage Maps 002 (4/07/2014)

FIGURE 2: Yaralla Street Heritage item (521)

Base Map Source: LEP 2013 Heritage Maps 002 (4/07/2014)


Although Yaralla Street is not located within a Conservation Area the street trees,

including more recent planting east of Concord Street (e.g. Liquidambars), have a

local heritage listing (Item 521). Warbrick Park is also heritage listed (item 520).

See Figure 2: Yaralla Street Heritage Item.

Description of road reserve and plantation

Yaralla Street has a sealed bitumen carriageway, kerb and guttering and public

verges including a mown grass nature strip and concrete footpath adjacent to

property boundaries. Public verges are approximately 3550mm wide with a narrow

(800mm wide) central concrete pathway. The street trees are planted within the

bitumen carriageway in a formal grid pattern. Thirteen (13) camphor laurels

(Cinnamomum camphora) and two (2) brush box (Lophostemon confertus) have

been retained in the plantation. All of these trees have a set-back of 1750-1800mm

(tree centreline) from kerb-line (i.e. set approximately 9.5 metres apart).

Overhead powerlines are located along the northern verge. Due to the off-set

locations of trees within the road carriageway, overhead power-lines only partially

affect canopies. Nevertheless, alignment pruning still has a significant impact on

form, balance and integrity of all trees located adjacent to the northern verge.

Street trees are also subject to alignment pruning (i.e. low canopies/ lateral

branching affecting adjoining residences, light poles, wires to individual houses,

sub-stations, etc.). Most of the camphor laurels are causing significant damage to

the road surface, kerb and guttering, crossings and service infrastructure). Public

footpaths and private property (e.g. walls, paving, etc.) are less affected by tree

root damage. See Tree Management History.

Landscape character statement

The landscape setting and streetscape character of this portion of Yaralla Street is

largely defined by an Inter-war period plantation of camphor laurels. These mature

trees create a memorable landscape setting. Eleven (11) camphor laurels and two

(2) brush box are located between Concord Road and Consett Street. Here, the

trees retain a formal grid-pattern with interlocking canopies over the carriageway.

Two (2) remaining camphor laurels are located between Consett Street and Queen

Street adjacent to the northern verge. Together these trees are considered to have

high local significance in terms of their contribution to the visual and aesthetic

character of this streetscape. Furthermore, these trees provide visual continuity

with mixed planting and landscaping within Warbrick Park. See Figure 3: Yaralla

Street Landscape Context. This portion of Yaralla Street has no recent additional

or infill planting. No remnant native species are present.


FIGURE 3: Yaralla Street Landscape context

Base Map Source: Nearmap aerial photomap (23/01/2014)

The camphor laurels in Yaralla Street represent an ageing group of trees of

substantial scale and visual integrity. All of the trees have a long history of

pollarding and more than half the plantation is subject to ongoing alignment

pruning for overhead powerlines (see following discussion). The camphor laurels

were planted during the Inter-war period (possibly c.1930). The 1943 (SixLite)

aerial photo image displays a distinctive grid pattern and formal avenue treatment

of twenty-three trees in this portion of Yaralla Street. The two brush box trees,

located within the camphor laurel plantation, are believed to be part of the original

plantation or possibly Post-war period replacements. In adjacent streets,

Mackenzie Street and northern end of Consett Street retain significant single

species avenue plantations of brush box which also date from the Inter-war period.

The formal grid-pattern layout of these avenues has been retained and together

with Yaralla Street they demonstrate the importance placed on civic design and

embellishment of local streetscapes during the early twentieth century.

Site Investigation

The site inspections conducted on 3/07/2014 and 17/07/2014 included a visual tree

assessment at ground level. Data collected included measurement of canopy and

trunk diameters (DBH measured at 1.4m HT) and an estimate of tree heights.


Presence and extent of buttressing and surface roots, general condition, health,

vigour, canopy density values, pruning history, presence of cavities and crown

dead wood, key issues and threats were also recorded. No aerial inspections, root

mapping or woody tissue testing has been conducted. Details of location within the

road carriageway, verge/ footpath widths, kerb and driveway locations, walls,

building alignments, materials, services (including pit covers/ grates and overhead

power-lines), trip hazards and damage to adjacent property were noted. See Table

1: Yaralla Street Inventory of street trees in road carriageway and Figure 4:

Location of camphor laurels (Items D1-D13) and brush box.

TABLE 1:

Yaralla Street Inventory of street trees in road carriageway

ITEM ADJACENT

VERGE

LOCATION/ DESCRIPTION HERITAGE

LISTING

Concord Road to Mackenzie Street intersections

D1 northern Adj. to south-eastern cnr. Warbrick Park YES

D2 southern Adj. to No.244 Concord Rd/ entry driveway YES

#1 bb northern Adj. to southern edge of. Warbrick Park YES

D3 southern Adj. to No.63 Mackenzie St (opp. brush box) YES

D4 northern Adj. to south-western cnr. Warbrick Park YES

D5 southern Adj. to No.63 Mackenzie St (front garden) YES

Mackenzie Street to Consett Street intersections

D6 northern Adj. to No.64 Mackenzie St (front garden) YES

D7 southern Adj. to No.62 Mackenzie St (front garden) YES

D8 northern Adj. to No.64 Mackenzie St (opp. brush box) YES

#2 bb southern Adj. to No.6 Yaralla Street YES

D9 northern Adj. to rear boundary No.63 Consett Street YES

D10 southern Adj. to No.67 Consett St (rear garden) YES

D11 southern Adj. to No.67 Consett St (front garden) YES

Consett Street to Queen Street intersections

D12 northern Adj. to No.66 Consett Street/ entry driveway YES

D13 northern Adj. to No.87A Yaralla Street YES

NOTES:

ITEM: Item numbers D1, D2, D3 refer to camphor laurels only. # refers to brush box.

