street trees in loam with suspended pavement

Big Trees in the City: Suspended PavementUrban Trees Urban Soils Stormwater Management

September 30, 2010

Urban Trees, Urban Soils, Stormwater Management

I. Ecological challenges in the urban environmentII. Rethinking utilitiesIII. How do we grow big trees?IV. Silva Cell case studiesV. Integrating trees, soil & stormwaterVI. Next steps

AN INTEGRATED BLUE+GREEN FUTURE FOR OUR CITIESOUR CITIES

“Where is the water going Dad?”

L. Peter MacDonagh, ASLA, ISA, RHS, LEED AP

Director of Science & Design

Kestrel Design Group, Inc.

Adj Faculty Arch & Land ArchAdj. Faculty Arch. & Land. Arch.

Univ. of Minnesota

Natural Areas Agriculture Suburban City

Science + Design

Primarily Recharge Not Discharge

Prairies often grade imperceptibly into savannas, oak woodlands, and/or wetlands (From: Packard and Mutel, Eds, 1997)

T i l C S ti f W tl d P i iTypical Cross-Section of Wetland, Prairie, Savanna(Ingels, 1989)

Green Infrastructure“Avoided Gray Infrastructure Costs”: Mayor RT RybakAvoided Gray Infrastructure Costs : Mayor RT Rybak

Green Infrastructure to Reduce Gray Stressors and Improve Blue Quality1st inch of Rain = 90% Water Quality Solution1 inch of Rain 90% Water Quality Solution

GRAYInfrastructure

GREEN Infrastructure

RUN OFF the RECHARGE the

BLUE Infrastructure

Landscape

How can we RECHARGE our landscape?

RECHARGE the Landscape

How can we RECHARGE our landscape? Wet the Uplands……

Does Green Infrastructure Work?Recharge v. Discharge

Source: Patrick Graham, Marian Kim. Evaluating the Stormwater Management Benefits of Green Roofs Through Water Balance Modeling, 2003.

Urban At-Source Stormwater Control

N t l A l G R f Green Walls/Living WallsNatural Analog Green Roof Green Walls/Living Walls

CisternsLarge Urban Trees

Pervious Paving

MORE & BIGGER CONCRETE PIPES

Where Can Ecological Services Happen? EVT Cooling? Habitat? Hydrologic Balance?Cooling? Habitat? Hydrologic Balance?

50’-200’

30’-50’50’

Rethinking UtilitiesgLarge deciduous trees as “Green Infrastructure”

“A 30 inch DBH tree provides 70 times the ecological services of a 3” DBH tree.”

Dave NowakUSDA Forest ServiceCo-Author of i-Tree

(Urban, 2008, Up By Roots)

Stormwater Benefits of Trees

The amazing baobab [wiki] (Adansonia) or monkey bread tree can grow up to nearly 100 feet (30can 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 (http://www neatorama com/2007/03/(http://www.neatorama.com/2007/03/21/10-most-magnificent-trees-in-the-world/).Combination Tree & Cistern!

Teapot baobab, Madagascar (Image credit: Gilles Croissant)

Stormwater & Urban Trees

• How Can Trees Handle the Water? Rate?How Can Trees Handle the Water? Rate? Volume? Quality?

• 1) Static Storage within the Media Volume• 1) Static Storage within the Media Volume

• 2) Water Droplet Interception by Canopy

• 3) EVT of Media borne Water

• 4) Infiltration of Water into Deep Soil) p

Static Storage Within the Media

• Abundant Mature ResearchAbundant Mature Research

• Accepted Volumetric Quantities

R li bl M d lli C it i• Reliable Modelling Criteria

• Numerous Modelling Choices: Structural Soil (Muddy Rock), Amsterdam Soil (Dirty Sand), Raingarden Mixes, Loams (Garden Soil), Compacted (Dirt)

Soils: For Stormwater Storage & Tree Growthg50:25:25

Saturation Point Field Capacity Wilt Point

Macro-poresMicro-pores

Water movement is highly dependent on soil structure and soil ped retention


Stormwater Storage in Structural Soil

Stormwater Storage in Amsterdam SoilStructural Soil Amsterdam Soil

30% stormwater storage>16” per hour drainage rate


Stormwater Storage in Compacted Soils

Stormwater Storage in Loam SoilsCompacted Soils…….. Loam Soils………….


