A Historical Cost/Benefit Analysis of Urban Tree Canopy and Dutch Elm Disease in Milwaukee, WI

An Analysis of DED, EAB, and Historical Tree Canopy in Milwaukee, WI Arbor Day Partners Conference| November 19, 2015

Ian Hanou, Owner/PrincipalPresented by:

www.planitgeo.com | [email protected] 1

What if Milwaukee could have retained

elm street trees from DED mortality and what does this

mean for EAB management?

David Sivyer, Milwaukee Forestry Services Manager

Rich Hauer, Ph.D., Univ. of Wisconsin, Stevens Point

Ian Hanou and Richard Thurau, Ph.D., Plan-It Geo

Wisconsin DNR (50% of funding)

Collaborators


Background and Purpose Historical Tree Canopy Ecosystem and Economic Methods Management Scenario Modeling Take Homes

Overview


Background

Historical Canopy

Eco & Economic Methods

Mgmt. Scenario Modeling

Take Homes

Questions

Aggressive pathogens are devastating urban forests

UF pest management is often reactive

UF management is being driven by canopy benefits

Total cost to restore canopy from major pests is staggering and poorly understood.

Background

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Background

Historical Canopy



Take Homes

Questions

Background

www.planitgeo.com | [email protected]

When was the low point in Milwaukee’s canopy?

What was the cumulative loss in benefits from >100k

DED elm removals?

What is the B/C to have maintained elms, requiring

what level of maintenance?

How long did it take to recover?

What lessons can be applied to EAB?

What can we model of the elm population (structural

attributes, mortality, growth, and condition)?

Management Questions of this Study

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Background

Historical Canopy



Take Homes

Questions

Background


Street tree population and EAB impacts ~195,000 street trees 31,500 ash street trees Or 16% loss of ROW canopy $46M structural damage $27M remove and replace cost (3” cal.)

Current EAB approach in MKE Treat ash every other year ($3.75/dia. inch, 18” avg. DBH, $33.75/yr)

Case study for phased conservation / treatment and flat-lining budgets

Background: EAB in MKE


Background

Historical Canopy



Take Homes

Questions

Background

Lack of science/research/options in 1960’s in MKE MKE 1956 elm population: 106,738

Currently <1,000 Removals peaked @ 16,580 in 1968

> 10,000/year for 4 years straightReplanting peaked @ 18,966 in 1970 Avg. 11,000/year from 1956-1982

Less on maintenance / beautification for 1-2 decades

Background: DED Impact in MKE


19561957

19581959

19601961

19621963

19641965

19661967

19681969

19701971

19721973

19741975

19761977

19781979

19801981

19821983

19841985

19861987

19881989

19901991

19921993

19941995

02,0004,0006,0008,000

10,00012,00014,00016,00018,00020,000

MKE Trees Planted by Year

Background

Historical Canopy



Take Homes

Questions

Background

Urban trees provide quantifiable benefits / value Benefits can outweigh costs (positive B/C) Risk management / sanitation scenarios

No DED

Do Nothing

Actual

Fair

Good

Best

Assumptions and Approaches


Source: Cannon and Worley 1976

Background

Historical Canopy



Take Homes

Questions

Background

Modeling Inputs and Tools Used


Elm population (cohorts)

Avg. DBH by cohort elm pop.

Mortality – natural and from DED – by sanitation

level (management scenarios)

Growth

Benefits (i-Tree and CTLA)

Costs (DED/EAB-PLANS)

Inflation CPI / PPI)

Background

Historical Canopy



Take Homes

Questions

Background

Canopy Cover Estimation Aerial Examples Methods Imagery Used Results

Phase 1: Historical Tree Canopy Baseline

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Background

Historical Canopy



Take Homes

Questions

Historical Canopy


Historical Canopy Cover Estimation

11www.planitgeo.com | [email protected]

Elm Loss Over Time, Neighborhood Scale

1956 1979

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Historical aerial view of continuous street tree canopy cover in Milwaukee along West Capitol Drive (Top), North 27th Street (West), North Teutonia Ave (East), West Vienna Ave (South)


Canopy Loss From 2013 to 1956

Canopy Points

All Other Points

Study Area: Rights-of-Way Sample Points: Rights-of-Way Sample Points: Citywide

Historical Canopy Cover Estimation Methods

13www.planitgeo.com | [email protected]

Imagery Year

Spectral Bands

Known or Approximate Resolution

Example

1956 Black & White ¼ meter



1979 Black & White ½ meter

1986 Color Infrared 1 meter

2013 True Color (NAIP) 1 meter

Historical Imagery Used

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Background

Historical Canopy



Take Homes

Questions

Historical Canopy


Year Canopy Points

(of 500)

Canopy Cover

S.E. (±)

C.I. (±)

Canopy Area

(Acres)

Canopy Change by time period

(Acres)

% Change from prior assessment

year

1956 1,500 8.7% 0.7 1.4 5,365 N/A N/A 1963 1,500 12.5% 0.9 1.8 7,754 2,389 44.5%

1969 1,000 10.0% 0.9 1.8 6,188 -1,566 -20.2% 1979 1,000 14.3% 1.1 2.2 8,849 2,661 43.0% 1986 1,000 14.6% 1.1 2.2 9,035 186 2.1% 2008 0 20.5% N/A N/A 12,663 3,628 40.2% 2013 1,500 22.7% 1.1 2.2 14,066 1,403 11.1%

Historical Canopy Cover: Citywide

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Background

Historical Canopy



Take Homes

Questions

Historical Canopy


Year Canopy Points

(of 500)

