AN ANALYSIS OF THE BIODIVERSITY AND TREE AGE STRUCTURE IN

CLINTON, IOWA’S URBAN FOREST

by

Jacob Michael Smith

A senior thesis submitted in partial fulfillment

of the requirements for the degree

of

Bachelor of Arts

in

Environmental Studies

AUGUSTANA COLLEGE

Rock Island, Illinois

February 2016

©COPYRIGHT by

Jacob Michael Smith2016

All Rights Reserved

ii

ACKNOWLEDGEMENTS

I would like to thank Dr. Matthew Fockler for mentoring and assisting me in the research,

writing, and map making process of my senior inquiry. I would also like to thank Dr. Michael

Reisner for his aid throughout my research project. A special thanks to the faculty and students

of Augustana College’s Environmental 380 Special Topics course, the Davey Resource Group,

and the Upper Mississippi Center for their aid in collecting and providing me with the necessary

tree inventory data that made my research possible. I also would like to thank my fellow

colleagues for listening to my research presentation and providing beneficial feedback. Lastly, I

would like to thank Dr. Reuben Heine for his help in developing a methodology for this research.

iii

TABLE OF CONTENTS

Introduction…………………………………………………………………………………….....1-2

Study Area………………………………………………………………………………...............3-5

Literature Review…………………………………………………………………………………6-10

Biodiversity………………………………………………………………….....6-7

Urban Forests and Stresses……………………………………………………..8-9

Biodiversity Management…..…………………………………………………..9-10

Methodology…………………………………………………………………..………………....9-13

Results……………………………………………………………………………………………15-18

Discussion………………………………………………………………………………………..19-22

Bibliography……………………………………………………………………………………...23-24

Appendix 1……………………………………………………………………………………….25- 29

iv

LIST OF TABLESTable Page

1. Table 1: Analysis Areas’ Shannon Values…….…………………………………….17

LIST OF FIGURES

Figure Page

1. Figure 1: Study Area Map………………………………………………………...5

2. Figure 2: Analysis Area Map……………………………………………………..12

3. Figure 5: Private Tree Map……………………………………………………….13

4. Figure 6: Public Tree Map………………………………………………………..14

5. Figure 5: Shannon Diversity Map………………………………………………..17

6. Figure 6: Tree Age Structure Map……………………………………………….18

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ABSTRACT

Biodiversity and tree age structure diversity are key components to maintaining and/or enhancing the aesthetic and ecological value that urban forest ecosystems provide for human well-being. This study analyzes the current state of Clinton, Iowa’s urban forest in terms of tree genus diversity and age structure diversity in order to develop an urban forest planting regime that aims to foster species and genus richness, while also planting for an even tree age structure. Using Clinton’s tree inventory, the Shannon’s Diversity Index, and spatial interpolation, it could be concluded that Clinton, like other cities in the Upper Mississippi River Valley, has a lack of biodiversity and an uneven age structure throughout its urban forests. As a result of this study, specific areas in Clinton have been identified as areas of concern due to their high public visibility, large numbers of trees, low levels of diversity, and lack of an even age structure. These areas of concern could benefit significantly from the implementation and management of an urban forest planting regime that aims to foster biodiversity and tree structure diversity, with the overall goal of enhancing tree genus and age diversity throughout Clinton’s urban forest.

1

Introduction

Biodiversity is a critical ecosystem service that is in dire need of management. Human

well-being and other ecosystem services are directly dependent upon it (Naeem et al. 1999;

Alvey 2006; Chapin lll et al. 2009; Cardinale et al. 2012). High levels of biological diversity

within social-ecological system functional groups promote resilience and sustainability (Chapin

lll et al. 2009). A biodiverse functional group acts as insurance against the loss of a species, thus

well-being and vital ecosystem services are preserved.