5% stormwater storage0.1” per hour drainage rate

How Do We Grow Big Trees & Manage Stormwater?g gProvide adequate usable soil volumes in the built environment

Canopy Interceptiony

• Significant & Developing ResearchSignificant & Developing Research

• Reliable Modelling Criteria

Li it d M d lli Ch i• Limited Modelling Choices

• Limited Number of Tree Species Modelled: Planes, Hackberries, Crabapples, Red Oak

Estimated Value of Tree Canopy Interception

Annual Interception:

py pMinneapolis Streetscape Study, 2003-2005

16” DBHHackberry

12” DBHRed Oak

8” DBHCrab Apple

Annual Interception:- 8,543 street trees are Elms >30” DBH, representing 4.46% of the total Minneapolis street tree population.

These 8 543 trees pro ide 30 75% of-These 8,543 trees provide 30.75% of the annual stormwater interception of the entire street tree population –2,058,500 cubic feet/47.26 acre feet, or241 cubic feet per tree per year.p p y

(McPherson et al 2005)Co-Author of i-Tree

Estimated Value of Stormwater InterceptionBenefits of Large TreesBenefits of Large Trees

Stormwater Interception by Hackberries versus Age of Tree

ear

Gallons of Interception/Year

rcep

tion

per

yest

orm

wat

erin

te

Tree Age

Gal

of

s

Source: McPherson et al 2006

Stormwater Interception Volumes

2” Caliper Jacaranda versus 22” DBH Plane Tree

Source: Based on data from McPherson et al 2003

Estimated Economic Value to StormwaterOf Benefits of Large Street TreesOf Benefits of Large Street Trees

Tree size Stormwater Interception

American Elms

DBH (cm)

DBH (inches)

cubic meters/ tree/yr

Gal/tree/yr cf/tree/yr

38 15 5.4 1,427 191

-American Elms: 9 9% of total street trees

114 45 63 16,640 2,225

-American Elms: 9.9% of total street trees-3142 total elms >36” DBH-Elms >36” DBH = 2.6% of total street tree population (total street tree population = 120,676 trees)

-Elms >36” DBH provide 30 75% of total-Elms >36 DBH provide 30.75% of total street tree stormwater benefits (total tree stormwater benefits = 447,500 Ccf)

Source: Minneapolis Municipal Tree Resource Analysis, McPherson et al, 2005, and personal communication

Large Trees – How Large?

The Quinault Lake red cedar (left) is the largest known western red cedar in

Large Trees How Large?

gthe world with a woodvolume of 500 cubic meters. It is located near the northwest shore of Lake Quinault north of AberdeenLake Quinault north of Aberdeen, Washington.(http://purpleslinky.com/trivia/science/worlds-tallest-and-largest-trees)

Tree EvapoTranspiration

• Very Limited Early Research on TreesVery Limited, Early Research on Trees

• Most Complete Research Confined to EVT of Cropsof Crops

• Few Accepted Tree Studies

• Limited Reliable Modelling Data

• Numerous Data Gapsp

Infiltration of Water to Deep Soil

• Well Accepted Mature ResearchWell Accepted Mature Research

• Technical & Financial Difficulties Hinder Reliability in Urban HardscapesReliability in Urban Hardscapes

Soil FilteringBioretention Soil Mix: 65% sand, 20% compost, 15% clay silt

Cumulative percent removal by depthL b t /fi ld

Soil Depth

Cu

Copper

Pb

Lead

Zn

Zinc

P

Phosphorous

TKNKeldahl nitrogen

Laboratory/field summary

12” 90 93 87 0 37

24” 93 99 98 73 60

36” 93 99 99 81 68

Data on bioretention removal rates of pollutants such as ammonium and total nitrogen is variable, so has not been included here.Adapted from Prince George’s County Bioretention Manual

