Urban Forest Management Plan
2 0 1 3 ~ wake fore s t , NC
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Urban Forest Management Plan
Acknowledgements
WAKE FOREST BOARD OF COMMISSIONERS
WAKE FOREST URBAN FORESTRY BOARD
TOWN STAFF
Suzanne Beaumont Don Daria Anna Faatiliga Brian Haines Sarah Hutchins Will Opio Wayne Pratt Michael Reischman Charles Sheffield
Mark Williams, Town Manager Ruben Wall, Parks & Recreation Director Evan Keto, Urban Forester
Vivian A. Jones, Mayor Zachary Donahue Frank Drake Greg Harrington Anne Hines Margaret Stinnett
Chip Russell, Planning Director Aileen Staples, Finance Director
Bill Crabtree, Public Information Officer Bess Martinson, Communications Specialist Sarah Sheldon, GIS Planner
Supported by the U.S. Department of Agriculture under the North Carolina Urban and Community Forestry Grant Program
Special thanks to Alan Moore, North Carolina Forest Service
Accepted in 2013
Town of Wake Forest | 301 S. Brooks Street, Wake Forest, NC 27587 | 919-435-9400 | www.wakeforestnc.gov
“No town can fail of beauty, though its walks were gutters and its houses hovels, if venerable trees make magnificent colonnades along its streets.”
~ H enry W ard B eecher
Executive Summary BACKGROUND: Wake Forest is recognized for its continuing commitment to maintaining an at- tractive and productive urban forest. The town currently is responsible for 14,700 street trees, 630 acres of forests, and more than 1,100 maintained trees in parks and town property. There are approximately 5,400 sites where additional trees may be planted in the future. Currently, the town’s street trees provide annual benefits valued at approximately $389,000 and have an estimated replacement value of $16.9 million. VISION: “Wake Forest’s Urban Forestry Program develops and maintains the health, beauty, and value of the town’s urban forest as a key feature that draws residents, businesses, visitors, and recognition to our community.”
GOALS: The following goals are recommended to achieve this vision:
• maintain a town-wide canopy cover of at least 40%, • maintain at least 90% of public trees in “good” condition (defined as 75%-100% of perfect condition) • maintain living trees in at least 95% of available public planting spaces • ensure that no species, genus, or family of trees comprise more than 10%/20%/30%, respectively, of the town’s street tree population RECOMMENDED ACTIONS, FY2013-2014: Current staff and funding levels are inadequate to pro- vide the recommended level of service in maintaining the town’s tree resources. These mainte- nance demands are increasing as a result of both continued development within the town, and the increasing size of the individual trees that comprise the urban forest. To meet the goals and vision outlined above, we recommend that the town: • Hire, train, and equip 2 Arborist Technicians to plant, maintain, and remove trees. If all currently needed street tree maintenance activities were performed by staff, the town would save approximately 39% to 66% versus contractors. The difference in total costs over the next 5 years is estimated at between $498,000 to $859,000, depending on staff salaries. • Hire and train 2 seasonal interns to complete the street tree inventory. It is estimated that this will save about $100,000 compared to the quote given by the town’s previous tree maintenance contractor. A complete inventory will reduce the town’s liability for deaths or injuries caused by hazardous trees and allow for efficient maintenance of this resource. • Continue to contract out work for hazardous tree removal, large tree pruning, and insect and disease treatment until the necessary skills and equipment can be developed to perform this work in-house. • Continue to provide adequate funding levels for tree maintenance, planting, and education programs, maintenance, planting, and education programs. • Update the Official Planting List using knowledge gained from the 2012 inventory.
Table of Contents
Introduction & Background
7
Purposes of this Plan—7 Visions and Policies from the 2009 Community Plan—7
Overall Urban Forestry Program Vision—9 A Brief History of Wake Forest’s Trees—10
Urban Forest Resources & Recommendations
12
Wake Forest’s Tree Resources—12 Condition and Maintenance Needs—16 Species—17 Type and Size Class—19 Value & Benefits of Street Trees—21 Maintenance Needs—22
Work Management Plan, Staffing and Budget
27
Addressing the Current Street Tree Workload—29 Estimated Costs for Street Tree Work—32 Additional Responsibilities—38 Staff and Volunteers—39 Vehicles, Tools and Equipment—43 Budget—45
Summary and Recommendations
49
Recommendations—50 References—51 Appendix A: Trees for Tomorrow Program—52 Appendix B: Maps—53 Appendix C: Changes in Wake Forest Landcover—56
I
INTRODUCTION & BACK-
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Introduction & Background
Purposes of this Plan “Without a management plan, the governments and individuals responsible for taking care of an urban forest will not be effective in meeting the true needs of the trees and the community. A management plan establishes a clear set of priorities and objectives related to the goal of maintaining a productive and beneficial community forest.”
~ A merican P ublic W orks A ssociation , 2007 c .
This document is intended: • To identify the town’s goals and priorities for managing its trees and forests • To describe the current status of the town’s urban forest resources and its management program • To document the methods, resources, and personnel that will be used to achieve these goals over the next five years Statutory Requirements The Town’s Ordinance Sec. 34-74 requires the Urban Forestry Board “To study, investigate, counsel, develop and/or update annually, and administer a written plan for the care, preserva- tion, pruning, planting, replanting, removal or disposition of trees, shrubs and other planting materials in parks, street and utility rights of way and easements and any other public areas. This plan shall constitute the official town urban forestry plan.” This document is intended to fulfill this obligation by the Urban Forestry Board.
