PLAN-IT GEO LLC
AN ASSESSMENT OF URBAN TREE CANOPY IN LITTLE ROCK, ARKANSAS November 2013
Plan-It G eo LLC | 5690 Webster Street, Arvada, Col orado, 80002 | www.planitgeo.com
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Urban Tree Canopy in Little Rock, Arkansas Prepared By
Acknowledgements Funding for this project was provided by the USDA Forest Service
Core partners included the Arkansas Forestry Commission, the U.S. Forest Service Urban Forestry South, and the City of Little Rock. In addition, thanks go specifically to Patti Erwin, Dudley Hartel, Bryan Day, and Dennis Webb for their invaluable assistance at many stages of this project. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, sexual orientation, marital status, family status, status as a parent (in education and training programs and activities), because all or part of an individual’s income is derived from any public assistance program, or retaliation. Prepared For Arkansas Forestry Commission City of Little Rock
An Urban Tree Canopy study is one of many elements needed to inform management and planning initiatives for urban forests. Complete and sustainable urban forestry programs involve a shared vision for the desired quality of life and level of service that tree canopy can provide the urban environment.
CONTENTS Executive Summary
1
Urban Forest Assessment Approach
1
Urban Tree Canopy In Little Rock
1
Ecosystem Services Analysis
2
Potential Tree Planting Sites
2
Goal Setting
2
Recommendations and Summary
2
Project Background
3
Major Findings
5
Project Fundamentals
6
Mapping Land Cover and Urban Tree Canopy 6 Terminology
7
UTC Assessment Boundaries
8
Ecosystem Services Analysis
9
Locating and Prioritizing Potential Planting Sites 10 Goal Setting by Zoning District
11
Assessment Results and Products
12
Land Cover in Little Rock
13
Policy & Planning
15
Community & Recreation
17
Stormwater Management and Tree Canopy 18 Street Trees
20
Ecosystem Services
21
Prioritizing Potential Planting Sites
22
Suggested Canopy Cover Goals
24
Recommendations
25
Summary
27
Appendix
29
EXECUTIVE SUMMARY The City of Little Rock’s urban forest is comprised of trees, forests, gardens, green spaces and other natural areas. This urban forest provides numerous benefits by making environments cleaner, safer, and more livable, therefore contributing directly to public health and reducing the costs associated with many required services. To manage, monitor and enhance the quality and stream of benefits received from its urban forests, the Arkansas Forestry Commission and City of Little Rock initiated this study assessing the extent of Urban Tree Canopy (UTC) across the city. This report presents results for current land cover and UTC distribution and offers data analysis, potential planting locations, custom maps and tools, and broad recommendations for setting and achieving canopy goals.
URBAN FOREST ASSESSMENT APPROACH Natural resource managers use top-down (aerial imagery) and bottom-up (field-based) approaches to measure land cover, trees and other green infrastructure, and associated ecosystem services. Terms and methods for UTC assessment are presented in this report. See Project Fundamentals on page 7.
URBAN TREE CANOPY IN LITTLE ROCK
Plantable Area (Impervious): 13%
Unsuitable UTC Area: 14%
This study encompasses 77,379 acres (117 square miles) UTC: defined by the city limits of Little Rock, Arkansas. Based on a land area 48% (after excluding water) of 75,818 acres, the City has 36,606 acres (48%) Plantable Area of existing tree canopy, 28,160 (37%) of total Possible Planting Area, or (Vegetation): 24% PPA, which is defined as non-building, non-road land area where tree planting is possible. Additionally, 11,052 acres (14%) of Little Rock is Figure 1: Distribution of UTC Metrics unsuitable for tree planting. The land cover data was used to assess similar metrics for the City’s wards, watersheds, planned neighborhood associations, zoning districts, street rights-of-way, and City parks. See Results section on pages 12-19.
75,818
48% Little Rock City Limits
Land area in acres for this assessment
37
Percent of Little Rock Available for Tree Planting
57
Highest canopy cover percent in a Ward (Ward 4)
33
Percent of Total UTC from the Coleman Creek Watershed
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ECOSYSTEM SERVICES ANALYSIS Urban trees and forests in communities provide many “ecosystem services”, or direct and indirect economic and environmental benefits such as removing air pollutants, storing and sequestering carbon, mitigating stormwater runoff, conserving energy through shade and wind block, improving public health, and providing wildlife habitat. Little Rock’s tree canopy currently provides an estimated $12.0M in air quality services each year, $3.4M in annual carbon sequestration benefit, and $239.9M in total stormwater management savings ($20.9M annually). See Ecosystem Services section on page 21.
POTENTIAL TREE PLANTING SITES Planting locations were generated from the land cover data using a GIS model, resulting in 287,092 potential sites citywide. To help the City prioritize locations for plantings that achieve specific benefits, numerous attributes were joined based on proximity overlay to the GIS points. Examples (with a count of sites) include parks (15,082), schools (6,431), within floodplains (68,605), near streams (10,591), near parking lots (28,510), and near residential homes (99,968) where associated tree benefits impact social well-being, environmental health, and economic vitality. See Planting Sites Prioritization on pages 23-24.
GOAL SETTING To support and facilitate future tree planting and canopy preservation policies, UTC goals were analyzed using GIS methods and a Canopy Calculator tool. Recent annexations and acquisitions in the western half of the City are heavily forested and zoned for residential development. The potential for forest loss in these areas should be considered during canopy goal setting. A suggested city-wide canopy cover goal of 53% (an additional 6,539 acres of tree canopy) is presented along with goals for individual zoning types. These should be used as a starting point for an interdisciplinary goal setting process. See Suggested Canopy Cover Goals on page 25.
RECOMMENDATIONS AND SUMMARY To balance future development and growth with effective urban forestry planning, city officials must value Little Rock’s canopy cover in environmental, social, and economic terms during planning processes. Maintaining and enhancing this green infrastructure will involve ongoing care and protection, strategic canopy increases, and education to increase the awareness of UTC benefits. This will ensure that trees appreciate over time and that their contributions toward addressing environmental issues and improving community health are maximized. Little Rock exhibits an impressive 48% UTC; a laudable achievement and contribution towards the City's overall sustainability and greening efforts. This study provides hard data required for natural resources planning, monitoring, and decision-making. See the Recommendations and Summary sections on pages 26-28.
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PROJECT BACKGROUND The Capital City of Little Rock is located in Central Arkansas, covers approximately 117 square miles, and has a population of 175,561 (2011 census). With funding from the US Forest Service, the Arkansas Forestry Commission contracted with Plan-It Geo to conduct Little Rock’s first Urban Tree Canopy (UTC) Assessment. This project is part of the Canopy in the Mid-South grant, comprised of 16 cities throughout Mississippi, Arkansas, and Tennessee. Using Geographic Information Systems (GIS), the process measures existing canopy cover, provides a baseline of information for increasing environmental services from the urban forest, strengthens local/state partnerships, builds awareness of urban forest benefits, and enables Little Rock and State of Arkansas to establish canopy goals and strategies.
Figure 2: City boundary of Little Rock, Arkansas and the study area for the UTC Assessment.
Local Involvement: Several local non-profit organizations focus resources on tree planting and conservation. These groups may assist the City in reaching and maintain tree canopy goals. Audubon Arkansas is a proven partner for forest conservation through reforestation and educational programs relating to trees and invasive pests. For more information, visit: http://ar.audubon.org Tree Streets, a Little Rock based non-profit organization, stimulates tree planting within Little Rock. This group has planted over 1,000 trees in Little Rock over the past 15 years. For more information, visit:
http://www.treestreets.com
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Using color-infrared 2010 aerial photography, this assessment mapped five primary land cover classes listed below. Land cover was further categorized by using additional local GIS data layers to separate impervious surface types (building, road, and parking lot).
Urban Tree Canopy: Tree cover, when viewed and mapped from above Vegetation: Irrigated and non-irrigated vegetation Impervious: Surfaces: roads, buildings, sidewalks, parking areas and other impervious surfaces Soil: Dry vegetation/ bare soil Water: All water bodies, including lakes, rivers, and streams The land cover data is used to examine area and percent metrics for existing tree canopy, possible planting areas, and areas unsuitable for planting. These metrics were calculated for the following GIS assessment boundaries: (1) City Limits, (2) Zoning Districts, (3) Wards, (4) Watersheds, (5) Planning Neighborhood Associations (PNAs), (6) Street Rights-of-Way by Ward, and (7) City Parks (see Table 1 on page 10). Finally, a GIS model is used to locate and create priority attributes for potential planting sites. This information serves as the basis for all maps, summaries, and potential planting sites presented in this report. Little Rock’s UTC Assessment is a top-down approach which provides data and tools to enhance planning, management, and value received from the City’s urban forest. Additional bottom-up inventory and assessment can ground-truth viable planting areas as well as provide data on species composition, condition/quality, safety, and forest structure to augment this assessment. The products and outcomes will support developing and monitoring of canopy goals, data-driven resource management plans, refinement of policies and ordinances, and help to foster a greater understanding of urban forest benefits.
What the UTC Assessment provides: This project provides maps and statistical quantification of existing urban tree canopy, possible planting areas and other land cover classes across the City of Little Rock, and targeted areas for tree planting and forest preservation.
Why the UTC Assessment is necessary: This assessment provides an up-to-date benchmark of tree cover, a critical component for effective urban forest management planning and a key measure of environmental sustainability in urban areas.
How Little Rock will use this UTC Assessment: The tools and information resulting from this analysis should be used by planners, resource managers, and community members to understand, improve, and promote forest management across the City.
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MAJOR FINDINGS LAND COVER: Little Rock has 48% (36,606 acres) urban tree canopy and 37% (28,160 acres) of additional area available for tree planting. 24% (18,676 acres) of Little Rock is covered by impervious surfaces, of which 9,737 acres (13%) is available for tree planting. About 10% of all impervious surfaces (2,077 acres) are covered by tree canopy.
CANOPY BY WARDS: Out of seven Wards in Little Rock, Ward 4 has the highest UTC at 57% (3,874 acres) while Ward 1 has the lowest UTC at 27% (4,123 acres). Ward 7 has the highest UTC acreage (9,437 ac), or 26% of total tree canopy citywide.
