Street Tree Preservation And Planting Design Guidelines

Transcription

1 REGIONAL MUNICIPALITY OF YORK Street Tree Preservation And Planting Design Guidelines Environmental Services Department Environmental Promotion and Protection Branch - Natural Heritage and Forestry February 2013

2 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York Forward The Street Tree Preservation and Planting Design Guidelines were originally prepared for the Region s Road Design Guidelines (developed by Capital Delivery - Roads Branch). The Road Design Guidelines were prepared to assist professional service providers and Regional staff in the preparation of construction drawings for Regional road improvement projects. Street tree preservation and planting design also occurs outside this process by others including developers, utility companies and local municipalities. To provide design guidelines to these other groups, a stand alone version of the Street Tree Preservation and Planting Design Guideline has been prepared. In the preparation of this stand alone version, minor modifications were made to the original version. February 2013 Page i

3 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York TABLE OF CONTENTS Forward... i 1.0 PURPOSE STANDARD REFERENCES STREET TREE PRESERVATION AND COMPENSATION Street Tree Inventory Street Tree Preservation Plan Street Tree Compensation Planting STREET TREE PLANTING PLAN STREET TREE PLANTING DESIGN CRITERIA Site Context Spacing Between Trees Offset From Curb Offset From Intersections and Entrances Offset From Sidewalk and Property Boundaries Offset from Ditches and Drainage Other Design Considerations Hydro (Energized) Lines Telephone and Other Non-Energized Lines Light Standards and Utility Poles Watermains and Sewers Other Utilities Species Selection:... 8 a) General:... 8 b) Stock:... 9 c) Diversity: Provision for tree root development Construction requirements and planting specification COMMON DESIGN ERRORS February 2013 Page 1 of 14

4 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York 1.0 PURPOSE To ensure that tree preservation and tree planting requirements are incorporated into the design process and plans for construction projects (road infrastructure, water and wastewater infrastructure and utility relocations). This includes the review and implementation of innovative design alternatives that preserve existing trees and provide opportunities for sustainable tree planting. Street trees and other vegetation form an important component of our green infrastructure. York Region, through its Streetscape Policy, Greening Strategy, and other initiatives, has made a strong commitment to the preservation and enhancement of our green infrastructure. 2.0 STANDARD REFERENCES York Region s Utility Design Guidelines York Region s Drawing Information Manual York Region s Consultant Package York Region s Streetscaping Policy December 2001 Roadside Safety Manual (MTO Document) Canadian Standard for Nursery Stock York Region s Site Triangle Manual, 2007 York Region s Street Trees - Enhanced Planting Strategies, 2008 Appendix S (a) Tree Protection Details (NHFS-04) Appendix S (b) Tree Protection Notes and Sign Detail (NHFS-05) Appendix S (c) Tree Protection Specifications Appendix S (d) Acceptable Street Tree Species List for Regional Roads Appendix S (e) Tree and Shrub Planting, Transplanting and Maintenance Specification Appendix S (f) Caliper Deciduous Tree Planting Detail for Softscape Boulevards (NHFS-01) Appendix S (g) Caliper Coniferous Tree Planting Detail for Softscape Boulevards (NHFS-02) Appendix S (h) Container Grown Shrub Planting Detail (NHFS-03) Appendix S (i) Caliper Deciduous Tree Planting Detail on Slope (NHFS-06) Appendix S (j) Caliper Coniferous Tree Planting Detail on Slope (NHFS-07) Appendix S (k) Container Grown Deciduous Tree Planting Detail on Slope (NHFS-08) Appendix S (l) Container Grown Coniferous Tree Planting Detail on Slope (NHFS-09) Appendix S (m) Container Grown Shrub Planting Detail on Slope (NHFS- 10) Appendix S (n) Container Grown Deciduous Tree Planting Detail (NHFS-11) Appendix S (o) Container Grown Coniferous Tree Planting Detail (NHFS- 12) February 2013 Page 2 of 14

5 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York Appendix s (p) Boulevard Tree Planting Soil Trench for Softscape Boulevards (NHFS-13) 3.0 STREET TREE PRESERVATION AND COMPENSATION Existing street trees and roadside vegetation communities are an integral part of our green infrastructure and are considered an asset within the Regional right-ofway. Preserving established trees requires careful design considerations to mitigate negative impacts. Grade changes and other construction activities in proximity to trees cause direct and indirect physical damage to trees, and often have long term negative consequences for tree structural stability and tree survival. The following sections outline the information and plans required to respond to the need for tree protection, relocation, and replacement during the planning and design stages. These plans are to be prepared by landscape/forestry professionals such as foresters, arborists, or landscape architects in consultation with engineering designers. Designers should also refer the Environmental Study Report for the additional information on tree preservation requirements specific to the project. 3.1 Street Tree Inventory During the initial design phase, the Environmental Study Report s street tree inventory shall be reviewed, updated and supplemented if necessary for trees within and adjacent to the right-of-way for the entire project limits. At a minimum the street tree inventory shall: 1. Identify natural vegetation communities, including species composition, diameter at breast height (DBH), crown diameter, location, and spatial extent. This includes communities within and adjacent to the right-of-way. 2. Identify single trees, including location, species, size and condition: a) Rural cross sections identify all trees greater than 10-cm in diameter, and trees smaller than 10 cm in diameter that have been planted. b) Urban cross sections identify trees of all sizes c) Trees on adjacent lands whose crown extends onto the right-of-way. The street tree inventory shall be completed for submission with the initial design (30% design submission for York Region projects). 3.2 Street Tree Preservation Plan Using the information collected from the street tree inventory, a street tree preservation plan shall be developed for the 30% detailed design review February 2013 Page 3 of 14

