The Urban Forest Model is BROKEN! It will NOT be Fixed with Tweaking... It Has to be Fundamentally Remade.

Transcription

1 The Urban Forest Model is BROKEN! It will NOT be Fixed with Tweaking... It Has to be Fundamentally Remade. What is the Current Model? Super Trees Growing in Horrible Soils or Sand or Scree What s the New Model? Diverse Tree Species Growing in Forest Floor Soils ALL Bets on Million Tree Programs, etc. are OFF Until The Fundamentals of Adequate Soil Volumes are Solved

2 SuperTrees that Can Grow Anywhere? BUT Can t Survive Monocultures American Elms: Dutch Elm Disease American Chestnut: Chestnut Blight What We Had & Lost Image to the right from the Forest History Society, Inc. at

3 SuperTrees that Can Grow Anywhere? BUT Can t Survive Monocultures American Ash Genus: Emerald Ash Borer American Plane Tree: Anthacnose What We Had & Lost Image above by Lisa Dejong/The Plain Dealer at Image to right from

4 Tree Canopy Cover Annual Rain High > 90 F/33 C Atlanta# 37% # 48 Low < 32 F/0 C Minneapolis 32% New Orleans 21% Philadelphia 20% Chicago*@ 17% 17* 129 Phoenix 13% Los Angeles 21% Washington DC# 29% # 68 New York* 24% * 77 Paris* >20% * 25 London@ 20% 0 64 Dallas, TX 26% 100* 39

5 Green Infrastructure Avoided Gray Infrastructure Costs : Mayor RT Rybak Green Infrastructure to Reduce Gray Stressors and Improve Blue Quality 1 st inch of Rain = 90% Water Quality Solution GRAY Infrastructure GREEN Infrastructure RUN OFF the Landscape BLUE Infrastructure How can we RECHARGE our landscape? Wet the Uplands RECHARGE the Landscape Copyright The Kestrel Design Group, Inc. 2009

6 A 30 inch DBH tree provides 70 times the ecological services of a 3 DBH tree. Green Infrastructure Rethinking Utilities Large deciduous trees as Green Infrastructure Target: 1 / 24 hour storm McPherson et al USDA Forest Service (Urban, 2008, Up By Roots)

7 Conflicts Typical US Street Tree Behaving Badly? Unable to make environmental contributions; but able to cause damage in search for adequate soil Skiera & Moll: 13 years/top 20 - Poor drainage - Short lifespan - Escalating replacement costs - Heaving of sidewalks - Root Intrusions to Utilities - Few Ecological Function /Services How can We Put People on the Moon & Not Grow a Decent Street Tree? Oxygen, Oxygen, Oxygen Skiera & Moll 1992; Urban, 2001; Stahl, 2003

8 Conflicts Gray & Green Infrastructure Conflicts Root constriction Where do the roots go? Wherever there are macropores Oxygen Copyright The Kestrel Design Group, Inc. 2009

9 Stal

10 Conflicts Good Trees? Teapot baobab, Madagascar (Image credit: Gilles Croissant) How About Big Trunks With Small Roots? The amazing baobab [wiki] (Adansonia) or monkey bread tree can grow up to nearly 100 feet (30 m) tall and 35 feet (11 m) wide. Their defining characteristic: their swollen trunk are actually for water storage the baobab tree can store as much as 31,700 gallon (120,000 l) of water to endure harsh drought conditions ( 21/10-most-magnificent-trees-in-theworld/). Stormwater Cistern in a Tree!

11 Sofloox.com

12 Courtesy of Orjan Stahl

13 Supporting Tree Function with Large Oxygenated Soil Volumes Ideal Conditions Growing Big Trees Loam Soil Volumes for Root Growth Grabosky, Trowbridge and Bassuk (2002) Growing Large Trees is all about Volume of and Quality of Oxygenated Soil. In addition to suffering from poor quality soil, the Average street tree only has access to between 2.8 m 3 (100 ft 3 ) and 5.6 m 3 (200 ft 3 ) of soil.

14 Stormwater Storage on Day 1 Field Capacity to Saturation 20% by Volume 12 Tree 20 Tree Urban, 2007, Up By Roots

15 Why ARE MOST USA & International CHAMPION TREES Growing in LOAM? Why AREN T More Champion Trees Growing in COMPACTED SOIL or SHALLOW SOIL or SAND or ROCK?