Biodiversity loss is a global phenomenon that threatens ecosystem services and human

well-being (Cardinale et al. 2012). Knowing the importance of biodiversity is important in order

to maintain and/or enhance current levels of biodiversity within social-ecological systems across

the globe. By 2100, global biodiversity losses could be between 50 and 75 percent (Naeem et

al. 1999). Biodiversity loss mostly occurs from human induced habitat loss by means of

deforestation, urban sprawl, and introduction of pest and diseases caused by biotic

homogenization (McKinney 2006). When humans design cities we tend to only develop them to

meet the needs of our species and this plays a large role in biodiversity loss and the degradation

of critical ecological services within our urban forests (McKinney 2006).

Urban forests are any collection of trees that live within an urban environment. These

forests are comprised of private land trees, public park and right of way trees, and trees that

naturally exist within an urban boundary. Urban forests play a vital role in the maintenance of

biodiversity and critical ecosystem services, such as water regulation and air filtration, nutrient

cycling, carbon sequestration, microclimatic regulation, and soil maintenance (Bolund and

2

Hunhammar 1999). Therefore, urban forests greatly contribute to the resilience and

sustainability that comes with high levels of functional group biodiversity (Nyström 2006).

A majority of the world’s population now resides in urban areas and these populations

depend on healthy and intact ecosystem services that urban forests provide for survival (Collinge

1996; Alvey 2006). However, biodiversity in urban forests is threatened by habitat

fragmentation, climate change, and introduction of invasive species (Collinge 1996; Alvey

2006). Many urban forests are under attack from anthropogenic sources and require an in-depth

urban forest management plan to preserve the integrity of their ecosystem services (Chapin lll et

al. 2009).

This paper focuses on urban forests and their importance within a social-ecological

system. This research makes use of the Shannon Diversity Index and spatial interpolation in

ArcGIS to interpret the level of tree diversity within Clinton, Iowa’s urban forest. The analysis

of this information will allow an urban forest planting regime to be designed and incorporated.

The planting regime will be based on areas of concern in order to enhance tree species’ diversity,

tree age diversity, resilience, and sustainability in Clinton’s urban forest.

Clinton’s urban forest is currently dominated by the maple genus and is also lacking tree

age evenness. Both stresses pose serious threats to the biodiversity, resilience, and sustainability

of Clinton’s urban forest. Many other urban forests throughout the Upper Mississippi River

Valley are suffering from these same ailments. The methods as well as the planting regime

itself can act as a template for other cities facing similar stresses who wish to analyze the health

of their urban forest and implement an urban forest management plan that addresses

3

enhancement and/or preservation of their urban forests and the vital ecosystem services they

provide.

Study Area

This study was conducted in Clinton, Iowa which is located in the Upper Mississippi

River Valley in the eastern part of Clinton County (Figure 1). Clinton is located along the

western shores of the Mississippi River and spans a total area of 38.01 square miles (U.S. Census

Bureau 2014).

The Upper Mississippi River Valley is currently under threat of losing species diversity.

In floodplain forests of the Upper Mississippi River Valley, oak and hickory species are in

decline, and flood and shade-tolerant silver maple is to dominant. These forests are also losing

the green ash species of trees as the Emerald Ash Borer (EAB) beetle continues to migrate

westward (Romano 2010).

Clinton is a critical location to conduct urban forest biodiversity and resilience research

because the city of Clinton is currently encountering a lack of urban forest biodiversity.

Increasing the tree species’ diversity within Clinton’s urban forest is critical because enhancing

biodiversity will act as ecological insurance in the face of stresses and disturbances (Nyström

2009). Other cities within the Upper Mississippi River Valley are currently dealing with an EAB

infestation and maple dominance. The biodiversity, resilience, and EAB research that has been

conducted for the urban forest planting regime for Clinton is important because they allow for

replication and implementation of similar urban forest planting regimes for any cities that

currently do not have an urban forest plan. Such a plan may help them prevent a further decline

in tree diversity due to disease or pest infestation and/or a tree monoculture presence.

4

The goal of this study is to analyze the biodiversity of Clinton’s urban forest in greater

depth to determine areas of biodiversity concern in order to establish an effective urban forest

planting regime. This planting regime can then be implemented to enhance species diversity in

areas of concern in order to foster biodiversity and resilience within Clinton’s social-ecological

community.