Urban Design Options for Stormwater Treatmentg p1st Gallon CostsRate, Water Quality and Water Quantity Design Goals1. Increase volume & time that water is held at the site using tree soil volumes2. Increase canopy size & reduce water volume falling to ground plane3 R d ll t t l d & t t t i il filt & l3. Reduce pollutant load & water temperature using soil as a filter & a cooler4. Infiltrate & use tree evapo-transpiration to reduce surface runoff volume & cool air temperatures

$2.00 to $2.50 $28 to $35 $6 to $8

Central LibraryMinneapolis, MN

The QueenswayToronto, ON

Central LibraryMinneapolis, MN

Suspended Pavement Research Study: Trees & StormwaterToronto, ON (Cooperative between Ryerson University & University of Minnesota)

Suspended Pavement Research Study: Trees & StormwaterToronto ON (Cooperative between Ryerson University & University of Minnesota)Toronto, ON (Cooperative between Ryerson University & University of Minnesota)

Perforated distribution pipe is installed to bring water from the catch basin through the Structural Cell systemStructural Cell system

Case Study: Trees & StormwateryOlympic Village Bike & Pedestrian Link, Vancouver, BC

Aggregate d i

Silva Cell decks and geotextile

and paving

Silva Cells frames and soil Setting onCompacted SubBase

Case Study: Trees & StormwaterOlympic Village Bike & Pedestrian Link, Vancouver, BC

Silva Cells provide the required soil volume to grow large shade trees adjacent a seawall and promenade. Stormwater runoff (1”/72 hour) to Vancouver Bay volume is reduced & quality is improved.

Case Study: Trees and stormwateryMarquette & 2nd Avenue, Minneapolis, MN

5 5 acres of5.5 acres of Impervious Surface Capacity for 1”/24 hour1 /24 hour storm-Small storm impact to MississippiMississippi River reduced

Washington State Department of EcologySilva Cell Received General Use Designation for Western Washington State inSilva Cell Received General Use Designation for Western Washington State in

September 2009: Functional Equivalent of a Raingarden under Pavement

Tree Roots: How Deep?

The Tree of Ténéré or L’Abre du Ténéré was the world’s most isolated tree – the solitary acacia, which grew in the Sahara desert in Niger, Africa, and was the only tree within more than 250 miles (400 km) around.This tree was the last surviving member of a group of acacias that grew when the desert wasn’t as dry. When scientists dug a hole near the tree, they found its roots went down as deep as 120 feet (36 m) below to the water table!

The Tree of Ténéré in the 1970s (Image credit: Peter Krohn)

Tree Roots & Soil MacroporespOxygen-rich soil volumes support root growth Saturation Point

Field Capacity

Wilt Point

Tree Roots in Mollisols…. Tree Roots in Entisols…..

Tree Roots and PipesNumber of IntrusionsNumber of Intrusions

Intrusion Number

Feet

Courtesy of Stahl

Typical US Street TreeypUnable to make environmental contributions; but able to cause damage in search for adequate soil

Moll: 13 years- Poor drainage

Short lifespan- Short lifespan- High replacement costs- Root heaving of sidewalks- Root intrusions into Utilities

Limited ecological function- Limited ecological function

Moll 1997; Urban, 2001; Stahl, 2003

How Can We Grow Big Trees?St t l S il?Structural Soil?

Here’s theAnswer:

1994

Structural

Rock

Tree pit soil115 cf

Soil 200 cf


Structural Soil 1994-1998What Happened?

Trees in open soil trench

Trees in Structural Soil


Structural Soil 1994 – 2006What Happened?

Year 12 Year 12Year 12 Year 12

Soil - 275 cubic feet / tree in open planter Structural soil - 350 cubic feet / tree Provides: 70 cubic feet / tree actual soil Plus 55 cf soil in tree pitTotal soil 125 cf / tree


How Can We Grow Big Trees?Value of the soil in structural soilValue of the soil in structural soil

Large (4.87) structural soil and Small (1.00) l il l t f illoam soil are equal amounts of soil.