HERITAGE LISTING: All street trees in Yaralla Street are listed as a heritage item (521).


FIGURE 4:

Location of camphor laurels (Items D1-D13) and brush box BASE MAP SOURCE: NSW GLOBE (GOOGLE EARTH)

Tree Management History

Typical patterns of growth in mature camphor laurels

The mature camphor laurel (Cinnamomum camphora) plantation [Items D1-D13] in

Yaralla Street range in height (14-20 metres), canopy width (12-22 metres) and

trunk diameter (850-1600mm DBH). Most of the camphor laurels in this plantation

have significantly larger dimensions compared to the trees documented in previous

reports for Tranmere Street, Wrights Road and Tavistock Street. For example, ten

trees are 16 metres or greater in height and five trees have a canopy diameter

equal or greater than 20 metres. More than half of these trees display some degree

of buttressing. Basal coppicing may also occur where the tree has suffered

physical damage or large roots have been cut or damaged.

Typically, these trees develop massive surface roots around their bases leading to

deformation of the bitumen road surface and creation of localised hummocks

within the roadway. This raised basal area extends longitudinally (i.e. parallel with

roadway) up to 4.0-8.0 metres in length and up to 300mm above finished road

levels. Sub-surface roots typically extend well beyond the canopy drip-line.


PHOTO 1: Camphor laurel [Item D1] adj. to Warbrick Park -

Deformation to road surface by surface roots (3/07/2014)

PHOTO 2: Camphor laurel [Item D4] on corner Mackenzie Street -

Extensive root damage to road surface, kerb and gutter (3/07/2014)

PHOTO 3: Camphor laurel [Item D5] adj. to 63 Mackenzie Street -

Uplifted road pavement by raised surface roots (3/07/2014)


Tree root damage includes extensive deformation of bitumen road surface, uplifting

of concrete kerbing, guttering, footpaths and crossings and damage to drainage

pits/ grates and underground services. Public safety may also be compromised by

uneven surfaces and trip-points.

PHOTO 4: Camphor laurel [Item D8] adj. to 64 Mackenzie Street -

Raised bitumen hummock due to basal surface roots (3/07/2014)

Historic pollarding of street trees

These camphor laurels share a similar pruning history to those in Tavistock Street,

Wrights Road, Tranmere Street and other early twentieth century camphor laurel

plantations in Concord and Drummoyne. All these street trees have a history of

pollarding (i.e. regular pruning back to a pre-determined point encouraging callous

formation). The camphor laurels in Yaralla Street typically have a single trunk to

approx. 1.5-1.8 metres in height (above adjacent road level) and multi-stemmed

regrowth above this point. For a detailed description of pruning history refer to

previous reports Tranmere Street and Wrights Road.

Recent pruning history and management

The current management regime aims to promote a more natural form without

excessive pruning. This approach enables these trees to achieve far greater

dimensions and scale within the streetscape. Such opportunities may allow avenue

plantations to develop inter-locking canopies over the roadway and streetscapes of

high visual quality and amenity. It also promotes a multi-stemmed, vertically

exaggerated form in this species with a varying level of lateral branching in the

mid- to upper canopy. For further details refer to previous reports Tranmere

Street and Wrights Road. In Yaralla Street, this form has been further encouraged

by heavy alignment pruning for adjacent powerlines along the northern verge.


Alignment pruning for adjacent powerlines and properties

Of a total of thirteen (13) camphor laurels in this plantation, the seven (7) located

along the northern verge are impacted by ongoing alignment pruning for overhead

powerlines. Typically, the lower to mid-canopy (northern side) of these trees is

removed to comply with minimal clearance requirements. This action affects overall

form, balance and visual integrity of the trees, particularly when viewed from the

footpath on the northern verge or from Warbrick Park. A brush box specimen

(opposite D3) is heavily impacted by this pruning regime.

Aerial bundling and cabling (ABC) is minimal.

This strategy however would reduce the

amount of pruning necessary to maintain

clearances whilst providing opportunities to

promote visual continuity within the

streetscape. This action would deliver

significant benefits for a new replacement

planting strategy.

PHOTO 5: Camphor laurels [Items D12 background &

D13 foreground] alignment pruning for overhead

powerlines impacts form, balance and integrity of all

trees along the northern verge (3/07/2014)

Property alignment pruning is a further management issue affecting these trees.

Camphor laurel (Item D10 southern verge) has been heavily pruned adjacent to

property boundary No.67 Consett Street (Yaralla Street frontage). Approximately

50% of the trees canopy has been removed.

Tree Assessment

The camphor laurels in this plantation generally display good health, condition and

vigour for this age cohort. Most of the trees have relatively dense crowns with low

levels of small branch dead wood. Dense coppiced regrowth is a typical response

to the ongoing pruning regime (i.e. maintaining clearances for overhead powerlines

and property boundary alignment). Large cavities are evident in at least three of

the camphor laurels (see Table 2: Items D9, D12 and D13).