Canopy Cover

S.E. (±)

C.I. (±)

Canopy Area

(Acres)

Proportion of All Canopy Citywide

Canopy Change (Acres)

% Change

1956 96 19.2% 1.8 3.5 2,731 51% N/A N/A 1963 119 23.8% 1.9 3.7 3,385 44% 654 24.0% 1969 80 16.0% 1.6 3.1 2,275 37% -1,109 -32.8% 1979 63 12.6% 1.5 2.9 1,792 20% -484 -21.3% 1986 71 14.2% 1.6 3.1 2,019 22% 228 12.7% 2008 0 25.7% N/A N/A 3,655 27% 1,636 81.0% 2013 116 23.2% 1.9 3.7 3,299 23% -356 -9.7%

Historical Canopy Cover: Rights-of-Way

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Background

Historical Canopy



Take Homes

Questions

Historical Canopy


Historical Canopy Cover: City vs. ROW

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In 23 years, the proportion of canopy in the ROW to the entire city dropped from 51% to just 20%, due to DED removals and increase private-property canopy.

Background

Historical Canopy



Take Homes

Questions

Historical Canopy


• Elm Pop. Modeling for Historical Tree Attributes • Ecosystem Benefits Assessment Modeling

• i-Tree Eco (benefit assessment & valuation)• CTLA Valuation

• Economic Modeling• Management Costs (DED-PLANS / CTLA)

Phase 2: Ecosystem and Economic Modeling

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Background

Historical Canopy



Take Homes

Questions

Ecosystem & Economic Methods


Elm Street Tree Structure Estimates

Year

Tree Structure Estimates

All Tree Species AOI ROW

% Canopy

% Canopy Estimate City

Wide

Elm Tree Diameter

(in)

Elm Tree Height

(ft)

Elm Crown

Width (ft)

1956 19.2 8.7 11.78 32.92 24.89

1963 23.8 12.5 14.6 36.14 28.93

1969 16 10 16.2 38.7 32.4

1979 12.6 14.3 19.6 42.63 38.18

1986 14.2 14.6 21.98 45.18 42.23

2008 25.7 21.9 29.46 N/A N/A

2013 23.2 22.7 31.16 N/A N/A

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Background

Historical Canopy



Take Homes

Questions



Elm Pop. by Mgmt. Scenario 1956-1996

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 400

20,000

40,000

60,000

80,000

100,000

120,000

Number of Trees Surviving No Control

Fair Control

Good Control

Best Control

Actual Outcome

No DED

Years

Num

ber o

f Tre

es

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Background

Historical Canopy



Take Homes

Questions



Ecosystem Service Types: Actual vs. “Best”

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Background

Historical Canopy



Take Homes

Questions



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Combined Annual Ecosystem Services by Sanitation (Management) Level

“Good” is half of “Best” after 40 years

Background

Historical Canopy



Take Homes

Questions



$11.2M in lost stormwater management benefits $74.0M in lost air pollution removal benefits $27.3M in lost energy savings benefits $8.3M in lost carbon sequestration/storage benefits Total of $120.8M in lost ecosystem benefits

(1956 – 2013)

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Cumulative “Foregone” Ecosystem Services(“Best”, net from Actual)

Background

Historical Canopy



Take Homes

Questions



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Cumulative “Foregone” Ecosystem Services

(net compared with Actual)Backgroun

d

Historical Canopy



Take Homes

Questions



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Costs: DED-PLANning Simulator)Backgroun

d

Historical Canopy



Take Homes

Questions


• DED ManagementCostsNPVB/CMethod Comparison

• EAB Management NPVB/C

• Take Homes

Phase 3: Management Scenario Modeling

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Background

Historical Canopy



Take Homes

Questions



Like it or not, urban pests (DED) will cost you $$

Background

Historical Canopy



Take Homes

Questions



Net Benefit of DED ManagementBackgroun

d

Historical Canopy



Take Homes

Questions



$0

$5,000,000

$10,000,000

$15,000,000

$20,000,000

$25,000,000

$30,000,000

$13,419,019

$3,410,017

$14,316,026 $14,762,930

$9,119,333

$2,185,120

$0

$12,129,979

$0

$18,885,048 $0

$0 Treatment Cost Planting Cost Removal Cost

Management Option

Man

agem

ent C

ost

EAB Management: it will cost you moneyBackgroun

d

Historical Canopy



Take Homes

Questions



EAB Management: Net Benefit

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Background

Historical Canopy



Take Homes

Questions



Do Nothing is the lowest cost, if you don’t look at benefits.

Take Home’s

33

Background

Historical Canopy



Take Homes

Questions

Take Homes


Urban trees are a long-range solution, but don’t make shortsighted decisions

Focus on the host population, not the pest, for proactive management & flat-line budgets

Benefits from one ecosystem service, e.g. air pollution reduction, can pay for UF pest management alone.

Active management of urban forest pests results in net benefits, if trees have value.

Alberta, Canada: Still DED Free

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Historical Photos

ContactsIan Hanou, Owner and Director, Business [email protected]

A geospatial analysis, technology consulting, and planning firm specializing in urban natural

resource [email protected]

www.facebook.com/PlanItGeo

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David Sivyer, Forestry Services Manager, City of [email protected]. Rich Hauer, University of Wisconsin, Stevens [email protected]

mailto:[email protected]

http://www.planitgeo.com/

http://www.facebook.com/PlanItGeo

A Historical Cost/Benefit Analysis of Urban Tree Canopy and Dutch Elm Disease in Milwaukee, WI

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