6 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York submission. The street tree preservation plan shall provide information regarding street trees and vegetation communities, minimum tree protection zones and other mitigation measures, such as transplanting. Utilizing the information provided in the street tree inventory and street tree preservation plan, the designer shall incorporate design measures, such as adjustments to grading, which will minimize the impact to vegetation. The design drawings shall identify all street trees and vegetation communities to be removed, transplanted, and preserved. For York Region projects this shall be included with the 60% design submission. To ensure that trees identified for preservation and transplanting are protected during construction, tree protection and mitigation measures should be identified during the design. Tree protection measures should be identified on the design drawings as a set of separate tree protection and mitigation sheets. For York Region projects this should be included with the 90% design submission. The tree protection and mitigation sheets should include at a minimum: 1. The location of all trees to be preserved or transplanted. For trees to be transplanted their existing and future locations should be identified. 2. The location of tree protection fencing and other mitigation measures for all trees to be preserved or transplanted. 3. A tree protection and mitigation details sheet with standard drawings and specifications for protection fencing, transplanting, and other mitigation measures. Please refer to Appendices S (a), S (b) and S (c) for the Region s standard tree protection details and specifications and Appendix S(e) for the Region s transplanting specifications. Tree transplanting should be completed when the tree is dormant. As such transplanting may need to be completed in advance of the construction project. Where woodlots will be impacted as a result of tree removal, pre-stressing techniques (e.g. edge thinning) should be employed as a means to minimize the negative impacts associated with the creation of a new edge. York Region Natural Heritage and Forestry Services staff shall be consulted on tree preservation, removal and compensation matters and special operational constraints prior to and during construction. 3.3 Street Tree Compensation Planting York Region considers the principle of no net loss of trees or forest cover when reviewing the footprint of individual projects. It is recognized that this approach will not be feasible in all cases. Where vegetation removal can not be avoided, efforts should be made to provide compensation in the form of new plantings. February 2013 Page 4 of 14

7 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York These new plantings shall be incorporated into the design to offset what was lost, and where possible enhance the streetscape and/or natural environment. For vegetation communities, such as woodlots, compensation plantings should be designed on an area basis to restore what was lost and take into consideration the functions and attributes of the feature. This compensation can be accomplished through right of way plantings which buffer impacts. In urban areas, plantings should integrate the urban form with the natural vegetation adjacent to the right-of-way (e.g. stream valley corridors). In locations where there is limited space for tree planting, consideration should be given for providing tree planting at the edge or beyond the right-of-way. Street tree compensation plantings shall be prepared as part of the streetscape design and included as separate landscape sheets. The streetscape/tree planting plan shall address compensation as well as the Region s streetscaping/tree planting requirements. 4.0 STREET TREE PLANTING PLAN Street Tree Planting shall complement and conform to the Region s Streetscape Policy and Towards Great Regional Streets Design Guidelines. The Street Tree Planting Plan should be submitted early in the design process to ensure the proposed road design allows for sustainable street tree planting opportunities. For Region projects the Street Tree Planting Plan shall be submitted with the 60% submission. The Street Tree Planting Plan will clearly show both the proposed trees and relocated trees. The relocated trees are to be distinguished graphically for easy reference. Trees will be labelled clearly with plant keys and a plant list will be shown complete with symbol, botanical and common name, quantity, and condition. The planting plan shall conform to the following Street Tree Planting Design Criteria. 5.0 STREET TREE PLANTING DESIGN CRITERIA The concept of a green infrastructure recognizes that street trees provide many important and measurable benefits which are vital to the overall health of our landscapes and communities. However, successfully establishing and maintaining the green infrastructure requires more than just planting trees. The following design parameters shall be considered when developing street tree planting plans: 5.1 Site Context February 2013 Page 5 of 14

8 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York Site context is of paramount importance in the planting of trees, since adjacent land uses such as commercial, industrial, institutional, and residential present different needs. Transition between uses is imperative so the streetscape is unified and integrated. The following are guidelines to suitable tree location and planting: Visibility and sight line requirements at intersections need to be maintained. Public safety and security needs to be ensured by planting appropriate species that keep their form to maintain clear visibility. Co-ordinate the location of street trees with the site landscaping for a unified streetscape. Plant street trees closer together (6-8m) approaching a major intersection or highly visible locations such as gateways or nodes. Introduce coniferous plant material where visual screening is appropriate such as along railway corridors, rail overpasses, parking lots. Choose plant material with ecological compatibility, appropriate for site conditions (e.g. salt and drought tolerant). Maintain a pedestrian connection to the street and enhance this by planting trees flanking this connection. 5.2 Spacing Between Trees The spacing of trees along Regional roads is defined in York Region s Streetscaping Policy December The desired spacing of trees is based on the size and form of the tree species at maturity. For full form species: Trees should be spaced at 10 metres on centre Spacing can be varied from 8 to 12 metres on centre For small form species (hydro acceptable): Trees should be spaced at 8 metres on centre Spacing can be varied from 6 to 10 metres on centre Designers are encouraged to consider alternative tree planting schemes that are compatible with the site context. 5.3 Offset From Curb Preference is given for the offset from curb to follow the minimum distances for fixed objects as defined in the Roadside Safety Manual. The absolute minimum February 2013 Page 6 of 14