CANOPY BY ZONING DISTRICTS: Residential zoning comprises of 63% (47,350) of the total land area, and with 26,805 acres of UTC, makes up 73% of all tree canopy. Additionally, residential districts have 14,706 acres (31%) of additional possible planting area. Commercial and industrial zoning districts have 31% (2,096 acres) and 21% (2,365 acres) UTC, respectively. Tree protection and preservation should be a focus in these areas.
CANOPY BY DRAINAGE BASINS: The majority of Little Rock’s stormwater funnels into the Arkansas River at Fourche Creek, the drainage basin with the lowest UTC a t 15% (481 acres). This basin has 50% (1,603 acres) of total possible planting area.
CANOPY BY PNA’S: Little Rock’s 148 planning neighborhood associations average 50% (16,459 acres) UTC and 34% (11,318 acres) total possible planting area.
ECOSYSTEM SERVICES: The current urban forest removes nearly 2,800,000 pounds of air pollutants from the air annually, valued at $12 million per year. Tree canopy provides an estimated value of $239.9 million in avoided stormwater infrastructure costs, valued at $20.9 million annually. Little Rock’s canopy provides $3.4 million in carbon storage and sequestration benefits annually.
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How Are UTC Results Used? To set and implement canopy cover goals To prioritize areas for tree planting and preservation To analyze and visualize tree planting opportunities To work with multiple, diverse partners to achieve and maintain goals
PROJECT FUNDAMENTALS This section describes: Mapping Land Cover & Urban Tree Canopy UTC Terminology Assessment Boundaries Urban Forest Ecosystem Benefits Potential Planting Sites Prioritization
The “top-down” UTC assessment conducted for Little Rock provides an accurate evaluation of canopy cover within the desired boundary. The following section describes the data and methods used for land cover classification, the terminology for defining and assessing Urban Tree Canopy (UTC) and Possible Planting Areas (PPA), and the boundaries (geographic units of scale) that were assessed.
MAPPING LAND COVER AND URBAN TREE CANOPY Aerial photography (2010 National Agricultural Imagery Program) at 1-meter pixel resolution was used as the basis for this UTC assessment. Object-based image classification results were combined with GIS data provided by the City to produce a five (5) class land cover layer. Numerous GIS layers from the city, county and state were used to map the following five land cover classes in Little Rock: (1) tree canopy, (2) other low-lying vegetation, (3) impervious surfaces, (4) bare soil/dry vegetation, and (5) water. Roads were included in the analysis and added to eliminate areas that are unsuitable for planting. Once finalized, the land cover data was the input to assessing boundaries to provide UTC metrics at multiple scales. Impervious land cover was broken into multiple groups and measured as Comprehensive Impervious (roads, buildings, and parking lots), and Canopy over Impervious, which extracts the impervious areas covered by canopy; a benefit for reducing stormwater runoff. See page 45 in the Appendix for more information.
Figure 2: Accurate land cover mapping is the foundation of a UTC assessment.
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TERMINOLOGY Land cover classes were grouped into UTC Types for the assessment. UTC types categorize the landscape so that metrics can be summarized across spatial scales consistently for different applications. These terms are the metrics used in the project, and the following page illustrates the boundaries they were used for. The metrics also target land uses, neighborhoods, natural areas, or individual properties for tree planting activities and policies.
UTC Types assessed in this Report: Existing UTC comprises forests and individual trees when viewed and mapped from above.
Possible Planting Areas - Vegetation is the total area of grass and open space where tree canopy does not exist and it is biophysically possible to plant trees.
Possible Planting Areas - Impervious is non-road, non-building hardscape surfaces that contribute to stormwater runoff where establishing tree canopy is biophysically possible.
Unsuitable UTC - the combination of bare soil, roads, water, and buildings where it is not feasible to plant trees.
UTC types were mapped across GIS boundaries, described on the next page. From the city to the parcel-level, the area and percent of these UTC Types was calculated for map-making and Excel summaries.
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UTC ASSESSMENT BOUNDARIES Assessment boundaries provide geographic units linked to where we live, work and play. Metrics for UTC Types were assessed for the GIS boundaries in Table 1. These summaries provide data for resource managers and planners at different spatial scales. Assessment Boundary
# of Features
Description
City Limits
1
Little Rock City Limits
Zoning
10
Districts designated by City officials in which specific structures are allocated to each zone.
Watersheds
10
An area or ridge of land that separates waters flowing to different rivers or basins.
Wards
7
Divisions of Little Rock for representative, electoral, or administrative purposes
Street Rights-ofWay by Ward
7
Portion of land dedicated to public use for street and utility purposes
Planning Neighborhood Association (PNA)
148
A group of residents or property owners who advocate for or organize activities within a neighborhood.
City Parks
45
Parks owned and managed by the City.
Map
Table 1: Seven (7) assessment boundaries examined in Little Rock
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ECOSYSTEM SERVICES ANALYSIS Urban forests are an integral part of the character of Little Rock. Trees are often appreciated for their aesthetic appeal; however, they greatly contribute to the health and vitality of resident’s daily life. This report quantifies some of the benefits of urban trees, referred to as “ecosystem services.” While the net benefits of urban trees are usually positive, costs are also part of this study’s ecosystem service evaluation and scenario tools for managers. CITYgreen and i-Tree Vue software were used to estimate the benefits of Little Rock’s existing urban tree canopy and scenarios with decreased and increased canopy cover. i-Tree Vue benefits related to carbon storage and sequestration and air pollutant removal. CITYgreen was used to calculate stormwater mitigation benefits of urban forests. See complete details below and in Figure 18. Current and future values were estimated for the following three ecosystem service types: o o
o
Air Quality—Trees naturally remove pollutants and lower air temperature Stormwater mitigation—Trees intercept stormwater, reducing runoff and filtering out pollutants that would otherwise enter rivers and lakes Carbon sequestration and storage—Through photosynthesis, trees absorb atmospheric carbon and use it for new growth (stems, branches, roots and leaves), acting as a natural carbon sink
http://www.itreetools.org/resources/reports/Corvallis_Urban _Tree_Assessment.pdf
Other Benefits of Urban Trees and Forests: Wildlife habitat – Trees create local ecosystems that provide habitat and food for birds and animals, increasing biodiversity in urban areas. Property value – numerous studies across the country show that residential homes with healthy trees add property value (up to 15%). Energy conservation – trees lower energy demand through summer shade and winter wind block, additionally offsetting carbon emissions at the power plant. Economic Development – trees attract businesses, tourists, and increase shopping. Public health – trees help reduce asthma rates and other respiratory illnesses. Safe walking environments – trees reduce traffic speeds and soften harsh urban landscapes. Crime and domestic violence – urban forests help build stronger communities. Nature and trees provide settings in which relationships grow stronger and violence is reduced.
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LOCATING AND PRIORITIZING POTENTIAL PLANTING SITES Potential planting sites were identified, prioritized, and analyzed within the study area as part of this assessment. The resulting GIS points will assist the City in targeting areas to plant trees, summarizing the quantity and quality of planting opportunities, identifying partners, and evaluating canopy goals. To get a more realistic estimate of where trees could be practically planted, exclusions and constraints were applied to a sophisticated GIS model to automate the mapping of potential tree planting sites. The land cover data, UTC results, zoning and infrastructure data provided from the City were inputs to the model. The complete list of these constraints and exclusions with their definition is provided in Table 2 below. Figure 3 illustrates the input at left, constraints/exclusions in the middle, and final outputs at right.
GIS Layers
Rule Applied
Reason
Tree Canopy Polygons
Buffered by 4 meters
To allow room for spacing and growth of existing trees
Building Footprints
Buffered by 2 meters
To avoid tree and building conflicts
Fire Hydrants
Buffered by 4 meters
To avoid tree and hydrant conflicts
Manholes
Buffered by 2 meters
To avoid tree and manhole conflicts
Table 2: Constraints/exclusions in generating potential planting sites
Figure 3: Interim and final stages of the planting sites analysis, viewed from left to right.
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GOAL SETTING BY ZONING DISTRICT To support and facilitate future tree planting and canopy preservation policies, GIS and statistical methods were used to provide UTC goals for the City and generalized zoning districts. Plan-It Geo’s canopy goal-setting process uses current canopy and potential planting conditions to provide Little Rock with goals that are appropriate and attainable in the future. Parcels merged with the generalized zoning classes (Commercial, Industrial, Park, and Residential) as well as UTC and PPA percent are the primary input for the goal setting procedure. With more than 79,000 parcels in Little Rock, an important step is to ensure that individual parcels used to calculate canopy goals are representative of what is possible and feasible across the City. The goal-setting parcel selection process is described below. UTC metrics are calculated for all parcels. Generalized Zoning Districts are merged with parcels. Representative parcels are selected for the goal-setting process by eliminating extraordinary parcels. Parcels with greater than 95% and less than 5% UTC and PPA represent areas that are extraordinary either because of extreme protections (e.g. 100% canopy) or because trees are very unlikely to survive in the location (e.g. 0% canopy). UTC Percent is summarized by generalized land use. Representative parcels are sorted according to UTC percent by generalized land use and ranked from lowest to highest value. The UTC percent at which 75 percent of parcels in each land use are below and 25% of parcels are above represents the 75th percentile (Poracsky 2004).The 75th percentile has been used in past UTC studies since it represents a goal that is likely attainable (25% of parcels have already met the goal) but challenging (75% of parcels are below the goal). An appropriate and attainable goal is selected for each generalized land use. The challenge of attaining the 75th percentile goal may be appropriate for communities that are particularly active, but our purpose is to provide goals that are attainable under most circumstances across Little Rock. 50% of the land use-specific 75th percentile goal is considered an attainable target for increasing tree canopy over time in every community in the City.
Figure 4: Steps used for suggested goal setting
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ASSESSMENT RESULTS AND PRODUCTS The UTC boundaries assessed in Little Rock are governed, owned, managed, and used in different ways by diverse constituents in the community. Therefore, the UTC data and analysis results are presented for multiple scales and purposes to inform planners, managers and citizens alike. The following sections present canopy cover and planting potential across geographic assessment boundaries and describes how the City can use the data to develop ways to manage this important resource.