5

Figure 1: This figure represents a map of Clinton, IA including its city limits and proximity to the Mississippi River. Map by author.

6

Literature Review

Biodiversity

Biodiversity plays an important role in fostering resilience in social-ecological systems

by stabilizing certain ecosystem services (Alvey 2006; Chapin lll et al. 2009). Human well-

being is dependent on a multitude of ecosystem services, including regulating, supporting,

provisional, and cultural services. Biodiversity is a supporting service that other ecosystem

services are dependent upon (Chapin lll et al. 2009). Ecosystems with higher levels of

biodiversity tend to be more resilient to exogenous stresses and disturbances than systems with

lower levels of biodiversity (Peterson et al. 1998). High orders of biodiversity at the species

level act as an insurance policy for ecosystem services against stresses and disturbances such as

disease and pest infestation, drought, flooding, and invasive species. Biodiversity degradation

can then have a negative impact on human well-being, increase social-ecological systems

vulnerability to stresses, thereby lowering their resilience (Peterson et al. 1998). Proper

management techniques to maintain or foster biodiversity should be taken (Chapin lll et al.

2009).

Biodiversity is typically thought of as the number of species, or species richness, present

in an ecosystem. This is an important part of biodiversity because as species richness increases

in an area, the invasibility of invasive species decreases due to increased competition for

nutrients (Hooper et al. 2005). Species richness is a critical aspect, but it is not the only

important aspect of biodiversity (Thompson et al. 2009). Chapin lll et al. (2009) explains that

the maintenance of biodiversity factors such as effect diversity, response diversity, keystone

species, functional types, and functional redundancy all play vital roles in fostering ecosystem

resilience. Functional redundancy and response diversity are two imperative elements of

7

biodiversity that are enhanced by species richness (Chapin lll et al. 2009). The maintenance of a

large diversity of species that contributes to the same ecosystem function, or functional

redundancy, increases the capacity of multiple species to compensate for the loss of another

species within that functional group. This conservation of diversity among functional groups

acts as a preventative measure to stresses and disturbances and can increase resilience in

ecological services (Nyström 2006). However, functional groups containing high functional

redundancy can actually increase vulnerability to stresses and disturbances if there is low

response diversity within the group (Nyström 2006). High response diversity mixed with high

functional redundancy within a functional group reduces the vulnerability of a social-ecological

system while increasing its resilience (Nyström 2006).

Effect diversity is another aspect of biodiversity that should be taken into account when

evaluating the overall biodiversity of an ecosystem. In agricultural landscapes, high effect

diversity can have ecological and economic benefits by reducing exposure to herbivores,

pathogens, weeds, and the invasion of invasive species by increasing the amount of natural

predators present in an ecosystem. This in turn enhances the overall resilience of that

ecosystem. Polycultures not only create biodiversity within an ecosystem they also reduce the

cost of pest and disease control for agriculturists while increasing the amount of pollinators that

food crops depend on. Biodiversity has economic and ecological benefits as aforementioned

above, but when considering human well-being it is also important to evaluate the biodiversity of

urban forests and the multitude of benefits that it provides for humans residing in urban

communities (Chapin lll et al. 2009).

8

Urban Forests and Stresses

Human health is dependent on urban forests for ecosystem services and well-being

(Bolund and Hunhammar 1999). These urban ecosystems provide the following services that are

beneficial to human welfare: air filtration, microclimatic regulation, reduced water runoff,

recreational and cultural values, carbon sequestration, and noise reduction (Bolund and

Hunhammar 1999). These benefits can be mitigated by exogenous and endogenous stresses and

disturbances endemic to urban landscapes (Collinge 1996; Alvey 2006). These stresses and

disturbances can result in habitat loss and isolation.

Habitat loss and isolation from land development poses a serious threat to the

biodiversity of urban forests. The conversion of continuous forest habitat into discrete habitat

fragments reduces biodiversity by creating edge habitats, decreasing habitat size, and/or isolating

habitats. Research suggests that edge habitats can create different microclimatic conditions e.g.

higher wind velocities, warmer temperatures, and lower moisture along the edges of forest.