9 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York offset is 2.5 metres in order to allow for snow storage. A tree species salt tolerance is also a concern when considering the offset from curb. 5.4 Offset From Intersections and Entrances Sight distance triangles are maintained free of tree trunks and branches. Branches may droop over time and interfere with sightlines. To maintain minimum site line distances the following offsets shall be followed: Trees should not be planted within 9.0 metres of an intersection Trees should not be planted within 3.0 metres of an entranceway or driveway Other landscaping elements may be considered within site distance triangles. Designers should refer to the Region s Sight Triangle Manual for design criteria. 5.5 Offset From Sidewalk and Property Boundaries Street trees should be planted to minimize conflicts with sidewalk construction and maintenance. To allow for sidewalk construction and maintenance the following offsets shall be followed: Trees shall be planted a minimum of 1.0 metres from edge of sidewalk, a 1.5 metre offset is preferred. Where no sidewalk exists trees should be planted at a 3.5 metre offset from the property line. This offset allows for the future construction of a sidewalk at York Region s standard location, 0.6 metres from the property line. Where sufficient room exists between an existing sidewalk and property boundary, tree planting may occur at the following offset: Trees should be planted a minimum of 1.0 metres from property boundaries. 5.6 Offset from Ditches and Drainage Trees should not be located within 1.0 metre of the ditch line in order to allow for maintenance of the ditch. Tree should not be planted where water may collect and temporarily pool. 5.7 Other Design Considerations Trees should not be planted in urban cross sections fronting undeveloped properties or in areas where future grade changes are anticipated. February 2013 Page 7 of 14

10 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York 5.8 Hydro (Energized) Lines Where overhead hydro wires are present, tree species whose mature form is relatively small should be selected. Conversely, where there are no overhead wires present, full form trees shall be used. Designers shall refer to the York Region Acceptable Tree Species List for Regional Roads, Appendix S (d). 5.9 Telephone and Other Non-Energized Lines Full sized trees may be planted directly under overhead utilities which are nonenergized, such as telephone wires Light Standards and Utility Poles Trees should not be planted within 3.0 metres of a utility pole or light standard Watermains and Sewers For watermains and sewers, the offset guideline from the centre of the pipe is 1.0 metres, or as much as possible. However, where no other suitable locations exist trees may be located directly over pipe(s) Other Utilities Minimum required offsets from other utilities should be observed. Where none is specified a minimum of a 1.0 metre offset is acceptable Species Selection: a) General: Street tree planting and streetscape design is an integrated effort. Street tree species need to withstand the tough conditions on regional roads and be tolerant of drought, salt, and wind. When selecting a species the designer should consider the current and future site conditions and select a species appropriate for the site. Some factors affecting species selection include: Presence of overhead hydro. Achievable offset from curb Available soil volumes, boulevard vs. median Road side, east vs. west, north vs. south Adjacent land use (e.g. avoid invasive species near nature areas) To ensure that only species suitable for planting in this environment are used, the Region has prepared an acceptable species list with species selection guidelines. February 2013 Page 8 of 14

11 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York A copy of the York Region Acceptable Street Tree Species List for Regional Roads can be found in Appendix S (d). b) Stock: 1. High quality nursery stock is a pre-requisite to tree survival 2. Balled and burlap wrapped stock is the York Region standard for trees. 3. Tree planting stock shall conform to the following sizes: Deciduous trees shall be 50-mm in calliper Coniferous trees shall be 1.5 metre in height 4. Shrub planting stock shall be potted and 50 cm in height 5. A copy of the Region s tree planting specifications can be found in Appendix S (e). 6. Whips (bare root stock 1.0 to 1.5 metres in height) may be planted in low profile, rural areas 7. Seedlings or whips may be used for naturalization or restoration areas c) Diversity: The Region supports the creation of a diverse urban forest while providing for an aesthetically pleasing streetscape. Diversity will be created at the urban forest level allowing for the creation of aesthetically pleasing streetscapes at the street block level. The creation of monocultures (i.e. dependence on one species) is not supported as part of this balanced approach to species diversity. This design approach supports our commitment to maintaining a healthy urban forest and biodiversity, and recognizes the importance of a proactive integrated pest management approach to street tree planting. While acknowledging the need for species diversity, the Region requires that 75% of species planted be selected from its top performing street tree list, Appendix S (d). Designers should attempt to incorporate the following species diversity guidelines: Maximum of 20% of plantings to be from the same genus of trees Maximum of 10% of plantings to be from the same species of tree. The table below provides the minimum number of species required associated with a given size of a planting. Number of Trees in Planting Minimum Number of Species February 2013 Page 9 of 14

12 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York Species selection should consider the harsh environment in the road right of way and where reasonable incorporate species native to the area Provision for tree root development For street tree planting plans to be successful they must be based on the principle of sustainable design. Criteria such as species selection, offset from curb, etc. are important components in sustainable designs. In addition, designs most provide for the healthily development of tree root systems capable of supporting tree growth and health. In order to monitor the success of our designs and tree planting efforts, the Region has developed the following street tree performance standard: Medium to large form trees should reach a minimum size of 40 centimetres in diameter and a crown width of 10 metres. To achieve this standard adequate, space for tree root development will be required. Root development requires both below ground space and an appropriate growing medium. Based on the Region s performance target, each tree requires a minimum of 16 cubic metres of good quality soil for root development. The growing medium or soil shall follow the specification provided in the document Street Trees, Enhanced Planting Strategies. During the design process, consideration must be given to providing adequate soil volume and quality for root development. Innovative techniques may be required to provide this space in constrained environments (e.g. soil cells, structural soils, root paths, etc) Construction requirements and planting specification The majority of Regional plantings on capital projects are carried out through a separate contract administered by the Natural Heritage and Forestry Services Section of the Roads Branch. This allows for better timing of plantings and involves technically skilled personnel in the administration of the contract. Where tree planting is to be incorporated into a construction contract, the attached tree planting specifications and standard drawings should be incorporated into the tender package: Appendix S (e) Tree and Shrub Planting, Transplanting and Maintenance Specification February 2013 Page 10 of 14