Tree Canopy in Little Rock This study encompasses 77,379 acres defined by the City limits of Little Rock and provides a snapshot of land cover based on 2010 aerial imagery. Tree canopy covers 35,962 acres (51%) of Little Rock (based on total area including water). The predominate land cover types for the study area are vegetation (grass and open space) at 16,342 acres (23%) and impervious surfaces (roads, buildings, parking lots, driveways, patios, and other paved surfaces) at 16,986 acres. Water covers 2% of the City’s area (1,561 acres) and “bare soil/dry vegetation” covers 1,788 acres, or 3% of Little Rock.
Aerial View of Julius Breckling Riverfront Park
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LAND COVER IN LITTLE ROCK
1,561 Ac. 5,196 Ac. 4,541 Ac. 4,204 Ac. 4,733 Ac.
2,115 Ac.
36,606 Ac.
18,423 Ac.
Figure 5: Distribution of eight land cover classes in Little Rock.
= Total: 77,379 Acres
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TREE CANOPY BY ZONING Many of the policies, regulations, ordinances, and actions influencing tree canopy in Little Rock are dependent on zoning. To provide data that advances urban forest management, ten zoning categories were assessed for tree canopy and possible planting areas (Figure 8). Results can be queried and symbolized using GIS to drill down and identify specific planting opportunities in wards or zoning types. Table 3 provides complete results for UTC and PPA metrics by zoning.
City Limits
Zoning Agriculture
Park
Planned Residential
Commercial
Planned Commercial
Residential
Industrial
Planned Industrial
State Capitol N/A
Figure 6: Map of Zoning classes in Little Rock.
6% 7% 9% 2% % 2%
73% Table 3: UTC and PPA metrics by Zoning
Figure 7: Distribution of total UTC by zoning class. (Note: State Capitol, Agriculture and Planned industrial districts had no significant UTC percentages.)
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POLICY & PLANNING Policy & Planning within Wards City council members have direct influence on development patterns and policies within their Ward. Therefore, Wards in Little Rock were assessed as a benchmark of green vs. gray infrastructure, for council members to understand their urban tree canopy, and allocate forest management and conservation resources and efforts optimally.
Tree Canopy by Wards In Little Rock’s seven wards, UTC ranged from 27% (4,123 acres in Figure 8: UTC Metrics across Little Rock’s seven wards. Ward 1) to 57% (3,874 acres in Ward 4). The following pages illustrate how authorities can use the assessment data to focus resources on planting and tree protection within their own Ward, and contribute to the overall sustainability of the City for future generations. While 27% UTC in Ward 1 is commendable for a highly developed urban part of Little Rock, a ‘drill-down’ approach on the following page uses Wards, Parcels, and Potential Planting Sites to identify areas where additional tree canopy would contribute greatest to overall environmental services (mitigating the urban heat island effect, managing stormwater, improved air quality, etc.). Similar areas for planting or canopy protection/preservation can be quickly generated by ward.
We all Impact UTC: Within the City of Little Rock, the fate of urban forests relies upon City planners, council members, business owners, and residents alike. Sustainable community efforts must be met by all parties of Little Rock in order for the City’s urban forest to thrive. Local involvement includes: Establishing and enforcing tree preservation ordinances across all zoning types. Community outreach to educate residents of the economic and health benefits of trees and provide incentives to promote tree planting on private property. Preserving or offsetting existing tree canopy in areas at risk to forest loss (i.e. development pressures, storms, etc.), and planned maintenance of mature trees. Involvement from City council members in development of an urban forest management plan.
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Figure 10 (Above): Percent UTC by Wards and drillingdown to Ward 1 where parcels with less than 20% canopy cover and more than 30% impervious planting area are shown in red.
Figure 11 (Left): Optimal planting sites (green points) to alleviate the urban heat island effect.
Planting Prioritization within Wards: Ensuring that Little Rock’s tree canopy directly contributes to a sustainable environment across all social, political, and natural boundaries, the City can use the data provided to promote tree planting as well as protect existing canopied areas from forest loss during development. Council members within each Ward may compare existing UTC percent to their total possible planting area and possible planting sites to determine: -
Whether tree planting, tree preservation, or forest regeneration should be the primary objective. How effectively City tree preservation or tree planting ordinances are working in their jurisdiction across different zoning and land use types. Where on the ground tree canopy may be enhanced most equitably and resources are needed using a ‘drill-down’ approach (e.g. from the neighborhood- to individual parcel-scale).
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COMMUNITY & RECREATION Tree Canopy and Planned Neighborhood Associations (PNAs) Street trees, yard trees, and forests are an integral part of the character for many residents in Little Rock. 148 Planned Neighborhood Association’s (PNAs) were assessed to provide the City with a smaller scale baseline of tree canopy. Tree cover across PNAs ranged from 3% (0.6 acres in River Market) to 81% (321 acres in River Ridge P.O.A.), while Upper Baseline had the highest UTC by acreage (900 acres). Overall, PNAs contain 11,318 acres of total possible planting area, 7,272 acres of which are vegetated areas (PPA Vegetation) such as grass and open space.
Tree Canopy and City Parks City parks help satisfy the social, environmental, and physical health requirements for neighborhood residents. City officials have direct influence of tree canopy enhancement within City parks. Tree cover across Little Rock’s City parks ranged from 0% (Acsa Park) to 93% (139 acres in Allsop Park), while Two Rivers Park had the highest UTC by acreage (216 acres). Collectively, there are 687 acres of total possible planting area within parks, 606 acres of which are vegetated areas (PPA Vegetation). Figure 12: Percent UTC by PNA
Percent UTC in PNAs
Figure 13: Planting Sites in MacArthur Park (357 total sites)
< 25% 25 - 45% 45 - 60% > 60% Areas Not In a Neighborhood
Table 4: City Park Metrics Total Land % of Total UTC Acres Acres Land Area
2,008
3%
1,251
UTC %
62.3%
Total PPA Total PPA Acres %
687
34.2%
# Planting Sites in Parks
Figure 14: Percent UTC by Parcels in MacArthur Park Neighborhood.
15,082
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STORMWATER MANAGEMENT AND TREE CANOPY Stormwater Benefits of Trees Trees and forests play an important role in stormwater management. As new development occurs and impervious surface cover increases, less rainwater infiltrates into groundwater and more runoff enters nearby rivers, often resulting in greater flood damage. Tree canopy not only intercepts stormwater runoff and release it back into the atmosphere through evapotranspiration, but also promote infiltration into soil, reduce peak flows, and filter pollutants before entering streams. Ultimately, tree canopy helps to offset the need for costly stormwater infrastructure.
Watersheds and Tree Canopy Tree canopy in Little Rockâ&#x20AC;&#x2122;s watersheds ranged from 15% to 77% while PPA Impervious ranged from 6% to 16%. By assessing UTC within watersheds, the city may target watersheds with low UTC and high PPA and determine priority planting areas. Complete results are shown below in Table 5.
Land Area UTC (Acres) Acres
Watersheds Coleman Creek-Maumelle Faulkner Lake-Ark. River Fletcher Creek-Maumelle Fourche Creek-Ark. River Little Fourche Creek Little Maumelle River Maumelle River-Ark. River McHenry Creek Owner Creek-Fourche Creek White Oak Bayou
TOTALS
29,303 4,190 1,390 3,221 6,879 8,334 168 18,495 1,589 2,249 75,818
12,137 1,574 1,071 481 3,820 5,102 134 9,953 920 1,414 36,606
UTC % 41% 38% 77% 15% 56% 61% 80% 54% 58% 63%
% of PPA PPA Total (Veg.) (Veg.) UTC Acres % 33% 7,445 25% 4% 1,056 25% 3% 121 9% 1% 1,100 34% 10% 1,665 24% 14% 1,468 18% 0% 32 19% 27% 4,674 25% 3% 388 24% 4% 474 21% 100% 18,423
PPA (Imp.) Acres 4,544 675 115 503 681 830 0 2,090 162 137 9,737
PPA Total (Imp.) PPA % Acres 16% 11,989 16% 1,731 8% 235 16% 1,603 10% 2,347 10% 2,298 0% 32 11% 6,765 10% 550 6% 611 28,160
Total PPA % 41% 41% 17% 50% 34% 28% 19% 37% 35% 27%
Table 5: Complete UTC Assessment results by watershed.
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The example here highlights the Coleman Creek Watershed. Possible planting areas from the land cover data are highlighted in parcels within 500 feet of a waterway where canopy cover is low (less than 30%) and PPA Impervious is high (at least 20%) as potential restoration areas to manage stormwater runoff.
Figure 15: Optimal available planting areas in Coleman Creek watershed parcels within 500ft of a waterway.
Planting Prioritization for Stormwater: Planting Site Prioritization and Stormwater
Figure 16: Planting sites near waterway to assist stormwater management.
Within the City of Little Rock, 74,394 planting sites were derived from areas floodplains, and 19,771 Little Rockâ&#x20AC;&#x2122;s Publicwithin Worksmapped has developed a ofstormwater these sites management fall within 100program feet of waterways. An emphasis to address key on tree planting in these areas can help support stormwater issues related to the planning, maintenance, and management. regulation of facilities which collect, store, or convey stormwater. Areas with high impervious surfaces may The Watershed Manual to Part 1: Methods forrisk be Urban targeted for tree planting help reduce the Increasing Forest in awater Watershed, developed of flooding, and Cover improve quality within the by the US Forest waterService table. outlined techniques for maintaining and increasing current canopy within drainage basins (table of goals and techniques provided in appendix). To read more, MENTION UFSF TABLE visit: http://nemonet.uconn.edu/images/resources/FREMO/ completepart1forestrymanual.pdf
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STREET TREES Tree Canopy in Street Rights-of-Way Little Rock’s urban forestry program plants, manages, and maintains trees in the street rights-of-way (ROW) where the City has the most direct opportunity to increase tree planting. Using the UTC assessment data, the city may target strategic areas to increase tree canopy in streets and highway corridors to improve aesthetics and air quality. ROW metrics were assessed for both wards and PNAs. Little Rock’s total ROW land area is equal to 10,724 acres (14%) of the City’s total land area. Key findings in Little Rock’s ROW are: Existing UTC in the ROW is 2,694 acres or 25% average cover. This represents 8% of all UTC Citywide. PPA – Vegetation totals 2,593 acres or 24% of the ROW, and PPA – Impervious totals 1,595 acres, or 15% of the ROW. ROW in Ward 3 has the highest UTC at 37%, or 17% of all UTC in Little Rock’s Street ROW
Figure 17: Percent UTC in Street ROW by Ward. (Inset): Percent Total PPA in Street ROW by PNA
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ECOSYSTEM SERVICES Assigning a dollar value to the benefits provided by Little Rock’s trees and forests can motivate leaders to preserve and enhance the urban forest. This is critical to understanding how trees impact on our homes, communities, and overall environment.