Conclusion:Structural Soil provides21% of the Value of LoamPer Cubic UnitOR

Large structural soil: 1 9 c f

Small LoamSoil:0 39 c f

Large LoamSoil:1.9 c.f.(0 054 c m )

Needs a 4.87 MultiplierTo Equal the Same PerCubic Unit Measure

1.9 c.f. (0.054 c.m.)

0.39 c.f.(0.011c.m.)

(0.054 c.m.)

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)

How Can We Grow Big Trees?Value of the soil in structural soilValue of the soil in structural soil

Large (4.87) structural soil and small (1.00) loam soil are equal amounts of soil.

1 72 Ti H i ht Diff 3 0 Times Leaf Count

PLANT HEIGHT VS. DAYS OF STUDY LEAF COUNT VS. DAYS OF STUDY1.72 Times Height Difference 3.0 Times Leaf Count

Days of StudyDays of Study

Is Loam Always the Best Choice?

……..There are Exceptions:J k Pi B i tl Pi

s oa ays t e est C o ce

Jack Pines; Bristlecone Pine; Limber Pines; Colorado Blue Spruce OFTEN Grow Best in Rock Scree & SandRock, Scree & Sand

However, None of These Trees Are Street Trees OR Even Urban Trees

Bartlett Tree Lab – Urban Plaza StudyyUrban Plaza at 14 Months

E. Thomas Smiley et al 2009, 2010; Bartlett Tree Laboratory

Bartlett Tree Lab – Urban Plaza StudyyUrban Plaza at 2.5 Years




Bartlett Tree Lab – Urban Plaza StudyyUrban Plaza at 4+ Years




Bartlett Tree Lab – Urban Plaza StudyUrban Plaza at 6 5 YearsUrban Plaza at 6.5 Years

Supporting Tree Function with Large Soil Volumespp g gSoil volumes for root growth

“Id l” C diti“Ideal” Conditions

Grabosky, Trowbridge and Bassuk (2002)Grabosky, Trowbridge and Bassuk (2002)

How Large the Soil Volume? How Large the trees?g gProvide large soil (Sandy Loam; <4”/hour) volumes to Manage Stormwater Runoff Volume & Quality

240 cf rain water4250 sf. drainage area (.75” rain)



(Urban, MacDonagh et al, 2008)

Case Study: Large Trees Under Suspended PavementCharlotte NCCharlotte, NCOver 170 Trees Planted in 1985 in Suspended Pavement System


Case Study: Large Trees Under Suspended Pavement Charlotte, NC: Trees are flourishing 25 years after planting

Willow Oak (Quercos phellos):

Per Tree Averages:

-Average height: 44 feet

-Average DBH: 16”

-Average soil volume: 700 ft3

(not counting soil sharing)

-167 of 170 Trees Survived to be

Included in Study

- Low Standard of Care: 5 Year Pruning IntervalsgNO Supplemental Water, MulchingHigh Limbing 15’+

Case Study: Large Trees Under Suspended PavementBethesda, MD: Trees are flourishing 25 years after planting

Plane (Platanus x “Bloodgood”);Plane (Platanus x Bloodgood ); Poor Mans Tree (Zelkova serrata); American Elm Various CV (Ulmus CV) :

Per Tree Averages:-Average height: 40 to 44 feet-Average DBH: 14” to 20” -Average soil volume: 400 ft3 (not counting soil sharing)

Very High Standard of Care: 1 Year Pruning IntervalsSSupplemental Water, Mulching

Cost DecisionsConsider both cost and value

T d li ht h l t b t tTrees and lights have equal cost – but a tree increases in value as it grows.