13 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York Appendix S (f) Caliper Deciduous Tree Planting Detail for Softscape Boulevards (NHFS-01) Appendix S (g) Caliper Coniferous Tree Planting Detail for Softscape Boulevards (NHFS-02) Appendix S (h) Container Grown Shrub Planting Detail (NHFS-03) Appendix S (i) Caliper Deciduous Tree Planting Detail on Slope (NHFS-06) Appendix S (j) Caliper Coniferous Tree Planting Detail on Slope (NHFS-07) Appendix S (k) Container Grown Deciduous Tree Planting Detail on Slope (NHFS-08) Appendix S (l) Container Grown Coniferous Tree Planting Detail on Slope (NHFS-09) Appendix S (m) Container Grown Shrub Planting Detail on Slope (NHFS-10) Appendix S (n) Container Grown Deciduous Tree Planting Detail (NHFS-11) Appendix S (o) Container Grown Coniferous Tree Planting Detail (NHFS-12) 6.0 COMMON DESIGN ERRORS Trees as an afterthought Designs that do not take into account that street trees are part of the design and construction process. Tree damage For existing trees to be preserved, soil compaction or other direct and indirect physical damages have to be proactively considered. Such impacts often have long term negative consequences for tree survival. Tree protection measures must be effectively identified and deployed in the contract documents. Proximity to curb Trees are often identified on plans less than 2.5 metre setback from the curb. Obstructions Trees should not be planted where they will obstruct sight lines to intersections, signs, entrances or traffic control signals. Overhead Wires February 2013 Page 11 of 14

14 Street Tree Preservation and Planting Design Guidelines Regional Municipality of York Avoid planting trees which will grow to full size within 2.5 metres of overhead wires. Monoculture Plantings While this type of planting is preferred by some for aesthetic reasons, these plantings should be avoided to prevent future pest management problems. February 2013 Page 12 of 14

15 APPENDIX S YORK REGION STREET TREE PROTECTION AND PLANTING SPECIFICATIONS Appendix S is for information purposed only, the following tree protection and planting specifications and species selection listings can be found using the following hyperlinks: Appendix S (a) Tree Protection Details (NHFS-04) Appendix S (b) Tree Protection Notes and Sign Detail (NHFS-05) Appendix S (c) Tree Protection Specifications Appendix S (d) Acceptable Street Tree Species List for Regional Roads Appendix S (e) Tree and Shrub Planting, Transplanting and Maintenance Specification Appendix S (f) Caliper Deciduous Tree Planting Detail for Softscape Boulevards (NHFS-01) Appendix S (g) Caliper Coniferous Tree Planting Detail for Softscape Boulevards (NHFS-02) Appendix S (h) Container Grown Shrub Planting Detail (NHFS-03) Appendix S (i) Caliper Deciduous Tree Planting Detail on Slope (NHFS-06) Appendix S (j) Caliper Coniferous Tree Planting Detail on Slope (NHFS-07) Appendix S (k) Container Grown Deciduous Tree Planting Detail on Slope (NHFS- 08) Appendix S (l) Container Grown Coniferous Tree Planting Detail on Slope (NHFS- 09) Appendix S (m) Container Grown Shrub Planting Detail on Slope (NHFS-10) Appendix S (n) Container Grown Deciduous Tree Planting Detail (NHFS-11) Appendix S (o) Container Grown Coniferous Tree Planting Detail (NHFS-12) Appendix s (p) Boulevard Tree Planting Soil Trench for Softscape Boulevards (NHFS-13)

16 PLAN VIEW SIDE VIEW REFER TO NHFS-05 FOR TREE PROTECTION NOTES AND SIGN DETAIL Transportation Services TREE PROTECTION DETAIL DATE: DECEMBER 2008 REV. SCALE N.T.S. REV. X X NHFS - 04