Carbon and Air Quality Findings: Plan-It Geo’s environmental analysis reveals that existing canopy in Little Rock stores approximately 5.3 million tons of carbon, valued at $103.6 million, and each year sequesters approximately 176 thousand tons of carbon dioxide, valued at $3.4 million. An increase in tree canopy to the suggested goal of 52% would result in 5.8 million tons of carbon stored, increasing the City’s annual savings to $113 million.
Credit: http://www.itreetools.org/resources/report s/Corvallis_Urban_Tree_Assessment.pdf
Findings from the i-Tree Vue software also reveal that tree canopy in Little Rock removes 2.8 million pounds of air pollution annually, valued at $12 million. Increasing tree canopy to 52% would remove 3.1 million pounds of air pollution annually; a value of $13.2 million.
Stormwater Mitigation Findings:
Monetary Gains
Little Rock’s current tree canopy intercepts 80 million cubic ft. of stormwater runoff every year, a benefit valued at $20.9 million in annually avoided stormwater infrastructure costs, or a total stormwater value of $239.9 million. An increase of 5% canopy to 53% overall UTC would intercept roughly 86.1 million cubic ft. of stormwater runoff annually; a total stormwater value of $258.4 million. A decrease in canopy cover to 38% would intercept 72.9 million cubic ft. of stormwater runoff annually; a reduction in stormwater mitigation benefits by $21.2 million. $300,000,000 $250,000,000 $200,000,000 $150,000,000 $100,000,000 $50,000,000 $0
Air Pollution
Existing 47% UTC
$12,020,751
Annual Carbon Sequestration $3,415,823
Stormwater
TOTALS
$239,901,082
$255,337,656
Increase to 52% UTC
$13,153,100
$3,737,592
$258,373,466
$275,264,157
Decrease to 37% UTC
$3,180,824
$2,694,253
$183,764,229
$189,639,306
Figure 18: Ecosystem benefits by canopy cover scenario.
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PRIORITIZING POTENTIAL PLANTING SITES The tables on the following pages present the planting sites prioritization criteria and results. These numbers may be used to collectively, or within each criterion to target specific tree planting benefits.
Planting Site Attribute
GIS Criteria Used
No. of Planting Sites
Floodplain
Within mapped floodplains
68,605
Riparian Area Schools Parks Public Buildings Urban Heat Islands Energy Conservation Connectivity Median Income
Within 100 feet of water Within a parcel that contains a school Within park UTC zoning class Within a parcel that contains a public building Within 25 feet of parking lots Within 50 feet of buildings Within 100 feet of forest tracts (tree canopy >1 acre) Median Income of the census block the point is within
10,591 6,431 15,082 36,339 28,510 99,968 4,599 N/A
CITYWIDE TOTAL
287,092
Table 6: Planting site prioritization criteria.
Figure 19: Number of planting sites per acre within PNAs.
Figure 20: Planting site prioritization by criteria
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Planting sites within each ward ranged from 17,402 sites (Ward 4) to 76,851. Connectivity criteria produced the least amount of planting sites (4,599), while planting sites for energy conservation totaled 99,968.
Total Planting Sites by Ward < 18,000 18,000 - 26,000 26,000 - 43,000 > 43,000
Figure 21: Number of total planting sites per ward
Ward 1 2 3 4 5 6 7 TOTALS
Prioritization Factors
Land Acres 15,359 10,279 6,780 6,814 11,136 8,355 17,061 75,784
Flood Plain
Riparian
Schools
Parks
Public Building
Urban Heat Island
Energy
Connectivity
19,989 17,017 3,678 1,681 3,499 3,740 19,001 68,605
3,086 1,181 631 653 1,760 1,334 1,946 10,591
2,115 635 1,135 298 669 622 957 6,431
4,220 2,813 2,867 905 604 907 2,766 15,082
14,073 2,962 3,499 1,627 3,567 2,504 8,107 36,339
8,100 4,615 2,417 2,359 3,126 3,482 4,411 28,510
18,710 11,463 9,406 9,886 18,379 13,691 18,433 99,968
252 926 310 503 1,006 358 1,244 4,599
Table 7: Number of planting sites per criteria in each ward.
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SUGGESTED CANOPY COVER GOALS In Little Rock’s temperate climate, a tree canopy goal should be attainable physically, fiscally, and desired socially. UTC goal setting should be incorporated into landscape ordinances, tree preservation policies and planning documents such as the comprehensive plan. Due to large variances in tree cover across broad zoning types, goals are suggested citywide and for each zoning type. Suggested practical and attainable UTC goals for Little Rock are presented here for the City to use as a starting point in canopy goal setting discussions and planning.
Commercial: Increase UTC to 39% (add 759 acres). Industrial: Increase UTC to 37% (add 1,883 acres). Park: Increase UTC to 71% (add 232 acres). Residential: Increase UTC to 64% (add 3,665). Successful implementation of these goals would result in an overall citywide UTC of 53% (6,539 acres). Commercial IndustrialPark Residential 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%
Commercial Industrial
Park
Residential
Figure 22: Comparison of suggested goals to existing UTC and PPA by generalized zoning
Aspects of Increasing UTC: In order to effectively increase UTC in Little Rock, the City may consider incorporate 1) greater tree planting, 2) preservation of existing trees, and 3) establishing areas suitable for forest regeneration. Areas suitable for regeneration include:
Areas adjacent to large patches of tree canopy and forest Areas within a riparian buffer (i.e. public conservation lands along the Arkansas River) Where soils will experience conditions of flooding or high saturation Vacant or abandoned properties
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RECOMMENDATIONS This project mapped land cover across the City of Little Rock, identified 287,092 possible planting locations with extensive attributes, assessed benefit values of current and future canopy cover, and developed data and tools allowing managers to identify where urban trees can be planted for specific purposes. Based on the results of this work, the following broad recommendations are provided on how to best use these data, tools, and information to implement urban tree canopy objectives in Little Rock.
LAND COVER ANALYSIS Disseminate the land cover data to diverse partners for urban forestry and other applications while the data is current and most useful for decision-making and implementation planning. Re-assess canopy cover in no less than 10-year intervals, and use LiDAR data if available, aiming for 95% overall accuracy.
ECOSYSTEMS SERVICES & PRIORITY PLANTING SITES Overall Use the results to develop targeted presentations for city leaders, planners, engineers, resource managers, and the public on the functional benefits of trees in addressing environmental issues. Conduct i-Tree or similar ecosystem services analysis studies with local field data collection input to better understand and quantify forest structure, function and value. Air Quality This study identified 4,188 acres of possible planting area (Total PPA) within street rights-ofway. Officials can partner to target canopy increases in the corridors as an air pollution mitigation strategy. PPA Impervious, primarily parking lots, covers roughly 9,800 acres (13%) of the City. With 28,510 potential planting sites adjacent to parking lots, tree planting and maintenance will help reduce the urban heat island effect and formation of ground-level ozone. Conduct tree planting along highway 630 and 30 corridors where tree canopy is low, and where canopy would reduce the impact of noise pollution and enhance air quality. Energy Conservation Develop strategies to plant trees for energy efficiency. This study identified 99,968 potential planting locations near residential homes. 10 of 148 neighborhoods have less than 20% UTC and should be targeted for energy conservation from trees. Encourage the use of free online tools such as i-Tree Design to determine proper placement of trees around homes to maximize energy efficiency benefits. Encourage local electric utilities to partner with the Arbor Day Foundation and start an “Energy Saving Trees” program.
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Stormwater & Water Quality Field-verify and prioritize plantings in the Fourche Creek-Arkansas River drainage basin, where canopy cover averages just 15% and polluted stormwater runoff can enter the Arkansas River. 10,591 planting sites were identified in riparian corridors and 28,510 adjacent to parking lots, prime areas where tree canopy can improve impaired water quality. Work with the Stormwater Management Program and others to prioritize areas for restoration. Promote the use of trees and forests as stormwater Best Management Practices (BMPs), where appropriate. To reduce the flow of contaminated runoff into surface waters, develop, implement, and enforce programs and policies to plant and maintain large trees in parking lots.
GOAL SETTING Establish canopy cover goals for the city, wards, and zoning in a collaborative, multidisciplinary planning process. Use data from this assessment along with Plan-It Geo’s “Canopy Calculator Tool” and suggested goals in this report to play with scenarios and drive discussions. Aim for tree species diversity in planting practices and determine desired levels of service in landscape design for new and redevelopment that result in a sustainable community forest.
PLANNING Work closely with the City of Little Rock Parks and Recreation, Arkansas Audubon, Tree Streets, and other entities to develop a Master Tree Plan. Increase UTC in Commercial/Industrial zones, which have 49% and 56% Total PPA, respectively. Map, quantify, and protect priority lands at risk of forest loss from development, starting with Planned Commercial, Industrial and Residential zones which contain 5% of current UTC citywide. Host the UTC data and potential planting sites in a web-mapping application focused on urban forest planning. Use the tool to engage public/private partners to advance urban forest benefits.
