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…”

plus

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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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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Size class distribution compared to ideal

All trees

Suggested ideal

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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