17 TREE PROTECTION SIGN TREE PROTECTION NOTES FENCE MATERIAL: PLASTIC ORANGE FENCING (120 CM TALL) SHALL BE USED OR EQUIVELANT AS APPROVED BY YORK REGION AND INSTALLED WITH WIRE TIES ON METAL T- BAR POSTS (180 CM TALL) SPACED 250 CM APART FENCE MAY BE COMBINED WITH SILT FENCING FENCE LOCATION: INSTALL FENCE AS PER NHFS-04 TREE PROTECTION DETAIL FOR INDIVIDUAL TREES, FENCE IS TO BE INSTALLED AT THE LIMITS OF CONSTRUCTION OR AT THE DRIPLINE OF THE TREE, WHICHEVER IS FURTHER FROM THE TREE. FENCE CAN BE LOCATED CLOSER TO THE TRUNK ONLY WITH AUTHORIZATION FROM YORK REGION FOR ROWS OF TREES, SUCH AS FOUND IN BOULEVARDS, A SINGLE LINEAR FENCE SHOULD BE INSTALLED WHICH FOLLOWS THE LIMITS OF THE CONSTRUCTION ZONE SIGNAGE: INSTALL TREE PROTECTION SIGN ON FENCE FACING CONSTRUCTION ZONE AT 100 METER INTERVALS AS PER NHFS-04 TREE PROTECTION DETAIL PRUNING: ALL ROOTS WHICH ARE EXPOSED THROUGH EXCAVATION ARE TO BE PRUNED BACK TO THE SOIL SURFACE BRANCHES DAMAGED OR INTERFERING WITH CONSTRUCTION ACTIVITIES ARE TO BE PRUNED BY AN INTERNATIONAL SOCIETY OF ARBORICULTURE (ISA) CERTIFIED ARBORIST FENCE MAINTENANCE: MAINTAIN FENCE IN WORKING CONDITION AT ALL TIMES DO NOT STORE MATERIALS OR EQUIPMENT IN THE PROTECTED AREA DO NOT MOVE FENCE WITHOUT PRIOR AUTHORIZATION FROM YORK REGION MONITORING: CONDUCT WEEKLY MONITORING OF FENCE AND TREE HEALTH THROUGHOUT THE DURATION OF THE CONSTRUCTION PROJECT OR ACCORDING TO A SCHEDULE NOTED IN AN APPROVED TREE PRESERVATION PLAN. Transportation Services TREE PROTECTION NOTES AND SIGN DETAIL DATE: OCTOBER 21, 2011 REV. SCALE N.T.S. REV. X X NHFS - 05

18 THE REGIONAL MUNICIPALITY OF YORK TRANSPORTATION SERVICES DEPARTEMENT ROADS BRANCH TREE PROTECTION SPECIFICATIONS Revised March 2009

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20 THE REGIONAL MUNICIPALITY OF YORK TRANSPORTATION SERVICES DEPARTMENT ROADS BRANCH TREE PROTECTION SPECIFICATIONS This item shall include all Work required for the supply, installation, maintenance and removal of Tree Protection Fencing in accordance with Natural Heritage and Forestry Services Standard Drawings NHFS-04 and NHFS-05. Tree Protection Fencing shall be constructed using steel posts, spaced at 250 cm, and plastic orange fencing, minimum height of 120 cm, attached to the steel posts. Tree protection signs shall be attached to Tree Protection Fencing at a minimum interval of 100 m. The Contractor shall install Tree Protection Fencing as shown on the Contract Drawings. Tree Protection Fencing shall be installed at the edge of the tree crown (drip line) or edge of the construction zone, whichever is furthest from the tree. The Contractor will be responsible for providing and installing additional quantities of Tree Protection Fencing, as may be necessary to protect trees including their root systems from damage. Tree Protection fencing shall be installed prior to commencement of construction activities and shall remain until construction activities have been completed. The Contractor is responsible for the maintenance of Tree Protection Fencing at all times during construction. Maintenance includes repairing damaged fence sections and reinstatement of Tree Protection Fencing as required. Revised March 2009

21 THE REGIONAL MUNICIPALITY OF YORK ACCEPTABLE STREET TREE SPECIES FOR REGIONAL ROADS Regional road allowances present an extremely harsh environment for street tree establishment and growth. Only a select group of hardy tree species establish and thrive in this environment. The Regional Municipality of York has developed the following street tree species lists and guidelines to ensure that only those hardy tree species proven to establish and thrive along Regional roads are planted. The Region continually reviews these lists and guidelines in an attempt to ensure they reflect the most current knowledge and are as broad as possible. The Region is continually trying new species and varieties in controlled trials to identify additional species for the lists. Top Performing Street Tree Species The Regional Municipality of York has developed a list of Top Performing Street Tree Species based on an extensive literature review, results of recent street tree health assessments and anecdotal records of species performance in Regional road allowances. This list represents species which have desirable characteristics and are tolerant of the harsh growing environment present along Regional roads. While being sensitive to species diversity, this list has been developed to ensure that trees planted meet performance expectations and achieve the expected benefits for Region residents. These species will form the majority of species planted within Regional road allowances. At a minimum, 75% of trees planted along Regional roads will come from the Region s top performing street tree species list. In road side locations where conditions are particularly harsh, up to 100% of species planted may come from the top performing street tree species list. TABLE 1: Top Performing Small Form (Hydro Acceptable) Species List Species Name Native Characteristics Very susceptible to black knot, requires annual pruning to control Shubert cherry (Prunus virginiana Shubert ) 1 Yes fungus Prone to suckering from base of tree Showy lilac-like blooms in early summer, followed by seed Ivory silk lilac (Syringa reticulata) No capsules that persist on the tree Fairly pest and disease resistant February 7, 2013 Page 1 of 4