Maximizing the Urban Forest: Community Objectives In order for Little Rock to successfully reach and maintain a higher tree canopy goal, collective commitments must be met by City officials, business owners, and residents. With the attainment of this UTC assessment, continuing objectives include: Involvement of large private and institutional land holders Citizen-municipality-business interaction and involvement in urban forest management Intense management and maintenance of publicly owned trees Municipality-wide funding for a comprehensive urban forest management plan
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
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SUMMARY Little Rock’s urban forest is a living resource that changes through natural and human processes. Managing UTC requires an understanding of where trees are, where they can be planted equitably to maximize benefits, and how to work within regulatory and physical restrictions to achieve goals. Little Rock’s UTC Assessment provides an accurate benchmark and tools to assist in the City’s near and longterm vision of urban natural resource management. Some highlights from this study include: 48% (36,606 acres) of Little Rock land area is covered by tree canopy with 37% (28,160 acres) available for addition tree planting (Total PPA). Wards ranged from 27% UTC (4,123 acres in Ward 1) to 57% UTC (3,874 acres in Ward 4). Residential zoning comprises 63% (47,350) of total land area. With 26,805 acres of UTC, this makes up 73% of all UTC. Additionally, residential districts average 31% (14,706 acres) PPA. Commercial and industrial zones have 31% (2,096 acres) and 21% (2,365 acres) UTC respectively. The majority of Little Rock’s stormwater funnels into the Arkansas River at Fourche Creek, the drainage basin with the lowest UTC at 15% (481 acres) but 50% (1,603 acres) of Total PPA. Planning Neighborhood Association’s average 50% UTC and 34% Total PPA. Little Rock’s tree canopy currently removes nearly 2.8M pounds of air pollutants annually, valued at $12M per year, and provides an estimated value of $239.9 million in avoided stormwater infrastructure costs, valued at $20.9 million annually. A detailed an accurate baseline of land cover has been thoroughly analyzed and presented in this report. An ongoing challenge will be to balance new development with the protection and conservation of environmental values related to forest cover such as energy conservation, air quality, and climate adaptation related to carbon storage and stormwater mitigation. The social, environmental, and economic benefits of urban trees and forests are an incentive to continue in this direction.
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APPENDIX Additional details on the City of Little Rockâ&#x20AC;&#x2122;s 2013 urban tree canopy assessment are provided including supporting information on:
A1: Glossary of Terms A2: Comprehensive Assessment Boundary Results A3: Urban Forest Self Evaluation; Criteria & Indicators A4: Canopy Calculator A5: USFS Table for Increasing Forest Cover within Watersheds A6: Land Cover Classification Accuracy Assessment
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A1: GLOSSARY OF TERMS Air Quality – The quantity of particulates and other pollutants present in a volume of air relative to necessary compounds such as oxygen. Trees improve air quality by absorbing and trapping air pollutants such as particulate matter, ozone, sulfur dioxide, carbon monoxide, and CO2 and by decreasing volatility by lowering air temperatures. Carbon Sequestration – The rate that carbon is removed from the atmosphere by trees. Carbon is considered a very important element because of its recognized influence on climate regulation as a greenhouse gas. Carbon Storage – Cumulative amount of carbon stored in the stems, branches and roots of trees over time. Ecosystem Services – Direct and indirect benefits provided by natural systems. The most common ecosystem services associated with urban trees and forests are air quality improvement, carbon sequestration and storage, energy conservation, and storm water mitigation. Energy conservation – The amount of energy saved due to the presence of trees. Summer cooling through shade, and by wind blocking in the winter reduces total energy used. Geographic Information Systems – Computer mapping systems used to understand how resources are distributed across the Earth’s surface. Impervious Land Cover – Hardscape surfaces that do not allow rainfall to infiltrate the soil (Buildings, roads, parking lots). i-Tree Design– As part of the i-Tree suite developed by the USDA Forest Service, this tool calculates benefits of trees on a property PPA Vegetation – (Possible Planting Area) associated with vegetation and open space. These are areas where tree planting is possible. Urban Heat Island Effect – refers to developed areas that are hotter than surrounding rural areas due to the abundance of man-made materials which absorb the sun’s energy much more than trees or other plants, and in turn warm the air around them (Center for Environmental Studies, Brown University, “Trees and the Urban Heat Island Effect”, 2010). UTC – (Urban Tree Canopy) is defined as the layer of leaves and stems of trees that cover the ground when viewed from above. Stormwater Runoff Mitigation and Water Quality – Important ecosystem services related to precipitation events, hydrologic cycles, and urban forests. Trees reduce stormwater runoff and improve water quality by intercepting rainfall, increasing soil permeability, and evapotranspiration.
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A2: COMPLETE ASSESSMENT BOUNDARY RESULTS The following maps and tables on pages 32-41 provide more comprehensive results for each boundary assessed in this study. Waterways Percent UTC by Watershed
UTC results by Watershed
< 15% 15 - 50% 50 - 60%
Waterways
Percent Total PPA by Watershed
> 60%
< 20% 20 - 28% 28 - 36% > 36%
Figure 23: Percent Total PPA by Watershed Figure 24: Percent UTC by Watershed
Waterways
Percent PPA Impervious by Watershed < 6% 6 - 10% 10 - 12% > 12% Waterways
Percent PPA Vegetation by Watershed < 18% 18 - 22% 22 - 25% > 25%
Figure 25: Percent PPA Impervious by Watershed
Figure 26: Percent PPA Vegetation by Watershed
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Table 8: Complete UTC results for Little Rock Watersheds
Watersheds
Land Acres
Coleman Creek29,303 Maumelle River Faulkner Lake4,190 Arkansas River Fletcher Creek1,390 Maumelle River Fourche Creek3,221 Arkansas River Little Fourche 6,879 Creek Little Maumelle River-Maumelle 8,334 River Maumelle River168 Arkansas River McHenry Creek18,495 Fourche Creek Owner Creek1,589 Fourche Creek White Oak 2,249 Bayou TOTALS 75,818
UTC Acres
UTC %
% of Total UTC
PPA (Veg.) Acres
PPA (Veg.) %
PPA (Imp.) Acres
PPA (Imp.) %
Total PPA Acres
Total PPA %
Uns. UTC Acres
Uns. UTC %
12,137
41%
33%
7,445
25%
4,544
16%
11,989
41%
5,177
18%
1,574
38%
4%
1,056
25%
675
16%
1,731
41%
886
21%
1,071
77%
3%
121
9%
115
8%
235
17%
84
6%
481
15%
1%
1,100
34%
503
16%
1,603
50%
1,137
35%
3,820
56%
10%
1,665
24%
681
10%
2,347
34%
712
10%
5,102
61%
14%
1,468
18%
830
10%
2,298
28%
934
11%
134
80%
0%
32
19%
0
0%
32
19%
2
1%
9,953
54%
27%
4,674
25%
2,090
11%
6,765
37%
1,778
10%
920
58%
3%
388
24%
162
10%
550
35%
119
7%
1,414
63%
4%
474
21%
137
6%
611
27%
224
10%
36,606
18,423
9,737
28,160
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Percent Total PPA by Ward
UTC Results by Ward
< 30% 30 - 32% 32 - 38% > 38%
Figure 27: Percent Total PPA by Ward
Figure 28: Percent PPA Vegetation by Ward
Figure 29: Percent PPA Impervious by Ward
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Table 9: Complete UTC results for Little Rock Wards Ward
Total UTC UTC Land Acres % Acres