16 Tree Root Video: From:

17 VALUE OF THE SOIL IN STRUCTURAL SOIL 4 x Leaves LARGE QUANTITIES OF CU SOIL AND SMALL QUANTITIES OF LOAM SOIL CONTAIN EQUAL AMOUNTS OF LOAM SOIL. Large structural soil (0.39cf) Small Loam soil ((0.19cf) Source: Growth response of Ficus benjamina to limited soil volumes and soil dilution in a skeletal soil container study. Loh, Grabowsky, and Bassuk. Urban Forest, Urban Green, 2 (2003) Large Loam Soil (0.39cf)

18 VALUE OF THE SOIL IN STRUCTURAL SOIL 1.7 x Taller LARGE QUANTITIES OF CU SOIL AND SMALL QUANTITIES OF LOAM SOIL CONTAIN EQUAL AMOUNTS OF LOAM SOIL. Large structural soil (0.39cf) Small Loam Soil (0.19cf) Source: Growth response of Ficus benjamina to limited soil volumes and soil dilution in a skeletal soil container study. Loh, Grabowsky, and Bassuk. Urban Forest, Urban Green, 2 (2003) Large Loam Soil (0.39cf)

19 So What Will it Take to Grow Big Trees in the City? Structural Soils (Rock based) 2,200 cf per Tree for Connected Tree Pits Loam cf per Tree for Connected Tree Pits = 4,400 cf per Tree for Individual Tree Pits 1,100 cf per Tree for Individual Tree Pits = Copyright The Kestrel Design Group, Inc TORONTO 15 to 30 cu ms STOCKHOLM 50 to >100 cu ms

20 Urban Trees That We Get. In Compacted Soils. 40 cf per tree Copyright The Kestrel Design Group, Inc Trees are 8 years old

21 Urban Trees That We Get In CU Structural Soil Urban Trees That We Get In Amsterdam Soil. Staten Island, 16 years after installation 425 cf per tree Rose Kennedy Greenway 3 years after installation 300 cf per tree

22 Kestrel Design Group, Inc Copyright The Kestrel Design Group, Inc Urban Trees That We Get In Loams Under Suspended Pavement Lincoln Center, NY 2 Years Old: 6 Caliper; Average 600 cf loam per tree 30+ /762mm twig growth in 2010 (2nd Season) No significant transplant shock

23 Structural soil 2011 Suspended pavement Bartlett trees in structural soil or suspended pavement study Year 7 (2011) Note: all trees are irrigated Suspended pavement Structural soil Suspended pavement Structural soil

24 Stal

25 Stal

26 Stockholm: 50 to 100 cu ms to 3,500 cu ft Stal

27 25 Year Old Street Trees & Suspended Pavement (1985) Charlotte, NC (Design by: Don McSween, James Urban)

28 Suspended Pavement Charlotte, NC 1985 Tyron St. (25 years) Willow Oaks: 40mm (16 ) DBH 13.5m (44ft) High 19m³ (700ft³) of soil / tree 98% survival rate E. Thomas Smiley et al 2009, 2010; Bartlett Tree Laboratory

29 Case Study: 25 Year old Large Trees Under Suspended Pavement (1985) Bethesda, MD London Plane (Platanus x Bloodgood ); Poor Mans Tree (Zelkova serrata); American Elm DED resistant CV (Ulmus CV) : -Average Per Tree height: 40 to 44 feet/12.2 to 13.4m -Average DBH: 14 to 20 / 356mm to 508mm -Average soil volume: 600 ft3/17 m3 (not counting soil sharing) Very High Standard of Care: -1 Year Pruning Intervals -Supplemental Water -Supplemental Mulching Copyright The Kestrel Design Group, Inc Design by: James Urban

30 Christian Science Center, Boston, MA, 43 years old Little Leaf Lindens 700 cf of soil per tree average Sasaki & Assoc.

31 So You Want a Great Urban Forest? DO This Codify Minimum LOAM Soil VOLUMES FIRST >600cf per tree DIVERSIFY Species No Single Tree Species >5% No Single Tree Genus >10% Set Minimum CANOPY TARGET with Deadline >40% FIND & FILL GAPS with Trees Plant 100,000 Small Trees RIGHT Monitor & Apply Responsive O&M Simon, Urban, Smiley, Compton Don t Do This.. Plant Trees in Small PITS Plant Trees in COMPACTED SOIL or SAND or STRUCTURAL SOIL Plant Lots of A FEW Species Plant Trees Only After COMPLAINTS Plant Tree Root Packages LOW Plant Trees As BEFORE Respond to Merchants Complaining about Trees BLOCKING Their SIGNS Announce a MILLION Tree Planting Program Applying Above Steps Copyright The Kestrel Design Group, Inc. 2010