TABLE 2: Schedule of Camphor Laurel Street Trees provides a detailed summary

of the camphor laurels (Items D1-D13) including an image for each tree, location

details, height (metres), canopy diameter (metres) and DBH (mm), current status,

health, condition and overall vigour, an assessment of integrity value and key

issues as observed during visual tree assessments.

TABLE 2: Schedule of camphor laurel street trees

ITEM D1

Image: centre foreground

Location: within road carriageway/ adj. to northern verge and

south-eastern corner of Warbrick Park

Height: 20m; Canopy : 14m; DBH: 950mm

Health/ Condition: good; vigorous growth

Canopy density: relatively dense (upper)


ITEM D4



south-western cnr. Warbrick Park/ corner of Mackenzie Street


Health/ Condition: good; vigorous growth; cavities.



ITEM D8



64 Mackenzie Street (entry driveway & opposite #2 brush box)


Health/ Condition: good; vigorous growth



ITEM D12

Image: centre


66 Consett Street (entry driveway)


Health/ Condition: good; vigorous growth; large cavities.

Canopy density: open, medium canopy; 5% dead wood

Integrity value: poor asymmetrical form; heavily pruned (lower

canopy) for powerlines; extensive coppicing.

Key issues: damaged trunk/ cavities; deformation to roadway

surface/ uplifted conc. edging, footpath, kerb & guttering.

ITEM D13

Image: centre


87A Yaralla Street (entry driveway)


Health/ Condition: good; vigorous growth; large basal cavity.

Canopy density: open, medium canopy;


3.0 Heritage Significance

Overview

Legislative framework

The Environmental Planning and Assessment Act 1979 (EPA Act) forms the basis

of statutory planning in New South Wales. The Act governs the preparation of

planning instruments which broadly regulate land use and development. Local

councils are required to schedule items of local heritage significance in the Local

Environmental Plan (LEP).

Local heritage significance

The Australia ICOMOS Burra Charter established a set of commonly accepted

generic heritage values referring to historical, aesthetic, scientific and social

significance. Following Heritage Act 1977 amendments in 1999, items and places

are assessed in accordance with established heritage criteria to determine the

level of heritage significance (State or local). The Canada Bay Local Environmental

Plan 2013 (LEP 2013) incorporates standard heritage provisions including a

schedule of items and places of heritage significance. The City of Canada Bay has

over 500 heritage items and twenty (20) conservation areas scheduled in the LEP.

The proposed siteworks do not affect any items of State heritage significance. The

NSW Heritage Council publication Supplementary Guide to Assessing Heritage

Significance identifies seven heritage assessment criteria:

An item has local heritage significance when it is important in the local area for

one or more of the following criteria:

a) It is important in the course, or pattern, of the local areas cultural or

natural history known as historic significance

b) It has strong or special association with the life or works of a person or

group of persons, of importance in the cultural or natural history in the

local area known as historic associations

c) It is important in demonstrating aesthetic characteristics and/or a high

degree of creative or technical achievement in the local area known

as aesthetic or technical significance

d) It has strong or special association with a particular community or

cultural group in the area for social, cultural or spiritual reasons known

as social significance


e) It has potential to yield information that will contribute to an

understanding of areas cultural or natural history known as research

potential or educational significance

f) It possesses uncommon, rare or endangered aspects of the areas

cultural or natural history known as rarity

g) It is important in demonstrating the principal characteristics of a class of

the areas cultural or natural places or cultural or natural environments

known as representative significance.

Only one of the above criteria needs to be satisfied for an item to have local

heritage significance. An item is not excluded from having local significance

because other items with similar characteristics have already been identified or

listed (NSW Heritage Council, 2008, p.2). It is important to recognise the

contribution of local heritage in defining a sense of place. Local heritage makes

the greatest contribution to forming our living historic environment, more so than

the small number of outstanding items of state, national or world significance.

Greater than the sum of its parts, the varied collection of local heritage in an area

enriches its character and gives identity to a neighbourhood, region or town in a

way that cannot be reproduced (NSW Heritage Council, 2008, p.4). Refer to

ANNEXURE 2: Statement of Heritage Impact for application of criteria.

Heritage Conservation Areas

Heritage Conservation Areas are identified and mapped in Councils LEP to protect

and conserve heritage values associated with historic subdivisions, their buildings

and landscape setting. Yaralla Street is not located within a Conservation Area.

Notably, the Yaralla Estate Conservation Area conserves Concords largest single

subdivision release dating from the 1920s (City of Canada Bay DCP 2007). This

Conservation Area is located on the eastern side of Concord Road between Iandra

Street, Nullawarra Avenue and Wilga Street.

Heritage items

Canada Bay Local Environmental Plan 2013 - Schedule 5: Environmental heritage,

Part 1: Heritage Items identifies the Street Trees in Yaralla Street and Warbrick

Park as local heritage items (see TABLE 3: Schedule of Heritage Items Yaralla

Street, Concord West and ANNEXURE 2 TABLE A1: Local Heritage Listings).

Historic development

Although the Main North Rail Line was opened in 1886 and Concord Station (now

Concord West) one year later in 1887, much of Concord West remained as open

cleared paddocks until after the First World War. During the Inter-war period the


release of subdivisions for housing dramatically changed the area into a new

suburban landscape (City of Canada Bay DCP, 2007). Much of the landscape

character of Concord West is now defined by this regular subdivision and

consistency in scale, building form and materials of Inter-war period bungalows

(NSW Heritage data base, 2014; City of Canada Bay DCP, 2007).

