Works Committee Meeting

 

  BUSINESS PAPER

 

 

 

 

 

 

 

 

 

 

 

Tuesday 9 November 2010

 

 

 

 

 

 

 

 

 

Administrative Centre 30 Frances Street Randwick 2031

Telephone: 02 9399 0999 or

1300 722 542 (for Sydney metropolitan area)

Fax:02 9319 1510

general.manager@randwick.nsw.gov.au

www.randwick.nsw.gov.au


 

 

 

 

 

 

 

 

 

 

 

 


Works Committee

9 November 2010

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Works Committee Meeting

 

Notice is hereby given that a Works Committee Meeting of the Council of the City of Randwick will be held in the Council Chamber, Town Hall, 90 Avoca Street, Randwick, on Tuesday, 9 November 2010 at 6:00pm.

 

 

Committee Members:           The Mayor (M Matson), Andrews, Belleli (Chairperson), Bowen, Hughes, Matthews, Nash, Notley-Smith, Procopiadis, Seng, Smith, Stevenson, Tracey, White (Deputy Chairperson) and Woodsmith.

 

Quorum:                           Eight (8) members.

 

NOTE:    At the Extraordinary Meeting held on 28 September 2004, the Council resolved that the Works Committee be constituted as a committee with full delegation to determine matters on the agenda.

 

Apologies/Granting of Leave of Absences 

 

Confirmation of the Minutes  

Works Committee Meeting - 12 October 2010

 

Declarations of Pecuniary and Non-Pecuniary Interests

 

Address of Committee by Members of the Public

 

Urgent Business

 

Works Reports

W29/10     Alison Road, Randwick - Tree Removal/Replacement Program    

 

Notice of Rescission Motions

Nil 

 

 

 

…………………………………………………….

Ray Brownlee

General Manager


Works Committee

9 November 2010

 

 

 

Works Report No. W29/10

 

 

Subject:                  Alison Road , Randwick - Tree Removal/Replacement Program

Folder No:                   F2004/07359

Author:                   Bryan Bourke, Tree Management Officer     

 

Introduction

 

There are a large number of over-mature and senescing Council owned Populus nigra ‘Italica’ (Lombardy Poplars) growing along the northern side of Alison Road, Randwick, between Anzac Parade and Darley Road. Most of these fifty-four trees are now in such a poor and declining state of health that they represent a very serious and unacceptable risk to persons and/or property.

 

Issues

 

Council’s Tree Management Coordinator commissioned an independent arborist to assess the condition of all trees growing along the northern side of Alison Road because of concerns about their declining state of health, particularly the Lombardy Poplars. Several trees along this section of Alison Road are dead and require immediate removal but there is significant deadwood within the canopies of most of the Poplars, as well as inherent structural defects such as internal cavities and basal decay. The majority of diseased Poplars are located immediately adjacent to a cycleway and pedestrian walkway and are sandwiched between a busy main road (Alison Road) and bus lane linking Randwick with Anzac Parade.

 

It is estimated that the Poplars were planted during the post World War II period and that they are approximately 60-70 years old. This affords them some historic value but their heritage significance is only moderate.

 

The tree survey and report provided to Council by the commissioned arborist details the health and structural integrity of all trees along this section of the northern side of Alison Road and makes a number of recommendations, particularly in relation to the Poplars. Because there were obvious signs of extensive basal decay and large numbers of dead branches within the canopies of a large number of this tree species, all Poplars were drilled to assess the amount and extent of internal decay. As a result of this comprehensive inspection all fifty-four Poplars were recommended for removal in the short term. Forty-two various trees, including the thirty-three most diseased Poplars, are recommended for removal at the earliest opportunity. These particular trees were found to be the most structurally unsound and at risk of failure. Whole tree failure is the most likely form of failure because of the amount of fungal decay near ground level. Eleven of the remaining twenty-one Poplars were also recommended for removal because they are at the end of their Safe Useful Life Expectancy (S.U.L.E.). Their retention and proper management would be expensive and short lived.

 

Several dangerous trees have already been removed and an inspection of all the trees along Alison Road was undertaken by Council’s Tree Management Coordinator immediately after the August 2010 wind storms. This inspection concluded that at least thirty-three Poplars required removal at the earliest opportunity.

 

The twenty-one other Poplars will also require removal and replacement in the short term – over the next one-two years – as funding is made available.

 

There were a number of other trees species recommended for removal, including two Hill’s Weeping figs, two Coral trees and one Brushbox, but these trees can be retained in the medium term with appropriate maintenance pruning. They are not sandwiched between the bicycle track and the bus lane and are therefore not as serious a risk as the subject Poplars. They are also generally in better health and far less structurally compromised. 

 

Relationship to City Plan

 

The relationship with the City Plan is as follows:

 

Outcome 10:       A Healthy Environment.

Direction 10b:      Environmental risks and impacts are strategically managed.

Key Action:         Develop and implement policies, programs and strategies to manage environmental risks and impacts.

 

Financial impact statement

 

Council has allocated $60,000 in this year’s capital works budget for the programmed removal and replacement of diseased trees along the length of Alison Road between Anzac Parade and Darley Road, Randwick. The cost to remove and stump grind the thirty-three most hazardous trees has been quoted at $26,000. This cost incorporates required traffic management operations.