32 Contractor Installation Procedures:

33 Twins Timberwolves MARQ2: 180 TREES/48 BLOCK FACES Context Mississippi River Target Center Arena Green Roof Marquette and 2 nd Ave. Transitway Vikings

34 Stormwater Schematics From: Chicago s Green Alleys Handbook

35 Case Study: Marquette & 2 nd Avenue Trees and stormwater Silva Cell installation (Minneapolis, MN) Copyright The Kestrel Design Group, Inc Rather than spending $3.5M to enlarge the storm sewer system conveyance capacity, the City of Minneapolis spent $1.5M on Silva Cells to meet their stormwater quality goals. (SEH, URS, Kestrel)

36 SEFC: the site of the 2010 Olympic Village

37 Stormwater Schematics

38 Large Scale Stormwater Management with Soil & Trees SEFC 2010 Olympic Village Vancouver, Canada

39 Large Scale Stormwater Management with Soil & Trees June years old SEFC 2010 Olympic Village Vancouver, Canada

40 Green Infrastructure at Scale Let s Make Livable Cities: Waterfront Toronto: 2100 Acres On Lake Ontario; Largest Waterfront Project in the World Trees / Rain Water and Silva Cells Urban Streets Evapotranspiration 16 trees per acre capture -1 /24 hour storm in: Soil Pervious surface DBH capture 1.8 /24 hour storm in: Soil & Interception Imperviou s surface Surface flow Phase 1 Installed: 1,300 trees All Phases: 16,800 trees Structural Cells and Water Storage Over flow Infiltration Design West 8 + DTAH LR

41 Stormwater Schematics From: Chicago s Green Alleys Handbook

42 Stormwater Schematics From: Chicago s Green Alleys Handbook

43 Courtesy: West 8 + DTAH

44 West 8 + DTAH Waterfront Toronto Promenade

45 Next Steps for Municipalities: Big Trees & Clean Stormwater Soil Volumes and Stormwater Treatment Goals Emeryville, California (2008): Citywide Code Designated Small Sized Species Trees: 600 cubic feet per tree Designated Medium Sized Species Trees: 900 cubic feet per tree Designated Large Sized Species Trees: 1,200 cubic feet per tree Charlotte, North Carolina (1985): Guidelines All Trees: 1,000 cubic feet of loam per tree *Toronto, Canada (2009) Citywide Code Individual Tree Pits: 1100 cubic feet of loam per tree Multiple Trees Tree Pits: 550 cubic feet of loam per tree *Stormwater: Sites must retain all runoff from "small design" rainfall events (typically 0.20," or 6 mm) through rainwater reuse, on-site infiltration, and evapotranspiration 14 Major North American Cities (2011) Code

46 Urban Forestry Mature, healthy trees, planted in good conditions are less costly to maintain than are trees planted in poor conditions that limit growth. It has been established that about 30m³ of soil is required to achieve a tree with a trunk of 40cm diameter and able to reach 50% to 60% of its full size and age. This would be the minimum expectation of a residential street tree. This soil volume can be achieved on all of the proposed design standards by providing an average of 15m3 of soil per tree and by sharing soil between trees and establishing a minimum building setback from the property line in order to provide additional soil volume. Development Infrastructure Policy and Standards City of Toronto 2009

47 Total Benefits over 50 years: $2, Total Costs over 50 years: $5, Net Lifecycle COST over 50 years: $3, VALUE OF URBAN TREE BENEFITS over 50 YEARS: Tree In Compacted Soil Estimated Lifespan Of 13 Years Vs. Tree With Silva Cells + Bioretention Soil Estimated Lifespan Of 50+ Years Total Benefits over 50 years: $19, Total Costs over 50 years: $10, Net Lifecycle BENEFITS over 50 years: $8, Copyright The Kestrel Design Group, Inc 2010

48 So You Want a Great Urban Forest? DO This Codify Minimum LOAM Soil VOLUMES FIRST >600cf DIVERSIFY Species No Single Tree Species >5% No Single Tree Genus >10% Set Minimum CANOPY TARGET with Deadline >40% FIND & FILL GAPS with Trees Plant Lots 100,000 Small Trees RIGHT Monitor & Apply Responsive O&M Don t Do This.. Plant Trees in Small PITS Plant Trees in COMPACTED SOIL or SAND or STRUCTURAL SOIL Plant Lots of A FEW Species Plant Trees Only After COMPLAINTS Plant Tree Root Packages LOW Plant Trees As BEFORE Respond to Merchants Complaining about Trees BLOCKING Their SIGNS Announce a MILLION Tree Planting Program Applying Above Steps Simon, Urban, Smiley, Compton Copyright The Kestrel Design Group, Inc. 2010

