Graydon-Banning / Shevchenko (NORTH OAKVILLE)

Transcription

1 Graydon-Banning / Shevchenko (NORTH OAKVILLE) Tree Canopy Coverage Analysis Prepared by: NAK Design Strategies Prepared for: Martillac Estates Inc. September 9, 2016

2 02 GRAYDON-BANNING/SHEVCHENKO NORTH OAKVILLE

3 TABLE OF CONTENTS SECTION 1 INTRODUCTION Purpose of the Analysis Study Area North Oakville Urban Forest Strategic Management 06 Plan (NOUFSMP) Tree Classification and Sizing Projected Street Tree Canopy Coverage 06 (Residential) Projected Park Canopy Coverage Projected Tree Canopy Coverage 06 (Employment) Soil Volumes 06 SECTION 2 COMMUNITY TREE COVERAGE Street Tree Canopy Coverage Village Square Tree Canopy Coverage Village Square A Coverage Village Square B Coverage Combined Village Square ( A and B ) 09 Coverage 2.3 Employment Area Canopy Coverage Conclusion 11 TREE CANOPY COVERAGE ANALYSIS 03

4 SECTION 1: INTRODUCTION NINTH LINE 1.1 PURPOSE OF THE ANALYSIS The Graydon-Banning/Shevchenko Tree Canopy Coverage Analysis represents a general assessment of the projected tree canopy coverage for these lands within North Oakville. The proposed development area is planned as a mix of residential dwellings, including single detached dwellings and townhouse dwellings, as well as higher density built form associated with the Dundas Urban Core Area fronting Dundas Street West and a High Density Residential block situated in the north-east corner of the study area. Other land uses include portions of proposed Employment lands in the south-west, as well as Village Squares, a stormwater management pond facility and the interface with the designated NHS in the south-west, north and east edges of the study area. The analysis will determine how these land uses can contribute to the tree canopy coverage and will estimate the projected coverage for streets, Village Squares and parking lots based, in part, on standard calculation methods outlined in the North Oakville Urban Forest Strategic Management Plan (NOUFSMP - Natural Resource Solutions Inc. & Dillon Consulting Limited, November 2011). It will also address potential measures within the Graydon-Banning/Shevchenko study area that will help meet the criteria established by the NOUFSMP for achieving the Town of Oakville s long term objective of a 40% urban forest canopy cover, including criteria related to soil volume, tree health and tree spacing. This analysis will be informed by the current land use plan available, with future driveway, parking layouts and utility constraints considered as an average based on similarly developed residential streetscapes and employment lands. GRAYDON-BANNING / SHEVCHENKO SITE NORTH OAKVILLE dufferin county wellington county Guelph orangeville 7 halton regional 401 peel regional 107 TREMAINE RD. 403 milton brampton REGIONAL ROAD 25 HIGHWAY york regional 400 NEYAGAWA BOULEVARD 409 pearson international airport toronto 10 mississauga north oakville BURNHAMTHORPE ROAD EAST SIXTH LINE DUNDAS STREET WEST 404 toronto region TRAFALGAR ROAD markham 2 durham regiona 1.2 STUDY AREA The Graydon-Banning/Shevchenko study area consists of a combined 75.7 acres (30.6 ha.) of land that is designated as part of the North Oakville Secondary Plan Area. It is bounded to the north and east by the Sixteen Mile Creek Natural Heritage System (NHS), to the south by Dundas Street West, and to the west by future development and the Glenorchy Conservation Area. burlington LEGEND waterloo regional 6 north oakville development area hamilton division major centre major arterial hamilton arterial border 24 hamilton international airport brantford canada-usa 406 border st. catharines 253 niagara regional 405 brant county Fig. 1.2a - Regional Context Map and Graydon-Banning / Shevchenko Development Area. ni 04 GRAYDON-BANNING/SHEVCHENKO NORTH OAKVILLE

5 Fig. 1.2b - Proposed Graydon-Banning/Shevchenko land use plan over-layed on aerial view of existing land uses. TREE CANOPY COVERAGE ANALYSIS 05

