STRATUM: The Benefits and Costs of the Green Infrastructure
Paula Peper, Center for Urban Forest Research, Pacific Southwest Research Station, USDA Forest Service CenterCenter forfor UrbanUrban ForestForest ResearchResearch USDA Forest Service PSW Research Station Davis, CA Demonstrate new ways We convert research that trees add value - results into financial terms quality of life - to to stimulate community communities. investment in trees. BenefitBenefit--BasedBased ApproachApproach
Structure
Function
Management Value AreasAreas ofof ResearchResearch
Investment Value Benefits and Costs • Benefits – Air quality – Carbon storage – Storm-water interception – Energy savings – Property value •Costs – Planting – Care & Maintenance – Infrastructure damage – Liability – Pest control SStreettreet TrTreeee AAssessmentssessment TToolool forfor UUrbanrban ForestForest MManagersanagers •What? – STRATUM is a tool that provides users with the ability to evaluate tree populations and programs – UFORE and STRATUM are primary applications in i-Tree (www.itreetools.org ) •Who? – STRATUM is designed for use by managers, foresters, tree non-profits, designers/planners, and landscape architects WhyWhy StreetStreet Trees,Trees, WhyWhy STRATUMSTRATUM andand NotNot UFOREUFORE??
• Street trees are accessible • Minimal data needed – species, dbh, costs • Provides managers with answers for less initial cost STRATUMSTRATUM vs.vs. UFOREUFORE MinimumMinimum FieldField DataData RequirementsRequirements • STRATUM •UFORE – Species –Plot ID – DBH – Land use – DBH – DBH meas. Ht – Height to live top – Height to crown base – Crown width – % canopy missing –Dieback – Crown light exposure – Tree orientation to building – Setback ReferenceReference CitiesCities TreeTree MeasurementsMeasurements 25 measurements for each tree, including: • Diameter-at-breast-height • Tree height • Crown (bole) height • Crown diameter • Leaf area • Crown shape • Tree orientation and setback • Condition and location • Pruning level • Grow space type and size • Hardscape damage RegionalRegional EnvironmentalEnvironmental DataData CollectionCollection •Fuel Mix • Stormwater retention costs • Property values • Air quality emissions/costs • Carbon •Climate STRATUMSTRATUM • User - minimal input needed – dbh, species – Full inventory or sample – Tree costs (budget) – Local prices • Provides 120 reports on structure, function, value • Allows users to begin “benchmarking” forest activities STRATUMSTRATUM && BenchmarkingBenchmarking • What does this information mean – what can it do for me? • Benchmarking – Comparisons (internal & external) • Areas of success, need improvement
• Prioritize management & investment
• Baseline for future comparisons
• Compare program with similar cities
• Compare resources, budgets and outcomes IndicatorsIndicators ofof HealthHealth andand StabilityStability • Structural – Species importance –Age diversity – Condition • Managerial – Planting – Pruning –Removal – Conflicts • Economic –Expenditures – Benefits – Net benefits – Benefit-cost ratios Structure:Structure: KeyKey IndicesIndices
•Stability
– Distribution of Importance Values among species
– Age distribution
• Condition (health) SpeciesSpecies ImportanceImportance ValuesValues • Relative contribution of a species to the entire population due to numbers and SIZE – Percentage of total tree numbers – Percentage of total leaf area – Percentage of total crown projection area – Ranges from 0-100 by species • Why important? – Influences stability – Indicates reliance on functional capacity of each species – Linked to benefits and indicates future trends IVIV DistributionDistribution ComparisonComparison •Indicator
– Total IV for top 80 Siberian elm 5 species (%) American linden 70 Ponderosa/AustrianWhite/silver poplar pine • 11 City Littleleaf linden 60 Green ash Hackberry Norway maple Green ash Honeylocust Results Blue spruce 50 Siberian elm Sugar maple – Mean = 57.8% Cottonwood 40 Honey locust Siberian elm
– Std Dev = Green ash Siberian elm
% of Total IV Camphor 30 Mondel pine American elm Cherry plum 15.6% Mex fan palm Coast live oak – Range = 33- 20 American elm Arizona ash Green ash Cottonwood Sweetgum Willow acacia American elm 79% 10 Green ash Silver maple London plane Chinese elm • Minneapolis 0 Ft. Collins Cheyenne Bismarck Berkeley Glendale Minneapolis Boulder – 67.5% – Grade = D AgeAge DiversityDiversity
• Percentage of total tree numbers by DBH class – “Ideal” has 40% young, 30% maturing, 20% mature, 10% old • Why important? – Influences stability – Influences short-term management costs and benefits – Indicates future population trends and management issues Management:Management: KeyKey IndicesIndices
• Planting: % full stocking • Pruning: – % safety and general prune • Removals: % needed • Conflicts: % sidewalk & powerline •Why? – Prioritize needs – Budget for priority management – Identify species that perform well and poorly in different sites Management:Management: PlantingPlanting NeedsNeeds • Percentage of all street tree sites with trees (2 trees every 50-ft street is full stocking) • Why is it important ? – How many trees can be planted – Ability to increase net benefits – How well treed our city streets are compared with others’ EconomicEconomic IndicesIndices
• Expenditures – $/tree – $/capita • Benefits • Net Benefits • Benefit-cost ratios • Why is it important? – Evaluate return on investment – Compare across categories – Compare with other cities RecommendationsRecommendations
• Desired Future State of the Urban Forest?