49 References Donovan, G., and D. Butry Trees in the City: Valuing Trees in Portland, Oregon. Landscape and Urban Planning, vol. 94. Cited in Augustin, S. and J. Cackowski-Campbell What s a Street Tree Worth? Landscape Architecture Volume 100, Number 8. (Economic Benefits). Dwyer, J. F.; Schroeder, H.W.; Gobster, P. H The Significance of Urban Trees and Forests: Toward a Deeper Understanding of Values. Journal of Arboriculture 17(10). (Social Benefits). Dwyer, John F.; Schroeder, Herbert W.; Louviere, Jordan J.; Anderson, Donald H Urbanities [sic] Willingness to Pay for Trees and Forests in Recreation Areas. Journal of Arboriculture 15(10). (Social Benefits). Heisler, Gordon M Tree plantings that save energy. In: Rodbell, Philip D., ed. Proceedings of the Fourth Urban Forestry Conference; 1989 October 15-19; St. Louis, MO.Washington, DC: American Forestry Association. (Energy Benefits). Heisler, G.M Energy Savings With Trees. Journal of Arboriculture 12. cited in USDA (Energy Benefits). Kaplan, R.; Kaplan, S The Experience of Nature: A Psychological Perspective. Cambridge, MA: Cambridge University Press. (Economic Benefits). Kuo, F.; Sullivan,W Environment and Crime in the Inner City: Does Vegetation Reduce Crime? Environment and Behavior 33(3). (Social Benefits). McPherson, E.G Sacramento's Parking Lot Shading Ordinance: Environmental and Economic Costs of Compliance. Landscape and Urban Planning 57. (Economic Benefits). McPherson, E.G.; Simpson, J.R Potential Energy Savings in Buildings by an Urban Tree Planting Program in California. Urban Greening 2(2003). (Energy Benefits). Parsons, R.; Tassinary, L.G.; Ulrich, R.S.; Hebl, M.R.; Grossman-Alexander, M The View From the Road: Implications for Stress Recovery and Immunization. Journal of Environmental Psychology 18(2). (Social Benefits).

50 References Simpson, J.R.; McPherson, E.G Potential of Tree Shade for Reducing Residential Energy use in California. Journal of Arboriculture 22(1). (Energy Benefits). Taylor, A.F.; Kuo, F.; Sullivan,W Coping with ADD: The Surprising Connection to Green Play Settings. Environment and Behavior 33(1). (Social Benefits). Taylor, Andrea Faber; Kuo, Frances E.; Sullivan, William C Views of Nature and Self-Discipline: Evidence from Inner City Children. Journal of Environmental Psychology 22(1-2). (Social Benefits). The National Arbor Day Foundation The value of trees to a community. (January 12). (Energy Benefits). Ulrich, R View through Window May Influence Recovery from Surgery. Science 224. (Social Benefits). Ulrich, R.S Human Responses to Vegetation and Landscapes. Landscape and Urban Planning 13. (Social Benefits). USDA The Value of Trees. Urban and Community Forestry Appreciation Tool Kit USDA Forest Service NA-IN Statistics Sheet Downloaded from U.S. Department of Energy Energy Savers, Tips on Saving Money and Energy at Home. Energy Efficiency and Renewable Energy Clearinghouse. (Energy Benefits). Wolf, K. L Nature and Commerce: Human Ecology in Business Districts. In: Kollins, C., ed. Building Cities of Green: Proceedings of the 9th National Urban Forest Conference.Washington, DC: American Forests. (Economic Benefits). Wolf, Kathy L Trees in Business Districts: Positive Effects on Consumer Behavior! Fact Sheet #5. Seattle: University of Washington, College of Forest Resources, Center for Urban Horticulture. (Economic Benefits). Wolf, Kathy L The Calming Effect of Green: Roadside Landscape and Driver Stress. Factsheet #8. Seattle: University of Washington, Center for Urban Horticulture. (Social Benefits).

51 Let s End Magical Thinking about Trees* Abracadabra! Ta Da! *Peter MacDonagh The Kestrel Design Group

52 Contact: L. Peter MacDonagh Principal Kestrel Design Group, Inc. & Adjunct Faculty University of Minnesota (952) (612) Dad. We Need A Minimum Tree Rooting Soil Volume