STRATUM: The who, what, when, where and how of street trees

Transcription

1 STRATUM: The who, what, when, where and how of street trees Paula Peper, Center for Urban Forest Research, Pacific Southwest Research Station, USDA Forest Service

2 Center for Urban Forest Research USDA Forest Service PSW Research Station Davis, CA Demonstrate new ways that trees add value - quality of life - to communities. We convert research results into financial terms to stimulate community investment in trees.

3 Traditional & Urban Forestry Adapted methods/terms from traditional Stand structure, growth rates, site indices Carbon equations/estimates Carbon protocols for California Climate Action Registry

4 Applications to Traditional Forestry Change in how U.S. looks national forests Increasing recognition that rural forests have environmental and economic benefits beyond timber/wood product and biomass production. Structure, function, value Functions are expanding New ways to assign value How will value change/influence management?

5 Street Tree Assessment Tool for Urban Forest Managers Who? STRATUM is designed for use by managers, foresters, tree non-profits, designers/planners, and landscape architects. What? STRATUM is a tool that provides users with the ability to evaluate tree populations and programs. Benefits and Costs

6 Why Street Trees? Accessible Urban heat island mitigation Canopy cover

7 Benefit-Based Based Approach Structure (What and Where?) Management (Why?) Value (What, how much?) Function (What and How?)

8 Investment Value Benefits Air quality Carbon Stormwater interception Energy savings Property value Costs Planting Care & Maintenance Infrastructure damage Liability Pest control STRATUM Research Benefits and Costs

9 Conserving Energy Northeast Region 40-yr large tree 130 kwh/yr cooling 3,662 kbtu/yr heating $72.48/yr

10 Reducing Atmospheric Carbon Dioxide Typical 40-year old large tree Idaho: Dbh 45 cm Net annual= 362 kg $2.67 NY City Dbh 40 cm Net = 288 kg $2.12

11 Improving Air Quality Ozone: 160 million people Particulates: 100 million people Large Tree NE vs. Interior West 2.6 lbs/year $ lbs/year $3.75

12 Reducing Stormwater Runoff Large 40- year old tree Northeast: 3,708 gal/yr $30 Interior West: 1,705 gal/yr $9

13 Priced Benefits Regional market prices elec/gas (ConEd, PeoplesNatGas, Boston Elect. Municipal Utilities) Carbon trading credits - CO 2 ($15/ton) Cost of controlling air pollutants (Wang and Santini) Retention/detention costs stormwater runoff Property/Aesthetics 1 % median residential resale price

14 Tree Expenditures Planting, pruning, maintenance Administrative

15 Infrastructure Damage Compendium of Strategies to Reduce Infrastructure Damage

16 Other costs Sewer Pest control Liability trip and fall, storm damage, vehicle accidents Catastrophic tree loss

17 Extensive Regional Differences Tree level Cost of resources Air quality monitoring Building vintages/climate Infrastructure/repair costs Liability issues Employee costs

18 Reference Cities

19 Reference City Research Collect data predominant reference city street tree species Analyze growth rates and dimensions Estimate magnitude of annual benefits Price benefits Price tree care costs Calculate net annual benefits, benefit-cost ratios 25 measurements per tree Diameter-at-breast-height Tree height Crown (bole) height, crown diameter Leaf area Utility lines Tree orientation and setback Condition and location Pruning level recommendation Grow space type and size Tree condition & maintenance Hardscape damage

20 Tree & People Populations 250, ,000 1:4 1:9 208, , ,000 Trees 100,000 1:3 1:3 Population 50,000 30,943 53,011 56,234 17,010 17,821 23,262 0 Ft Collins Cheyenne Bismarck Boise

21 Expenditures ($) 1,000, ,000 $998k $771k 600, ,000 $317k $328k Admin/Inspect/Other Infrastructure & Liability Irr/Litter/Grn Waste Remove/Dispose Pruning Planting 200,000 0 Ft Collins Boise Bismarck Cheyenne

22 Benefits 2,000,000 $2.17M 1,500,000 Property Increase $ 1,000,000 $993k $979k $686k Stormwater Air Quality CO2 Energy 500,000 0 Ft Collins Boise Bismarck Cheyenne

23 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 st Place 2nd Place 3rd Place 4th Place Bismarck Fort Collins Cheyenne Boise New York City 5.60

24 Planning Green Infrastructure City expansion Greater economic services obtainable from trees

25 Regional Variation Local cost of living benefit prices Tree age distribution Tree location Size counts Building vintages Etc.

