A Report on the City of Norfolk s Existing and Possible Urban Tree Canopy

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1 A Report on the City of Norfolk s Existing and Possible Urban Tree Canopy Project Background The analysis of Norfolk s urban tree canopy (UTC) was carried out at the request of the Virginia Department of Forestry in collaboration with the City of Norfolk and the Chesapeake Bay Program. The analysis was performed by the Virginia Geospatial Extension Program (VGEP) at Virginia Tech s Department of Forest Resources and Environmental Conservation in consultation with the Spatial Analysis Laboratory (SAL) of the University of Vermont. The goal of the project was to apply the USDA Forest Service s UTC assessment protocols to the City of Norfolk. This analysis was conducted based on year 2008 data. Why is Tree Canopy Important? Urban tree canopy (UTC) is the layer of leaves, branches, and stems of trees that cover the ground when viewed from above. Urban tree canopy provides many benefits to communities including improving water quality, conserving energy, lowering city temperatures, reducing air pollution, enhancing property values, providing wildlife habitat, facilitating social and educational opportunities, and providing aesthetic benefits. Key Terms UTC: Urban tree canopy (UTC) is the layer of leaves, branches, and stems of trees that cover the ground when viewed from above. Land Cover: Physical features on the earth mapped from satellite or aerial imagery such as trees, or water. Existing UTC: The amount of UTC present within parcel boundaries. Possible UTC: The amount of land that is theoretically available for the establishment of tree canopy within parcel boundaries. Possible UTC excludes areas covered by tree canopy, roads, buildings, and water. It is the combination of Possible UTC - Vegetation and Possible UTC - Impervious. Possible UTC - Vegetation: The amount of land that is theoretically available for the establishment of tree canopy in non-tree vegetation areas within parcel boundaries. This excludes areas covered by tree canopy, impervious surfaces, and water. Possible UTC - Impervious: The amount of land that is theoretically available for the establishment of tree canopy in impervious areas within parcel boundaries. This includes impervious areas (roads, parking lots, and sidewalks) except for buildings. How Much Tree Canopy Does Norfolk Have? Figure 1 shows the urban tree canopy (UTC) analysis for Norfolk, which is derived from high resolution aerial imagery. 9,980 acres of Norfolk is covered by tree canopy (termed Existing UTC). This corresponds to 33% of all land area within the city (Table 1). An additional 64% (14,621.4 acres) of the city could theoretically be improved to support urban tree canopy (termed Possible UTC), Table 2. Existing UTC UTC Classes Acres Figure 1: Land cover for the City of Norfolk. 11/23/2009 % Total Land * Tree Canopy % 33% Non-Tree Vegetation % 21% Non-Building Impervious % 34% Buildings Impervious % 12% Water % 0% Total % 100% Table 1: Existing UTC area and percentages for the City * % Total Land includes area covered by water. 1

2 Using high-resolution (1 meter) National Agriculture Imagery Program (NAIP) imagery acquired in the summer of 2008 (Figure 2a) in combination with remote sensing techniques, land cover data for the city was generated (Figure 2b). An accuracy assessment was conducted. Single trees (tree canopies larger than 16 square meters) were detected with a 93% accuracy. Parcels Mapping Norfolk s Trees Who Owns Norfolk s Trees? The detailed land cover mapping conducted as part of this assessment allowed the percentage of Existing and Possible UTC to be calculated for each parcel of land (Figure 3). Using this data, ownership patterns for Existing UTC and Possible UTC (Figure 4) can be examined. Existing UTC 2008 NAIP Imagery (1m) Possible UTC Land Cover Derived from 2008 NAIP Imagery (1m) Figure 2a, 2b: Comparison of 2008 NAIP imagery to the resulting highresolution land cover. 11/23/2009 Figure 3: UTC metrics summarized at the property parcel level 2