These conditions often penetrate multiple meters into the forest. These micro changes in climate

can further reduce the size of the already fragmented habitat and create opportunities for invasive

species (Collinge 1996).

The size and shape of a habitat remnant are crucial for determining the area of interior

habitat available for animal and plant species that are dependent on continuous habitat.

Rectangular and smaller fragments tend to have less interior habitat available. This reduces the

biodiversity within these remnant patches and could potentially lead to local species extinction

(Collinge 1996). Conversely, larger and square remnant patches have more interior habitat and

less edge habitat that allow for greater biodiversity in these fragments (Collinge 1996).

9

Climate change poses a potential threat to urban areas and their forests and must be

assessed when considering the conservation of urban forest and biodiversity. Patterns of

warming have become more prevalent in cities and temperate zones of the world. These patterns

have created observable poleward and elevational shifts in certain species in response to

warming climates (Wilby and Perry 2006; Hunter 2011). Warming climate patterns have also

induced phenological shifts in certain species (Wilby and Perry 2006; Hunter 2011). These

movements and phenological shifts of species can reduce biodiversity in urban forests because

warmer and drier climates can potentially increase the amount of disease and pests present within

an area (Wilby and Perry 2006). A specific example of pest abundance due to warming winters

is the increased presence of the EAB (Crosthwaite et al. 2010). Research has shown EAB

prepupae to be freeze-intolerant, hence warmer winter temperatures increase survival rates of

this particular species of insect. An abundance of EAB presence endangers the ash trees within

urban forests, thus reducing biodiversity and tree canopy cover (Crosthwaite et al. 2010).

Research on fostering biodiversity and social-ecological system resilience in light of biodiversity

loss and climate change in urban environments have brought about different management and

adaptive strategy plans to mitigate these effects in urban forests.

Biodiversity Management

Management and planting regime strategies for urban forests should be designed to foster

and/or maintain ecological resilience to preserve or increase ecosystem health. Ways to

incorporate this concept is to increase functional and response diversity within urban forest

ecosystems (Chapin lll et al. 2009; Hunter 2011). Other concepts to consider when designing

urban forest planting regimes are the plasticity of specific tree species and structural diversity

10

(Hunter 2011). When considering specific species of trees to plant when promoting diversity

and resilience native species are typically preferred, but non-native or cultivar species that are

not invasive should also be considered in the planting regime (Alvey 2006). Developing an

urban forest planting regime is important for fostering resilience and biodiversity of a social-

ecological system. Humans play a large role in social-ecological systems, thus human tree

values should be taken into consideration when designing a feasible urban forest planting regime

(Dywer et al. 1991; Chapin lll et al. 2009). Once urban forest plans are implemented it is

important to manage the entire social-ecological system as a whole and not just the urban forest

aspect of the plan (Chapin lll et al. 2009).

Methodology

For this project, a methodology was developed to determine the estimated biodiversity

values throughout Clinton’s urban forest using its tree inventory data. Understanding the current

tree inventory and the estimated biodiversity values are vital to analyzing the state of Clinton’s

urban forest in terms of resilience and sustainability. To enhance the understanding of Clinton’s

urban forest, a multi-step process was developed.

To interpret the biodiversity of Clinton’s urban forest, a tree inventory was first

completed in the fall of 2015. The inventory involved the surveying of private and public trees

within Clinton. Semi-randomly selected city blocks were surveyed for private tree information

and the public trees were surveyed in total by the Davey Resource Group.

To complete the necessary biodiversity calculations, the Shannon Diversity Index was

chosen as the biodiversity metric. The Shannon Index is a commonly used calculation that

measures diversity based on the species richness and evenness within an area and is calculated

11

by H '=−∑i=1

R

❑ p i❑∗( ln∗pi), where piis the proportion of individuals belonging to the ith genus

and R is the genus richness (Tramer 1969). To prevent misrepresentation of the calculated

diversity values, genus richness and evenness were used instead of species richness and

evenness. This prevents the diversity data from appearing more diverse than it actually is by

removing the weight on the presence of multiple species located within the same genus.