TABLE 3:

Schedule of Heritage Items Yaralla Street, Concord West

Suburb Item name Address Property

description

Significance Item

no.

Concord

West

Concord

West

Street trees

Warbrick Park

Yaralla Street

87P Yaralla

Street

Road reserve

Lots 1-6 and

29-32, Sec. 1,

DP 6949

Local

Local

I521

I520

Source: Canada Bay Local Environmental Plan 2013

Schedule 5: Environmental heritage; Part 1: Heritage items

The Yaralla Street subdivision was first listed in the Sands Directory in 1916-17. In

1918 there was only one dwelling. Rapid residential development followed in the

10-year period between 1923 and 1932. By 1933 houses occupied all building lots

in Yaralla Street (Sands Directory, Sydney, NSW 1858/9-1932/3).

In 1918 a portion of land fronting Concord Road, Mackenzie Street and Yaralla

Street was acquired by Council and combined with other allotments (including land

dedicated by Walker Trustees). This land was dedicated as public reserve and

named Warbrick Park (after Alderman T.F. Warbrick, Mayor of the Municipality of

Concord) (Council of the Municipality of Concord Annual Report 1918).

Following residential subdivision and rapid expansion of the local population, there

was increasing demand for improvements in the landscape including street trees,

formal gardens and parkland facilities. During the 1920s, Concord West Progress

Association continued to raise issues regarding the upgrade of Warbrick Park

(including a proposed bandstand, playground, arise-rail fencing, trees and tree

guards) and maintenance (cleaning gutters) in Yaralla Street (Municipality of

Concord, Council Minutes Meeting Nos. 5/1926, 6/1926 and 19/1926).


FIGURE 5: Camphor laurels Yaralla Street (1943) Aerial photo image of immature camphor laurels in Yaralla Street, Concord West

FIGURE 6: Camphor laurels Yaralla Street (2012)

Aerial photo image of immature camphor laurels in Yaralla Street, Concord West


Street tree and memorial planting was a key initiative of the Council during the

Inter-war period. This program was implemented across the Municipality of

Concord and well established by the end of the First World War. In 1918 Councils

Annual Report records the planting of street trees in several streets. Notably, this

report also discusses comparative methods of tree protection and establishment

and identifies the importance of solid tree guards.

The number of trees planted in the streets of this Municipality now totals

2,700 and all have received attention during the year, the larger ones

having been pruned. Owing to the high cost of wire netting, tree-guards

constructed of palings and hardwood were provided during the period of the

War in several streets, and a comparison of the trees enclosed in these

guards and those enclosed in netting guards shows a striking difference in

favour of the former, the young trees having grown much more quickly and

also straighter.

Extract taken from Council of the Municipality of Concord

Annual Report 1918, pp.8-9

Street trees heritage significance

Development consent

All thirteen (13) camphor laurels and two (2) brush box located within the plantation

in Yaralla Street (between Concord Road and Queen Street) are scheduled as a

local heritage item (521). The more recent planting of Liquidambars, as referred to

in the LEP heritage listing, are located in the portion of Yaralla Street east of

Concord Road and are not included in this report. Part 5: Miscellaneous provisions

5.9 Preservation of trees or vegetation Item (7)(a) of Canada Bay Local

Environmental Plan 2013 (LEP 2013) states that if a tree or other vegetation is or

forms part of a heritage item or that is within a heritage conservation area,

development consent is required. Furthermore, 5.10 Heritage conservation Item

(1)(b) of the LEP identifies the objective to conserve the heritage significance of

heritage items and heritage conservation areas, including associated fabric,

settings and views.

Camphor laurels Inter-war period plantation (c. 1930)

All of the camphor laurels (and possibly the two brush box) in this section of Yaralla

Street are representative of the Inter-war period program of street tree planting in

Concord West. The date for planting remains unclear however the 1943 aerial

photo image (SIXLite 2014) suggests they were established c.1930 (see Figure 5:

Yaralla Street camphor laurels 1943). Twenty-three (23) immature trees are

clearly visible in this historic image. Notably, the thirteen (13) mature camphor


laurels and two (2) brush box trees show a high correlation in terms of location and

spacing with original trees (see Figure 6: Yaralla Street camphor laurels 2012).

By far the greatest level of fragmentation and loss of street trees has occurred

between Consett Street and Queen Street intersections with only two (2) of the

original seven (7) trees remaining. Notably, the section of Yaralla Street between

Concord Road and Consett Street intersections retains an avenue of high visual

and aesthetic value. Together these trees form a continuous inter-locking canopy

over the roadway creating a memorable avenue.

PHOTO 6: Avenue of camphor laurels in Yaralla Street this group

of trees creates a memorable landscape character (3/07/2014)

The presence of two mature brush box (Items #1 and #2) raises some intriguing

questions What was the composition of the original plantation? Was it a single

species avenue of camphor laurels with later replacements using brush box or a

mixed informal palette planted at the same time? Mixed species palettes using

both camphor laurels and brush box in a single plantation was not uncommon.

Interestingly, in the 1943 image trees along the north-side of the road appear to

have slightly larger canopies (av.4.5-5.7 metres in diameter) compared to trees on

the south-side (av.4.0-4.5 metres in diameter) with the exception of one tree (Item

D5 southern side/ 5.7m diameter). These differences may reflect local site

conditions (e.g. soil moisture availability/ soil depth, etc.), variation in stock sizes

and availability or a mixed species palette. The two remaining brush box (Items #1

and #2) are in the smaller size class. Most of the north-side trees in Yaralla Street

have markedly larger canopies than the brush box in surrounding streets (e.g.