• Stocking
•Stability
• Management
•Functionality Reference City Research: City Comparisons
• Cities in same region – Fort Collins, Colorado – Cheyenne, Wyoming – Bismarck, North Dakota – Boise, Idaho 250,000Tree & People Populations
208,000 200,000 9:1
150,000 4:1 135,000
Trees 100,000 Population 3:1 3:1
50,000 53,011 56,234 30,943 23,262 17,010 17,821 0 Ft Collins Cheyenne Bismarck Boise 1,000,000 Expenditures ($)
800,000 $998k $771k
600,000 Admin/Inspect/Other Infrastructure & Liability Irr/Litter/Grn Waste 400,000 Remove/Dispose $317k $328k Pruning Planting 200,000
0 Ft Collins Boise Bismarck Cheyenne Benefits 2,000,000
$2.17M
1,500,000
Property Increase 1,000,000 Stormwater
$ $993k $979k Air Quality CO2 $686k Energy
500,000
0 Ft Collins Boise Bismarck Cheyenne Comparison (?) per Tree
Ft Collins Cheyenne Bismarck Boise Benefits $70.15 $40.33 $54.94 $42.70 Costs $32.24 $19.28 $17.77 $33.13 B/C Ratio 2.18 2.09 3.09 1.29
1st Place Bismarck 2nd Place Fort Collins New York City 3rd Place Cheyenne 5.60 4th Place Boise Planning Green Infrastructure
Greater economic services City expansion obtainable from trees ExtensiveExtensive SubSub--RegionalRegional DifferencesDifferences
• Cost of resources • Tree level – growth, species, age • Infrastructure/repair costs • Liability issues • Employee costs Environmental Service Price Differences
Boise New York City Relative Age Distribution Boise Citywide DBH Class (in) Class DBH DBH Class (%) NYC 100 90
% of Populati 80 60 70 50 30 40 20 10 DBH Class 0 50% 60% 70% 80% 10% 20% 30% 40%
0-6 0% 0-6
6-12 6-12 100 90
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90 Silver Maple 80 Cheyenne 70 Ft Collins 60
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Height ( 30 58% 46% 20
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0 0 1530456075 Years After Planting Cheyenne Climate and Environmental Factors •Weather: –4th windiest city – Highest incidence of hailstorms – Average 14.4 inches precipitation annually – Low humidity and higher altitude (6138 ft) •Soils: – Alkaline – Low water-holding capacity Management Affects Tree Size and Growth
Sweetgum 20 Modesto 18 Santa Monica 16 14 12 10 26% 8 40% 70% 6
Bole & Total Height (m) 4 2 0 0 5 10 15 20 25 30 35 40 45 50 Years AreAre youryour pruningpruning cyclescycles
pruningpruning dollarsdollars offoff ofof trees?trees? Extensive Regional Differences
• Tree level • Cost of resources • Air quality monitoring • Building vintages/climate • Infrastructure/repair costs • Liability issues • Administrative/Employee costs i-Tree International?
• Canada •i-Tree Team •Europe meetings – Portugal – integration –Italy • Develop road plan – Spain – Reference cities • Australia – Resource units Planning tools for manager, foresters, designers, landscape architects, and others
USDA Forest Service Center for Urban Forest Research Street Tree Simulator
•Stream of future benefits • Level of service analysis • Adjustments for mortality, infrastructure damage, etc. by species and city Tree Visualization Urban Forest GHG/Carbon Reporting Protocols • Trees in cities affect GHG in 3 ways – Removing and sequestering GHG in trunks, roots, leaves as they grow – Reducing electricity and gas use through shading thereby reducing power plant emissions – Wood from dead trees produce bio- fuel, replacing fuels that produce more GHG Visit our Websites Center for Urban Forest Research http://www.fs.fed.us/ psw/programs/cufr/
i-Tree STRATUM http://www.itreetools. org/