PPA (Veg.) Acres
PPA (Veg.) %
PPA (Imp.) Acres
PPA (Imp.) %
Total PPA Acres
Total PPA %
Uns. UTC Acres
Uns. UTC %
Ward 1
3,016
714
24%
913
30%
430
14%
1,343
45%
958
32%
Ward 2
1,344
334
25%
354
26%
202
15%
556
41%
454
34%
Ward 3
1,240
459
37%
227
18%
124
10%
351
28%
430
35%
Ward 4
1,015
295
29%
194
19%
123
12%
317
31%
403
40%
Ward 5
1,172
186
16%
216
18%
227
19%
442
38%
544
46%
Ward 6
1,356
377
28%
304
22%
185
14%
489
36%
490
36%
Ward 7
1,580
329
21%
384
24%
304
19%
688
44%
562
36%
TOTAL
10,724 2,694 25.1%
2,593
24%
1,595
15%
4,188
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
3,842
34
UTC Results by PNA Percent PPA Total in PNAs < 6% 6- 12% 12 - 20% > 20%
Figure 31: Percent Total PPA by PNA
Percent PPA Vegetation in PNAs
Figure 30: Percent PPA Vegetation by PNA
< 15% 15 - 25% 25 - 35% > 35%
Percent PPA Impervious in PNAs < 8% 8 - 14% 14 - 24% > 24%
Figure 32: Percent PPA Impervious by PNA
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Table 10: Complete UTC results for Little Rock Planning Neighborhood Associations (PNAs) Total Land Acres ABERDEEN COURT 286.4 ALEXANDER ROAD 1,161.8 ALLENDALE 86.8 ANDOVER SQUARE 19.3 APPLE BLOSSOM 24.3 BAYONNE PLACE P.O.A 104.2 BENTLEY COURT 30.1 BEVERLY HILLS 16.9 BIRCHWOOD 194.0 BRIARWOOD 455.1 BROADMOOR 183.0 BROWNWOOD TERRACE 31.1 CAMPUS PLACE 81.8 CAPITAL LAKES ESTATES 195.4 CAPITOL HILL 107.3 CAPITOL VIEW - STIFFT STATION 512.5 CARRIAGE CREEK 71.3 CEDAR HILL TERRACE NA 46.2 CENTRAL HIGH 358.4 CHARLESTON HEIGHTS/N. Rahling 14.6 CHENAL RIDGE P.O.A 59.6 CHEVAUX COURT PROPERTY OWNER 27.9 CHICOT 253.8 CLOVERDALE 345.8 COLLEGE STATION 127.1 COLLEGE TERRACE 27.5 COLONY WEST 149.0 COMMUNITY OUTREACH 216.2 CRYSTAL VALLEY 29.8 CURRAN-CONWAY 374.9 DEER MEADOW 49.7 DOWNTOWN 1,055.0 DuQUESNE PLACE 215.6 EAGLE POINT 9.9 EAST LITTLE ROCK 487.1 EAST OF BROADWAY 355.5 EAST ROOSEVELT 172.9 ECHO VALLEY 98.4 EVERGREEN 71.6 FOREST HILLS 117.7 FOREST PARK 46.0 GEYER SPRINGS 510.5 GIBRALTAR HTS 390.3 GLEN EAGLES 9.7 GOODWILL 68.5 GRANITE MOUNTAIN 277.6 Hallen Court 25.2 HANGER HILL 210.7 HEIGHTS 739.5 HERMITAGE 118.2 PNA
PPA UTC UTC PPA (Veg.) Acres % (Veg.) % Acres 156.3 55% 49.1 17.1% 808.5 70% 219.8 18.9% 49.8 57% 17.1 19.7% 6.1 32% 1.6 8.5% 7.4 30% 6.9 28.5% 38.6 37% 21.8 20.9% 5.4 18% 11.5 38.2% 9.9 58% 2.7 16.1% 87.0 45% 27.8 14.3% 153.9 34% 85.5 18.8% 102.7 56% 32.9 18.0% 9.5 31% 7.0 22.7% 33.5 41% 14.0 17.1% 115.3 59% 34.1 17.5% 31.4 29% 31.7 29.5% 248.4 48% 107.6 21.0% 42.2 59% 12.0 16.9% 24.6 53% 9.3 20.0% 105.7 29% 83.0 23.1% 3.1 21% 5.4 36.7% 31.8 53% 9.4 15.8% 2.5 9% 6.8 24.3% 129.2 51% 56.8 22.4% 131.0 38% 99.0 28.6% 69.1 54% 37.2 29.3% 16.4 60% 4.9 17.9% 81.8 55% 21.6 14.5% 36.4 17% 92.3 42.7% 10.4 35% 6.6 22.3% 135.1 36% 65.8 17.6% 21.0 42% 14.0 28.1% 203.4 19% 230.1 21.8% 126.2 59% 29.1 13.5% 3.0 30% 2.2 22.5% 141.2 29% 220.9 45.4% 116.4 33% 85.2 24.0% 59.8 35% 76.7 44.4% 58.0 59% 13.5 13.7% 43.0 60% 8.6 12.0% 53.3 45% 20.5 17.4% 24.4 53% 5.7 12.4% 199.3 39% 156.3 30.6% 190.6 49% 85.5 21.9% 1.5 15% 2.6 27.1% 24.2 35% 18.4 26.9% 138.7 50% 93.1 33.6% 14.6 58% 4.8 18.9% 48.9 23% 77.0 36.6% 425.2 58% 96.3 13.0% 45.5 39% 56.7 47.9%
PPA (Imp.) Acres 45.3 73.8 5.1 5.9 0.9 18.3 5.1 1.1 43.2 101.1 13.9 6.9 15.3 26.9 15.4 52.9 5.9 3.9 73.2 2.8 7.6 8.1 29.5 52.4 8.8 2.0 15.3 43.0 5.0 98.6 5.6 246.0 31.8 0.9 58.0 53.2 17.8 9.5 7.6 16.7 4.9 72.2 39.5 1.1 12.0 20.0 2.2 33.0 84.2 1.7
PPA (Imp.) Total PPA % Acres 15.8% 6.4% 5.9% 30.6% 3.9% 17.6% 17.1% 6.7% 22.3% 22.2% 7.6% 22.3% 18.7% 13.8% 14.4% 10.3% 8.3% 8.5% 20.4% 19.2% 12.7% 29.0% 11.6% 15.1% 6.9% 7.3% 10.3% 19.9% 16.8% 26.3% 11.3% 23.3% 14.8% 8.7% 11.9% 15.0% 10.3% 9.7% 10.7% 14.2% 10.6% 14.1% 10.1% 10.9% 17.5% 7.2% 8.8% 15.7% 11.4% 1.5%
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
94.4 293.6 22.2 7.5 7.9 40.1 16.6 3.9 71.0 186.6 46.8 14.0 29.3 61.1 47.1 160.5 18.0 13.2 156.1 8.2 17.0 14.9 86.3 151.4 46.0 6.9 36.9 135.3 11.6 164.4 19.6 476.1 60.9 3.1 278.9 138.3 94.5 23.0 16.2 37.2 10.6 228.5 125.0 3.7 30.5 113.1 7.0 110.0 180.5 58.4
Total PPA % 33.0% 25.3% 25.5% 39.1% 32.4% 38.5% 55.3% 22.8% 36.6% 41.0% 25.6% 45.0% 35.8% 31.3% 43.9% 31.3% 25.2% 28.5% 43.6% 56.0% 28.5% 53.3% 34.0% 43.8% 36.2% 25.2% 24.8% 62.6% 39.0% 43.9% 39.4% 45.1% 28.3% 31.2% 57.2% 38.9% 54.6% 23.4% 22.7% 31.6% 23.0% 44.7% 32.0% 38.0% 44.5% 40.8% 27.7% 52.2% 24.4% 49.4%
36
HILLCREST HILLSBOROUGH HOPE HUNTERS COVE HUNTERS GREEN JOHN BARROW JOHNSON RANCH Katillus Court POA KENSINGTON PLACE KINGWOOD NEIGHBORHOOD ASSOC LAKE FOREMAN PRESERVATION LEANDER LEGION HUT LOVE M.L.K MACARTHUR PARK MARGEAUX PLACE P.O.A MARLOW MANOR MAVIS CIRCLE MAYWOOD MANOR MEADOWBROOK MEADOWCLIFF/BROOKWOOD MERIWETHER MEYER LANE MIDWAY NORMANDY-SHANNON O.U.R. OAK FOREST OTTER CREEK OVERLOOK OXFORD VALLEY PANKEY PARKWAY PLACE PECAN LAKE PENBROOK/CLOVER PIEDMONT PINE TO WOODROW PINEDALE PINNACLE VALLEY NEIGHBORHOOD PLEASANT FOREST PLEASANT VALLEY Pleasantree Recreation Assoc. POINT O'WOODS PROSPECT TERRACE QUAIL RUN RAINWOOD COVE RIVER MARKET RIVER RIDGE P.O.A RIVER VALLEY ROB ROY WAY ROBINWOOD ROLLING PINES SANDPIPER
986.6 594.4 85.3 54.7 184.0 67.4 10.1 3.3 10.2 1.1 3,055.2 1,801.3 90.9 57.0 5.5 1.1 75.0 31.0 346.0 208.6 16.0 8.9 105.2 77.7 189.3 76.6 172.2 78.0 273.2 105.8 276.7 61.7 106.7 50.8 114.5 72.7 28.1 22.6 14.5 9.3 111.2 39.7 270.6 169.0 160.8 72.2 264.8 99.5 225.7 103.3 66.5 43.9 109.0 66.6 327.6 187.2 546.2 211.1 256.6 189.9 16.1 5.4 104.3 66.0 477.8 228.6 247.2 111.9 26.2 10.1 73.8 51.1 107.1 47.0 23.5 7.6 339.9 198.2 44.6 25.6 897.0 511.2 66.8 43.4 40.9 22.0 63.9 42.1 42.7 22.8 49.6 11.1 20.1 0.6 395.9 320.5 13.8 4.4 15.2 7.4 172.0 139.2 28.5 20.4 71.8 39.9
60% 64% 37% 32% 11% 59% 63% 20% 41% 60% 56% 74% 40% 45% 39% 22% 48% 63% 80% 64% 36% 62% 45% 38% 46% 66% 61% 57% 39% 74% 34% 63% 48% 45% 38% 69% 44% 32% 58% 57% 57% 65% 54% 66% 53% 22% 3% 81% 32% 49% 81% 72% 56%
113.1 12.1 52.0 1.8 2.6 506.5 26.8 2.1 17.7 44.9 4.3 13.5 59.8 45.6 77.0 92.8 23.3 14.9 4.7 2.7 30.2 52.4 21.0 148.8 50.4 7.5 19.5 63.1 159.8 33.2 5.0 19.9 77.5 79.4 8.1 9.6 25.7 7.5 90.2 6.7 209.8 9.7 8.9 6.0 15.4 7.1 3.0 43.7 6.5 4.9 11.4 3.4 13.8
11.5% 14.2% 28.3% 18.2% 25.4% 16.6% 29.5% 38.1% 23.5% 13.0% 26.7% 12.8% 31.6% 26.5% 28.2% 33.6% 21.8% 13.0% 16.6% 18.5% 27.2% 19.4% 13.0% 56.2% 22.3% 11.3% 17.9% 19.3% 29.3% 12.9% 31.0% 19.1% 16.2% 32.1% 30.7% 13.0% 24.0% 31.8% 26.5% 14.9% 23.4% 14.5% 21.8% 9.3% 36.2% 14.2% 14.8% 11.0% 47.0% 32.2% 6.6% 12.0% 19.3%
107.4 5.5 22.9 1.1 1.9 397.5 3.0 1.2 10.8 34.8 1.2 7.9 23.6 15.9 33.0 43.1 16.6 6.7 0.2 0.6 14.9 11.9 31.6 9.1 27.5 4.5 7.8 23.9 70.1 7.7 1.9 7.9 85.7 23.6 2.2 7.3 10.2 2.5 27.0 3.7 62.6 2.6 1.9 4.6 0.4 19.9 4.5 11.1 2.3 1.6 6.1 1.4 4.5
10.9% 6.4% 12.4% 10.6% 18.5% 13.0% 3.3% 21.1% 14.4% 10.0% 7.7% 7.5% 12.5% 9.2% 12.1% 15.6% 15.5% 5.9% 0.8% 4.1% 13.4% 4.4% 19.7% 3.4% 12.2% 6.7% 7.1% 7.3% 12.8% 3.0% 11.6% 7.6% 17.9% 9.5% 8.4% 9.9% 9.5% 10.7% 7.9% 8.4% 7.0% 4.0% 4.7% 7.2% 1.0% 40.1% 22.5% 2.8% 16.4% 10.3% 3.5% 5.0% 6.3%
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
220.6 17.6 74.9 2.9 4.5 904.0 29.8 3.3 28.4 79.7 5.5 21.4 83.5 61.6 110.0 136.0 39.9 21.7 4.9 3.3 45.1 64.3 52.6 158.0 77.8 12.0 27.3 87.0 229.9 40.9 6.9 27.8 163.1 103.0 10.3 16.9 35.9 10.0 117.1 10.4 272.4 12.3 10.8 10.5 15.9 27.0 7.5 54.8 8.7 6.5 17.4 4.8 18.4
22.4% 20.6% 40.7% 28.8% 43.9% 29.6% 32.8% 59.3% 37.9% 23.0% 34.4% 20.3% 44.1% 35.7% 40.3% 49.1% 37.4% 18.9% 17.4% 22.6% 40.6% 23.8% 32.7% 59.7% 34.5% 18.1% 25.0% 26.5% 42.1% 15.9% 42.6% 26.6% 34.1% 41.7% 39.2% 22.9% 33.5% 42.6% 34.5% 23.3% 30.4% 18.4% 26.5% 16.5% 37.2% 54.3% 37.4% 13.8% 63.3% 42.5% 10.1% 17.0% 25.6%
37
