Oregon State University Master of Natural Resources capstone project. Integrating Urban forestry growth with regional greenway planning to increase both greenway network mileage and connectivity with urban forest growth and sustainability.

1. From the Bayous to the Bay: Increasing Houston’s
Regional Urban Forest Sustainability and Public
Health through Regional Trail Networks
Josh DuBois
MNR 561
Spring 2021
In partial fulfillment of the requirements for the Master of Natural Resources
Degree, Oregon State University

2. OUTLINE
• ABSTRACT
• INTRODUCTION
• LITERATURE REVIEW
• MAKING CONNECTIONS: TYING IT ALL TOGETHER
• A TALE OF THREE CITIES
• METHODOLOGY
• DISCUSSION, RESULTS AND RECOMMENDATIONS
• CONCLUSION

3. ABSTRACT
• Houston, TX is the 4th largest metro area in the USA
• Greenspace, including Greenways = connections and numerous social, economic and environmental
benefits—Bayou Greenways 2020 (BG 2020).
• Urban forests (UF) provide similar and overlapping benefits as greenways.
• Integrate UF management with greenway development
• Clear Creek Greenway (CCG) 30 miles
• Atlanta, Singapore and Boston
• CCG increased UTC in Houston by 10,560 trees or .032% UTC.
• Multiplying this by 100 = 1,056,000, 3.2% UTC increase, 3,000 miles of greenway
• The New England Greenway Vision plan proposes 19,300 miles of greenways!
• City of Houston Resilient Houston Plan = 4.6 million trees by 2030
• Million TreesNYC plan = this decade
• Parks Master Plan Surveys reflect support for more trails, connections and trees.

4. INTRODUCTION
• Houston, TX
• Semi tropical climate = hurricanes
and flooding
• 2,500 mile drainage network
• BG 2020
• Integrating (UF) growth and
Greenway development
• Atlanta BeltLine partnership with
Kaiser Permanente of Georgia
• Singapore Parks Connector Network
• Boston, MA, Emerald Necklace

5. INTRODUCTION
• Equitable connections
• Integrated management
• Ecosystem Services
• Biodiversity = Ecosystem Resilience
• More trees= more shade and habitat
• Houston bike and greenway paths are “bursting at the seams”
(Southey, 2021).
• Surveys reflect public support
Clear Creek Greenway proposal captures the benefits of:

6. LITERATURE REVIEW
Three Sections
• Urban Forestry benefits
• Ecosystem Services
• Green Infrastructure
(GI) and a GI Network

7. LITERATURE
REVIEW of
Urban
Forestry
Benefits
• Urban Forests = social, environmental and economic benefits (Mulaney, 2015).
• Reduce air pollution, mitigate stormwater, increase property value, reduce
heating/cooling costs and increase public health (Donovan, 2017).
• Public health benefits of UF include avoided costs (Donovan 2017).
• Healthcare cost savings worth millions of dollars in Houston (TNC, 2017;
Crompton, 2012).
• Urban trees provide important stormwater benefits (Elliot et al, 2018).
• A basic planning model asks three questions (What do we have, What do we
want, How do we get what we want) (Miller et al., 2015).
• Cities that recognize the importance of a strategic urban forestry plan “are
more readily positioned to achieve desired aesthetics, have greater street tree
density and are recognized as memorable places of character” (Galenieks, 2017).
• Failure to properly plan and manage urban forests = higher costs in the long
run and loss of net benefits from urban trees (Galenieks, 2017).

8. LITERATURE
REVIEW of
Ecosystem
Services (ES)
“The benefits people obtain from ecosystems” (United
Nations Millennium Assessment, 2005).
4 categories: Provisioning, Regulating, Cultural,
Supporting services (UNMA, 2005).
Biodiversity is crucial to the capacity of an ecosystem
to continue to provide services, especially in
fragmented urban areas.
Connected habitat (structural and functional) supports
biodiversity in urban areas (Lynch 2018).
Habitat size exerted positive influence on species
richness and abundance in urban forest bird
communities (Kang et al., 2015)

9. LITERATURE
REVIEW of
Green
Infrastructure
(GI) and GI
Networks
Section 502 of the Clean Water Act defines green
infrastructure as "...the range of measures that use
plant or soil systems, permeable pavement or other
permeable surfaces or substrates, stormwater
harvest and reuse, or landscaping to store, infiltrate,
or evapotranspirate stormwater and reduce flows to
sewer systems or to surface waters“ (EPA, 2020).
Manmade or designed systems that harness
ecosystem services to provide multiple benefits.
Green Infrastructure also an “interconnected
network of natural areas and other open spaces that
conserves natural ecosystem values and functions…”
(Benedict & McMahon, 2006).
Many definitions….