3 Figure 4: UTC metrics summarized by property parcel. 11/23/2009 3

4 Urban Tree Canopy Summarized by Property Parcels Using the parcel data provided by the City of Norfolk, Existing and Possible UTC were summarized by property parcels. This summary excludes any area outside of property parcel boundaries and areas covered by water. Norfolk has 36% (8,082.2 acres) Existing UTC and 64% (14,621.4 acres) Possible UTC. Possible UTC has two components, Possible UTC - Vegetation and Possible UTC - Impervious. 22% (5060 acres) of parcel land area is associated with Possible UTC - Vegetation. 42% (9,561.4 acres) of parcel land area is associated with Possible UTC - Impervious (Figure 5). Figure 4 shows Existing UTC through out the City of Norfolk. UTC Parcel Metrics Acres % Parcel Land Parcel Land % Existing UTC % Possible UTC % Possible UTC - Vegetation % Possible UTC - Impervious % Not Suitable for UTC* % Table 2: Acres and percent land area from UTC metrics summarized by property parcels. *Not Suitable for UTC includes all water areas some of which may lay outside of parcel boundaries. Urban Tree Canopy Summarized by Zoning Using the zoning data provided by the City of Norfolk, Existing and Possible UTC were summarized by zoning classification (pages 4-8). The zoning category One-Family R-8 has the largest amount of land area with 3,213 acres (Table 3c). One-Family R-8 also has the largest amount of Existing UTC, 20.6% One Family R-6 and R-7 are 2nd (17.2%) and 3rd (16.5%) in Existing UTC respectively. Figure 6a,6b, and 6c, compare zoning categories by the amount of land area within the categories. 6a compares zoning categories that have more than 450 acres which comprises 84% of the land area. 6b compares zones with 50 to 450 acres of land area (14% of the land area) and 6a contains those with less than 50 acres (2% of the land area). Figure 7 shows Possible UTC by Zoning for the City. Figure 5: Pie chart showing Norfolk UTC distribution. Business and Commerce Park District BC-2 Corridor Commercial District C-2 Deep Waterfront Industrial District I-5 General Airport District GA General Industrial District I-3 Possible UTC Possible -Vegetation Possible -Impervious Existing UTC Land Institutional Campus District IN-2 Institutional District IN-1 Light Industrial District I-2 Medium Density Multiple-Family R-12 Moderate Density Multiple-Family R-11 One-Family R-5 One-Family R-6 One-Family R-7 One-Family R-8 Open Space Preservation District OSP Retail Center District C Acres Figure 6a: UTC metrics summarized by zoning categories with more than 450 acres of land area (not including water area) which comprises 84% of the land area in zoning. 11/23/2009 4

5 Urban Tree Canopy Summarized by Norfolk s Zoning Categories Broad Creek-Mixed Use Planned Development District (PD-MU Business and Commerce Park District BC-1 Downtown Cultural and Convention Center District D-4 Downtown Regional Center District D-2 Downtown Waterfront District D-1 East Beach Planned Development Mixed Use (PD-MU-East Beach) Freemason/Granby Conservation and Mixed Use District D-3 Ghent Historic and Cultural Conservation District HC-G2 High Density Multiple-Family Housing R-15 High Density Multiple-Family R-14 Large Scale Commercial District C-4 Limited Industrial District I-1 Military Installation District MI Possible UTC Possible -Vegetation Possible -Impervious Existing UTC Land Moderately High Density Multiple-Family R-13 Office District O-1 One-Family R-1 One-Family R-2 One-Family R-3 One-Family R-4 One-Family R-9 Planned Development (PDMU- 1) Planned Development (PDMU- 4) Planned Development (PDR-7) Acres Figure 6b: UTC metrics summarized by zoning with 50 to 450 acres of land area (not including water area) which comprises 14% of the land area. 11/23/2009 5

6 Urban Tree Canopy Summarized by Norfolk s Zoning Categories Courtney Avenue Urban Multiple Use CSECPD East Freemason Historic and Cultural East Harbor Beach (EBH) Ghent Historic and Cultural Ghent Historic and Cultural Granby/Monticello Corridor Mixed Use Hodges House Historic and Cultural Limited Commercial District C-1 Little Creek Apartments Planned Manufactured Home Park District MHP Possible UTC Possible -Vegetation Possible -Impervious Existing UTC Land Ocean View Residential District (OVR) Planned Development (PDMU-2) Planned Development (PDMU-3) Planned Development (PDR-10) Planned Development (PDR-11) Planned Development (PDR-5) Planned Development (PDR-6) Planned Development (PDR-8) Planned Development (PDR-9) Planned Development Harbor Walk River House Residential Planned River s Edge at Berkley Residential Spectrum at Willoughby Mixed Use Taylor's Landing Planned Development Townhouse District R-10 University Village District UV Urban Residential District (UR) Waterfront Industrial District I-4 Waterfront Mixed Use District D-5 WaterMark Planned Development West Freemason Historic and Cultural West Freemason Historic and Cultural Acres Figure 6c: UTC metrics summarized by zoning with less than 50 acres of land area (not including water area) which comprises 2% of the land area. 11/23/2009 6