22 Acceptable Street Tree Species For Regional Roads TABLE 2: Top Performing Full Form Species List Species Name Native 1 Characteristics Silver maple (Acer saccharinum) 1 Yes Develops large crown, therefore plant in locations with adequate space Showy flower spikes followed by seed husks covered in soft Ohio Buckeye (Aesculus glabra) 1 spines Yes Less susceptible to leaf scorch and leaf blotch than horsechestnut Showy flower spikes, less seed production than Ohio buckeye, Horsechestnut (Aesculus hippocastanum) 1 No seed husks covered in soft spines Honeylocust (Gleditsia triacanthos var. inermis) Kentucky coffee tree (Gymnocladus dioicus) 1 Yes Yes Susceptible to leaf scorch and leaf blotch Small leaves provide a filtered shade Can be susceptible to defoliation by leafhoppers Acceptable cultivars for Regional roads include: Shademaster Coarse branching structure, large double-compound leaves with small leaflets Dioecious tree with male and female plants, male tree preferred Notes: 1 Spring planting only 2 A native tree is defined as a tree whose natural range is within Ontario and/or the northern U.S lake states. Notable Street Tree Species for Select Planting Sites The Regional Municipality of York has developed a list of Notable Street Tree Species for Select Planting Sites based on an extensive literature review, results of recent street tree health assessments and anecdotal records of species performance in Regional road allowances. This list represents species which have many desirable characteristics and tolerances, but are sensitive to specific environmental conditions (exposure to prevailing winds, deicing salt, etc,). Their use is limited to specific sites where the environmental conditions are ideal for their initial survival and long term performance. These species will form a minor component of species planted within Regional road allowances. The Region has developed a series of street tree species fact sheets that provide additional information on many of these species. These are available upon request. February 7, 2013 Page 2 of 4

23 Acceptable Street Tree Species For Regional Roads TABLE 3: Notable Full Form Species List Species Name Native 2 Planting/Site Restrictions Norway maple (Acer platanoides) Autumn Blaze maple (Acer x freemanii Autumn Blaze ) 1 No Invasive Yes This species is invasive. Although some of the cultivars are less invasive, it is not to be planted near natural areas. Sensitive to desiccation from winter winds. Use in locations sheltered from prevailing winds. Sensitive to de-icing salts (airborne spray). Use in locations where Hackberry (Celtis occidentalis) 1 Yes exposure to salt spray will be minimized, e.g. wide boulevards (6 m +) on the north and west sides of roads. Of the oak species, this has shown the greatest tolerance to Regional Swamp white oak (Quercus bicolor) 1 Yes road conditions. Still considered sensitive to de-icing salts (airborne spray). Use in locations where exposure to salt spray will be minimized, e.g. wide boulevards (6 m+) on the north and west sides of roads. Bur oak (Quercus macrocarpa) 1 Littleleaf linden (Tilia cordata) Accolade elm (Ulmus japonica x Ulmus wilsoniana) Colorado spruce (Picea pungens) 1 White spruce (Picea glauca) 1 Norway spruce (Picea abies) 1 Austrian pine (Pinus nigra) 1 Yes No No No Yes No No Has shown tolerance to Regional road conditions. Still considered sensitive to de-icing salts (airborne spray). Use in locations where exposure to salt spray will be minimized, e.g. wide boulevards (6 m+) on north and west sides of roads. Sensitive to desiccation from winter winds and de-icing salt. Plant in locations were exposure to salt spray will be minimized, e.g. wide boulevards (6 m+) on the north & west sides of roads and in a location sheltered from prevailing winds. Acceptable cultivars for Regional roads include: Glenleven and Greenspire Initial plantings of this species have shown tolerance to the growing conditions on Regional road allowances. Experience with this species is limited and it should be used in limited quantities until further evaluation of its performance is completed. Sensitive to desiccation from winter winds and de-icing salt. Plant a minimum of 6 m from edge of road, and preferably in a sheltered location. Should always be planted behind sidewalk/pedestrian zone Susceptible to yellow-headed spruce sawfly defoliation More sensitive to desiccation from winter winds and de-icing salt than Colorado or Norway spruces. Plant a minimum of 6 m from edge of road, and preferably in a sheltered location. Should always be planted behind sidewalk/pedestrian zone Can be susceptible to yellow-headed spruce sawfly defoliation Sensitive to desiccation from winter winds and de-icing salt. Plant a minimum of 6 m from edge of road, and preferably in a sheltered location. Should always be planted behind sidewalk/pedestrian zone Fairly pest and disease resistant Sensitive to desiccation from winter winds and de-icing salt. Plant a minimum of 6 m from edge of road, and preferably in a sheltered location. Should always be planted behind sidewalk/pedestrian zone Susceptible to Diplodia blight, select locations with good air flow and avoid mass plantings of this tree February 7, 2013 Page 3 of 4

24 Acceptable Street Tree Species For Regional Roads TABLE 4: Notable Small Form (Hydro Acceptable) Species List Species Name Native 2 Planting/Site Restrictions Hedge maple (Acer camprestre) No Sensitive to desiccation from winter winds. Use in locations sheltered from prevailing winds. Sensitive to desiccation from winter winds. Use in locations sheltered Ornamental pear (Pyrus calleryana) 1 No from prevailing winds. Acceptable cultivars for Regional roads include: Chanticleer Pear Columnar Norway Species suitable for planting adjacent to overhead hydro due to its narrow maple (Acer No width. Must be planted a minimum of five (5) metres from overhead platanoides Invasive hydro Columnare ) English pyramidal oak (Quercus robur fastigiata ) 1 No Species suitable for planting adjacent to overhead hydro due to its narrow width. Must be planted a minimum of five (5) metres from overhead hydro Should always be planted behind sidewalk/pedestrian zone Notes: 1 Spring planting only 2 A native tree is defined as a tree whose natural range is within Ontario and/or the northern U.S lake states. February 7, 2013 Page 4 of 4

