Transcript City of Melbourne – An Urban Forest Perspective

The Melbourne Urban Forest
Accord Group’s approach to
Urban Ecological Management
Melbourne Urban Forest Accord
Group
City of Melbourne
City of Port Phillip
Moonee Valley City Council
HOW DID IT ALL BEGIN?
Policy Gaps - 2009
Targets:
• Saving Water – 25%
water saving by 2020
Achieve this by:
• Reduce potable water in
parks
• Irrigation efficiencies
• Drought tolerant
species
Is reducing water the
best outcome for our
Parks and Trees?
Drought and water restrictions vs
parks and trees
Alexander Park – Feb 2004
Alexander Park – Feb 2010
ideal
Kings Domain & surrounds
852 trees assessed
CoM Urban Forest Strategy
Trees + Water = Healthy
Environments
Further gaps
•Trees seen purely as a risk in causing
damage during extreme weather events
•No value given to their ability to “cool” the
local environ - adaptation
•No value given to carbon sequestration
Further gaps
• At present, we can only value our trees
using The Burnley Amenity Value Formula
= cost of replacing the tree
• Currently very small fines/permit costs for
removing urban trees
• No economic incentive for tree retention
Unable to truly quantify the environmental
benefits of urban trees
How can we value Urban
Trees?
• Funding bid submitted to the Victorian
Sustainability Accord
• Need recognised at State
Government level
• Funding of $70,000 awarded
• MUFAG thus initiated!
Working Group
University of Melbourne
Monash University
RMIT
Melbourne Water
Department of Health
City West Water
Arboriculture Australia
DEVELOPMENT OF A PROJECT BRIEF
What are the benefits of urban
trees?
Social
Environmental
Economic
Chicago Urban Forest Project 1991
Chicago trees removed 6,154 tons of air pollutants valued at US$9.2m
Total Co2 sequestration = 155,000 tons per year
Cost benefit ratio of 2.83
Increasing tree cover by 10% (3 trees per building) could
reduce total heating and cooling energy use by 5-10%
Existing Valuations in Melbourne
Valuing Urban Trees
Parameter Measurements
CoM Amenity Value Formula
I Tree Streets/Eco
This project
Replacement value from nursery
Energy conservation
Greenhouse gas
Species Factor
Air quality
improvement
Water use
Aesthetics
Co2 reduction
Air Quality
Locality
Stormwater
amelioration
Climate adaptation
Tree Condition/Health
Property value
increase
Infrastructure and horticultural
implications
I Tree Streets
• Free to all users
• Must have good base data on existing urban forest i.e.
species, health of canopy, DBH, cost of maintenance
programs, demographic data for selected area, resident
populations, linear miles of streets, local electricity costs
• Doesn’t value social benefits such as community
wellbeing and health
• Biggest issue: customised for USA (species, hardiness
zones etc etc)
• Tom Fairman from Melbourne University: pilot project to
overlay usefulness of I Tree Streets into Australian
context
I Tree
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Model needs to be redesigned to include Australian climatic data and tree
species
Results valued urban forests in Carlton and NW Melbourne at roughly
$1.06m. Biggest benefits in aesthetics and energy savings
Need to look at return samples to understand the change in value of the
trees over time. This will determine age mix of trees that provide greatest
benefit
Also need to look at economics of the urban forest: how costs vary under
different management regimes over time and for different trees to determine
exact cost of running an urban forest. May be that councils may lose money
on some trees!
BUT, there are international users
CITYgreen
• Uses GIS software to quantify benefits and map
urban canopy
• Fee charged for software
• Similar parameters: reducing stormwater run-off,
mitigating air pollution, energy savings, tree
growth, water quality
• Developed by American Forests, a not for profit
conservation group
• Coupled with urban ecosystem analysis to map
urban canopies and their dollar values
• Not recommended for international use due to US
specifications
UFORE Program
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Urban Forest Effects Model
Calculates structure, environmental effects and values of urban forests
Funded and developed by USDA Forest Service
4 types of data needed: field data, tree cover, meteorological data and
pollution concentration data
It then quantifies:
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forest structure (species, density, health, biomass)
Volatile organic compounds ( urban forest emissions)
Carbon storage and sequestration
Dry deposition of air pollution (ability of urban forest to remove pollution)
Effects of trees on building energy use
Compensatory value of urban forest
IS NOW i-tree ECO
Australian attempts to value urban forest
Brisbane City Council: desktop study mapping the urban canopy using GIS and
satellite imagery coupled with existing on-ground data. Consultant based
report in 2001. No field studies.
• Suburbs averaged 27% canopy cover
• Modelled valuation on CITYgreen’s approach
Results:
• Urban forest absorbing co2 equivalent to 130,000 cars annually
• Cooling surfaces in October by 5 degrees Celsius
• Potential for tree shading on east and west sides of buildings to provide
energy savings of up to 50%
• Value of homes in leafy streets were 30% higher than non-leafy streets in
same suburb
Australian attempts to value urban forest
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Canberra: Set up an Urban Forest Renewal Program to account for mature
trees reaching end of their lives. ANU study in 2005 on the urban forest
valued it at $15m, saved up to $3.9m in energy costs, provided $7.9m in air
pollution mitigation and $3.5m in stormwater mitigation and reduced wind
speed by up to 50%
i-tree Eco
• MUFAG developed close
collaboration with USDF and
Davey Trees, Dave Nowak and
Scott Maco
• Agreement to create i-tree Eco
International, using Melbourne as
a pilot program
• If successful, i-tree Eco will be
rolled out for other international
users
Recalibration
Consultant = Enspec
Requirements:
• List of Australian tree species
• Meteorological and Climate Data
MANY QUESTIONS……..
Dave Nowak
Is Australia ready to use i-tree?
• Not yet, but its worth considering what
data needs to be collected by council
arborists:
- Species name
- Location of each tree, land use, distance and
direction to nearest buildings, sunlight source, street
tree or park tree.
- Size of each tree, trunk diameter, trunk height,
crown width,
Health of each tree, age, canopy missing, crown
dieback.
Some councils have already begun data collection
First version due for completion July 2011
How will this project help us?
Council:
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Development of our Urban Forest Strategy
Investment planning: $1 invested in street trees
returns $x
State Government:
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Robust evidence for inclusion of trees in
planning
Understand the economic consequences of
water restrictions and provide cost benefit
analysis for WSUD
Community
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Raise awareness of urban tree benefits
Encourage private landholders to include real
tree values in their development analysis