In order to successfully implement the Shannon Index, the city of Clinton was divided up

uniformly into 60 analysis areas (Figure 2). The Shannon index was calculated and then

assigned for any of the areas containing tree data. These Shannon Index values were input into

ArcGIS, where spatial interpolation was used to generate estimated biodiversity values based on

neighboring area values for any areas with insufficient data.

12

Figure 2: A visual representation of the 60 analysis areas used to generate individual Shannon Index values. Map by Jacob Smith.

13

Figure 3: This map displays the semi-randomly surveyed private trees in Clinton’s urban forest. Map by author.

14

Figure 4: This map displays the locations of all of the public trees surveyed in Clinton. Map by author.

15

Results

The Shannon values range from 0.0-2.66. The Shannon diversity scale itself ranges from

0.0-3.5, where 0.0 represents an absolute lack of biodiversity, or monoculture, and 3.5 exhibits

an evenly-spaced and a high level of biodiversity within an area. A total of 13 areas had a

Shannon Diversity of 0.0. This is not due to a monoculture presence in these areas and instead,

are a result of a lack of private tree data (Table 1) .

All of the trees that were surveyed in Clinton were condensed into their common name

genus (Appendix 1). Tree genus was selected over species type because using tree species would

give a false sense of diversity in areas with multiple species that fall under the same genus.

Overall, 6,807 trees were surveyed falling under 68 different genera. The gamma diversity of

Clinton is 2.82. This value depicts Clinton’s urban forest as diverse, but the top ten genera make

up 76 percent of the surveyed trees. The maple genus made up 29.4 percent of all surveyed

trees in Clinton, indicating a maple dominance in the city (Appendix 1).

The age structure of Clinton’s surveyed urban forest is fairly uneven with a majority of

its trees being mature. Planting efforts appear to have been focused on in northeastern Clinton as

there are a large number of younger trees in this region. Southeastern Clinton, conversely, is

dominated by mature trees. Areas 17, 18, 46, and 55 are sections of structural concern as these

are public areas where a majority of their trees are mature (Figure 2; Figure 6).

A majority of the surveyed trees in Clinton are located on the eastern side of town, yet

these areas have a low diversity index and a mature tree age structure (Figure 5; Figure 6).

Despite these low Shannon values, these eastern urban areas yield higher levels of biodiversity

than the western semi-rural areas. Areas 49, 50, 46, and 47 are of concern as they are located in

16

a downtown area with many trees, but they have poor Shannon values of 2.06, 2.03, 1.64 and

2.03. Areas 21 and 16 have the highest Shannon values 2.66 and 2.65 and are evidence that

higher levels of diversity are attainable in the urban areas of Clinton (Figure 5; Table 1).

Table 1: Shannon diversity Index for each of the 60 analysis areas in Clinton, IA. JJJ Represent areas of Concern where ABC represent areas of higher biodiversity.Analysis Area

Shannon's Diversity

Analysis Area

Shannon's Diversity

Analysis Area

Shannon's Diversity

Analysis Area

Shannon's Diversity

1 0 16 2.65 31 0 46 1.64

2 1.59 17 2.47 32 1.9 47 2.03

3 1.66 18 2.13 33 1.76 48 2.38

4 1..96 19 0 34 1.05 49 2.06

5 2.16 20 0 35 1.87 50 2.03

6 0 21 2.66 36 0 51 2.5

7 0 22 2.38 37 2.12 52 2.4

8 1.75 23 0 38 0 53 1.27

9 1.72 24 2.12 39 1.9 54 1.67

10 0 25 1.51 40 1.24 55 2.22

11 1.8 26 1.09 41 1.68 56 1.42

12 2.4 27 1.61 42 1.16 57 2.39

13 1.59 28 0 43 1.5 58 2.15

14 2.18 29 0 44 2.46 59 1.89

15 1.91 30 0 45 2.5 60 2.56

17

Figure 5: This map exhibits the tree diversity and estimated tree diversity in terms of the shannon diversity. Green represents areas of low levels of biodiversity and red represents areas with higher levels of diversity. Areas outlined in magenta are areas of biodiversity concern, where areas outlined in white are areas with a fair amount of diversity.