$450$500

ts in

$

Tree Without Silva Cells: Benefits vs. Year Total Benefits

Stormwater Interceptionst

Total Benefits over 60 years: $1,563.45Total Benefits over 40 years: $1,084.78Net Lifecycle Cost over 40 years: $2,901.43

VALUE OF URBAN TREE BENEFITS VS. TIME: $200

$250$300$350$400$450

rage

Ann

ual B

enef

it Stormwater Interception

Energy Savings

Property Value

0 Ye

ar Li

fecy

cle

Cos

Stud

y Pe

riod

Tree In Compacted Soil -Estimated Lifespan Of 13 Years $0

$50$100$150$200

0 20 40 60

Valu

e of

Ave

r

Air Quality

Carbon Dioxide Net Storage

End

of 4

0 S

Vs.

Tree With Silva Cells + Bioretention Soil –Tree With Silva Cells for Stormwater:

fiTotal Benefits

Year

Estimated Lifespan Of 60 Years

$$350$400$450$500

nual

Ben

efits

in $ Benefits vs. Year

Stormwater Interception

Energy Savings

Property Valuefecy

cle

Co

st

erio

d

$50$100$150$200$250$300

lue

of A

vera

ge A

nn

Property Value

Air Quality

Carbon Dioxide Net Storage

En

d o

f 40

Yea

r L

iS

tud

y P

e

$0$50

0 20 40 60

Va

Year

Bioretention

Stormwater Utility Credit

Total Benefits over 60 years: $19,197.60Total Benefits over 40 years: $10,733.65Net Lifecycle Cost over 40 years: $-1,331.74

E

Brugge, Belgium

Urban Trees That We Want……………….

What Do People Living in Cities Want?Want?Big Trees

Li l C t (2 S d d P t I t ll)

What Do Public Officials Want?

Lincoln Center (2 year Suspended Pavement Install)

What Do Public Officials Want?

Happy Constituents & Strong Tax Base

Bethesda, MD (25 year Suspended Pavement Install)

What Do LandscapeWhat Do Landscape Architects Want?

Draw Pictures & Grow LargeDraw Pictures & Grow Large Trees - to Hug

DEPTH 23’Photo Credit: Orjan Stahl

What Do Civil Engineers Want?Stormwater Infrastructure that Will Last Beyond Their Retirement

Photo Credit: Orjan Stahl

Stormwater Infrastructure that Will Last Beyond Their Retirement

Urban Trees That Landscape Architects DrawUrban Trees That Landscape Architects Draw…………………Mister/Ms Client………Imagine if You Will…………….

Urban Trees That We Get Urban Trees That We Get

• In Structural Soil………. • In Amsterdam Soil…….

Rose Kennedy Greenway, North End Parks, 2 years after installation

Staten Island, 16 years after installation

Urban Trees That We Get:In CompactedIn Compacted Soils………….

Trees are 8 years old

“If the Trees Die, LandscapeLandscape Architecture is NOT Art……………..”JAMES URBAN, FASLA, PRESIDENTIAL MEDAL AWARDEE

“Nor Can It Manage…………… Stormwater”

Urban Trees That We Get in SLoams Under Suspended

Pavement……………

Lincoln Center NYLincoln Center, NY2 Years Old: 6” Caliper

30+” twig growth in 2010, no significant

transplant shock

Urban Trees We Get in Loam Under Suspended PavementSuspended Pavement…………..Downtown Bethesda, MD

25 Years Old

Success Rate Not Tabulated

Urban Trees That We Get in Loams Under Suspended Pavement……………Downtown Charlotte, NC

25 Years Old

98% Success Rate

Next Steps for Municipalitiesp pSoil volume targets and stormwater treatment goals

Emeryville California (2008)Emeryville, California (2008)Designated Small Sized Species Trees: 400 cubic feet per treeDesignated Medium Sized Species Trees: 600 cubic feet per treeDesignated Large Sized Species Trees: 1,200 cubic feet per tree

Charlotte North CarolinaCharlotte, North CarolinaAll Trees: 1,000 cubic feet of loam per tree

Toronto, Canada (2009)Individual Tree Pits: 1100 cubic feet of loam per tree Multiple Trees Tree Pits: 550 cubic feet of loam per treeMultiple Trees Tree Pits: 550 cubic feet of loam per tree

Stormwater: Sites must retain all runoff from "small design" rainfall events (typically .19," or 5 mm) through rainwater reuse, on-site infiltration, and evapotranspiration.