Visions and Policies from the 2009 Community Plan
“Support for street trees in Wake Forest is very strong. Area residents at town meetings held for the community plan offered a firm consensus in support of tree planting and preser- vation. Comments received at the first town meeting, for example, included ‘strong tree preservation ordinance’ and ‘replant trees’. Another citizen simply said ‘Keep Wake Forest green.’ Regardless of the exact words chosen, there is little doubt that residents want Wake Forest to be a beautiful community and street trees are one of the most effective, least costly ways to do that.” ~ W ake F orest C ommunity P lan , 2009
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Overarching street trees provide shade along neighborhood sidewalks.
In 2009, an 11-member steering committee appointed by the Town Board created a Community Plan, containing vision statements and policies to guide staff decisions and proposed changes in town facilities and services. The Wake Forest Community Plan contains a number of visions involving the town’s trees. Together, they paint a picture of a town in which quality of life benefits greatly from trees in parks, along greenways and streets, and in town-owned open space. Vision 1: Small Town Character, Attractive Appearance “…Streets in Wake Forest exude a welcoming, small town charm; overarching street trees, lush landscaping, understated signage, and wide, shaded sidewalks combine to create a truly invit- ing community character… Greenery is everywhere. Small parks and natural areas are within walking distance of most parts of town. Office and retail parking lots, once viewed as “seas of asphalt”, are now tree-shaded and landscaped.” Vision 7: Open Space and Environmental Quality “In managing its growth, Wake Forest has worked to preserve open space and minimize adverse impacts to the region’s air and water quality… Streams and drain-age ways passing through Wake Forest receive less storm water runoff and pollution due, in part, to policies on dedicated open space, tree preservation, landscaped parking areas, compact two and three story build- ings, and vegetated buffer strips along streams and roadsides.” Vision 8. Expanded Park and Recreation System “As the community has grown, Wake Forest has steadily added to its system of parks and open space…An extensive system of greenway trails, primarily adjoining area streams, is enjoyed by hikers, bicyclists, and others. These greenways also serve as natural corridors for the movement of wildlife in Wake Forest.” Vision 11. Affordable Housing and Quality Neighborhoods “Wake Forest is known for safe, secure, quiet neighborhoods in every part of the community, with well-tended yards and gardens, and small parks close at hand.”
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Policy ST-1: The town should prepare and maintain an official STREET TREE PLANTING MASTER PLAN to address: 1) the retrofitting of existing streets, where appropriate, 2) the planting of future streets and 3) the maintenance and replacement of dead, diseased or disfig- ured trees.
Policy ST-2: So as to create a unity of design and effect, CONSISTENT STREET TREE SPECIES should occur along predetermined sections of streets.
Policy ST-3: To prevent future decimation of tree cover over entire areas of the community by disease (e.g. Dutch Elm disease), NO SINGLE TREE SPECIES should comprise more than 10 to 15% of the total street tree population of the town. Further, trees in a neighborhood area should vary from street to street.
Policy ST-4: REGULARLY SPACED STREET TREES should be planted in central medians, front- age street medians, plaza strips and, where necessary, in dedicated easements on private property.
Policy CC-5: Large trees, ponds, creeks, or other natural features of the landscape should be saved when locating new streets, buildings, parking lots, etc.
Policy HSE-6: VEGETATED RIPARIAN BUFFERS (natural or planted) shall be required along all creeks, rivers, lakes and other water bodies in Wake Forest.
Policy HSE-12: A combination of incentives and disincentives may be employed to protect EXISTING TREES and/or require the replacement of trees removed for development.
Overall Urban Forestry Program Vision
To summarize these statements, the following vision is offered:
“Wake Forest’s Urban Forestry Program develops and maintains the health, beauty, and value of the town’s urban forest as a key feature that draws residents, businesses, visitors, and recognition to our community.”
Program Goals To achieve this vision, the following goals are recommended:
• maintain a town-wide canopy coverage of at least 40% • maintain at least 90% of public trees in “good” condition (defined as 75%-100% of perfect condition) • maintain living trees in at least 95% of available public planting spaces • ensure that no species, genus, or family of trees comprise more than 10%/20%/30%, respectively, of the town’s street tree population
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A Brief History of Wake Forest’s Trees In the early 1700s, botanist and explorer John Lawson passed through the piedmont of North Carolina, including the Falls of the Neuse River, and described a landscape far different from today’s: “However, we all got safe to the North-Shore, which is but poor, white, sandy Land, and bears no Timber, but small shrubby Oaks. We went about 10 Miles, and sat down at the Falls of a large Creek. …I take this to be the Falls of Neus-Creek….We lay here all Night….The next Morning we set out early….We went, this day, above 30 Miles, over a very level country, and most Pine Land.”
-J ohn L awson , 1709
Because pine trees cannot grow in the shade of their ancestors, it is likely that the pine forests around this area were dependent on grazing herbivores and frequent fires that prevented hardwood forests from developing. These two disturbing forces also would have reduced the underbrush enough to allow the explorers to cover 30 miles per day.