18

Figure 6: This map displays the locations and sizes of each surveyed tree in Clinton’s urban forest canopy.19

Discussion

The map in Figure 5 reveals the Shannon Diversity for areas of Clinton’s urban forest.

The higher levels of biodiversity in the urban forest occur on the eastern side of Clinton where a

majority of Clinton’s public trees are located. The southeastern portion of Clinton along

highway 30 holds the areas of greatest diversity with the highest recorded Shannon value there

being 2.66 in area 21 (Table 1; Figure 5). Ironically enough, these areas along highway 30 were

planted at roughly the same time, creating an uneven age structure (Figure 6). Despite the higher

levels of diversity, the trees in these areas are unevenly aged and when these trees reach maturity

they will be less resilient to pests, disease, and death due to old age, putting these areas at risk of

mass canopy loss in a short period of time.

Figure 5 is misleading and indicates that values such as 2.66 in area 21 are high.

However, the Shannon Diversity Index is on a scale from 0.0-3.5 and is sensitive to changes in

the hundredths place. Analysis of Figure 5 and Appendix 1 make it evident that Clinton has a

tree diversity issue in its urban forest due to a maple dominance and an uneven distribution

amongst tree genera present within Clinton. The top ten tree genera in Clinton account for 76

percent of the urban forest canopy (Appendix 1).

Specific areas of biodiversity concern indicated by Figure 5 and Table 1 were areas 46,

47, 49, 50, and 55. These areas are highly visible and each contain a large number of trees, but

have low levels of biodiversity within them. This makes them vulnerable to loss of biodiversity

and the degradation of other ecosystem services through exogenous and endogenous stresses,

making these priority areas for management.

20

Analysis of Figure 6 revealed that Clinton has an unevenly aged urban forest, with the

majority of its trees being mature in age. Areas in northeastern Clinton have a large number of

younger trees, where in southeastern Clinton, a majority of the trees are mature in age. This

uneven age structure throughout Clinton places specific sections such as areas 17, 18, 46, and 55

at risk of severe canopy loss. These areas are highly visible to the public and contain a large

amount of mature trees, making them more vulnerable to pests, diseases and death in a short span

of time. Significant canopy loss in these areas could severely damage the aesthetics and the

ecological processes occurring here. Like areas 46, 47, 49, 50, and 55, these are priority

management areas.

The areas of immediate management concern are areas 46 and 55. These sections both

have low levels of biodiversity and are dominated by mature-aged trees. Area 46 is a downtown

area that is highly visible to the public. Any mass loss of canopy coverage in this area would

have detrimental aesthetic effects and would result in the degradation of critical ecological

processes. Area 55 is a densely wooded section in Eagle Point Park. This area is also visible to

the public and a significant loss of trees here would result in forest fragmentation, leading to

further loss of biodiversity and the depreciation of area aesthetics.

The spatial diversity and tree inventory data acquired as a result of this study are critical

because they provide information on areas of diversity concern and allow for the development of

an urban forest planting regime that fosters and restores diversity and resilience to specific areas

of Clinton’s urban forest.

Clinton is not the only area in the Upper Mississippi River Valley suffering from a maple

dominance and an uneven forest age structure. River floodplain forests throughout the Upper

21

Mississippi River Valley have seen a shift from heliophilic oak and hickory forests to mesophilic

maple dominated forests (Nowacki and Abrams 2008; Romano 2010). The findings observed in

this study appear consistent with research on the mesophication of forests in the Eastern U.S. and

in the Upper Mississippi River floodplain forests. As forests in these regions become more

dominated with shade-tolerant species, they are more vulnerable to reductions in diversity and

resilience (Nowacki and Abrams 2008; Romano 2010). The methods in this study can possibly

contribute to the way that forests in the Eastern U.S. and Upper Mississippi River Valley are

managed by identifying areas of biodiversity and age structural concern. As these areas are

identified, forest planting regimes can be developed to improve the resilience of these regions

while also maintaining areas with significant amounts of biodiversity and age diversity.