Green Infrastructure at ScaleLet’s Make Livable Cities: Waterfront Toronto: 2100 Acres On Lake Ontario; Largest Waterfront Project in the World

Trees / Rain Water and -16 trees per acre captureSilva CellsUrban Streets

Evapo-transpiration

-16 trees per acre capture 1”/24 hour storm in: Soil-16 trees @ 16” DBH capture2”/24 hour storm in: soil, EVT,& Interception

Pervious surface

i

& Interception

Phase 1 Installed: 1,300 treesAll Phases: 16,800 trees

Impervious surface

InfiltrationStructural Cells and Water Storage

LR

Thank you!yAudience questions & comments

“Top 10 Green Building Product of 2009,” Architectural Recordp g ,

“Top 10 Green Building Product of 2009,” Building Green

“Top 15 Green Building Product of 2009,” Environmental Design + Construction

“New & Noteworthy Product,” Architectural Products

Upcoming Speaking events: ASCE (October 29 in Las Vegas, NV), GreenBuildp g p g ( g )(November 17-19 in Chicago, IL), & CSLA (August 19-21 in Edmonton, AB)

Contact:Contact:L. Peter MacDonaghKestrel Design Group IncKestrel Design Group, Inc.

pmacdonagh@tkdg [email protected]@deeproot.com

(952) 928-9600Cell (612) 730 4381Cell (612) 730-4381

“Dad. We Need Big Trees”

Green Infrastructure at Scale• Largest extensiveLargest extensive

vegetative roof installed on an existing sports building.

• First extensive vegetative roof on an arena.

• Fifth-largest extensive gvegetative roof in North America.

• Tenth-largest extensive gvegetative roof in the world

Green Infrastructure at ScaleLet’s Make Livable Cities: Minneapolis, MN

Target Center ArenaTarget Center ArenaGreen Roof-115,000 sf/1 million gallons per year capturedcaptured

How Will We Meet Our Storm Water Management Regulations?G I f t tGreen Infrastructure

U f d d F d l M d tUnfunded Federal Mandates:

-Stormwater Utility Fees (there are over 1,400 existing stormwater utilities in the U it d St t d b i dUnited States, and more being proposed every week).

- Soil volume targets:600 f l t i C t d t h600 cf loam per tree in Connected trenches1200 cf loam per tree in Individual Pits

- Healthy, viable, long-living trees in the b ilt i tbuilt environment

EPA Green GrantsCity of Utica, NY

The New York State Environmental Facilities Corporation administered an EPA grant foran EPA grant for $700,000 for street tree planting.

Approximately 20% new trees will use Silva Cells.

Silva Cells were installed June 2010.

Where Do We Go From Here?EPA Section 438, and beyond

“Any development or re-development project involving a Federal facility with a

footprint that exceeds 5,000 square feet shall… maintain or restore, to the

maximum extent technically feasible, the predevelopment hydrology of the property

with regard to the temperature, rate, volume and duration of flow.”

S il l t t ill i iti th iti l t t i i dSoil volume targets will prioritize the critical water-retaining and evapotranspirating functions of soil and trees in the built environment.

Silva Cells: Proven Technologygy2006 – Present: Over 130 installations

95th Percentile Rainfall Event for Select U.S. CitiesGreen infrastructure managing small, daily rainfall events

City 95th Percentile Event R i f ll T l (i )

City 95th Percentile Event R i f ll T l (i )Rainfall Total (in) Rainfall Total (in)

Atlanta, GA 1.8 Kansas City, MO 1.7

Baltimore, MD 1.6 Knoxville, TN 1.5

Boston, MA 1.5 Louisville, KY 1.5

Buffalo, NY 1.1 Minneapolis, MN 1.4

Burlington, VT 1.1 New York, NY 1.7

Charleston, WV 1.2 Salt Lake City, UT 0.8

Coeur D’ Alene ID 0 7 Phoenix AZ 1 0Coeur D’ Alene, ID 0.7 Phoenix, AZ 1.0

Cincinnati, OH 1.5 Portland, OR 1.0

Columbus, OH 1.3 Seattle, WA 1.6

Concord, NH 1.3 Washington, DC 1.7

Denver, CO 1.1

Hirschman, David and John Kosco. 2008. Managing Stormwater in Your Community: A Guide for Building an Effective Post-Construction Program,Center for Watershed Protection, www.cwp.org/postconstruction.