10. LITERATURE
REVIEW of
Green
Infrastructure
(GI) and GI
Networks
continued
Too much emphasis on greenway connectivity can
reduce ecological benefits to a city (Chin & Kupfer
2020).
Greenway goals = three-legged stool of Recreation,
Active Transportation and Conservation that are
rarely supported equally so explicit goals are a
necessity (Erickson, 2004).
Recreation possibly most important factor in gaining
public support (Erickson, 2004).
Local level community support is required for equity
and success (NRPA, 2018).
Open space must provide a positive function to
remain open (Whyte, 1968).

11. MAKING CONNECTIONS
• Combining Greenway benefits and Urban Forestry grows both.
• Education and outreach on shared benefits, i.e. UF benefits and
recreation benefits.
• Trees for Schools plants trees in 50 schools per year on average with
42,000 total trees planted.
Integrating Urban Forestry and Greenway Development
= Sustainability and Public Health

12. MAKING CONNECTIONS
• Human built infrastructure that
harnesses ES
• Hubs provide undisturbed habitat
• Migration of wildlife, plants and
recreation, transportation for
humans
• Planting space for trees
GI Hubs/Corridors and benefits

13. MAKING CONNECTIONS
• UTC is a type of GI (EPA, 2020)
• Peak flow = max rate of
stormwater runoff during a rainfall
event.
• Trees reduce peak flow in 3 ways:
Interception, Stemflow and
Infiltration (Elliot et al., 2018).
• Detention and gradual re-release
of stormwater reduces peak flow
by increasing the “lag time”
between the peak of a rainfall
event and peakflow.
Trees as Green Infrastructure

14. MAKING CONNECTIONS
• First Greenroads certified project in Texas, 2013
• 12 block project reduced traffic from four to two lanes
• Rain gardens capture 437,000 gallons of stormwater or 100% of a 2-year storm
• 175 newly planted trees intercept 38,564 gallons of stormwater annually
• 26% ($53 million) increase in surrounding property values from 2013-2015
• Mayor executive order for Planning and Public Works departments
Recent GI Projects in Houston: Bagby Street

15. MAKING CONNECTIONS
• Formerly a 200-acre golf course
• Currently in phase 4 construction
• 6 miles of greenways = 1300 trees planted in phase 1 and 2
• 500,000 gallon stormwater retention capacity
• 39 acres of wetlands and 38 acres of permanent lakes
• 200 homes saved from flooding during Hurricane Harvey
• 2,000 homes and businesses protected from flooding when
complete
Recent Green Infrastructure Projects in Houston: Exploration Green

16. MAKING CONNECTIONS
• Synergy: the combined power of a group of things working together being
greater than the total power achieved by each working separately
(Cambridge Press).
• Integrating UF and greenway development achieves multiple overlapping
goals
• Trees positively affect greenway use in the U.S. (Akpinar, 2016).
Trails and Trees are a synergistic relationship

17. MAKING CONNECTIONS
• Proper planning benefits and
consequences
• Every $1 invested in UF = average
return of $5.82 to community
(Galeneiks, 2017).
• UF Strategic Management Plan
includes 3 questions:
-What do we have?
-What do we want?
-How do we get what we
want?
-Feedback
Urban Forestry Importance of Planning

18. A TALE OF THREE CITIES
• 33 greenway miles
• 22 million annual users, one of most heavily
used multi-use trail in U.S.
• All parks designed to mitigate stormwater
• Fourth Ward park saved $16 million through
GI design.
• $500,000 grant from Kaiser Permanente of
Georgia.
• Health Impact Assessment (Ross et. al, 2012)
• 4,965 trees planted
• Increased biodiversity
Atlanta BeltLine, Georgia

19. A TALE OF THREE CITIES • Urbanized, island country.
• Drainage canal network utilized to
create linear greenspace and
greenways.
• 211-mile network = 134,000 trees
planted.
• Low economic value drainage ROW
= “palatable” cost to decision
makers (Tan, 2006).
• Sub-committee recommendation =
parks and open space planned as
part of network
Singapore Parks Connector Network

20. A TALE OF THREE CITIES
Emerald Necklace, Boston, Massachusetts
• 1,100 acre linear park designed by Frederick Law Olmstead starting in 1878.
• 7-mile trail connects 5 parks.
• Visionary, historical precedent for linking parks through greenways.

21. A TALE OF THREE CITIES
• Large and rapidly expanding, highly urbanized = fragmentation,
flooding.
• Regional UF plans lack specific goals
• Cities lack UF plans
• Surveys = major support
• Extensive 2,500 mile drainage canal network
• Opportunity for regional UF and Greenway vision
• Can be a model for other cities to follow
Why study Houston, TX?