Mackenzie and Consett Streets).

The street tree plantations of the Inter-war period reflect a consistent approach in

their formal layouts and species palettes. Together this planting reinforces the

landscape character, scale, building form and materials of this period. Notably,


there are interesting variations on this theme. The formal grid-pattern layout of

street trees within the road carriageway of Yaralla Street is less common than the

verge plantation. Here, the trees are spaced closer together over the carriageway

providing greater opportunity for canopies to link overhead. Similar examples of

planting within the roadway can be found in Consett Street (brush box planted

both sides) and also Stuart Street (partial only highly fragmented). Mackenzie

Street however retains a more traditional public verge plantation (brush box

planted both sides). Consett Street (north of Yaralla Street) and Mackenzie Street

retain relatively intact Inter-war period plantations of high visual quality.

Furthermore, Consett Street retains most of its original Inter-war period concrete

edging to tree pits within the roadway. The edging design has an unusual modular

ogee or S-shaped form which rises and falls with respect to the surrounding road

surface (i.e. alternating between raised and flush finishes see photo 7). The

design may have been borrowed from Spanish Mission colonial revival which was

popular during the Inter-war period (1925-1939). The brush box plantation has had

little impact on most of these surrounds. By comparison, only damaged fragments

of the same concrete edging remain around two camphor laurels (items D12 and

D13), located between Consett and Queen Streets. All other tree pit edging in

Yaralla Street has been cracked and uplifted by tree roots and removed over the

years. Unfortunately, this edge finish creates potential trip-points in this context.

PHOTO 7: Inter-war period edge detail Consett Street, Concord

West (similar to original detailing in Yaralla Street) (17/07/2014)


Why is heritage significance threatened?

Key processes affecting integrity and intactness

The camphor laurels in Yaralla Street represent an ageing and increasingly

fragmented population. Their large size and scale create a distinctive sense of

place. Together they share significant historic, cultural, visual, aesthetic and

representative values. The trees have a long history of intervention with

intensifying building works and service infrastructure altering the local physical

environment. As a consequence, these trees have been subject to a process of

gradual attrition and fragmentation over time.

Moreover, the robust growth pattern of these trees has placed them in direct

conflict with the objectives of maintaining service infrastructure, public safety and

risk management. The camphor laurels are causing significant damage to road

surfaces and finishes, kerb and guttering, footpaths and service pits leading to

escalating costs for repairs. Measures have been implemented by Council to

address damage to service infrastructure and improve public safety whilst

protecting these trees. The results however suggest that this intervention offers

only a temporary solution.

It is important to recognise that all of these trees have been planted within a highly

compacted soil profile which effectively reduces opportunities for deeper root

growth. In effect the potential for lateral growth of large surface roots has been

encouraged by compacted sub-grade and surrounding asphaltic concrete surfaces.

In addition, the ongoing clearance pruning regime for overhead powerlines affects

over half the camphor laurel population. Aerial bundling and cabling (ABC) of all

overhead wires remains a very costly option but worth considering in this heritage

context. This action would also have far-reaching positive benefits for a new

plantation using a more suitable tree species.

The continued protection and management of the trees and ongoing maintenance

of service infrastructure are posing serious challenges for Council and there is now

a need to find alternate solutions.


4.0 Minimising Heritage Impacts

Management realities

Current intervention strategies to minimise damage

The Council of the City of Canada Bay has implemented a range of intervention

strategies in order to address damage to public infrastructure and services and to

improve public safety whilst protecting the camphor laurels in Yaralla Street. These

works have included re-alignment of footpaths, crossings, kerb and guttering and

installation of new drainage pits, together with root pruning and canopy re-

alignment. In other locations, the kerb-line has been extended into the roadway

creating large planting pits around each of the trees. This approach aims to protect

mature trees, enhance streetscape character and provide parking bays whilst

restricting potential tree root damage.

Root barriers have been installed to restrict and isolate extensive root zones

however these measures have proved costly and largely ineffective. Although

studies have shown positive results with deep root barriers (Smiley 2008) the

experience locally with camphor laurels has been less than satisfactory. Root

barriers are often challenged over time leading to a further cycle of intervention.

After initial root pruning, camphor laurels tend to respond with increased vigour

particularly where tree pits have been enlarged and soil conditions improved.

Furthermore, excessive removal of large roots may also have adverse impacts on

both the tree (e.g. structural stability and premature failure) and adjacent property.

Recent testing on a select group of tree species (not including camphor laurels)

demonstrated a high level of variability in stability following pruning of large roots

(Smiley & Percival, 2011). Damage or cutting of surface roots may also initiate

coppicing and the growth of new trees in adjacent gardens.

Many of the camphor laurels in this plantation display some degree of buttressing,

massive surface root development and significantly raised ground levels around

the bases of trees. This raised surface root mass may extend for some metres

parallel with the kerb-line creating hummocks within the road carriageway and

extensive areas of cracking and deformation of the road surface. This uneven

surface poses further issues in terms of public safety and risk management. It is

important to recognise that this level of damage has been exacerbated by the

compacted soil conditions and surrounding asphaltic surfaces. Relatively high soil

moisture content and aeration immediately beneath asphaltic paving is likely to

attract root development accelerating cracking, heaving and deformation

(Kopinga 1994; Leake n.d.).