Over the next century, trees had become a defining feature of this area, and by 1820, this area was known as “Wake Forest Township”. In the late 1800s, trees were planted along town streets. Historical maps show trees in the campus that is now the Southeastern Baptist Theological Seminary, and some of these trees still survive. The 1909 Sanborn fire insurance maps show two large lumber planing mills on between South White Street and the railroad, indicating the economic impor- tance of local timber harvesting. Aerial photos from 1938 reveal Wake Forest as a town surrounded by farms and forests, with shade trees planted in yards and along Main Street. The Wake Forest Tree Board was es- tablished in 1978. That same year, the first recorded street tree inventory was conducted. Wake Forest was one of the first communities in North Carolina to be named a “Tree City USA” in 1979. In
The area around Wake Forest once contained a mix of pine forests and prairies grazed by bison and elk, as documented by explorer John Lawson in 1709.
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1990, the Tree Board commissioned an Urban Forestry Report, and this information was used to amend the town’s zoning ordinance.
During the 1990s, multiple grants helped to fund tree planting and educational projects throughout town. During the 2000s, Wake Forest grew rapidly, and many developments were created that incorporated street trees. In 2004, another street tree inventory was conducted by Davey Resource Group. In 2010, Wake Forest was named North Carolina’s Tree City USA of the year. The town also received the prestigious Sterling Award for 10 years of continuous pro- gram growth. To date, only eight other municipalities in North Carolina share this distinction.
Growth of Wake Forest’s Street Tree Population Previous tree inventories per- formed by Davey Resource Group in 2004 and by the NC Division of Forest Resources in 1978 and 1990 show slow, steady growth in the num- ber of street trees. Between 2004 and 2012, many new developments were added to the town, and both popula- tion and the number of street trees increased dramatically (Figure 1).
10000 15000 20000 25000 30000 35000
Population
Street Trees
0 5000
1970
1980
1990
2000
2010
FIGURE 1: Population of residents and street trees by decade, 1970 to Present
Durham 233,252
Raleigh 416,468
Wake Forest has been a Tree City since 1979, received the Tree City USA Sterling Award in 2002, and was named North Carolina’s Tree City USA of the Year in 2010.
tree image to go here
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Urban Forest Resources and Recommendations
Wake Forest’s Tree Resources: Tree Canopy, Forests and Public Trees
tree canopy coverage Tree canopy coverage is a measure of the portion of the town that is shaded by trees. Digital aerial photos taken during the 2010 growing season and iTree Canopy software were used to estimate townwide canopy cover at 44% ± 3% (Figure 2).
American Forests’ General Tree Canopy Goals American Forests, a national not-for-profit conservation organization, has developed tree canopy goals for various areas in the United States, with the following recommended generally for cities east of the Mississippi:
WATER 2%
CANOPY 44%
NON-CANOPY 54%
• 40% tree canopy overall • 50% tree canopy in suburban residential areas • 25% tree canopy in urban residential areas • 15% tree canopy in central business districts
NON-CANOPY 54%
FIGURE 2: Approximately 44% of Wake Forest was shaded by trees in 2010
TABLE 1: Urban Tree Canopy in North Carolina Municipalities
CITY
TREE CANOPY COVERAGE
TREE CITY USA?
POPULATION (2011)
CANOPY GOAL
Hickory
32% (2009)
Yes
39,965
40%
Selma
34%
No
6,209
-
Smithfield
43%
No
11,194
-
Yes
31,073
40% (proposed)
Wake Forest
44% (2010)
Clayton
52%
Yes
16,472
-
Yes
751,087
50% BY 2050
Charlotte
49% (2008)
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AQUATIC 1%
AQUATIC
1% SHORT VEG 9%
SHORT VEG 13%
DEVELOPED 42%
FOREST 29%
DEVELOPED 61%
FOREST 44%
NON-CANOPY 54%
2001
2006
FIGURE 3: Total Town Landcover by Category, 2001 and 2006
FIGURE 4: Landcover in Acres, 2001-2006, for Areas Within the 2012 Town Limits
While the town exceeded this goal in 2010, continued development is likely to result in falling below this threshold. Significant investments in tree preservation, planting, and protecting forested open space from future development are needed to keep Wake Forest from falling behind other North Carolina municipalities (Table 1). Using diameter estimates and US Forest Service canopy models, the town’s street trees are estimated to provide 3 million square feet of canopy, or about 70 acres. This is a relatively tiny percentage of overall canopy cover, but represents an important type of canopy that shades heavily used ar- eas of pavement, sidewalks, and buildings. Overall Town Landcover Free landcover data provided by the MRLC, a consortium of Federal agencies, shows a de- crease in forest and an increase in developed land between 2001 and 2006 (Figures 3 & 4). Data from 2011 is expected to be available in December 2013. In 2001, the area within the current corporate limits was predomi- nantly covered by forest, and there was 1 acre of forest for every acre of developed land. By 2006, developed land was predominant, with 2 acres of development for every acre of
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000
2001
2006
Developed Total
Short Veg Total
Forest Total
Aquatic Total
RECOMMENDATION: Set a goal of at least 40% canopy coverage overall. Identify areas of below-average coverage, and encourage measures to preserve and expand tree canopy coverage. Continue to purchase and preserve forested open space to offset canopy loss due to new development.
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forest. During this 5-year period, more than 1/3 of the forest (2.3 square miles) was removed, and more than 3 square miles of developed areas were created. Almost half of the forest removed was evergreen, likely from pine plantations or old fields. Landcover on Town Property For property currently owned by the town, forest was the dominant landcover in both 2001 and 2006 (Figure 5). About 6% of forested land (37 acres) was converted to developed prop- erty. Using digital aerial photos taken in 2010, it is estimated that the town currently owns approximately 630 acres of forested land (0.98 square miles). Upland deciduous forests are the most common type of forest on town property (Figure 6). town forests Currently, there is no written plan for the management of the town’s significant holdings of forested land. However, the following general issues have been identified: • Overly thick stands of loblolly pines need to be thinned to reduce the threat of wildfires, pests, and disease. • Invasive exotic plant species such as kudzu, Chinese privet, Japanese stiltgrass, Callery pear, and Chinaberry have infested town property and should be controlled.