22. A TALE OF THREE CITIES
• Arthur Comey’s 1912 plan envisioned
Houston’s bayous as the backbone for a park
system.
• Beyond the Bayous follow-on project to
intersect BG2020
• Plans do not specifically integrate or include
UF goals or initiatives.
BG 2020 and Beyond the Bayous

23. A TALE OF THREE CITIES
• Tying shared benefits of UF to greenways could elevate UF awareness
• Avoidable health care costs of UF in Houston = $1.8 million (McDonald et al.,
2017)
• Avoided cost approximately 10% of annual tree planting and maintenance
costs for Houston
• 2021 Houston Greenspace Management budget approximately $23.1 million
• Annual avoidable healthcare costs would be approximate $2.3 million
Multiple benefits including Public Health

24. METHODOLOGY
• Walkscore used by H-GAC scored Houston 49.8%
• Maps for walkscore were not available for
download
• Would be insightful to add to GIS and overlay with
other data such as UTC

25. METHODOLOGY
• Approximately 30
miles
• El Franco Lee park
following Clear Creek
to Kemah, TX
• Provides lacking
regional connections
to the BG2020 and
Beyond the Bayous
networks
Clear Creek Greenway Proposal (CCG)

26. METHODOLOGY
• 11 interconnected parks
• 51 to 365 acres
• GI hubs provide numerous benefits
• Parks Master Plans survey results =
support for regional greenways,
connections, shade and trees.
• Galveston County plan = creation of
a tree planting and maintenance
program
• Opportunity to turn support into
Integrated UF and Greenway
Development Plan
Clear Creek Greenway Proposal (CCG)

27. DISCUSSION, RESULTS AND RECOMMENDATIONS
• Houston’s large area encompasses many different ecosystems = lack of regional
planting standards
• Most cities follow City of Houston planting standard “Trees shall not be spaced at
intervals of less than 30 feet” (City of Houston Code of Ordinances, 2021).
• Assuming zero planting conflict and ideal conditions on the approximately 30-mile
CCG proposal this looks like:
• 1 mile = 5,280 feet / 30 feet space = 176 trees per mile X 30 miles = 5,280 trees on
one side X 2 = 10,560 trees.
• With Houston’s approx. 33 million tree urban forest or 18.4% UTC, these additions
would add .032% to the UTC.
Clear Creek Greenway Proposal (CCG)
Calculated UTC benefits

28. DISCUSSION, RESULTS AND RECOMMENDATIONS
• UF value
added
calculated
for:
• Stormwater
Mitigation
• CO2 removal
• Air pollution
removal
• Avoidable
healthcare
costs
Total trees
Houston UF
annual
stormwater
mitigation
value
Individual tree value
stormwater mitigation
CCG annual
stormwater
remediation
value
Houston UF annual
CO2 removal value
Individual tree
value CO2
removal
CCG annual CO2
removal value
Houston UF annual air
pollution removal value
Individual
tree value
air
pollution
removal
CCG annual air
pollutant removal
value
Houston UF annual
avoidable
healthcare costs
Individual
tree value
avoided
healthcar
e costs
CCG annual avoided
healthcare costs
33,000,000.00 $7,800,000.00 $4.23 $44,676.92 $18,600,000.00 $1.77 $18,735.48 $20,400,000.00 $1.62 $17,082.35 $1,770,488.00 $18.64 $196,827.09
Monetized benefits of Houston’s UF and CCG

29. DISCUSSION, RESULTS AND RECOMMENDATIONS
• Atlanta BeltLine KPGA
example applied to Houston
• Houston Health Department
should be initial stakeholder
• Mission statement “…to
work in partnership with the
community to promote and
protect the health and social
well-being of Houstonians
and the environment in
which they live” (HHD,
2021).
Identifying Stakeholders

30. DISCUSSION, RESULTS AND RECOMMENDATIONS
Identifying Stakeholders
Potential stakeholder cities, counties
GIS data can help identify stakeholders
UTC, watershed, floodmaps, etc.
Data at different scales
Need more data!

31. DISCUSSION, RESULTS AND
RECOMMENDATIONS
Site Suitability
Sass et al. (2019) combined publicly
available data into a spatial analyst
model.
Divided tree planting sites in urban areas
into four parts:
-Highest suitability,
-High-medium suitability,
-Low-medium suitability
-Low suitability
Apply to the CCG for:
-Equitable tree planting strategies
-Strategic greenway connections
-Right tree in the right place

32. DISCUSSION, RESULTS AND RECOMMENDATIONS
• Numerous disconnected trails already present in cities and HOA parks
• Surveys say public support
• Small, incremental projects that create a regional network = HUGE benefit
• HCFCD extensive network of under-utilized drainage canals
• Integrating UF management with greenway development = great potential to
drastically increase public health, UF sustainability and growth.
Clear Creek Greenway Proposal (CCG)
Unrealistic? No Way!

33. CONCLUSION
• Integrating UF and Greenway development = cost-efficient way to increase UF
sustainability and resilience of cities
• Successful examples of large, complex regional projects abound
• Build on historical precedent and harness momentum from recent projects
BG2020 and Beyond the Bayous
• Big Thinking = Big Results
• BHAG (Jim Collins)—New England Greenway Vision Plan, Resilient Houston, Million
TreesNYC
• Houston’s greenways are “bursting at the seams” (Southey, 2021).
• Public support exists, if you build it they will come