 

The cost to supply 30 x 100-litre litre Agathis robusta (Qld Kauri pines) that will plant at approximately two metres has been quoted at $9,000. The cost to plant and construct wooden tree guards around these 30 trees and to maintain them for a period of six months has been quoted at $21,150. Therefore, the total cost to remove the thirty-three worst affected trees and to replace them with 30 x two-metre tall Qld Kauri pines would be in the vicinity of $56,150. 

 

Conclusion

 

The danger these Poplars pose was dramatically highlighted during severe wind storms in early August 2010 when large dead branches from a number of these trees snapped off and fell onto the cycleway and adjacent bus lane. Fortunately, no-one was injured as a result of these failures but the situation could have been quite different if these heavy winds had occurred at a different time.

 

There is a compelling case for the removal of all existing dead trees and the thirty-three most compromised Poplars growing on the northern side of Alison Road, Randwick, between Anzac Parade and Darley Road. This species of Poplar is unusual in terms of its relatively short lifespan and typical failure from structural decay within the main trunk. Most of the Poplars have been recommended for removal either immediately (for safety reasons) or certainly within the next two-five years. 

 

Council’s duty of care obligation is made even more pressing by the fact that these are tall trees planted between a busy main road and a bus lane. If one of these trees were to fail, it would most likely fall onto Alison Road or the adjacent bus lane and the results could be catastrophic. This is further compounded by the fact that recent wind events have highlighted to Council the very real danger these trees now constitute.

 

The removal of all the Poplars along Alison Road at one time would have a severe impact on the visual amenity of this section of the road and this was a major consideration when assessing how many trees should be removed in Stage 1 of this removal/replacement program. This is particularly the case west of Doncaster Avenue where the Poplars are the only trees of any significance along the northern side of Alison Road. It is less so to the east of Doncaster Avenue where there is a row of reasonably healthy trees to the north of where the nominated Poplars are to be removed and replaced.

 

 

Recommendation

 

That Council removes all existing dead trees and the thirty-three (33) most diseased Poplars growing along the northern side of Alison Road, between Anzac Parade and Darley Road, and that these trees be replaced with 30 x 100-litre advanced Agathis robusta (Qld Kauri pines) as planted extensively along Parkes Drive in Centennial Park and nearby Tay Reserve.

 

 

Attachment/s:

 

1.View

Series of photographs detailing the poor condition and compromised structure of a number of Council owned tree assets growing along the northern side of Alison Road, Randwick.

 

2.View

Series of photographs showing the growth habit and visual impact of Qld Kauri pines planted along Parkes Drive in Centennial Park

 

3.View

Summary of tree survey undertaken by Arborcraft of all Council owned trees on the northern side of Alison Road, Randwick, between Anzac Parade and Darley Road.

 

 

 

 


Series of photographs detailing the poor condition and compromised structure of a number of Council owned tree assets growing along the northern side of Alison Road, Randwick.

Attachment 1

 

 

Typical examples of senescing Lombardy Poplars along north side of Alison Road

 

Most Poplars exhibit extensive deadwood within their canopies and decay within trunks


Medium sized dead Quercus ilex (Holly Oak) between Poplars adjacent to bus lane

 

Typical example of large dead branches that drop from most diseased Poplars


Deadwood extends throughout entire length of worst affected Poplars

 

Typical example of large dead snapped branch within canopies of most trees

Internal decay is evident in the trunks of most Poplars and is generally quite extensive

 

Basal decay typical of that found in the lower trunk area of a number of Poplars


Series of photographs showing the growth habit and visual impact of Qld Kauri pines planted along Parkes Drive in Centennial Park

Attachment 2

 

 

Row of Agathis robusta (Qld Kauri pines) growing along Parkes Drive, Centennial Park

 

Typical form and growth habit of the species Agathis robusta


Summary of tree survey undertaken by Arborcraft of all Council owned trees on the northern side of Alison Road, Randwick, between Anzac Parade and Darley Road.

Attachment 3

 

 

Arborcraft LH_A4.jpg

 

 

 

 

 

Wednesday,  6 October 2010

 

Bryan Bourke

Tree Management Officer

Randwick City Council

30 Frances Street

Randwick NSW 2031

 

Summary of Tree Survey, Alison Rd, Randwick

 

On Wednesday, October 06, 2010, in company with Baraniko Siers (Niko) of this firm I inspected 100 Street Trees between Alison Road and Centennial Parklands (between Anzac Parade and Darley Road).  Two Lombardy Poplars (Populus nigra ‘Italica’) and one Holm Oak (Quercus ilex) at the Anzac Parade end were removed some time ago.  The majority of the trees are over-mature Lombardy Poplars. 

Arborcraft has been involved with the site since January 2007 when we surveyed the trees.  In January 2009 we were asked to update our Tree Survey.  Due to recent branch failures from several of the over mature Poplars, Brian Bourke, Randwick Council’s Tree Management Officer, has asked to provide an updated survey.  Our survey is presented as an 11 page Excel Spreadsheet.  An updated 2 page tree location plan is also attached.