RECOMMENDATION: Create management plans for all town forests, describing these resources and detailing how they are to be managed. Create a wildfire risk management plan.
AQUATIC
MIXED FOREST 9%
AQUATIC
2% DEVELOPED 20%
2% DEVELOPED 15%
EVERGREEN FOREST 19%
DECIDUOUS FOREST 47%
LOW GROWTH 17%
FOREST 62%
LOW GROWTH 16%
FOREST 66%
WOODY WETLANDS 25%
NON-CANOPY 54%
2001
2006
FIGURE 6: Forest Types on Town Property, 2006 National Land Cover Dataset
FIGURE 5: Landcover of Town Property, 2001 and 2006
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• Species composition and regeneration within town forests may be affected by high populations of white-tailed deer. Therefore, it is recommended that a forest management plan be developed to describe and manage each stand of forest on town property. This will reveal opportunities to make these forests safer, healthier, more productive, and possibly economically pro- ductive through carefully planned thinning or harvesting operations.
TABLE 2: Estimated Number of Maintained Trees on Town Property
TOWN PROPERTY
MAINTAINED TREES
E. Carroll Joyner Park
300
Wake Forest Cemetery
250
Town Hall and Miller Park
150
Flaherty Park
150
Heritage High Park
100
Smith Creek Soccer Center
75
See Appendix on page 53 for maps of forested land in Wake Forest.
Plummer Park
50
Holding Park
25
trees on public grounds Using aerial photos, it is estimated that there are more than 1,100 maintained trees in town parks and cemeteries, and around public facilities (Table 2). The pecan grove at Joyner Park, historic trees of the Wake Forest Cemetery, and shade trees in town parks represent some of the most highly visible and appreciated trees in town, and should be maintained at a level equal to or exceeding the town’s street trees. In addition to these maintained trees, there are thousands of trees along trails and gre- enways in the town’s park system, which periodically require inspection and pruning to ensure that the trails are safe and clear for pedestrians and bicyclists.
Public Works Facility
20
Ailey Young Park
20
Tyler Run Park
20
Taylor Street Park
15
TOTAL
1,175
RECOMMENDATION: Conduct a tree inventory for all maintained trees on Town property, and inspect all trees along trails and greenways periodically. Create a plan to respond to trees damaged by storms, which may fall across streets or greenways.
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Condition and Maintance Needs
FIGURE 7: Location of Current Street Trees
TREE PIT 1% 8 ' TREELAWN 2% MEDIAN 3%
street tree population
4 ' TREELAWN 4%
6̇ ' TREELAWN 16%
The Town of Wake Forest is currently responsible for maintaining approximately 14,700 trees along the public right-of-way (ROW) (Table 4). The town now contains a street tree population that rivals mu- nicipalities that are known nationally for their trees, such as Burlington, Vermont (6,987) and Charleston, South Carolina (15,244). The total number of street trees has grown rapidly from the 2004 tree inventory, likely due to the large number of trees planted in new neighborhoods. Most of these trees are along streets maintained by the town, while some are found on streets maintained by the NC Department of Transportation (NCDOT), with Main Street (Route 1A) being the most visibly forested. Most of the trees in the right of way are of a size and species appropriate for town maintenance, but a small percentage of the trees were small-growing ornamen- tals, which would not qualify for town maintenance.
YARD 74%
FIGURE 8: Current Use of Potential Planting Spaces for Street Trees
DEAD TREE 1% STUMP 1%
VACANT 26%
LIVING TREE 72%
Planting Site Types Most trees are planted behind the sidewalk, which is ideal for root growth (Figure 7). A large number are also planted in the space between the sidewalk and the street, known as a “treelawn”, “verge”, or “devil strip”. In most cases, this space is 6 feet wide, which is adequate for many species, though 8 feet or wider is better for tree health. Relatively few trees are planted in tree pits, sidewalk cutouts, or in street medians. Stumps, Dead Trees, and Vacant Planting Sites There are approximately 200 stumps from recently removed trees, 100 standing dead trees, and more than 5,000 locations where additional trees could be planted (Figure 8). More than 70% of spaces that could support street trees currently contain a living tree. This “stocking level” is fairly good, but indicates that there is a significant opportunity to plant additional trees. Standing dead trees and stumps are unattractive and potentially hazardous, and should be removed.
RECOMMENDATION: Identify and remove standing dead trees and stumps as soon as possible, and plant additional trees as resources allow.