25 ITEM xx SUPPLY AND INSTALLATION OF CALIPER TREES GENERAL REQUIREMENTS Planting Locations Planting locations will be identified by the Commissioner by: 1. Detailed drawings provided to the Contractor; or 2. A wooden stake, coloured flag, or painted T on the curb or sidewalk, accompanied by a tree planting details sheet. In the event of any discrepancies between the planting details sheet and the on site markings, the Contractor shall contact the Region for clarification. The Contractor is responsible for the collection and disposal of all wooden stakes and coloured flags. Inspections The Commissioner has the right to inspect all plant material and planting practices at his/her discretion. All plant material and/or planting practices which do not meet the requirements of the Contract Documents shall be corrected by the Contractor within 20 Working Days of receiving written notification from the Region. Planting Time The supply and installation of caliper trees shall be completed beginning on May 1 and ending on June 30. The Commissioner at his/her sole discretion may extend or shorten the planting time based on weather conditions. Site Operations and Work Conditions All planting Work shall be carried out by personnel who are qualified, skilled and experienced in the various aspects of tree and shrub planting, transplanting and maintenance. The Contractor shall ensure consistent and continuous operations once planting commences. The Contractor shall minimize the amount of mud and debris deposited on boulevards and roadways as a result of excavation and hauling operations. The Contractor shall be responsible for dust control and shall minimize the amount of dust created by its operations. Any mud, debris or dust deposited on boulevards and roadways as a result of the Work shall be removed by the Contractor, at its own expense, within 24 hours of being directed to do so by the Commissioner. Any damage to the roads and/or boulevards as a result of the Work shall be repaired by the Contractor, to the satisfaction of the Commissioner, at the Contractor s expense, within five (5) Working Days of being directed to do so by the Commissioner. 1

26 SUPPLY AND INSTALLATION OF CALIPER TREES The Contractor shall supply and install caliper trees in accordance with the following: Caliper Tree Planting Stock Origin Information concerning the geographical origin of seed or cuttings used to produce the caliper trees for this Contract shall be made available to the Commissioner upon request. If, in the sole opinion of the Commissioner, the plant material is of an origin unsuitable climatically to the Regional area, it will be refused. All caliper trees for this Contract shall have been grown for a minimum period of two (2) growing seasons at a nursery located within Canadian Plant Hardiness Zones 4b, 5a, 5b or 6a. The Contractor shall provide written documentation confirming that this requirement has been satisfied. If, in the sole opinion of the Commissioner, the documentation does not satisfy this condition, the plant material will be refused. Conformity to Species and Variety The botanical nomenclature used for species and cultivars of caliper trees shall conform to the publication Hortus Third, All caliper trees shall conform to the species and/or varieties named in the Bid Form. No substitutions will be accepted without the prior written approval of the Commissioner. The Contractor shall not be entitled to any increase in the Contract Price in the event that a species substitution is approved by the Region, and may be required to provide a credit should the Region deem, in its sole discretion, that the substituted species is of a lesser quality than that specified in the Contract. Form and Vigour of Caliper Trees All caliper trees shall be nursery stock conforming to the 8 th Edition of the Canadian Standards for Nursery Stock as published by the Canadian Nursery Landscape Association, unless specified otherwise in the Contract Documents. All caliper trees shall be true to type, structurally sound with no evidence of dead branches, sun scald, frost cracks, abraded or broken bark, included bark, and shall be free of insect or disease infestation. All caliper trees shall have a full, well-developed crown with one distinctive vertical leader and a root system typical of the species, free of girdling roots. All parts of the plant shall be moist and show active green cambium when cut and show vigorous growth for a minimum of the last two growing seasons. All caliper trees shall meet the requirements of these Specifications at the time of planting and the warranty inspections. Caliper trees that do not meet the 2

27 requirements of these Specifications shall be replaced by the Contractor at its own expense. Stock Type and Size of Caliper Trees Unless otherwise stated by the Commissioner: 1. All caliper trees shall be wire basket stock; 2. All deciduous caliper trees shall be a minimum of 50 millimetres in caliper, measured at 15 centimetres above the root collar; 3. All deciduous caliper trees shall have a minimum of 150 centimetres of clear stem, measured above the root collar; and 4. All deciduous caliper trees shall have a minimum of ten (10) scaffold branches in the crown. 5. All coniferous caliper trees shall be a minimum of 150 centimetres in height, measured from the top of the root ball to the base of the leader. 6. All caliper trees shall have the root collar at the surface of the root ball. 7. All caliper trees shall have the stem centred in the root ball. 8. All caliper trees shall have a root ball that is firm and intact and free of cracks. Minimum Root Ball Diameter and Height, Caliper Trees The minimum acceptable root ball diameter for caliper (wire basket) deciduous trees shall be: 60 centimetres for 40 millimetre caliper trees 70 centimetres for 50 millimetre caliper trees 70 centimetres for 60 millimetre caliper trees 80 centimetres for 70 millimetre caliper trees 100 centimetres for 100 millimetre caliper trees 150 centimetres for 150 millimetre caliper trees The minimum acceptable root ball height for caliper (wire basket) deciduous trees shall be: 40 centimetres for 40 millimetre caliper trees 40 centimetres for 50 millimetre caliper trees 40 centimetres for 60 millimetre caliper trees 50 centimetres for 70 millimetre caliper trees 50 centimetres for 100 millimetre caliper trees 80 centimetres for 150 millimetre caliper trees The height of the root ball shall be measured from bottom of the root ball to the root collar. 3