How can we manage change in this context?

In terms of current and future economic, social and community benefit the choice

to retain these camphor laurels appears questionable. This avenue of trees is

scheduled as an item of local heritage significance however it is likely that heritage

values will continue to be compromised. In this context of ongoing tree root

damage and escalating cost of repairs it is recommended that phased removal and

replacement of the trees with a more suitable species be considered. This section

reviews strategies for minimising heritage impacts using an appropriate native

species consistent with conservation principles.

Key recommendations

A. Phased replacement strategy

It is recommended that all thirteen (13) camphor laurels (Items D1-D13) and brush

box #1 as described in this report be removed and replaced with a suitable tree

species over three stages:

1. Seven (7) camphor laurels and a single (1) brush box Concord Road to

Mackenzie Street (Items D1, D2, D3, D4, D5, D6, D7 and brush box #1);

2. Three (3) camphor laurels Mackenzie Street to Consett Street (Items D8,

D9 and D10). Note: retain brush box #2;

3. Three (3) camphor laurels Consett Street intersection southern verge

(Item D11) and Consett Street to Queen Street (Items D12 and D13).

B. Suitable replacement tree species

The replacement tree species should be based on established selection criteria

including consistency with the broadleaf evergreen heritage palette, climatic

suitability and tolerances, soil preferences, functional traits, aesthetic qualities,

resilience, performance and sustainability in this context (see Selection Criteria).

C. Structural soils and deep root barrier

The existing compacted soil profiles do not offer a great start for new trees. Key

requirements for healthy, sustainable tree growth include provision of soils with

adequate pore space for aeration and drainage as well as organic matter. The

compacted soils in Yaralla Street require significant amendments for healthy tree

growth in the new plantation. It is recommended that a structural soil or gap-

graded profile be established as the growing medium for the new plantation. This

would encourage tree roots to be drawn down deeper within the soil profile as

opposed to lateral development within upper layers of compacted sub-grade. Since

implementation of works for the Sydney Olympics 2000 (Leake n.d.), this approach


has been used successfully in many streetscapes within the Sydney metropolitan

area. It is essential that structural soil depth and mixing ratios for stone aggregate

size/ pore space and high quality filler soil mix meet both tree specifications and

engineering requirements for compaction (Grabosky & Bassuk, 2008; Leake 2007).

Test results suggest that installation of a deep root barrier in conjunction with

structural soils may further reduce potential tree root damage to road and footpath

finishes (Smiley, 2008). Other advanced structural soil solutions are available

including use of recycled plastic structural soil cells. These are laid as a substrate

in the roadway (Magill & Leake 2013). This method significantly enhances soil

volume availability for tree growth however is considered too costly in this context.

D. Aerial bundling and cabling (ABC)

Overhead powerlines affect all of the trees along the north-side of the roadway (i.e.

more than half of the plantation). Alignment pruning has a negative impact on

overall balance and integrity of these trees. These actions disrupt continuity and

cohesion in the street tree plantation and limit potential visual and aesthetic values

in this streetscape. It is therefore recommended that aerial bundling and cabling

(ABC) of all powerlines be investigated. This action would have a significant benefit

for growth, overall balance and establishment of the selected tree species in the

replacement strategy.

Proposed phasing strategy for tree replacements

The tree removal and replacement strategy aims to deliver sustainable outcomes

for the environment, the community and heritage conservation based on a whole-

of-life-cycle approach to tree management. It is a vital requirement that the

selected replacement species should be consistent with the historic tradition of a

broad-leaf evergreen palette. Proposed phasing would be in three stages.

Replacement planting using super-advanced or semi-mature trees would be an

integral part of each phase. Phasing would be as follows:

1. Seven (7) camphor laurels and a single (1) brush box Concord Road to

Mackenzie Street (Items D1, D2, D3, D4, D5, D6, D7 and brush box #1);

2. Three (3) camphor laurels Mackenzie Street to Consett Street (Items D8,

D9 and D10). Note: retain brush box #2;

3. Three (3) camphor laurels Consett Street intersection southern verge

(Item D11) and Consett Street to Queen Street (Items D12 and D13).

Brush box #1 is included for replacement as this specimen is highly compromised

by alignment pruning for overhead powerlines and displays an extensive level of

damage to the base of the trunk. It is recommended that brush box #2 (14 metres

high/ 14 metres canopy diameter/ 750mm DBH) is retained. This tree is in good


condition with excellent vigour and a well-developed, symmetrical crown. Tree root

damage to surrounding road surface is minimal.

Table 4: Phasing strategy: replacement of camphor laurels identifies proposed

staging, item description, verge location, presence of overhead powerlines and

proposed replacement species. The strategy aims to address and prioritise key

issues such as localised flooding, traffic management and public safety.

TABLE 4: Phasing strategy: replacement of camphor laurels

ST

AG

ING

ITEM LOCATION OHEAD

LINES

REPLACEMENTTREE

SPECIES*

PH

AS

E

1

Concord Road to Mackenzie Street intersections

D1 Adj. SE cnr. Warbrick Pk (north-side) YES Waterhousea floribunda cv.

D2 Adj. No.244 Concord Rd (south-side) NO Waterhousea floribunda cv.

#1 bb Adj. to Warbrick Park (north-side) YES Waterhousea floribunda cv.