SANTA FE HEIGHS 48.5 SANTA MONICA 156.6 SECLUDED HILLS 99.8 SHERRILL HEIGHTS 52.6 SHILOH 82.9 SO. OF ASHER 21.8 SOUTH BROOKWOOD 165.0 SOUTH END 114.6 SOUTH END 166.2 SOUTH NORMANDY 20.2 SPRING VALLEY MANOR 126.5 ST. CHARLES 419.0 STAGECOACH-DODD 733.2 STEPHENS AREA FAITH 241.9 STURBRIDGE 268.4 TALL TIMBERS 44.6 THE VILLAGES OF WELLINGTON 296.6 TOWN AND COUNTRY 183.9 TREASURE HILLS 57.2 TULLEY COVE NEIGHBORHOOD 12.3 TWIN LAKES 80.7 TWIN LAKES 45.0 TWIN LAKES ""B"" 95.0 UNIVERSITY PARK 84.7 UPPER BASELINE 2,144.6 WAKEFIELD 1,001.1 WALNUT VALLEY 180.5 WALTON HEIGHTS - CANDLEWOOD 414.7 WAR MEMORIAL 48.6 WATERS EDGE HOMEOWNERS ASSOC. 65.4 WEDGEWOOD CREEK POA 28.4 WEST BASELINE 421.2 WEST HEIGHTS PLACE 80.2 WESTBROOK 18.7 WESTBURY 21.0 WESTCHESTER 82.9 WESTWOOD 1,018.1 WHITMORE CIRCLE 9.4 WINDAMERE 161.0 WINGATE PROP. OWNERS ASSOC. 35.3 WOODLAND EDGE COMM. ASSOC. 760.2 WOODLAND HILLS/ASPEN HIGHLAND 42.5 WOODLAND RIDGE 71.9 WRIGHT AVENUE 237.3 YORKWOOD 101.5 TOTAL 33,006
26.6 71.2 45.3 38.4 35.1 3.8 88.5 61.3 61.3 12.4 90.0 238.2 434.0 98.9 138.1 16.9 76.8 81.2 31.1 6.7 41.0 24.2 45.8 21.8 898.6 397.8 114.7 304.1 23.5 30.8 1.7 200.9 49.3 9.2 7.7 36.2 603.1 2.8 76.4 26.7 582.4 24.3 29.5 87.7 39.2
55% 45% 45% 73% 42% 17% 54% 53% 37% 61% 71% 57% 59% 41% 51% 38% 26% 44% 54% 54% 51% 54% 48% 26% 42% 40% 64% 73% 48% 47% 6% 48% 61% 49% 37% 44% 59% 30% 47% 76% 77% 57% 41% 37% 39%
9.9 43.4 19.6 7.9 22.9 4.7 50.7 33.3 53.4 2.6 19.5 62.2 256.5 62.9 38.3 13.4 86.4 48.4 11.0 3.6 16.5 6.3 19.5 30.0 494.0 204.5 28.6 51.9 9.6 17.7 11.4 106.2 16.7 4.7 4.0 20.4 287.5 2.8 25.4 3.9 79.9 7.1 18.7 70.9 27.7
20.4% 27.7% 19.7% 15.1% 27.6% 21.5% 30.7% 29.0% 32.1% 12.9% 15.4% 14.8% 35.0% 26.0% 14.3% 30.0% 29.1% 26.3% 19.1% 29.4% 20.4% 13.9% 20.6% 35.4% 23.0% 20.4% 15.8% 12.5% 19.6% 27.0% 40.2% 25.2% 20.8% 25.1% 19.0% 24.6% 28.2% 29.6% 15.8% 11.1% 10.5% 16.6% 26.0% 29.9% 27.3%
3.3 20.6 15.5 1.6 8.9 7.8 7.0 12.2 17.7 1.4 8.4 41.2 23.9 25.2 42.9 4.6 61.0 29.8 4.1 0.9 7.5 5.7 11.1 10.8 412.9 212.5 10.8 19.6 6.2 5.8 7.2 42.9 5.9 1.2 3.0 10.3 59.9 1.5 29.6 0.8 48.6 1.9 12.3 24.8 10.6
6.8% 13.1% 15.5% 3.0% 10.7% 36.0% 4.2% 10.6% 10.6% 7.1% 6.6% 9.8% 3.3% 10.4% 16.0% 10.3% 20.6% 16.2% 7.2% 7.7% 9.3% 12.7% 11.7% 12.8% 19.3% 21.2% 6.0% 4.7% 12.8% 8.9% 25.4% 10.2% 7.4% 6.6% 14.1% 12.4% 5.9% 16.2% 18.4% 2.4% 6.4% 4.5% 17.1% 10.4% 10.4%
13.2 63.9 35.1 9.5 31.8 12.5 57.7 45.4 71.0 4.0 27.9 103.4 280.4 88.2 81.2 18.0 147.4 78.2 15.0 4.6 24.0 12.0 30.7 40.8 906.9 416.9 39.3 71.5 15.8 23.5 18.7 149.1 22.6 5.9 7.0 30.7 347.4 4.3 55.0 4.8 128.6 8.9 30.9 95.6 38.3
27.2% 40.8% 35.2% 18.1% 38.3% 57.5% 35.0% 39.6% 42.8% 20.0% 22.0% 24.7% 38.2% 36.4% 30.2% 40.4% 49.7% 42.5% 26.3% 37.1% 29.8% 26.6% 32.3% 48.2% 42.3% 41.6% 21.8% 17.2% 32.4% 35.9% 65.6% 35.4% 28.2% 31.7% 33.1% 37.0% 34.1% 45.8% 34.2% 13.5% 16.9% 21.1% 43.0% 40.3% 37.7%
16,459 49.9% 7,272
22.0%
4,046
12.3%
11,318
34.3%
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
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Table 11: Complete UTC results for Little Rock City Parks City Parks Acsa Park Allsopp Park Barton Park Birchwood Park Booker Homes Park Butler Park Centennial Park Cheetam Park Craig Park Dunbar Park East End Park Fair Park School Forest Park School Gillam Park Granite Heights Park Hangar Hill Park Hindman Park Holt Park Interstate Park Junior Deputy Park Kanis Park Knoop Park Little Oaks Park Macarthur Park Meriwether Park Morehart Park Murray Park Ottenheimer Park Overlook Park Pankey Park Pettaway Park Reservoir Park Richland Park River Mountain Park Riverfront Park Royle Park South Little Rock Southwest Park Taylor Loop Park Thom Park Two Rivers Park University Park Wakefield Park War Memorial Park West End Park TOTAL
Total Land Acres 9.4 149.3 8.8 2.0 0.0 5.8 1.9 2.0 16.6 5.3 35.2 0.6 1.8 259.7 0.0 2.5 50.9 10.4 68.7 11.9 41.2 4.5 7.5 36.9 7.6 28.0 449.1 5.3 2.0 4.9 1.5 59.0 0.3 93.9 14.0 191.3 3.3 33.3 36.2 6.6 264.9 1.7 9.2 54.3 8.6 2,008
UTC Acres
UTC %
0.0 139.3 1.5 0.9 0.0 3.9 0.9 0.4 6.6 0.7 7.4 0.1 0.3 204.6 0.0 0.7 44.5 8.3 10.5 0.5 28.4 3.4 2.2 7.9 3.8 20.5 145.1 1.9 0.9 2.5 1.1 49.3 0.0 83.2 2.6 162.1 0.1 21.0 24.5 5.1 216.3 1.1 7.5 24.2 4.5 1,251
0.0% 93.3% 16.9% 47.8% 100.0% 68.0% 47.8% 22.2% 40.0% 12.5% 21.1% 15.9% 15.0% 78.8% 1.0% 29.9% 87.5% 80.2% 15.3% 4.5% 68.8% 76.2% 29.8% 21.4% 50.0% 73.2% 32.3% 34.9% 46.0% 52.4% 78.1% 83.7% 7.8% 88.6% 18.6% 84.7% 2.3% 63.2% 67.7% 77.8% 81.7% 65.2% 80.9% 44.6% 51.8% 62.3%
PPA (Veg.) Acres 0.7 7.6 6.2 1.0 0.0 1.5 0.8 1.4 8.4 3.5 22.9 0.2 0.2 44.5 0.0 1.7 5.8 1.8 42.7 7.9 9.9 1.0 2.6 21.2 3.3 6.0 259.1 3.0 0.6 1.5 0.3 4.7 0.3 10.7 8.4 25.0 1.5 6.0 10.4 1.4 46.7 0.5 1.6 19.1 3.0 606
PPA (Veg.) % 7.1% 5.1% 71.0% 50.7% 0.0% 25.5% 42.6% 71.6% 50.7% 65.0% 64.9% 28.5% 11.9% 17.1% 99.0% 67.5% 11.3% 17.3% 62.1% 66.2% 24.0% 21.7% 33.9% 57.5% 43.0% 21.5% 57.7% 57.2% 29.1% 31.7% 21.2% 8.0% 92.2% 11.4% 60.0% 13.1% 44.2% 18.2% 28.7% 21.7% 17.6% 32.4% 17.2% 35.1% 34.9% 30.2%
PPA (Imp.) PPA (Imp.) Total PPA Total PPA % Acres % Acres 0.0 1.2 0.2 0.0 0.0 0.4 0.2 0.1 1.2 0.6 3.7 0.4 0.7 6.2 0.0 0.0 0.3 0.2 8.1 1.8 0.6 0.1 2.0 3.6 0.5 1.1 26.5 0.3 0.1 0.4 0.0 2.6 0.0 0.0 2.2 1.8 1.4 4.6 0.1 0.0 0.4 0.0 0.1 6.2 1.1 81
0.0% 0.8% 2.6% 1.3% 0.0% 6.5% 9.0% 6.2% 7.2% 11.3% 10.5% 55.6% 42.3% 2.4% 0.0% 1.2% 0.5% 2.1% 11.7% 14.9% 1.4% 2.1% 26.4% 9.7% 6.9% 4.1% 5.9% 6.0% 6.3% 7.2% 0.7% 4.3% 0.0% 0.0% 15.5% 0.9% 41.3% 13.7% 0.2% 0.5% 0.1% 2.4% 1.6% 11.4% 12.7% 4.0%
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
0.7 8.8 6.4 1.0 0.0 1.8 1.0 1.6 9.6 4.1 26.5 0.5 1.0 50.7 0.0 1.7 6.0 2.0 50.7 9.6 10.5 1.1 4.6 24.8 3.8 7.2 285.6 3.4 0.7 1.9 0.3 7.3 0.3 10.7 10.6 26.8 2.8 10.6 10.4 1.5 47.1 0.6 1.7 25.3 4.1 687
7.1% 5.9% 73.6% 52.0% 0.0% 32.0% 51.7% 77.8% 57.9% 76.3% 75.4% 84.1% 54.1% 19.5% 99.0% 68.7% 11.9% 19.4% 73.8% 81.0% 25.4% 23.8% 60.4% 67.2% 49.9% 25.5% 63.6% 63.2% 35.4% 38.9% 21.9% 12.4% 92.2% 11.4% 75.6% 14.0% 85.5% 31.9% 28.9% 22.2% 17.8% 34.8% 18.8% 46.5% 47.6% 34.2%
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UTC Results in Street Rights-of-Way by Ward Table 12: Complete UTC metrics in street Rights-of-Way by ward Ward
Total Land Acres
UTC Acres
UTC %
% of Total UTC
PPA (Veg.) Acres
PPA (Veg.) %
PPA (Imp.) Acres
PPA (Imp.) %
Total PPA Acres
Total PPA %
Ward 1
3,016
714
24%
27%
913
30%
430
14%
1,343
45%
Ward 2
1,344
334
25%
12%
354
26%
202
15%
556
41%
Ward 3
1,240
459
37%
17%
227
18%
124
10%
351
28%
Ward 4
1,015
295
29%
11%
194
19%
123
12%
317
31%
Ward 5
1,172
186
16%
7%
216
18%
227
19%
442
38%
Ward 6
1,356
377
28%
14%
304
22%
185
14%
489
36%
Ward 7
1,580
329
21%
12%
384
24%
304
19%
688
44%
TOTAL
10,724
2,694
25%
2,593
24%
1,595
15%
4,188
UTC Results by Zoning Classes Table 13: Complete UTC metrics in zoning classes Zoning
Land Acres
% of Total Land Area
UTC Acres
UTC %
Agricultural Commercial Industrial Park Planned Commercial Planned Industrial Planned Residential Residential State Capitol N/A TOTALS
135 6,848 11,472 5,102 2,239 292 1,623 47,350 532 90 75,683
0% 9% 15% 7% 3% 0% 2% 63% 1% 0% 100%
66 2,096 2,365 3,391 689 104 873 26,805 144 4 36,535
48% 31% 21% 66% 31% 36% 54% 57% 27% 4% 48%
PPA (Veg.) PPA (Veg.) PPA (Imp.) PPA Acres % Acres (Imp.) % 36 1,241 3,923 1,359 520 69 312 10,750 122 43 18,375
26% 18% 34% 27% 23% 24% 19% 23% 23% 48% 24%
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
14 2,099 2,461 199 615 76 190 3,956 107 10 9,728
11% 31% 21% 4% 27% 26% 12% 8% 20% 11% 13%
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A3: URBAN FOREST SELF EVALUATION; CRITERIA & INDICATORS The table below illustrates Criteria and Indicators (Clark 1997) to self-evaluate various components necessary for an effective and sustainable urban forest model. This is a useful tool in guiding the process of developing an urban forest management plan.
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
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A4: CANOPY CALCULATOR To assist in advanced UTC goal setting, Plan-It Geo’s Canopy Calculator (MS Excel) tool is provided as an advanced but easy-to-use tool to the City of Little Rock. The City may quickly and easily enter various goals and determine future tree canopy cover and tree planting scenarios.
