Summary

Introduction
Adelaide St (2)
Purpose of project

Streetscape enhancement

Installation type

Structural soil

Tree planting date

1999

Tree species

Caesalpinea ferrea (Leopard tree)
Botanical name (Common name)

Number of Trees Planted

50+

Tree Stock Size at Planting

100+ or ex-ground

Number of Trees Surviving

100%

Survival Assessment Date

2018

Features
Owner of Site

Brisbane City Council

Contact Details

Contact Name

Dr. Lyndal Plant

Contact Phone

0408-779-488

Contact Email

Location Details

Location Address

Adelaide Street Brisbane, between George St and Edward St.

As above

Council/LGA

Brisbane City Council

Technical Detail

If you require details not available here, see contact details.

Case Study Description

Continuous tree trenches within new footpath extension from back of kerb within portions of 2 city blocks on both sides of street (Portions considered 6 existing trees along footpath outside City Hall)

Geotextile lined trench

Structural soil mix = 200mm bluestone spalls, clay-loam media (filler soil) of calculated void volume (40%) washed in during installation stages, 2 horizons of soil mix used within tree planting sites

Design &/or as constructed detail

Refer to earlier Case Study Description.

Depth of Engineered Space

1.0

Volume of Engineered Space

Total volume for project approx. 450 cubic metres. Volume per tree – approx. 9 cubic metres

Drainage Type

Under drainage in bottom layer of trench to stormwater inlet (see design detail within attached paper)

Drainage Type Resource/Image/Document
Surface Treatment

Tree Grates Within Reinforced Concrete

Growing Media Detail

Clay-loam media (filler soil) of calculated void volume (40%) washed in during installation stages, 2 horizons of soil mix used within tree planting sites (see design detail diagram within paper)

Surrounding Site Soil Detail

Geotech core sampling survey done for the project – report not available

Findings were predominantly mixed fill, stiff clay with some portions of sandy loam where existing trees were growing well

Surrounding site soil detail Resource/Image/Document
Watering Regime

Manual

Maintenance Detail

watering regime is manual for the establishment period of 24 months only

initial aluminium tree grates replaced with new alloy style in 2013

clearance pruning of trees two yearly to maintain bus, car, truck clearance

Images:

Primary Case Study image = 2018 view of portion of boulevard, looking south from cnr Adelaide St and Albert St, City Hall side

Other images of related projects within the paper (Treenet Symposium paper link)

Non-Technical Detail

Challenges Overcome

Justifying the need for tree trench space
Satisfying pavement engineering standards

Stakeholder Feedback

Positive

Stakeholder Support for future projects of this kind

Yes

Funding Source

Brisbane City Council and Australian Government Grant Funding

1

Project Cost

Estimated 5% of total project cost of $35m in 1999

Total project included street narrowing, new kerb and channel, services relocations, new footpath paving, street furniture and street resurfacing

1

Partners/Sponsors Information