7 Urban Tree Canopy Summarized by Zoning Zoning Land (Acres) Existing UTC Possible UTC Vegetation Possible UTC Impervious Broad Creek-Mixed Use Planned Development District % 16.5% 0.2% 0.2% 43.1% 0.7% 0.1% 40.3% 0.4% Business and Commerce Park District BC % 16.7% 0.4% 0.2% 19.8% 0.8% 0.6% 63.6% 1.4% Business and Commerce Park District BC % 9.6% 0.5% 0.4% 21.3% 1.9% 1.4% 69.2% 3.3% Corridor Commercial District C % 11.7% 1.6% 0.6% 13.0% 2.9% 3.7% 75.1% 8.9% Courtney Avenue Urban Multiple Use District (CAU-MU) 4 0.0% 8.2% 0.0% 0.0% 14.5% 0.0% 0.0% 77.3% 0.0% CSECPD 5 0.0% 3.6% 0.0% 0.0% 32.0% 0.0% 0.0% 64.4% 0.0% Deep Waterfront Industrial District I % 6.3% 0.9% 0.6% 12.1% 2.7% 4.1% 81.6% 9.7% Downtown Cultural and Convention Center District D % 13.1% 0.1% 0.0% 11.2% 0.2% 0.3% 75.7% 0.7% Downtown Regional Center District D % 11.9% 0.1% 0.0% 10.5% 0.2% 0.3% 77.6% 0.8% Downtown Waterfront District D % 14.1% 0.1% 0.1% 20.6% 0.3% 0.2% 65.4% 0.5% East Beach Planned Development Mixed Use % 9.9% 0.1% 0.2% 52.7% 1.0% 0.2% 37.4% 0.4% East Freemason Historic and Cultural Conservation District 7 0.0% 27.7% 0.0% 0.0% 21.1% 0.0% 0.0% 51.2% 0.0% East Harbor Beach (EBH) % 4.7% 0.0% 0.0% 22.3% 0.1% 0.0% 73.0% 0.1% Freemason/Granby Conservation and Mixed Use District D % 8.6% 0.1% 0.0% 8.2% 0.1% 0.2% 82.6% 0.5% General Airport District GA % 11.4% 1.1% 1.7% 47.4% 7.6% 1.5% 41.2% 3.5% General Industrial District I % 12.1% 0.8% 0.4% 14.3% 1.6% 1.8% 73.5% 4.3% Ghent Historic and Cultural Conservation District HC-G % 44.8% 0.2% 0.0% 17.2% 0.1% 0.1% 38.0% 0.1% of UTC type for specified land use = of all land of UTC type for specified land use % = of all land for specified land use of UTC type for specified land use = of all UTC type The % value of 0.3% indicates that 0.3% of Norfolk s land area is tree canopy in areas where the land use is General Industrial District I-3. The Use value of 12.1% indicates that 12.1% of General Industrial District I-3 land is covered by tree canopy. The value of 0.8% indicates that 0.8% of all Existing UTC lies in areas of General Industrial District I-3 land use. Table 3a: UTC metrics by type, summarized by zoning categories. For each zone, category UTC metrics were computed as a percent of all zoned land in the city ( ), as a percent of land area by zoning categories ( ) and as a percent of the area for the UTC type ( ). 11/23/2009 7