 

Our 2010 inspection was from ground level.  We did not climb the trees and we did not drill the trees.  We did drill the trees in 2007 on the eastern side at about 1.2-1.4m above ground. We used a 10mm speed bore. We drilled until we found decay or to a depth of 200mm.

 

Our initial Survey (2007) and Summary in the same year recommended the removal of all the Poplars.  Due to budgetary constraints, Randwick Council asked that we re-prioritise the trees. 

 

Summary

We recommend that 42 trees be removed now and 11 trees be removed within 2 years. We recommend that a further 12 trees be assessed and considered for removal in 2-5 years from now.

 

Of the 42 trees recommended for removal 33 are Poplars with poor structure, 4 are dead (2 WA Flowering Gums and 2 Holm Oaks), 2 are Coral Trees with poor structure, 2 are Hill’s Figs with poor structure and 1 is a  partially ringbarked small Brush Box tree.

 

The 11 trees recommended for removal within 2 years are all Poplars.  Of the 12 trees to be assessed in 2-5 years 10 are Poplars and 2 are Holm Oaks.

 

We recommend that any Poplar not removed immediately be deadwooded.  1 Holm Oak is also recommended for removal of major dead wood.

 

Discussion/Recommendations

 

1.      42 trees are recommended for immediate removal.

 

1.1.      33 Poplars are recommended for immediate removal.  These trees are over mature and are close to the end of their life expectancy.  These trees have cavities in the lower trunk which are visible or were detected when the trees were drilled in 2007. The trees are structurally unsound and at risk of failure. Whole tree failure is the most likely form of failure because of fungal decay near ground level. This is obvious from cavities near ground level (e.g. Tree #5) or from drilling into large hollows which show that the tree is structurally unsound (e.g. Tree #8)

 

1.1.1.         The basal cavities in the Poplars are unlikely to have decreased in size relative to the size of holding wood.  If anything, the cavity is likely to have       increased in size since 2007.

    

1.2.      2 Holm Oaks are recommended for removal. 1 is dead and the other is dying with less than 1% leaf cover.

 

1.3.      1 Brush Box is recommended for removal.  It is a small tree that has been partially ringbarked by a whipper snipper.  Around 66% of the circumference of the trunk has been damaged. 

 

1.4.      2 Hill’s Figs are recommended for removal.  The 2 Figs have Included Bark in the main unions. 

 

1.5.      2 Coral Trees are recommended for removal.  There is a history of branch shedding with 1 branch of 150mm diameter on the ground. 

 

1.6.      2 WA Flowering Gums are recommended for removal.  Both trees are dead.

 

2.      11 trees are recommended for removal within 2 years.  The 11 trees are         all Poplars.  They were drilled in 2007 and were found to have 200mm of    solid wood (the drill bit was 200mm long).  Structurally, I regard the Lombardy Poplars as inherently suspect at this stage of their life cycle. 

 

3.      12 trees are recommended for re-assessment within 2-5 years.  10 of    these are Poplars and 2 are Holm Oaks.  ….  One of the Holm Oaks (#4)    has a fungal fruiting body at the base.  We have recommended that it be         assessed further with a Picus Tomograph®.  A follow up inspection within    2-5 years is recommended if it is not assessed with the Picus.  The         second Holm Oak (#23) has a basal cavity.

 

4.      21 Poplars and 1 Holm Oak are recommended for pruning.  The 21        Poplars are made up of 11 trees we have recommended to be removed   within 2 years and 10 trees we have recommended for re-assessment in      2-5 years.  The Holm Oak has a dying stem that can be pruned back to a         growth point 4m above ground.

 

Number of tree types and recommendations

Tree Type

Total no.

Remove Now

Remove within 2 years

Assess within 2-5 years

Prune

Retain

Poplar

54

33

11

10

 

 

Holm Oak

14

2 (dead)

 

2

1

12

Live Oak

1

 

 

 

 

1

Brush Box

21

1

 

 

 

20

Hill’s Fig

5

2

 

 

 

3

Coral trees

2

2

 

 

 

0

WA Flowering Gum

2

2 (dead)

 

 

 

 

0

Deciduous Fig

1

 

 

 

 

 

1

Total

100

42

11

12

1

 

 

Tree identification numbers and recommendations

 

Poplar             

Holm Oak

Brush Box

Hill’s Fig

Coral Trees

WA Gum

Remove Now

5,6,8,9,11,13,15,18,20,24,25,26,29,31,32,33,34,35,36,37,

39,41,42,46,47,51,63,64,65,

66,67,68,69

21,

27

72

80,81

40,74

38, 62

Remove within 2 years

7, 14, 16, 19, 28, 44, 45

57, 58, 59, 61

 

 

 

 

 

Assess in 2-5 years

22, 30, 49, 50, 52, 53, 54,

55, 56, 60,

4, 23

 

 

 

 

Prune Now

All Poplars not removed now need to be pruned

4

 

 

 

 

                                                                                                      

Please contact me for further information if there is anything which is unclear.

 

 

Bruce Macleod, MAIH, Member, National Arborists Association, Member, International Society of Arboriculture