Living in the Shade of Social Injustice
Greg CooperThe Nicholas School of the Environment
Partner’s in Community Forestry Conference 2016
My Story
Greg Cooper, Anne Liberti & Michael Asch
• Master of Forestry and Master of Environmental Management Student at the Nicholas School of the Environment at Duke University
• Our Master’s Project Group began working on the project for the City of Durham as part of an Urban Forest Assessment
Are there distributional differences in the Canopy Cover in the City of Durham?
The Question
The Data
• 4-Band, High-Resolution (1-meter) National Agricultural Imagery Program (NAIP) photos (2014)
• Census Block Groups and demographics from 2010-2014 American Community Survey
Canopy Cover and Demographics
Overall vs. Right-of-Way
Block Group Canopy Cover
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Total Linear (Total)ROW Linear (ROW)
Non-White Population (%)
Can
opy
Cov
er (%
)
0
2000
0
4000
0
6000
0
80000
1000
00
12000
0
1400
00
1600
00
18000
00
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Total Linear (Total)ROW Linear (ROW)Median Household Income ($)
Can
opy
Cov
er (%
)
Is there a better explanation?
When were the street trees planted?• In Durham, street trees began to be planted in the 1930’s under
direction of the City Tree Commission• The chairman of the Commission, Clarence Korstian,
recommended widespread planting of Willow Oaks (Quercus phellos)
Aerial photograph of Watts Hospital in the late 1920s (Kueber 2009) 2014 NAIP Imagery
Home Owner’s Loan Corporation (HOLC)
• A 1930’s Federal Program designed to slow foreclosures
• Created color coded maps to depict real estate risk levels with grades from A to D
• Colors classified by racial composition “Redlining”
(Hillier 2003), (HOLC 1937), (Michaels & Stasio 2014)
The Assumptions
• In Durham, the trees were planted in the 1930’s
• Trees for the most part, don’t move; people do
• Trees making up the canopy are mostly 80+ years old
• Demographics in the 1930’s had an influence on tree planting efforts
• Using the historic redline map, modern canopy cover will reveal where trees were planted in the 1930’s
The Legacy Effects
A B C D0%
10%
20%
30%
40%
50%
60%
70%
80% Private ROW
Can
opy
Cov
er (%
)
Implications in Durham
• Durham is a gentrifying city with rapid changes in the socioeconomic composition of neighborhoods
• The tree canopy is senescing and most of the 1930’s trees will be removed in the next 15 years
• The current replanting strategy is to replace upon removal• Residents can request trees through a cost-share system that
may deter lower income people
• The result will likely be an upheld unequal distribution of street trees.
Does this same trend happen anywhere else?
Fresno, CA
A B C D0%
5%
10%
15%
20%
25%
30% Private ROW
Can
opy
Cov
er (%
)
Pittsburgh, PA
A B C D0%
10%
20%
30%
40%
50%
60% Private ROW
Can
opy
Cov
er (%
)
Portland, OR
A B C D0%
10%
20%
30%
40%
50%
60%Private ROW
Can
opy
Cov
er (%
)
Saint Louis, MO
A B C D0%
10%
20%
30%
40%
50%
60%
70% Private ROW
Can
opy
Cov
er (%
)
Richmond, VA
A B C D0%
10%
20%
30%
40%
50%
60%
70% Private ROW
Can
opy
Cov
er (%
)
Baltimore, MD
A B C D0%
5%
10%
15%
20%
25%
30%
35%
40%
45% Private ROW
Can
opy
Cov
er (%
)
Overall Trends
Durham Fresno Pittsburgh Portland St. Louis Richmond Baltimore0%
10%
20%
30%
40%
50%
60%
70%
A B C D
Cano
py C
over
(%)
Compared to City Averages
A B C D
-1
-0.5
0
0.5
1
1.5
Cano
py C
over
(Sta
ndar
dize
d)
HOLC Zones and Modern Demographics
A B C D0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
PortlandDurhamPittsburghRichmondFresnoSaint LouisBaltimore
Non
-Whi
te P
opul
atio
n (%
) 201
0
HOLC Zones and Modern Demographics
A B C D0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
PortlandDurhamPittsburghRichmondFresnoSaint LouisBaltimore
Non
-Whi
te P
opul
atio
n (%
) 201
0
Remember this…
…and these
HOLC Zones and Modern Demographics
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
-1.5
-1
-0.5
0
0.5
1
1.5
2
ABCD
Non-White Population (%)(2010)
Cano
py C
over
(Sta
ndar
dize
d)
HOLC Zones and Modern Demographics
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
-1.5
-1
-0.5
0
0.5
1
1.5
2
ABCD
Non-White Population (%)(2010)
Cano
py C
over
(Sta
ndar
dize
d) St. Louis
Baltimore
HOLC Zones and Modern Demographics
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
-1.5
-1
-0.5
0
0.5
1
1.5
2
ABCD
Non-White Population (%)(2010)
Cano
py C
over
(Sta
ndar
dize
d)
This could be gentrification…
What does this all mean?
• Historical investment of green infrastructure leaves a long legacy within Cities
• Canopy cover in the right-of-way reflects a social inequity in the historic distribution of public goods
• Cities may be implementing a replacement planting strategy instead of expanding plantings
Consequences
• People living in these historic redlined districts are receiving significantly fewer benefits
• More severe urban heat island effects• Poorer air quality• Decreased mental health benefits• Effects on property value?
• Cities that use a remove then replace practice will perpetuate this unequal distribution
What’s Next?
1. Managers need to raise awareness of tree benefits to all communities in order to increase citywide canopy cover
2. Managers need to think critically about where to plant trees
3. Managers need to think about infrastructure improvements that will allow for a more equal distribution of street trees
4. Tree planting distribution policies should accessible for all communities
More HOLC Redlining InformationWebsite: https://dsl.richmond.edu/panorama/redlining
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