Lifecycle Costs and B fit 40

Tree Without Sil C ll

Notes for Tree Without Sil C ll

Tree with Sil C ll

Notes for Tree With Silva Cells

URBAN TREE LIFECYCLE COSTS FOR A 40 YEAR STUDY PERIOD, BASED ON TYPICAL COSTS AND BENEFITS FOR MINNEAPOLIS, MN

Benefits over 40 years

Silva Cells:Estimated Lifespan 13 years

Silva Cells Silva Cells:Estimated Lifespan 60 Years

Installation Costs $3,000 Estimated at $1,000 per tree, i t ll d 3 ti 40

$8,000 Estimated at $8,000 per tree, i t ll d 1 ti 40 t dinstalled 3 times over a 40

year study periodinstalled 1 time over a 40 year study period

Total Benefits $1,084.78 Includes savings from reduced building energy costs, stormwater interception increased

$10,733.65 Includes savings from reduced building energy costs, stormwater interception, increased property values the net value of carboninterception, increased

property values, and the net value of carbon sequestration in the tree.1

values, the net value of carbon sequestration in the tree,1

bioretention3, and stormwater utility fee credit4.

Total Maintenance Costs

$586.21 Includes estimated costs for pruning pest and disease

$1,401.91 Includes estimated costs for pruning, pest and disease controlCosts pruning, pest and disease

control, infrastructure repair, irrigation, cleanup, liability and legal costs, and administration costs.2

pest and disease control, infrastructure repair, irrigation, cleanup, liability and legal costs, administration costs,2 and bioretention maintenance.

Removal Costs $400 Estimated at $200 per tree 2 $0 No removal necessary becauseRemoval Costs $400 Estimated at $200 per tree, 2 times over a 40 year study period

$0 No removal necessary because estimated tree life span is longer than study period

Net Lifecycle Cost $2,901.43 $-1,331.741 Values are based on values documented by i-tree, a peer-reviewed street tree management and analysis software tool for urban forest managers that uses tree inventory data to quantify the dollar value of annual environmental and aesthetic benefits of trees, produced by the i-Tree Cooperative (“the Cooperative”), consisting of the USDA Forest Service, Davey Tree Expert Co., National Arbor Day Foundation, Society of Municipal Arborists and International Society of Arboriculture.2 Values are based on values documented by McPherson, E.G., J.R. Simpson, P.J. Peper, S.E. Maco, S.L. Gardner, S.K. Cozad, and Q. Xiao.. 2006. Midwest Community Tree Guide: Benefits, Costs and Strategic Planting PSW-GTR-199. USDA Forest Service, Pacific Southwest Research Station, Albany, CA3 Bioretention storage for 1 tree with 80 cells, capturing 1” rain event in Minneapolis (approximately 15” per year on 630 s.f. = 4905 GAL per year) based on value of $0.027/GAL of storage per McPherson et al, 2005: 4905 GAL/year x $0.027/ GAL /year = $132/year.4 Stormwater utility credits for 1 tree capturing runoff from 630 s.f of impervious surface = $26.60 per year

Why is it so Hard to Believe that UrbanWhy is it so Hard to Believe that Urban Trees Grow Best in Loam?Why are Almost ALL of our State Champion Trees Growing Best in Loams?

Stormwater Interception

8” DBH Declining Elm 4” DBH Declining Oak8 DBH Declining Elm 4 DBH Declining Oak

Champion Savanna Tree Growing in Loam

Champion Forest Tree Growing in LoamGrowing in Loam…

• Burr Oak, Funks Grove, IL

Growing in Loam….