6 1.3 NORTH OAKVILLE URBAN FOREST STRATEGIC MANAGEMENT PLAN (NOUFSMP) The North Oakville Urban Forest Strategic Management Plan is a high level strategy and planning study prepared to provide the Town of Oakville with recommendations and guidelines for achieving a sustainable, healthy urban forest for the North Oakville lands. This strategy is an extension of the Town s long term vision to achieve its 40% tree canopy coverage target. North Oakville comprises approximately 4,000 hectares of land, with roughly 1,600 hectares of tree canopy coverage required to achieve the 40% target. The designated Natural Heritage System (NHS), which includes native forests, cultural woodlands, shrub lands and agricultural hedgerows, accounts for approximately 1,200 hectares of North Oakville s land area, making it a significant contributor to achieving the 40% target. The remaining approximately 400 hectares of coverage is expected to be achieved through land development (residential, employment/industrial, institutional and commercial), including streetscapes, parks, buffers, cemeteries, stormwater management facilities, parking lots, etc. The following is a brief summary of some of the targets, recommendations and measuring criteria described in the NOUFSMP that are pertinent to assessing the ultimate long term tree canopy coverage within the Graydon-Banning/Shevchenko study area Tree Classification and Sizing The canopy coverage plan shall comply with the following guidelines - ornamental trees (3-6m spread) = 15 sq.m and shown as 3m dia. small stature trees (7-8m spread) = 45 sq.m and shown as 7m dia. medium stature trees (9-11m spread) = 80 sq.m and shown as 10m dia. large stature trees (12+m spread) = 115 sq.m and shown as 12m dia Projected Street Tree Canopy Coverage (Residential) As a general proposed standard, the NOUFSMP recommends achieving a 20% street tree canopy coverage for residential developments. However, it is noted that trees will not reach their full genetic size potential within most streetscape environments. Furthermore, opportunities for street tree planting may be affected by the objective of achieving a more dense, compact and transit-oriented environment, as part of applying New Urbanism principles to planned North Oakville development Projected Park Canopy Coverage Village Square - 77% Neighbourhood Park - 57% Community Park - 66% Notwithstanding the above percentages, a more realistic standard of 50% may be used for estimating purposes, considering potential site and park facility constraints that may limit the plantable area available for tree planting. Canopy coverage reflects an estimate of the proportion of the ground area that is covered by tree and shrub crowns, expressed as a percentage value. Where canopies merge or overlap, the combined area contributes to the coverage requirement, as opposed to including the canopy area of each overlapping tree Projected Tree Canopy Coverage (Employment) Surface parking typically comprises the largest extent of open space within employment lands (outside of Natural Heritage System or SWM pond lands). Given the wide variation in surface parking lot sizes and configurations, the NOUFSMP recommends minimum standards for tree planting corresponding with parking spaces and associated buffers, as an alternative to the provision of percentage canopy cover. Refer to section Employment Area Canopy Coverage Soil Volumes A minimum of 15 cu.m of soil volume per tree is required (based on a maximum 900mm depth of cover). Notwithstanding the minimum soil volume, the following represents the recommended volumes per tree - ornamental trees (6m spread and less) = min. 10 cu.m small stature trees (7-8m spread) = min. 15 cu.m medium stature trees (9-11m spread) = min. 30 cu.m large stature trees (12m spread and greater) = min. 45 cu.m 06 GRAYDON-BANNING/SHEVCHENKO NORTH OAKVILLE

7 SECTION 2: COMMUNITY TREE COVERAGE Within the Graydon-Banning/Shevchenko study area, the canopy coverage contribution will be achieved through the proposed streetscape treatment, Village Squares, Dundas Urban Core, High Density Residential and Employment Area lands containing parking lots, landscape strips and private drive streetscaping. Although not measured specifically in this analysis, a secondary contribution may be considered through front and rear yard landscape treatment for dwellings. This can account for approximately 1-2% coverage and is typically derived from smaller stature trees. 2.1 STREET TREE CANOPY COVERAGE The street tree canopy coverage calculation for the Graydon-Banning/ Shevchenko study area is a preliminary estimate based on a conceptual land use plan. It corresponds with the proposed road hierarchy, with a particular relevance to the residential streets. It considers all trees to be planted within grass boulevards. Considering the nature of the community, it is not expected that engineered soils (e.g. structural soils or cell support structures) will be utilized. Given that the majority of canopy coverage for employments lands will be achieved through planting associated with surface parking areas and adjoining landscape buffers, the street tree canopy coverage assessment will focus on the residential land uses, including General Urban, Sub-Urban, Neighbourhood Centre, Dundas Urban Core and High Density Residential areas. Street trees have been indicated, on average, at one tree per lot. Most street trees in this assessment have been designated as small stature, until such time a more comprehensive streetscape plan can be undertaken as part of a detailed landscape plan review process. Medium stature trees have been situated along Dundas St. West, William Halton Parkway and the proposed Avenue/Transit and Connector Transit Corridor roads, where greater boulevard widths are anticipated, along with minimal driveway interruptions. The selection of smaller stature trees are largely due to the limited soil volumes characteristic of the standard street right-of-way boulevards proposed within North Oakville. Even when integrating measures such as root breakout zones beneath sidewalks, achieving 30 cubic metres of soil volume is not likely on any consistent basis. Therefore, adhering to the recommended soil volumes from the NOUFSMP requires the selection of predominantly smaller stature street trees. This, in turn, results in an overall tree canopy coverage percentage that is smaller than when using medium stature trees and short of the Town of Oakville s street tree target. The preliminary tree canopy coverage results are as follows (refer to figure 2.1.1): Total Graydon-Banning/Shevchenko Land Area - approx. 249,500 sq.m (not including the Village Squares, SWM pond, Employment Area, NHS and associated buffers and open spaces - 57,000 sq.m). Total Street Tree Canopy Coverage Area (based on small and medium stature trees) - approx. 37,500 sq.m (not including the Village Squares, SWM pond, Employment Area, NHS and associated buffers and open space). Street Tree Canopy Coverage = 15.0% (37,500/249,500) TREE CANOPY COVERAGE ANALYSIS 07