D3 Adj. No.63 Mackenzie St (north-side) NO Waterhousea floribunda cv.

D4 Adj. SW cnr. Warbrick Pk (north-side) YES Waterhousea floribunda cv.

D5 Adj. No.63 Mackenzie St (south-side) NO Waterhousea floribunda cv.

D6 Adj. No.64 Mackenzie St (north-side) YES Waterhousea floribunda cv.

D7 Adj. No.62 Mackenzie St (south-side) NO Waterhousea floribunda cv.

PH

AS

E

2

Mackenzie Street to Consett Street intersections

D8 Adj. No.64 Mackenzie St (north-side) YES Waterhousea floribunda cv.

#2 bb Adj. No.6 Yaralla Street (south-side) NO RETAIN BRUSH BOX

D9 Adj. bdy No.63 Consett St (north-side) YES Waterhousea floribunda cv.

D10 Adj. No.67 Consett St (south-side) NO Waterhousea floribunda cv.

PH

AS

E 3

Consett Street to Queen Street (incl. southern verge Consett Street intersection)

D11 Adj. to 67 Consett St (south-side) NO Waterhousea floribunda cv.

D12 Adj. to No.66 Consett St (north-side) YES Waterhousea floribunda cv.

D13 Adj. to No.87A Yaralla St (north-side) YES Waterhousea floribunda cv.

* NOTE: #1 bb and #2 bb refer to existing brush box.


It is important that the local community has the opportunity to respond to these

changes and the physical loss of local heritage items. This phased approach

reduces the impact of a single block removal and provides the opportunity to

address any community concerns and to review the program accordingly. The

program also takes into consideration the need for grouping of proposed removals

to permit a more cost-effective approach to restoration of civil infrastructure.

Selection criteria heritage landscapes

The preferred tree species should be selected for specific functional traits and

ability to meet established criteria including:

Conservation of cultural significance (e.g. local heritage palette) and

existing street tree palette (e.g. medium-scale, upright/ compact form,

broad-leaf, evergreen species);

Consistency in structure and composition height, scale, form, shape,

texture, character, evergreen, native or exotic, seasonal display;

Climatic suitability and tolerances including macro- and micro-climatic

influences and climate change adaptability and resilience to likely

changes (i.e. greater extremes in weather, higher maximum temperatures,

more intense rainfall events and extended periods of drought);

Suitability to physical context (i.e. local topography, aspect, geology and

soils) and proven performance under local environmental conditions (i.e.

expected longevity, resilience and durability);

Ecological value (native vs. exotic, habitat quality and connectivity);

Social/ cultural considerations (local community/ precinct values);

Urban infrastructure constraints (e.g. overhead powerlines, underground

services, road and verge widths, proximity to buildings, site distances, hard

pavements, etc.) and avoidance of species likely to cause damage to

existing property and service infrastructure;

Preferences for canopy density values, shading and solar access issues;

Nursery availability in advanced sizes (200-400L) including NATSPEC

compliance;

Non-invasive species avoidance of undesirable/ environmental weeds or

potential transformer weed species;

Resistance to pests and disease (e.g. Myrtle Rust Uredo rangelii, insect

herbivory and psyllid attack) and tolerance to soil-borne pathogens (e.g.

Fusarium oxysporum, Phytophthora cinnamomi, etc.);

Planting, establishment and maintenance regimes ensuring best practice

methods to optimise plant survival and development;

Tree management issues, including but not limited to:

- Physical constraints and service infrastructure (site specific)


- Limb shear, coppicing, buttressing and surface roots, etc.

- Pruning frequency

- Leaf fall (i.e. seasonal or ongoing blocking gutters and drains)

- Flowers/ fruiting (potential hazards)

- Health and public safety

- Risk management.

Minimising the impact of a replacement tree species

Recommended tree species

Weeping Lilly Pilly (Waterhousea floribunda cv. Green Avenue) is recommended

as the replacement tree species. This is a medium to fast growing, ornamental

broadleaf native evergreen species. This tree, a member of the Myrtaceae family

(i.e. same family as brush box), has proven to be highly adaptable to varying

climatic and soil conditions. The glossy dark-green lanceolate to narrow-elliptic

leaves have a pendulous appearance. New growth with fresh lime-green leaves

and red stems makes a stunning contrast with mature darker green foliage. Bark is

dark grey and finely fissured. In summer white to cream-coloured clustered flowers

are followed by fleshy green to reddish fruit. In recent years Weeping Lilly Pilly has

been widely planted throughout the Sydney metropolitan area.

Historically, the species has been grown in

larger private gardens and public parkland

since the mid-nineteenth century. Typically,

this species has a dense, rounded crown and

compact form and may grow into a large tree

under natural conditions.

The recommended cultivar Green Avenue

has been developed as a smaller growing,

compact tree of medium-size up to 12-14

metres in height and 12-14 metres canopy

diameter on deeper soils. This cultivar

responds well to pruning and shows greater

uniformity and consistency in its growth (i.e.

less variability than seed grown plants). Its

also highly resistant to Myrtle rust (Pucinnia

psidii s.l. syn. Uredo rangelii).