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TABLE 3: Current Estimated Street Tree Population All ranges represent 80% confidence intervals (rounded to 3 significant figures)
WAKE FOREST TOWN ROADS
NCDOT STATE ROADS
TOTAL
Publicly Maintained Trees
14,200 (±2,370)
474 (±202)
14,700
95 (±25)
413
Privately Maintained Trees in ROW
318 (±111)
24 (±20) 71 (±39) 213 (±95)
199
Stumps
175 (±65) 48 (±33)
119
Dead Trees
5,400
Potential Planting Spaces
5,190 (±830)
876 (±218)
20,800
Total Planting Spaces
19,900 (±2,530)
Species
The 10/20/30 Rule Each tree’s strengths, weaknesses, needs, and benefits are determined largely by its species. In order to reduce the threat and spread of devastating pests and diseases, such as those that decimated the American elm and the American chestnut, it is important to plant a variety of different species. It is generally recommended that no more than 10% of a town’s street trees be of the same species, no more than 20% of the same genus, and no more than 30% of the same family. Following this 10/20/30 rule will help to ensure that pests and diseases are isolated and controllable, and have little impact on the total value of the urban forest. According to the 10/20/30 rule, Wake Forest has too many oaks, red and Freeman maples, and crapemyrtles (Table 4). Recommendations for alternatives to commonly planted species are provided in Table 5.
Oaks In Wake Forest, one in four street trees is a member of the red oak group. This group contains the very popular willow oak, as well as Shumard, Nutall, pin, water, north- ern red, southern red, black, and other oaks. The white oak group, which includes the white, post, chestnut, and other oaks,
Oaks in the red oak group have lobed, pointed leaves originating on alternating sides of the stem.
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TABLE 4: Most Common Street Tree Species
SPECIES
PERCENTAGE
Red Oak group (multiple species)
25%
Crapemyrtle
15%
Red and Freeman Maples
10%
A Freeman maple, a cross between a red and silver maple, with outstanding fall color.
5%
Cherry group (multiple species)
Sycamore/Planetree
5%
is also represented. The large-growing, acorn-bearing oaks provide the majority of the value and benefits of the town’s street tree population. However, they are increas- ingly vulnerable to existing threats, such as root rot fungi, and potential future threats, such as oak wilt, sudden oak death, and gypsy moths. Maples Red maples are native trees, commonly found in lowlying areas and wetlands. Freeman maples are hybrid cross between red maple and silver maple. Both species are prized for their fall color and rapid growth rate. However, they are vulnerable to gloomy scale, and perform poorly com- pared to other species. Their thin bark, rel- atively weak wood, and low tolerance for decay can create a number of maintenance problems and lower their overall quality and lifespan. Crapemyrtles Crapemyrtles are extremely popular small trees that originate in East Asia. They are known for their summertime flowers and attractive bark, suffer from few health prob- lems, and tolerate dry, compacted soils. However, they provide fewer benefits than larger trees and represent only one of many available small tree species.
Lacebark Elm
4%
Leyland Cypress
3%
3%
Holly group (multiple species)
Chinese Pistache
2%
Juniper species
2%
American Elm
2%
2%
Arborvitae group (multiple species)
Eastern Redbud
2%
Loblolly Pine
2%
Zelkova
2%
Other
16%
A young crapemyrtle in full bloom
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Leyland Cypress Leyland cypresses are a popular ev- ergreen tree, as they grow quickly and provide a good hedge or screen. Leyland cypresses are intolerant of overly wet or dry conditions more than other evergreens, and can con- tract fatal fungus and other disease issues. Because they are commonly planted in groups or rows, disease can spread rapidly. These problems can be reduced by creating hedges of multiple alternating species, and by planting other evergreens for screening. Type and Size Class In this climate region, large-growing deciduous trees provide more to-
TABLE 5: Recommended Alternatives to Commonly Planted Street Trees
TREE TYPE PLANT FEWER: PLANT MORE:
Large growing deciduous
oaks, red or Freeman maple
river birch, tulip poplar, fruitless sweetgum, katsura tree, hackberry, hornbeam, black gum, and ginkgo
Evergreen
Leyland cypress
cryptomeria and arborvitae
Small ornamental
crapemyrtle
goldenrain tree, smoketree, fringetree, witchhazel, magnolia, waxmyrtle, and chaste tree
tal value and a better benefit-cost ratio than smaller-growing trees or conifers (USFS, 2006). About 40% of the town’s street trees are in the largest size category. There are some locations where large trees cannot be planted due to lack of root space, overhead power lines, or nearby buildings. Half of Wake Forest’s street trees are less than 4 inches in diameter (Figure 9). Some of these are small-growing trees, while others are larger growing trees that have been planted in recent years. Few trees were observed in the larger diameter classes; these largest trees provide the most value to the town, but many have not received the care they require. Following neglect or injury, it is not uncommon for a large growing tree to be removed as a potential hazard.
FIGURE 9 : Trees by Diameter Class
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000
RECOMMENDATION: Adopt the 10/20/30 rule to protect and improve the town’s street tree population. Discourage or disallow the planting of trees that are too commonly planted.
<1 1-3 4-7
31-36 25-30 19-24 13-18 7-12
37-42
>43
Diameter in Inches
20
An ideal size distribution would contain more large-diameter trees and fewer young trees. The large percentage of young trees also represents a maintenance challenge, as problems with health or structure are best addressed when a tree is young.
RECOMMENDATION: Focus efforts to identify, protect, and maintain large-diameter trees, which are relatively rare, but have tremendous value. Ensure that the large number of young trees are receiving necessary care to correct problems when they can be addressed quickly and inexpensively.
tree health condition
During the 2012 inventory, the health and structure of each living tree were assessed, and the tree given one of four condition ratings; “good”, “fair”, “poor”, or “very poor” (Figure 10). Most of the town’s street trees are in “good” condition, meaning that they have no health or structural problems that would reduce their value to less than 75% of a tree in perfect condition. They may have some minor issues with their foliage, stems, or roots, but are structurally sound. With neglect, however, these trees can degenerate into “fair” or “poor” health in a matter of years.