8 Urban Tree Canopy Summarized by Zoning Continued Zoning Land (Acres) Existing UTC Possible UTC Vegetation Possible UTC Impervious Ghent Historic and Cultural Conservation District % 34.5% 0.2% 0.0% 11.7% 0.1% 0.1% 53.8% 0.3% Ghent Historic and Cultural Conservation District 0 0.0% 29.3% 0.0% 0.0% 20.7% 0.0% 0.0% 50.0% 0.0% Granby/Monticello Corridor Mixed Use District G % 2.6% 0.0% 0.0% 3.6% 0.0% 0.0% 93.8% 0.1% High Density Multiple-Family Housing R % 23.5% 0.2% 0.0% 11.7% 0.1% 0.1% 64.8% 0.4% High Density Multiple-Family R % 20.5% 0.3% 0.1% 13.3% 0.4% 0.4% 66.2% 1.0% Hodges House Historic & Cultural Conservation District 1 0.0% 24.6% 0.0% 0.0% 73.0% 0.0% 0.0% 2.4% 0.0% Institutional Campus District IN % 20.0% 1.5% 0.7% 25.1% 3.0% 1.5% 54.9% 3.5% Institutional District IN % 28.0% 4.8% 2.2% 35.7% 9.6% 2.2% 36.3% 5.2% Large Scale Commercial District C % 3.9% 0.0% 0.0% 2.5% 0.0% 0.3% 93.6% 0.6% Limited Commercial District C % 14.9% 0.1% 0.0% 14.1% 0.1% 0.1% 71.0% 0.2% Limited Industrial District I % 12.7% 0.5% 0.2% 13.6% 0.9% 1.1% 73.7% 2.6% Little Creek Apartments Planned Development District 6 0.0% 7.3% 0.0% 0.0% 3.2% 0.0% 0.0% 89.6% 0.1% Manufactured Home Park District MHP % 30.8% 0.1% 0.0% 10.3% 0.1% 0.1% 59.0% 0.2% Medium Density Multiple-Family R % 24.5% 1.8% 0.6% 24.4% 2.8% 1.3% 51.0% 3.1% Military Installation District MI % 19.7% 0.3% 0.2% 32.6% 0.7% 0.2% 47.3% 0.5% Moderate Density Multiple-Family R % 42.3% 5.2% 1.1% 25.6% 5.0% 1.4% 32.0% 3.3% Moderately High Density Multiple-Family R % 29.9% 1.3% 0.2% 13.5% 0.9% 0.9% 56.6% 2.1% Ocean View Residential District (OVR) 2 0.0% 37.0% 0.0% 0.0% 43.1% 0.0% 0.0% 20.0% 0.0% Office District O % 37.3% 0.9% 0.1% 9.7% 0.4% 0.5% 53.0% 1.1% One-Family R % 57.8% 1.4% 0.2% 20.4% 0.8% 0.2% 21.8% 0.4% One-Family R % 67.2% 2.5% 0.1% 10.9% 0.6% 0.3% 21.9% 0.7% One-Family R % 61.9% 3.6% 0.3% 15.4% 1.4% 0.5% 22.7% 1.1% Table 3b : UTC metrics by type, summarized by zoning categories. For each zone, category UTC metrics were computed as a percent of all zoned land in the city ( ), as a percent of land area by zoning categories ( ) and as a percent of the area for the UTC type ( ). 11/23/2009 8