Figure 33: Screenshots of Little Rock’s UTC Calculator
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
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A5: INCREASING FOREST COVER WITHIN WATERSHEDS Recommendations for maintaining and increasing forest cover, taken from the US Forest Serviceâ&#x20AC;&#x2122;s Urban Watershed Forestry Manual, Part 1: Methods for Increasing Forest Cover in a Watershed.
Figure 34: Goals, objectives and techniques to increase forest cover within watersheds.
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
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A6: LAND COVER CLASSIFICATION ACCURACY ASSESSMENT Arkansas Land Cover Classifications This report describes the methods used and generated results in mapping land cover types across the City of Little Rock, Arkansas. National Agricultural Inventory Program (NAIP) aerial photography from 2012 and GIS data were combined to map five land cover classes: (1) Tree Canopy, (2) Impervious Surface, (3) Green Vegetation, (4). Soil and Dry Vegetation, and (5) Water. Object-based image analysis (OBIA) was used to map trees, other vegetation, impervious surfaces and soil/dry vegetation areas. Impervious surfaces were augmented with existing buildings (provided by MS) and by buffering existing road centerlines. Water was mapped using features provided in addition to manual digitizing at a 1:1,000 scale. Additional Land Cover Products Two additional land cover products related to impervious areas have been prepared for the City. A Comprehensive Impervious raster was created by joining input data provided by Little Rock (Roads, Buildings, and Parking Lots) with impervious areas mapped in the image classification procedure. The dataset breaks impervious areas down by type and allows users to see the impervious extent independent of overhanging canopy cover.
The Canopy Cover over Impervious raster is comprised the three classes of interest: (1) Tree Canopy, (2) Classified Impervious, and (3) Tree Canopy over Impervious. Classes 1 and 2 are extracted directly from the five-class land cover, while class 3 is derived by overlaying tree canopy with the Comprehensive Impervious raster discussed above. This dataset is helpful for identifying where impervious surfaces are covered by existing tree canopy which is a large benefit for reducing stormwater runoff.
Figure 35: This graphic depicts various imagery used in land cover classification.
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
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Accuracy Assessment Classification accuracy serves two main purposes: First, accuracy assessments provide information to technicians producing the classification about where processes need to be improved and where they are effective. Secondly, measures of accuracy provide information about how to use the classification and how well land cover classes are expected to estimate actual land cover on the ground. Even with high resolution imagery, very small differences in classification methodology and quality can have a large impact on overall map area estimations. The classification accuracy error matrix illustrated in Table 1 contains confidence intervals that report the high and low values that could be expected for any comparison between the classification data and what actual, on the ground land cover was in 2010. One thousand (1,000) sample points were randomly distributed across the study area and assigned a random numeric value. Sorting from lowest random value to highest, each sample point was referenced using the NAIP imagery and assigned one of the five land cover classes (Reference ID) mentioned above. Random values ensure sample points are geographically distributed across the entire study area. An automated script is then used to assign values from the classification (Evaluation ID). Misclassified points (where reference ID does not equal evaluation ID) and corresponding land cover are inspected for necessary corrections. The procedure was repeated until an acceptable accuracy percent and classification quality are achieved.
Reference Data
Classification Data
Tree Canopy Vegetation Tree Canopy Vegetation Impervious Soil / Dry Veg. Water Total
397 8 13 0 0 418
2 218 7 5 0 232
Overall Accuracy = Producer's Accuracy Tree Canopy Open Space / Grass Impervious Bare Ground / Soil Water
95% 94% 94% 78% 94%
Impervious
Soil / Dry Veg.
13 3 283 3 0 302
Total Reference Pixels 0 414 0 230 1 306 0 29 17 18 18 997
Water 2 1 2 21 1 27
94% User's Accuracy Tree Canopy Open Space / Grass Impervious Bare Ground / Soil Water
96% 95% 92% 72% 94%
Figure 36: Error Matrix Interpretation
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
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Sample Error Matrix Interpretation Statistical relationships between the reference pixels (representing the true conditions on the ground) and the intersecting classified pixels are used to understand how closely the entire classified map represents the Arkansas landscape. The sample error matrix represents the intersection of reference pixels manually identified by a human observer (columns) and classification category of pixels in the classified image (rows). The white boxes along the diagonals of the matrix represent agreement between the two pixel maps. Off-diagonal values represent the number pixels manually referenced to the column class that were classified as another category in the classification image. Overall accuracy is computed by dividing the total number of correct pixels by the total number of pixels reported in the matrix (397+218+283+21+17 = 936 / 997 = 95%), and the matrix can be used to calculate per class accuracy percent’s. For example, 418 points were manually identified in the reference map as Tree Canopy, but only 397 of those pixels were classified as Tree Canopy in the classification map, with 8 pixels misclassified as Vegetation, and 13 as Impervious. This relationship is called the “Producer’s Accuracy” and is calculated by dividing the agreement pixel total (diagonal) by the reference pixel total (column total). Therefore, the Producer’s Accuracy for Tree Canopy is calculated as: (397 / 418 = 0.95), meaning that we can expect that 95% of all tree canopy in the MS study area were classified as Tree Canopy in the classification map. Conversely, the “User’s Accuracy” is calculated by dividing the number agreement pixel total by the total number of classified pixels in the row category. For example, 397 classification pixels intersecting reference pixels were classified as Tree Canopy, but 2 pixels were identified as Vegetation, 13 as Impervious and 2 as Soil/Dry veg. in the reference map. Therefore, the User’s Accuracy for Tree Canopy is calculated as: (397 /414 = 0.96), meaning that pixels classified as Tree Canopy the classification were actual tree canopy in Little Rock. It is important to recognize the Producer’s and User’s accuracy percent values are based on a sample of the true ground cover, represented by the reference pixels at each sample point.
An Assessment of Urban Tree Canopy in Little Rock, Arkansas
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REFERENCES Clark, N. Matheny, G. Cross, V. Wake. "A Model of Urban Forest Sustainability." Journal of Arboriculture, 1997: 23: 17-30. Nowak, David J. Strategic Tree Planting as an EPA encouraged Pollutant REduction Strategy: How Urban Trees can Obtain Credit in State Implementation Plans. Syracuse, NY: Northern Reserach Station, n.d. Poracsky, Joseph. Urban Forest Canopy Cover in Portland Oregon. 2004. http://web.pdx.edu/~poracskj/Cart%20Center/psucc200404-047.pdf.
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