28 The minimum acceptable root ball diameter for caliper (wire basket) coniferous trees shall be: 45 centimetres for 100 centimetre height trees 50 centimetres for 125 centimetre height trees 60 centimetres for 150 centimetre height trees 70 centimetres for 175 centimetre height trees 80 centimetres for 200 centimetre height trees 90 centimetres for 225 centimetre height trees The minimum acceptable root ball height for caliper (wire basket) coniferous trees shall be: 40 centimetres for 100 centimetre height trees 40 centimetres for 125 centimetre height trees 40 centimetres for 150 centimetre height trees 40 centimetres for 175 centimetre height trees 50 centimetres for 200 centimetre height trees 50 centimetres for 225 centimetre height trees The height of the root ball shall be measured from bottom of the root ball to the root collar. Burlap and twine shall be biodegradable. Synthetic burlap and twine is not acceptable. Nursery Inspection and Tree Marking The Commissioner will inspect and mark all, or a portion, of the caliper tree stock at the nursery or holding yard prior to planting. The Contractor shall use the marked tree stock for planting. The Commissioner s inspection and marking of caliper tree material prior to planting does not imply acceptance of the tree material. All caliper trees must meet the requirements of these Specifications at the time of planting and warranty inspections. Caliper trees that do not meet the requirements of these Specifications shall be replaced by the Contractor at its own expense. Shipping of Trees Caliper trees must be transported to the planting site in a manner that will minimize damage to crowns, boles and/or roots. Trees shall be protected from sun and wind during transport. Wire basket trees must have no cracks in the ball. All trees must have their root systems in a moist state at all times. Trees shall be handled by their root balls at all times. If trees must be lifted by the stem as well as the root ball to maintain control, lifting forces shall be directed to the root ball and not the stem. 4

29 Temporary Storage of Trees If conditions preclude the immediate use of caliper trees, trees shall be stored in a sheltered area protected from the sun and wind. The root balls shall be kept in a moist state at all times. Deciduous and Coniferous Caliper Tree Planting The following specifications for Deciduous and Coniferous Caliper Tree Planting shall be read in conjunction with Natural Heritage and Forestry Standard Drawings NHFS-01, NHFS-02, NHFS-06 and NHFS-07. Digging and Size of Planting Holes The diameter of the planting holes shall be 60 cm wider than the diameter of the root ball. The depth of the holes shall result in the root collars being at 5 centimetres to 10 centimetres above the surrounding grade after settling (refer to Standard Drawings NHFS-01, NHFS-02, NHFS-06 and NHFS-07). The sides of the planting hole shall be constructed at a shallow angle, with the top of the planting hole being wider than the bottom. All planting holes shall be hand dug. Alternate digging methods and/or equipment may be approved, in writing, at the Commissioner s sole discretion. No holes shall be dug unless the trees are present for planting. Under no circumstances are planting holes to be left open overnight. Should an existing tree and/or root ball be encountered when digging the planting hole, the Contractor shall remove and dispose of the existing tree and/or root ball including wire basket, burlap and rope. This does not apply to trees or stumps over 70 mm in diameter. Orientation of Tree The tree shall be installed at the same azimuth as it was grown in the nursery. For trees selected and tagged at the nursery, a vertical white line at the base of the tree will mark the north side. The tree shall be planted with the vertical white line facing north. Backfilling of Planting Holes Existing soil shall be used to backfill planting holes. Any large soil clods shall be broken apart prior to backfilling. Any large stones or debris contained in the existing soil shall be removed prior to backfilling. Where soil needs to be added, it shall consist of friable natural loam and is to be mixed with the native soil material before backfilling. Wire basket stock shall have all wire, rope, burlap and twine removed from the top 1/3 of the root ball. The tree shall be placed in the planting hole such that the stem is in a vertical position prior to backfilling. The root ball shall not be damaged when straightening the tree. 5

30 Backfill shall be placed in layers approximately 15 centimetres in depth and firmly tamped in place in such a manner that the tree retains its vertical position without support. When the planting hole has been 50% backfilled, 20 litres of water shall be placed in the planting hole and allowed to fully drain before continuing to backfill. Particular care is to be taken to ensure that no air pockets remain under, or around, the root ball and that no damage occurs to the root system. At the time of backfilling, the Contractor shall supply and install Myke Pro Landscape G mycorrhizae inoculants according to the manufactures instructions. At grade, a ridge of soil located at the edge of the planting hole shall be formed to a height of 10 centimetres, to act as a catch basin for any watering and in order to retain mulch (refer to Standard Drawings NHFS-01, NHFS-02, NHFS-06 and NHFS-07). Existing sod removed from the planting hole may be used to create the ridge at the edge of the planting hole. Sod must be inverted such that the above ground grass growth faces down. All excess fill removed from the planting holes and any other debris resulting from the Contractor s performance of the Work shall be removed and disposed of by the Contractor. Bed Preparation Area At the time of planting the Contractor shall establish a circular bed preparation area extending 35 centimetres from the edge of the planting hole for the entire circumference of the planting hole. Within the bed preparation area all grass shall be removed and the soil cultivated to a depth of a minimum of 15 centimetres to improve future root growth (refer to Standard Drawings NHFS-01, NHFS-02, NHFS-06 and NHFS-07). Pruning The crown of the tree shall be pruned at the time of planting to remove all dead and damaged branches. All cuts shall be made flush with the branch collar leaving no stubs. Pruning shall be completed according to the ANSI A300 standard. Large wounds produced by any means other than branch pruning will render the tree unacceptable, requiring replacement by the Contractor, at its own expense. Staking The Contractor shall note that staking and securing of trees is not a typical requirement of the Region. However, should any trees move 10 degrees or more from the vertical plane prior to the expiration of the warranty period, or if a tree has excessive stem movement within the root ball at the time of planting, the Contractor will be required to straighten and stake the trees at its own expense. Straightening and staking shall occur within 20 Days of written notification from the Region. 6