i-tree eco analyses in the gta evaluating the ecosystem services provided by our urban forests
TRANSCRIPT
i-Tree Eco Analyses in the GTAEvaluating the Ecosystem Services Provided by Our Urban Forests
Outline
• Introduction to i-Tree Eco
• Collaboration on GTA studies
• Toronto study results
• GTA study results
• Next steps
Rationale for i-Tree Eco Studies
• USDA Forest Service i-Tree suite provides science-based analysis and benefits assessment tools
• Eco uses field plots, air pollution and meteorological data to quantify urban forest structure, environmental effects and value
• Generates baseline data that can inform management decisions, policy and strategic planning
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GTA i-Tree Collaboration
• 2008 TRCA joint planning session
– i-Tree experts, researchers, users from GTA and other Ontario municipalities
• Harmonized study design & methodologies
• Potential for consolidating data in future
• Opportunity to raise profile of urban forests
• Connected UF professionals across the GTA
Toronto Study Elements
• In Toronto: i-Tree Eco “plus…”
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Field data collection (407 plots)
i-Tree Eco data analysis (USDA)basics
i-Tree Hydro, Grow Out modeling
Forest & land cover change analysis
Digital land cover map
Street tree data
extras
1999
2005
Measuringland cover change using orthophotos
Automated land cover
classification using 0.6m
Quickbird satellite imagery
*Tree canopy is approximately 20% Goal: Achieve & maintain between 30-40%
Toronto’s urban forest is a vital city asset with a replacement value of $7 billion.
Toronto’s tree cover is
average compared to cities of
similar size.
Distribution of Tree CoverGoal: More even/equitable distribution of tree cover
• Distribution of tree cover is uneven• Data can be used to prioritize planting areas
Average tree cover by neighbourhood
Average tree cover by ward
6% located in City road allowances
34% located in City parks and natural
areas
60% located on private property
Ownership
Private property owners control a majority of the City’s existing and possible tree canopy.
City40%
Private60%
Land Use Affects Tree CanopyGoal: Improve distribution & quality of tree cover
Land use affects• Distribution of forest cover• Species composition & diversity• Average tree size
Generalized Land Use
% Tree Cover
% of City’s land area
Parks 44% 11%
Open Space 27% 6%
Residential Single 24% 41%
Residential Multi 16% 6%
Institutional 15% 7%
Other (vacant) 14% 7%
Utility & Trans 12% 4%
Commercial 5% 7%
Industrial 4% 11%
Land/Forest Cover Change (*preliminary)
Tree Cover-0.7%
46.2 47.7
31.4 30.6
20.6 19.9
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Forest cover
Land & Forest Cover Change: 1999-2005
Biggest change in
neighbourhoods
(-1.3%)
Forest Composition & ConditionGoal: High diversity, appropriate species, healthy trees
• Good species diversity overall - 144 species & cultivars
• Exception - maple & ash (41%)
• Majority of trees are in good condition (exception: street trees)
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Top tree species by leaf area (m2)
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Excellent Good Fair Poor
Average tree condition (% of population)
All Trees
Street Trees
Forest Size Class Structure Goal: Maintain regeneration, reduce mortality,
increase % mid- to large-size trees
• Number of large trees relative to small is low• Have good regeneration, but• Large trees provide maximum benefits
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0-15.2 15.3-30.5 30.6-45.7 45.8-61 61+
tree size class
Size class distribution compared to ideal
All trees
Suggested ideal
increase
Value of Ecological Services Provided by Toronto’s Urban Forest
• Carbon storage = 1.1 million tonnes
• Carbon sequestration = 46,700 tonnes
• Building energy reduction = 41,200 MWH
• Avoided carbon emissions = 17,000 tonnes
• Air pollution removed = 1,680 metric tonnes
Annual equivalent value = $60 million+
• i-Tree Hydro shows reduction in stream flow rates with increased forest cover
• % impervious cover has more significant effects
Hydrology
Other values?
Benefits of i-Tree Eco Study for Toronto Urban Forestry
Provides baseline information and a monitoring framework to inform management of the urban forest.
Results support current program direction & priorities.
Confirms that 60% of the urban forest is on private property - supports rationale for new policy/programs.
Provides an important information platform to continue engaging other operating divisions, Council and the public.
Study Elements
• Peel and York Regions– i-Tree Eco– Digital Land Cover Map– Priority Planting Index– Grow-out Scenarios– i-Tree Hydro
• Ajax and Pickering– i-Tree Eco– Aerial photo
interpretation
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Canopy Cover and Leaf Area
Study Area Canopy Cover Leaf Area (km2) Leaf Area Density
Mississauga 15 % 223.8 0.78
Brampton 11 % 145.2 0.54
Caledon East 29 % 13.1 2.74
Bolton 17 % 13.5 0.80
Toronto 20 % 1015 1.60
Ajax 18 % 85.6 1.27
New York City 21 % 740.6 0.93
Table 1: Canopy cover and leaf area metrics for study areas
Urban Forest Distribution
• Text
• Etc
Figure 1: Existing and possible tree canopy in Peel study areas summarized by service delivery areas (SDA)
Priority Planting Index
• Summarized by small geographic unit (SGU)
• Prioritize areas of high population density and low canopy cover
• Equitable distribution of ecosystem services
Figure 2: Priority planting index in Mississauga summarized by small geographic unit
Distribution by Land Use
Figure 3: Existing and possible tree canopy in Peel study areas summarized by land use
Species Composition - Mississauga
Figure 4: Dominant tree species in Mississauga by percent of total leaf area and total number of stems
• 10 most common species account for 57% percent of all trees• 56 % of species are native to Ontario• 58 % of all trees are planted
Species Composition - Brampton
Figure 5: Dominant tree species in Brampton by percent of total leaf area and total number of stems
• 10 most common species account for 72% percent of all trees• 43 % of species are native to Ontario• 20 % of all trees are planted
Tree Size
Figure 6: Diameter class distribution of trees in Peel study areas
In Brampton a tree that is 65 cm in diameter stores 10 times more carbon and 75 times more pollution than a tree that is 11 cm in diameter
Air Pollution Removal
Annual Removal Value:Mississauga: $4.8 millionBrampton: $ 3.2 millionBolton: $110,000
Annual sulfur dioxide removal in Mississauga = Annual sulfur dioxide emissions from 19,100 automobiles
Annual PM10 removal in Brampton = Annual PM10 emissions from 170,700 automobiles
Figure 7: Annual air pollution removal by trees in Peel study areas
Climate Change Mitigation
• Carbon storage = 405,000 tonnes or $11.5 million
• Annual carbon sequestration = 19,050 tonnes or $ 544,000
• Annual residential energy savings = $2.4 million
• Annual carbon emissions avoided = 4,300 tonnes or $128,000
Carbon stored in Mississauga = annual carbon emissions from 167,400 single family homes
Carbon stored in Brampton = annual carbon emissions from 116,000 automobiles
Next Steps
• Urban Forest Strategies and Management Plans– Educate and engage– Protect– Maintain– Plant
• Monitoring and Research– Repeat at 10 year intervals– Evaluate trends– Anticipate future challenges– Pursue partnerships
• Regional Study– Municipal comparisons– Encourage provincial support
Acknowledgments
Andy Kenney
Meaghan EastwoodToronto and Region Conservation AuthorityEcology Division
Rike BurkhardtCity of TorontoUrban Forestry