• Sugar Maple, Funks Grove, IL

About Us & Our TeamStormwater experts, designers, engineers, academics

The DeepRoot MissionTo restore ecosystem services to the built yenvironment by integrating trees, soil and stormwater.

Our PartnersThe Kestrel Design GroupJames Urban, FASLA Engineering Partners International, LLCStantec Innova Engineering

With significant contributions by:E. Thomas Smiley, PhDBartlett Tree Research Laboratory “Where is the water going Dad?”

Ecological Challengesg gHow can green utilities play a role?

“Stormwater Control Measures that harvest, infiltrate, and evapotranspirate stormwater are critical to reducing the volume and pollutant loading of small storms.”1

“Nearly all of the associated problems result from one underlying cause: loss of the water-retaining and evapotranspirating functions of the soil and vegetation in the urban landscape.” 2

1. EPA commissioned report – Urban Stormwater Management in the United States 20082. Ibid.3 S t i bl Sit I iti ti G id li d P f B h k D ft 2008 (ASLA 2008)

“The undervaluing of soils is one of the singular failings of the conventional development approach.”3

3. Sustainable Sites Initiative – Guidelines and Performance Benchmark Draft 2008 (ASLA, 2008)

An Upside Down WorldpAssociated problems with ultra-urban development

- Urban heat island effect - Non point-source pollution- Flooding- Failing urban canopy- Compromised air and water quality- Reduced home and business values- Psychological stress

Images from Fairfax County Park Authority, Fairfax VA

An Upside Down WorldTh Cl W t A t & NPDES Ph 1 2 3 (2012) TMDL iti ti l t 13 ft

HARD PARTHARD PART EASY PARTEASY PART

The Clean Water Act & NPDES: Phase 1, 2, 3 (2012); TMDL mitigation complete 13 years after

TMDL Identification

NonNon--Point Source PollutionPoint Source Pollution Point Source PollutionPoint Source Pollution

Cuyahoga River Fire, 1969Resulted in the Clean Water ActStarTribuneStarTribune

NASA, Goddard Space Center; 2001

Impervious Surfaces

PredevelopmentStreams and Rainstorms

pQuality and rate problems

Small storm

Higher and more rapid peak discharge

pPostdevelopment

Streams and Rainstorms

ow ra

te

More runoff volume

Lower and loss rapid peak

GradualHigher base flow

Stre

amflo

Gradual recession

Adapted From: Protecting Water Quality in Urban Areas. Best management Practices for Dealing with Storm Water Runoff from Urban and Suburban Developing Areas of Minnesota. MPCA 2000.

Time

Gray & Green Infrastructure ConflictsyRoot constriction

Where do the roots go? Wherever there are macropores.

Pipes After 11 YearspRoots will interfere with pipes if they have no other options

Stahl et al.; 2003

Dismantling PVC Pipe’s Elastometric Jointsg pRoots will interfere with pipes if they have no other options

Stahl et al.; 2001

Stahl et al ; 2003Stahl et al.; 2003

A Tree Root Tip can Develop a Pressure of 15 barsp pElastometric seal on a pipe resists pressure of 3-5 bars

Acorns growing on Geo-textileg gPress on Steel Plate 15 barsNutrient Rich Solution

Stahl et al.; 2003

Tree Roots and PipesRepair ImpactsRepair Impacts

Tree Roots and PipesRepair ImpactsRepair Impacts

Courtesy of Stahl23’ deep repaired PVC

Bring The Functionality of the Forest to the Cityg y yThe Silva Cell

Basic Applications:Parking lots; parking lay-bys; plazas and promenades; green walls; green roofs & break-out zones

Image courtesy of Sharp & Diamond Landscape Architects

Water Harvesting in Urban Spacesg pMultiple options for getting stormwater in to the Silva Cell system

Pervious pavers

Trench drains

Catch basins

Grate with catch basin and distribution pipe

Case Study: Marquette & 2nd Avenuey qCost savings

Rather than spending $3.5M to enlarge the storm

sewer system capacity, the City of Minneapolis spent

$1.5M on Silva Cells to meet their stormwater

treatment goals.

street trees in loam with suspended pavement

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