8 Fig Conceptual Street Tree Canopy Coverage Plan for Graydon-Banning/Shevchenko. 08 GRAYDON-BANNING/SHEVCHENKO NORTH OAKVILLE

9 2.2 VILLAGE SQUARE TREE CANOPY COVERAGE The Village Squares ( A and B ) canopy coverage calculation for the Graydon-Banning/Shevchenko study area is a preliminary estimate based on potential facility fit plans for the two parks. The Village Square designs are currently conceptual and subject to future modification as part of the detailed landscape design process. All tree sizes have been included in the design and assessment, including ornamental/coniferous, small stature, medium stature and large stature trees Village Square A Coverage Total Village Square A Land Area - approx. 2,800 sq.m Total Village Square A Tree Canopy Coverage - approx. 1,700 sq.m Village Square A Tree Canopy Coverage = 61% Village Square B Coverage Total Village Square B Land Area - approx. 2,975 sq.m Total Village Square Tree Canopy Coverage Area - approx. 1,750 sq.m Village Square B Tree Canopy Coverage = 59% Combined Village Square ( A and B ) Coverage Total Village Square Land Area - approx. 5,775 sq.m Total Village Square Tree Canopy Coverage Area - approx. 3,450 sq.m Village Square Tree Canopy Coverage = 59.7% Fig Conceptual Village Square A Tree Canopy Coverage Plan. TREE CANOPY COVERAGE ANALYSIS 09

10 Fig Conceptual Village Square B Tree Canopy Coverage Plan. 10 GRAYDON-BANNING/SHEVCHENKO NORTH OAKVILLE

11 2.3 EMPLOYMENT AREA CANOPY COVERAGE As indicated, surface parking typically comprises the largest component of open space areas associated with employment lands. Assessing tree canopy coverages for employment lands is difficult in the absence of detailed design related to built form layout, vehicular circulation and parking lot configuration. The NOUFSMP, therefore, recommends minimum tree planting targets to guide the placement of trees and achieve significant canopy coverage. The following summarizes these targets Tree Planting Targets for Parking Lots (Employment Areas) Minimum 1 shade tree per 5 parking spaces, with a minimum 60mm caliper size; Minimum 2 trees per parking lot island; All trees to be in or within 5.0 metres of the parking area for lots of 76 or more cars; No parking space shall be more than 30 metres from a tree; Where appropriate and necessary, small-statured trees (3.0m spread and less) will be acceptable to meet minimum standards; Minimum 1 deciduous tree for every 12 metres of street fronting the parking lot; Meet all provisions for landscape area widths and locations, as stipulated in the NOUFSMP, including the following - - Minimum 3.0m wide landscape buffer/strip from inside the property line, between the parking lot and adjacent street rightof-way; - Minimum 3.0m wide landscape buffer/strip for parking lots of 5 to 75 spaces, where it doesn t abut a street; - Minimum 4.5m wide landscape buffer/strip for parking lots of greater than 75 spaces, where it doesn t abut a street; - Minimum 4.5m wide landscape buffer/strip for parking lots abutting residential zones. The NOUFSMP recommendations pertaining to parking standards noted above are subject to an ongoing review by City staff prior to zoning implementation. 2.4 CONCLUSION There are many factors that will contribute to the health and long term sustainability of the tree canopy within Graydon-Banning/Shevchenko and the surrounding development areas. In addition to maximizing tree planting opportunities and protecting soil compaction, soil quality, soil volumes and tree species selection in an increasingly urban environment will be fundamental to reaching the overall 40% tree canopy coverage targeted for the Town of Oakville. These issues can be considered in a more comprehensive depth during the detailed landscape design process. TREE CANOPY COVERAGE ANALYSIS 11