A significant limitation of this study was the overall lack of private tree inventory data

(Figure 3). Figure 5 identifies many areas with a Shannon Diversity of 0.0 or values below 1.0.

These values only occur due to the lack of private tree information available in the absence of

public tree data. While Clinton’s urban forest does have tree diversity issues, this lack of private

tree information makes the diversity of Clinton’s urban forest appear worse than it actually is.

To build upon this study, more effective methods of surveying private yard trees need to be

developed, along with the public education on the importance of tree identification in hopes to

improve the Clinton’s current urban forest inventory.

Clinton’s urban forest is suffering from a lack of biodiversity and tree age diversity. No

analysis areas had a Shannon value greater than 2.66 and 76 percent of all the surveyed trees in

Clinton were classified under the top ten tree genera as well as a large portion are mature in age,

creating an uneven age structure of trees throughout Clinton (Table 1; Appendix 1; Figure 6).

22

Due to a lack of private tree information this plan should look to improve conditions within the

public tree realm (Figure 4). To address these issues, adaptive management techniques will be

need to be taken. These techniques should be determined and taken by an agency and the

stakeholders of Clinton to develop a planting regime that incorporates the following: Increasing

functional redundancy and response diversity and planting for species plasticity and structural

diversity within Clinton’s urban forest, all while taking into consideration the human values on

trees. These are all aspects that a planting regime should have in order to foster the biodiversity

and resilience within Clinton’s social-ecological system (Chapin lll et al. 2009).

23

References Cited

Alvey, A. A. (2006). Promoting and preserving biodiversity in the urban forest. URBAN FORESTRY & URBAN GREENING. 5, 195–201.

Bolund, P., & Hunhammar, S. (1999). Ecosystem services in urban areas. Ecological Economics, 29, 293–301.

Cardinale, B. J. et al. (2012). Biodiversity loss and its impact on humanity. Nature,486(7401), 59–67.

Collinge, S. K. (1996). Ecological consequences of habitat fragmentation: implications for landscape architecture and planning. Landscape And Urban Planning, 36(1), 59–77.

Chapin, III, F. S. (2009). “Managing Ecosystems Sustainably: The Key Role of Resilience”. In Principles of Ecosystem Stewardship: Resilience-Based Natural Resource Management in a Changing World (pp. 29–55). New York: Springer.

Dwyer, J.F., Schroeder, H.W., Gobster, P.H. (1991). The significance of urban trees and forests: toward a deeper understanding of values. Journal of Arboriculture 17(10):276-284.

Hooper, D.U. et al. (2005). Effects of Biodiversity on Ecosystem Functioning: a consensus of current knowledge. Ecological Monographs, 75(1):3-35.

Hunter, M. (2011). Using Ecological Theory to Guide Urban Planting Design: An adaptation strategy for climate change. Landscape Journal, 30(2-11), 173–193.

Mckinney, M. L. (2006). Urbanization as a major cause of biotic homogenization. Biological Conservation, 127(3), 247–260.

Peterson, G., Allen, C. R., & Holling, C. S. (1998). Original Articles: Ecological Resilience, Biodiversity, and Scale. Ecosystems, 1(1), 6–18.

Naeem, S. C. et al. (1999). Biodiversity and Ecosystem Functioning: Maintaining Natural Life Support Processes. Issues in Ecology.

Nowacki, G. J., & Abrams, M. D. (2008). The Demise of Fire and “Mesophication” of Forests in the Eastern United States. BioScience, 58(2), 123.

Nyström, M. (2006). Redundancy and Response Diversity of Functional Groups: Implications for the Resilience of Coral Reefs. AMBIO: A Journal of the Human Environment Ambio, 35(1), 30–35.