FIGURE 10: Overall Condition of Wake Forest’s Street Trees
VERY POOR 1%
POOR 7%
FAIR 20%
GOOD 72%
Approximately 20% of the street trees are in “fair” con- dition, meaning their health or structural integrity is be- tween 50% and 75% of a tree in perfect condition. With effort, these trees could become “good” trees, but without effort, they are likely to decline into “poor” condition. 8% of trees are in “poor” or “very poor” condition, indicating major health or structural prob- lems that can lead to death or structural failure. Trees in these conditions are likely to require removal in the near future, and recovery is only possible with sustained effort. It should be pointed out that the large number of “good” trees likely reflects the recent planting of these trees, and does not mean that the trees do not require immediate attention. The major- ity of trees observed in this inventory showed signs of significant issues that require correction, such as buried root collars, structural pruning needs, stakes, pests, or disease. Trees can have significant energy reserves that are depleted by stress, and decline rapidly once these reserves are exhausted. Without attention, many of the town’s street trees will decline in health.
Tree Condition by Species Tree condition varies significantly between species, indicating species that should probably be avoided (Table 6). Less than half of red and Freeman maples are in good condition. Ornamental cherries are affect- ed by a variety of defoliators and diseases.
RECOMMENDATION: Identify species that are performing poorly, and remove them from the official planting list. Avoid planting large numbers of trees that do not have a proven record of success, and expand the use of uncommon species that perform well.
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TABLE 6: Lowest Performing Street Tree Species
Eastern redbuds have a short lifespan, and have more trees in fair condition than good, and the highest percentage of very poor. Zelkovas are reported susceptible to Dutch elm disease and bacterial canker. Many trees were observed in very poor condition; if one tree contracts Dutch elm disease, then it could be spread to nearby trees. Because this disease can also be spread by pruning equipment, it is important to have all pruning done by qualified staff.
SPECIES
% IN “GOOD” CONDITION
TREES INVEN- TORIED
Eastern redbud
27%
15
Japanese zelkova
40%
15
Red and Freeman maple Ornamental cherry (multiple species)
43%
95
61%
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Value and Benefits of Street Trees
Replacement Value Wake Forest’s street trees have a financial value that can be calculated using industry accepted formulas, applied using the peer-reviewed iTree Streets program. These values are commonly used in legal cases, insurance claims, and in estimating the damage caused by storms and other disasters. The value of a tree is dependent on its species, condition, location, and size. These values may range from a few hundred dollars for a young tree to tens of thousands for a large, healthy tree of a desirable species (Figure 15). Because value is directly related to size, young trees can gain hundreds or thousands of dollars worth of value within years. To maximize the value of the town’s street trees, it is important to provide care for trees of all sizes.
} The current replacement value of the street tree population is approximately $16.9 million.
Replacement Value by Species More than a quarter of the value of the town’s street trees is in red oaks, with most of that
value concentrated in willow oaks (Table 7). Other species, including white oaks, loblolly pines, and the combination of red and Freeman maples, are each estimated to have a replacement value of more than $1 million. These values indicate the potential loss due to pests and disease, and un- derscore the need to plant a wider range of species.
FIGURE 11 : Average Tree Replacement Value by Diameter
$0 $5,000 $10,000 $15,000 $20,000 $25,000 $30,000 $35,000 $40,000
0-3
3-6 6-12
12-18
18-24
24-30
30-36
36-42
>42
Diameter in Inches
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TABLE 7: Total Street Tree Replacement Value by Species
} The total annual benefits of Wake Forest’s street trees are estimated at $389,000.
SPECIES
REPLACEMENT VALUE
Red oak group (Willow oak)
$4,200,000 ($2,380,000)
Annual Benefits Living trees provide services which can also be assigned a financial value, using the peer-reviewed iTree software suite. These services include increased property values, energy conservation, air quality improve- ment, stormwater retention, and carbon dioxide reduction. The total annual benefits of Wake Forest’s street trees are estimated at $389,000 each year (Figure 12). Property values and aes- thetic benefits represent more than half of these benefits, followed by stormwater retention and energy conservation. If the large numbers of small trees currently growing are maintained properly, these benefits are likely to increase dramatically.
White oak
$1,880,000
Red and Freeman Maple
$1,640,000
Loblolly pine
$1,560,000
Sycamore/Planetree
$798,000
Cherry group
$768,000
Crapemyrtle
$726,000
Lacebark elm
$584,000
Pines (other than loblolly)
$359,000
Southern sugar maple
$357,000
Other
$4,030,000
Total
$16,900,000
Maintenance Needs Pruning
FIGURE 12: Estimated Financial Value of Annual Benefits of Street Trees
• 98% of trees need at least one type of pruning • 75% need structural pruning • 35% need crown raising • 18% need to have dead branches removed (cleaning) • 11% have codominant stems or weakly attached branches • 1% need side pruning • 1% need reducing
Air Quality Improved $4,063
Carbon Dioxide Reduced $12,094
Energy Conserved $55,876
Property Values Increased $226,499
Stormwater Retained $90,512
• 1% need priority pruning • 1% have large dead limbs • 0.2% need thinning
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Pruning is the predominant need for most town street trees. Young trees need to have future structural problems “nipped in the bud,” while older trees have dead or decaying limbs that could pose a threat to people or property.