26 Environmental Service Price Differences Boise New York City

27 Relative Age Distribution Citywide 100 Boise NYC Cheyenne (%) % 70% 60% 50% 40% 30% 0 20% Citywide total Ideal Norway Ideal maple > % >36 0% Pear, callery Ash, green Honeylocust Silver maple Linden, Honeylocust little leaf Maple, Maple red Maple, Crabapple Norway Planetree, London Green ash American Ginkgo basswood Callery Oak, pin pear Maple, silver White ash American Citywide sycamore total DBH Class DBH Class DBH Class (in) Boxelder maple Crabapple Honeylocust Green ash Ponderosa pine Siberian elm Blue spruce Cottonwood/poplar Ideal Citywide total Willow Juniper species >36 % of Populati 0

28 Tree Size & Location

29 Climate Affects Tree Size and Growth Silver Maple Cheyenne Ft Collins Height (f % 58% Years After Planting

30 Accounting for Growth Differences

31 Cheyenne Climate and Environmental Factors Weather: 4 th 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

32 Cheyenne Trees Compared to like-aged trees Shorter Smaller dbh Smaller crown diameter Less leaf area

33 Municipal Forests: Planning + Tenacity =Benefits

34 Care Affects Tree Size and Growth Sweetgum Bole & Total Height (m) Modesto Santa Monica 40% 26% 70% Years

35 Are your pruning cycles pruning dollars off of trees?

36 Tree Size and Benefits $ Honey locust $120 $ Cheyenne Ft Collins $80 $60 $40 $20 $0 Fort Collins Cheyenne Height (ft) % 42% 61% Years After Planting

37 Reference Cities capture many of the differences between U.S. regions itree STRATUM helps users begin benchmarking the health and sustainability of benefits of their street trees

38 STRATUM & Benchmarking What does this information mean? 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

39 Indicators of Health and Stability Structure Species importance Age diversity Condition Management Planting Pruning Removal Conflicts Economic Expenditures Benefits Net benefits Benefit-cost ratios

40 Structure: Key Indices Stability Distribution of Importance Values among species Age distribution Condition

41 Importance Values 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 by species Why important? Influences stability Indicates reliance on functional capacity of each species Linked to benefits and indicates future trends

42 IV Distribution Comparison Indicator Total IV for top 5 species (%) 11 City Results Mean = 57.8% Std Dev = 15.6% Range = 33-79% Minneapolis 67.5% Grade = D % of Total IV Hackberry Siberian elm Honey locust American elm Green ash Siberian elm American linden Ponderosa/Austrian White/silver poplar pine Green ash Blue spruce Siberian elm Cottonwood Green ash American elm Camphor Cherry plum Coast live oak Sweetgum London plane Mondel pine Mex fan palm Arizona ash Willow acacia Chinese elm Littleleaf linden Norway maple Sugar maple Green ash American elm Honeylocust Cottonwood Siberian elm Green ash Silver maple Ft. Collins Cheyenne Bismarck Berkeley Glendale Minneapolis Boulder

43 Age Diversity 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

44 Management Needs Indices 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

45 Management: Planting Needs 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

46 Economic Indices Expenditures $/tree $/capita Benefits Net Benefits Benefit-cost ratios Why is it important? Evaluate return on investment Compare across categories Compare with other cities

47 Expenditures Comparison 11 City Results $/tree Mean = $33.53 Minneapolis = $46.36 Grade = C Total Other Infrastructure Repairs Green Waste & Other Litter & Storm Clean-Up Liability & Legal Irrigation Administration/Other Pest & Disease Inspection Removals Planting Pruning 0% 10% 20% 30% 40% 50% Mean Minneapolis

48 Recommendations Desired Future State of the Urban Forest? Stocking Stability Management Functionality

49 Learn more about i-tree? Visit:

50 i-tree International? Canada Europe Portugal Italy Australia i-tree Team meetings integration Develop road plan Reference cities Resource units

51 Visit our Websites Center for Urban Forest Research psw/programs/cufr/ i-tree STRATUM org/