Romano, S. P. (2010). Our current understanding of the Upper Mississippi River System floodplain forest. Hydrobiologia, 640(2010), 115–124.

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Thompson, I. et al. (2009). Forest Resilience, Biodiversity, and Climate Change: a synthesis of the biodiversity/resilience/stability relationship in forest ecosystems. Secretariat of the Convention on Biological Diversity, Montreal. Technical Series no. 43. 1-67.

Wilby, R. L., & Perry, G. L. (2006). Climate change, biodiversity and the urban environment: a critical review based on London, UK. Progress in Physical Geography, 30(1), 73–98.

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APPENDIX 1

26

Gamma Diversity Table: This table represents the genera found throughout Clinton’s urban forest, the percent composition (Pi) of each genus, and the gamma diversity (Sum of pi x ln(pi) column)of Clinton’s surveyed forest.

Genus Richness = 68Individuals = 6,807H = 2.82

Species # individuals(n)

pi

(n/N)pi x ln(pi)

maple 2039 0.294 -0.35995862

crabapple 647 0.093 -0.22138686

spruce 561 0.081 -0.20350572

ash 478 0.069 -0.1844407

oak 424 0.061 -0.17093879

honeylocust 332 0.048 -0.14556644

elm 260 0.038 -0.12316922

pine 231 0.033 -0.11337325

arborvitae 152 0.022 -0.08378061

fir 144 0.021 -0.08049458

redcedar 142 0.020 -0.07966319

hackberry 123 0.018 -0.07155353

stump 123 0.018 -0.07155353

lilac 117 0.017 -0.06890745

linden 114 0.016 -0.06756789

ginkgo 109 0.016 -0.06530983

birch 105 0.015 -0.06347962

serviceberry 86 0.012 -0.05446999

walnut 80 0.012 -0.05150463

pear 51 0.007 -0.03614737

Unknown 48 0.007 -0.03444096

mulberry 44 0.006 -0.03212334

hemlock 43 0.006 -0.03153591

sycamore 43 0.006 -0.03153591

dogwood 41 0.006 -0.0303509

aspen 31 0.004 -0.02419891

cherry 31 0.004 -0.02419891

cottonwood 31 0.004 -0.02419891

hawthorn 31 0.004 -0.02419891

redbud 25 0.004 -0.02029127

hickory 24 0.003 -0.01962099

juniper 22 0.003 -0.01826214

poplar 21 0.003 -0.01757301

blacklocust 17 0.002 -0.01474413

tree of heaven 15 0.002 -0.01328044

catalpa 14 0.002 -0.01253446

willow 12 0.002 -0.01101075

boxelder 11 0.002 -0.0102313

larch 11 0.002 -0.0102313

plum 10 0.001 -0.00943872

magnolia 9 0.001 -0.00863168

planetree 9 0.001 -0.00863168

Kentucky coffeetree 8 0.001 -0.00780857

buckeye 7 0.001 -0.00696738

amur 6 0.001 -0.0061055

chokecherry 6 0.001 -0.0061055

apple 5 0.001 -0.00521946

chestnut 5 0.001 -0.00521946

yew 4 0.001 -0.00430437

redceder 3 0.000 -0.00335282

baldcypress, common 2 0.000 -0.00235223

beech 2 0.000 -0.00235223

ginko 2 0.000 -0.00235223

osage 2 0.000 -0.00235223

pecan 2 0.000 -0.00235223

tuliptree 2 0.000 -0.00235223

whitepoplar 2 0.000 -0.00235223

butternut 1 0.000 -0.00127613

cyprus 1 0.000 -0.00127613

cyrpus 1 0.000 -0.00127613

douglas-fir 1 0.000 -0.00127613

euonymus 1 0.000 -0.00127613

privet 1 0.000 -0.00127613

smoketree 1 0.000 -0.00127613

sumac 1 0.000 -0.00127613

sweetgum 1 0.000 -0.00127613

unknown tree 1 0.000 -0.00127613

zelkova 1 0.000 -0.00127613

6,807 2.82362249