Street trees are pruned to maintain the health of the tree and to protect people and property from decaying limbs.
RECOMMENDATION: Provide necessary maintenance to allow this resource to grow in value and provide increased dividends to residents and business owners.
RECOMMENDATION: Increase the frequency of pruning cycles to correct and prevent problems that can become more difficult or impossible to address in the future.
Pruning for Health
Codominant stems; frequent structural pruning can prevent these weak joints, which can split like wishbones in a storm.
A tree with poor structure, with multiple limbs originating at the same point, and no dominant stem.
A tree in need of a crown raise.
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Root Health
• 58% need root collars excavated • 18% need mulch added • 12% have surface roots • 4% have girdling roots • 2% of trees have created sidewalk conflicts More than half of all street trees have more than 3 inches of soil and mulch piled on the root system. This can cause roots to girdle the stem, cutting off circulation to the can- opy. It also creates an environment that en- courages termites and fungus that can even- tually kill the tree. Other issues include lack of mulch on newly planted trees and surface roots, indicating very poor, compacted soil conditions.
An extreme example of excessive mulching, which creates perfect conditions for fungus and termites to attack the lower stem.
RECOMMENDATION: Excavate buried root collars and provide public education to prevent easily preventable tree death from excessive mulch and soil.
This cherry tree has roots that girdle the stem, and can cut of circulation and eventually kill the tree.
Pruning for Health
These two branches are poorly attached, and one should be removed during periodic structural pruning.
A tree with a low fork. This limb will need to be subordinated and removed to preserve the strength and long term health of the tree.
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Scale • 7% of all street trees are affected by scale Scales are small insects that suck the sap out of trees, reducing the tree’s resources. Freeman and red maples are affected by gloomy scale, which was observed in more than 80% of Freeman and 35% of red ma-
RECOMMENDATION: Reduce planting of willow oaks and maples
immediately and attempt to control these pests with insecticides. This can only be done at certain times of the year when the scale’s lifecycle allows.
ples. Additionally, a different type of scale (lecanium) was observed in willow oaks in Heritage and it is known to occur in Olde Mill Stream as well. Given the large amount of value in maples and willow oaks, the impacts of scale could be severe if untreated.
Defoliators • 14% are affected by defoliating insects
Ornamental cherries were heavily attacked by leaf eating insects, which is common for mem- bers of the rose family. American elms also show signs of insect damage. Some red oaks were entirely defoliated by orange striped oakworm. However, these can be treated easily, and even full defoliation should not kill the tree unless repeated annually.
4
Common Pests and Diseases
Gloomy scale on a red maple. These armored insects reduce the tree’s energy, making it more vulnerable to environmental conditions, pests, and diseases.
Severe defoliation by orange striped oakworm
Cristulariella leaf spots on a sycamore leaf
RECOMMENDATION: Inspect oaks for oakworm outbreaks, particularly where the trees were defoliated in previous years, and treat as necessary. Monitor American elms, and provide routine maintenance as needed.
Minor defoliation on an ornamental cherry tree
Leaf spots on water oak, a member of the red oak group
26
Disease • 25% have a level of disease that affects aesthetics Bacteria, viruses, and fungi can affect a tree’s leaves or trunk. Generally, these microbes had limited impact on overall tree health, and were mainly aesthetic concerns for cer-
RECOMMENDATION: Inspect elms and zelkovas for signs of Dutch elm disease, and monitor trees for signs of new diseases. Create a plan to prevent, identify, and respond to large-scale outbreaks of pests or diseases.
tain deciduous trees. Dutch elm disease, sudden oak death, and other diseases can have more severe consequences, and actions should be taken to limit the possible impact of these threats.
Trunk Health • 16% have wounds; 4% need to have these wounds traced to speed healing • 8% have internal decay • 3% have stakes or supports that need removal
RECOMMENDATION: Remove stakes and supports within 1 year of planting for all trees, and trace wounds as needed. These actions require very little staff time, but can have lasting impacts on tree health.
• 2% are leaning • 2% have cavities • 2% have termites • 1% have borers
The health of observed trunks was generally good; however, there are a number of trees that have uneven wounds that will not heal quickly, or stakes and supports that can constrict circu- lation. These issues can kill a tree if unchecked, but are easy to address if caught early.
Other
• 5% have foliage discoloration • 4% need to be removed and replaced • 3% require additional inspection
Some trees showed foliage discoloration, which may result from drought stress, lack of nutrients, disease, or other factors. Others need to be removed entirely due to their health or structural problems, or have follow-up inspections to identify and assess issues in further detail.
Trunk Health
Young maple tree with trunk wounds that should be traced with a sharp knife to speed healing and reduce decay
Borer hole in a Shumard oak
Supporting guide lines, if left on too long, can severely injure and kill young trees.
27
Work Management Plan, Staffing and Budget
Street Tree Management Priorities In order to minimize the hazards and costs and maximize the long term value of the town’s urban forest, the following management activities are recommended, in order of descending priority: 1. Inventory all trees, inspect potential hazard trees, and maintain inventory by inspecting 1/5 of the town’s trees annually. This will ensure the safety of people and property and ensure that accurate information is used to guide management decisions. 2. Remove any hazard trees, and correct any dangerous structural issues such as dead limbs and weak forks to ensure public safety. 3. Maintain large trees, particularly in heavily used parks and town property, as these are the town’s most valuable trees, and also those most likely to become hazardous if not maintained. 4. Maintain young trees to prevent problems that may become public safety concerns in the future, or which could lead to the decline or death of the tree in the future. 5. a. Remove stakes and ties that are no longer needed. b. Prune for structure and clearance. c. Excavate root collars and correct girdling roots. d. Provide mulch and water to ensure survival and increase growth rate. 6. Maintain pests and diseases at an acceptable level using an integrated pest management (IPM) approach. 7. Replace trees that have been recently removed. 8. Plant additional trees in available spaces using inexpensive stock and volunteers where possible.