9 Zoning Urban Tree Canopy Summarized by Zoning Continued Land (Acres) Existing UTC Possible UTC Vegetation Possible UTC Impervious One-Family R % 53.4% 17.2% 2.4% 20.7% 10.6% 3.0% 25.9% 7.1% One-Family R % 53.0% 16.5% 2.1% 19.3% 9.6% 3.1% 27.7% 7.3% One-Family R % 51.6% 20.6% 2.6% 18.1% 11.5% 4.3% 30.3% 10.3% One-Family R % 48.5% 0.4% 0.1% 27.5% 0.4% 0.1% 24.0% 0.2% Open Space Preservation District OSP % 39.7% 7.7% 3.5% 51.0% 15.7% 0.6% 9.1% 1.5% PLANNED DEVELOPMENT (PDR-5) % 48.9% 1.1% 0.1% 16.4% 0.6% 0.3% 34.8% 0.7% PLANNED DEVELOPMENT (PDMU-1) % 41.8% 0.2% 0.0% 25.8% 0.2% 0.1% 32.3% 0.1% PLANNED DEVELOPMENT (PDMU-2) % 37.8% 0.1% 0.0% 15.2% 0.1% 0.0% 47.0% 0.1% PLANNED DEVELOPMENT (PDMU-3) % 38.8% 0.3% 0.0% 11.2% 0.1% 0.1% 49.9% 0.3% PLANNED DEVELOPMENT (PDMU-4) % 21.8% 0.1% 0.0% 23.7% 0.1% 0.0% 54.5% 0.1% PLANNED DEVELOPMENT (PDR-10) % 20.3% 0.0% 0.0% 16.2% 0.0% 0.0% 63.5% 0.1% PLANNED DEVELOPMENT (PDR-11) % 36.2% 0.3% 0.1% 31.4% 0.5% 0.1% 32.4% 0.3% PLANNED DEVELOPMENT (PDR-6) % 17.3% 0.0% 0.0% 15.8% 0.0% 0.0% 66.8% 0.1% PLANNED DEVELOPMENT (PDR-7) % 35.9% 0.1% 0.0% 31.0% 0.2% 0.0% 33.1% 0.1% PLANNED DEVELOPMENT (PDR-8) 5 0.0% 41.9% 0.0% 0.0% 41.6% 0.0% 0.0% 16.5% 0.0% PLANNED DEVELOPMENT (PDR-9) % 10.7% 0.0% 0.0% 27.0% 0.2% 0.1% 62.3% 0.2% Planned Development Harbor Walk % 23.0% 0.0% 0.0% 25.9% 0.1% 0.0% 51.1% 0.1% Retail Center District C % 3.7% 0.2% 0.1% 5.0% 0.5% 2.0% 91.3% 4.7% River House Residential Planned Development District 7 0.0% 1.6% 0.0% 0.0% 15.8% 0.0% 0.0% 82.6% 0.1% River s Edge at Berkley Residential Planned Development District 6 0.0% 28.2% 0.0% 0.0% 60.5% 0.1% 0.0% 11.3% 0.0% Spectrum at Willoughby Mixed Use Planned Development District % 0.0% 0.0% 0.1% 90.3% 0.2% 0.0% 9.7% 0.0% Taylor's Landing Planned Development 9 0.0% 7.5% 0.0% 0.0% 9.3% 0.0% 0.0% 83.2% 0.1% Townhouse District R % 27.8% 0.1% 0.0% 13.8% 0.1% 0.1% 58.4% 0.2% University Village District UV % 2.1% 0.0% 0.0% 5.1% 0.0% 0.1% 92.8% 0.2% Urban Residential District (UR) 8 0.0% 31.4% 0.0% 0.0% 41.3% 0.1% 0.0% 27.3% 0.0% Waterfront Industrial District I % 10.0% 0.1% 0.0% 13.2% 0.1% 0.1% 76.8% 0.3% Waterfront Mixed Use District D % 6.8% 0.0% 0.0% 27.1% 0.2% 0.1% 66.1% 0.2% WaterMark Planned Development District (PD-R WM) % 24.2% 0.1% 0.0% 42.8% 0.2% 0.0% 33.0% 0.1% West Freemason Historic and Cultural Conservation District HC-WF % 29.9% 0.0% 0.0% 12.5% 0.0% 0.0% 57.7% 0.1% West Freemason Historic and Cultural Conservation District HC-WF % 10.3% 0.0% 0.0% 9.4% 0.0% 0.0% 80.3% 0.1% Table 3c: UTC metrics by type, summarized by zoning categories. For each zone, category UTC metrics were computed as a percent of all zoned land in the city ( ), as a percent of land area by zoning categories ( ) and as a percent of the area for the UTC type ( ). 11/23/2009 9

10 Figure 7: Possible percentage increase of UTC mapped using zoning categories provided by the City of Norfolk. 11/23/

11 Where to Plant Trees? Decision makers can use GIS to find out specific UTC metrics for a parcel or set of parcels. This information can be used to estimate the amount of tree loss in a planned development or set UTC improvement goals for an individual property. GIS Database Figure 8: Parcel-based UTC metrics can be used to support targeted UTC. Conclusions Norfolk s urban tree canopy is a vital community asset, reducing stormwater runoff, improving air quality, reducing the city s carbon footprint, enhancing quality of life, contributing to savings on energy bills, and serving as habitat for wildlife. With 33% tree canopy cover, Norfolk has similar coverage as Blacksburg, Leesburg, Manassas, and Winchester. Figure 9 shows how Norfolk compares to other Virginia localities participating in Urban Tree Canopy Assessments. When summarized by parcels, Norfolk has 36% Existing UTC with only 30% of all parcels with less than 30% canopy coverage. 62% (4,975 acres) of the Existing UTC is located within Open Space Preservation District OSP and One Family Districts R-6, R-7, and R-8 zoning categories. 58% 60% 47% 50% Existing UTC 44% 41% 41% 53% 40% 30% 30% 33% 27% 27% 27% 20% 20% 10% 0% * Data provided by University of Vermont **Data provided by Fairfax County Figure 9: Comparison of Existing UTC of % land area (excludes water area) with other Virginia localities that have completed UTC assessments. Prepared by: Additional Information Jennifer McKee Geospatial Project Developer Virginia Geospatial Extension Program Department of Forest Resources and Environmental Conservation Virginia Tech , jmckee@vt.edu The study was conducted with funding from the Virginia Department of Forestry. More information on the UTC assessment project can be found at the following web site. 11/23/