PHOTO 8:

Weeping Lilly Pilly (Waterhousea floribunda

cv. Green Avenue) preferred tree replacement


The broadleaf evergreen character, growth rate, compact form, size at maturity and

overall uniformity are all key performance criteria. This cultivar would reinforce the

traditional broadleaf evergreen character of this streetscape. Over time it would

significantly enhance visual and aesthetic qualities. Structural soil profiles are

recommended to minimise potential root damage. This cultivar is available from

wholesale nurseries in super-advanced and semi-mature sizes (200 litre/ 2.5-3.0m

HT to 400 litre size/ 4.5-5.0m HT) (see Appendix Nursery Suppliers).

PHOTO 9: Detail of new growth - Weeping Lilly Pilly

(Waterhousea floribunda Green Avenue)

It is important to recognise that overall performance and anticipated long term

benefits of the proposed replacement program would be subject to implementing

best practice methods. It is absolutely essential that tree selection and nursery

pruning (e.g. single straight stem/ calliper, branch alignment, adequate under-

pruning for clearances for traffic management), structural soils for optimum deep

root development, installation of adequate set-backs for edging/ kerbing and use of

robust tree guards, establishment and maintenance are all of the highest quality.

Is brush box a suitable option for replacement planting?

The Inter-war period street trees within this area and much of Sydneys inner west

are dominated by avenues of brush box (Lophostemon confertus). This native

species has an excellent performance record. It is highly adaptable to varying soil

conditions and shows a high level of resilience to climatic variability (e.g. tolerating

prolonged drought), insect attack and heavy pruning. Generally this species

displays uniformity in its pattern of growth and is well suited to avenue planting.


Adjacent streets such as Mackenzie Street and Consett Street (north of Yaralla

Street) retain relatively intact Inter-war period brush box plantations of high visual

quality (see discussion in 3.0 Heritage Significance). Consett Street has a similar

style of planting to Yaralla Street (i.e. within the road carriageway). Notably much

of the Inter-war period edging has been retained in Consett Street. Concerns

however have been raised over the robust growth of brush box and potential for

similar damage to occur should this species be planted. Generally, the Inter-war

period brush box avenue in Consett Street shows a relatively low level of impact on

road finishes, crossings and kerb and guttering (see Photo 7) compared to Yaralla

Street. Similarly, brush box #1 and #2 in Yaralla Street display a far lower level of

damage to adjacent finishes compared to the camphor laurels.

Brush box, as a traditional avenue species is therefore considered an alternative to

the proposed replacement species/ cultivar. Brush box may be an easier and less

costly option to establish compared to Weeping Lilly Pilly (Waterhousea floribunda

cv. Green Avenue). Nevertheless, the latter preferred option offers a distinctive

solution consistent with the character of Yaralla Street and the historic broadleaf

evergreen palette.

Tree sourcing, soil preparation and establishment

Sourcing appropriate trees nursery procurement

The proposed strategy would be subject to availability of appropriate nursery stock.

It is essential to ensure thorough planning for availability and secure procurement

of appropriate super-advanced containerised nursery stock. Trees should be grown

in accordance with NATSPEC guidelines. Additional quantities of Weeping Lilly

Pilly (Waterhousea floribunda cv. Green Avenue) will be required to fill existing

gaps in the plantation. Nursery sourcing and securing of large-container size stock

(200-400L size) will provide maximum potential benefit within the shortest time

frame (see Appendix for supplier information). This approach will significantly

reduce any negative visual and aesthetic impact associated with tree removals.

Moreover, it establishes the momentum for change with immediate positive

benefits delivered to the community.

Site preparation, asset protection and establishment

Site preparation is of utmost importance, particularly within this roadway context

where soil profiles have been highly compacted. Tree removal, stump grinding and

preparation of tree pits for planting, including adequate subsoil drainage, use of

structural soils, installation of edge-treatments, bollards and robust tree-guards,

mulching, maintenance and establishment should be in accordance with best

practice standards. The layout should reflect the original formal design of the


streetscape. Planting should be off-set from existing locations (avoiding existing

stump bases) maintaining the formal grid layout at appropriate centres (set at

nominal 12-14 metres centres). Trees should have a measured off-set from kerb

and road centreline. Avoid random positioning. Protect vehicular and pedestrian

sight-lines.

Tree planting surrounds (garden bed) should be a minimum 2.5 metres X 2.5

metres and structural soil should be a minimum 750mm depth. It is recommended

that a deep root barrier is installed around the perimeter of garden beds (i.e.

adjacent to kerb-line) in conjunction with structural soil amendments. Tree guards

and kerb-line bollards should be installed to provide adequate tree asset protection

during establishment and to reinforce the significance of the new plantation. Each

tree should have a robust tree guard 4 X hardwood timber or recycled plastic

posts (stained or painted) with top, mid and bottom rails. Timber or recycled plastic

bollards should be installed along the kerb face adjacent to parking bays to reduce

the potential for physical impacts on establishing trees.

Minimising impacts and maximising benefits

It is important to recognise that the proposed changes provide an opportunity for

renewal of this street tree plantation one which continues to be affected by

multiple impacts of fragmentation and heavy pruning for overhead powerlines and

property boundary alignment. The proposed strategy would deliver immediate

economic and social benefits to the community reducing the cost of repairs to

damaged public infrastructure and providing a safe, connected environment.

The approach would also secure long term environmental benefits in terms of

removing an undesirable tree species one which is widely acknowledged as a

transformer weed species in urban bushland. As the replacements mature a new

streetscape will emerge ensuring a high level of visual consistency with the historic

broadleaf evergreen palette. Refer to PART 2: ANNEXURES for Statement of

Environmental Effects and Statement of Heritage Impact.


References

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