Current Estimated Street Tree Maintenance Workload Staff costs could not be estimated for the following tasks using currently available information:
• Hazardous tree removal: (Number of trees unknown due to sampling methods, but likely to exceed 25 trees) $10,000 per year (A conservative estimate based on FY 2011/2012 tree removals) • Pest and disease control: 730 trees per year at $21,900 per year (Estimated using 2009 contract with Bartlett Tree Experts; data on equivalent staff time unavailable)
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TABLE 8: Estimated Total Workload and Total Costs of Performing Work with Contractors Versus Additional Staff
ACTIVITY
CURRENT ESTIMATED WORKLOAD
TOTAL ESTIMATED COSTS FOR CONTRACTORS $318,656 (Estimated using 2009 contract with Bartlett Tree Experts) $117, 000 (Based on quote from Bartlett Tree Experts, 2012) $282,834 (Estimated using 2009 contract with Bartlett Tree Experts) $372,335 (Estimated using 2009 contract with Bartlett Tree Experts)
TOTAL ESTIMATED HOURS FOR STAFF
ESTIMATED COSTS OF STAFF ($18-$33 PER HOUR)
CONTRACTOR COSTS MINUS STAFF COSTS
Large Tree Pruning
3,486 trees
6,945 hours (Estimated using per-tree pruning data provided in APWA 2007b)
$125,010 to $229,185
$89,471 to $193,646
Inventory and Inspection
15,000 trees
1,000 hours (estimated
$15,000 to $33,000
$84,000 to $99,000
based on work experience with tree inventories)
Small Tree Pruning
10,863 trees
7,280 hours (Estimated using per-tree pruning data provided in APWA 2007b) 6,375 hours (Estimated from demonstration at 2012 NCUFC conference) 675 hours (Estimated at 4 trees per hour) + cost of mulch
$131,040 to $240,240
$42,594 to $151,794
Root Collar Excavation
8,277 trees
$114,750 to $210,375
$161,960 to $257,585
Mulching
2,700 trees
$45,051 (Estimated using 2004
$12,150 to $22,275
$22,776 to $32,901
Tree Inventory Management Plan by Davey Resource Group)
Nonhazardous Tree Removal
545 trees
$71,087 (Estimated using 2004
525 hours (estimated based on removals performed in 2011 and 2012)
$9,450 to $17,325
$53,762 to $61,637
Tree Inventory Management Plan by Davey Resource Group) $86,000 + costs of trees (estimated from 2011 tree planting contract)
1,290 hours + costs of trees (estimated at 1.5 hours per tree for transport and planting)
$23,220 to $42,570
$43,430 to $62,780
Tree Planting
860 trees, stumps, and obvious vacancies currently in need of replanting
Total
41,731 trees
$1,293,000
24,090 hours
$434,000 to $795,000
$498,000 to $859,000
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Addressing the Current Street Tree Workload: The Levels of Service Concept The effectiveness of an urban forestry program is dependent on the resources available for each maintenance task. When fewer resources are available, the program must operate at a lower level of service often becoming reactionary and focusing on emergencies and major problems as they arise. While maintenance costs may be less, the health and quality of the forest is lower, and the work that is performed is less efficient. As service levels increase, more frequent pre- ventative work is possible, and the safety, health, aesthetics and benefits of the urban forest increase, often allowing the municipality to achieve both higher total benefits and receive more value per maintenance dollar.
Description of Service Levels
• SERVICE LEVEL 1 represents a minimum responsible level of service. Below this level, community safety is threatened by falling trees and limbs. At this level of service, large trees are periodically inspected and pruned, and dangerous trees or limbs are removed. Residents and volunteers are responsible for planting and maintaining trees. Wake Forest’s previously expressed goals for the urban forest cannot be met at this level of service, and it would be difficult to maintain Tree City USA status. • SERVICE LEVEL 2 represents a program that provides a degree of preventativemaintenance and planting. The town actively plants and maintains trees in the right of way, and problems with trees are eventually addressed. Without the assistance of residents and volunteers, trees cannot be replaced as quickly as they are removed. Currently, most aspects of Wake Forest’s Urban Forestry Program fall within this level of service. • SERVICE LEVEL 3 represents a typical mature urban forestry program that is both financially efficient and arboriculturally effective. A focus on preventative maintenance ensures that most problems are addressed at an early stage, decreasing mortality and unplanned work requests. More trees are planted than are removed, and the value of the resource steadily increases over time. This overall level of service is the recommended goal for the program by 2017. • SERVICE LEVEL 4 represents an advanced urban forestry program that provides the highest reasonable level of service for a given street tree population. While the total costs of level 4 are the highest, the benefits are also the highest, and the benefit to cost ratio is better than in other levels. This level of service is usually only seen in areas in which landscaping is of very high importance. Over the next 5 years, only a few program components are recommended for this level of service. • BEYOND SERVICE LEVEL 4 , the increased costs of maintenance are unlikely to result in significant improvements in the quality of the urban forest.
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