ARBOURIST REPORT - Vancouver · Arborist Report: 1157 Burrard St. - December 2018 Page 3 of 16 Summary This report specifies tree protection requirements for the proposed project

154 1157 Burrard Street | Rezoning Application | December 21st 2018

APPENDIX

ARBOURIST REPORT

1551157 Burrard Street | Rezoning Application | December 21st, 2018

APPENDIX

Arborist Report: 1157 Burrard St. - December 2018 Page 3 of 16

Summary This report specifies tree protection requirements for the proposed project and is intended to accompany a Rezoning Inquiry for the City of Vancouver.

A total of four trees were assessed for this report; two within the subject property, and two on City property. Should the project be approved, all trees within the property are recommended for removal. All trees on City property are to be protected by two Tree Protection Zones along Burrard St. Arborist supervision is required for proposed work near and within the Tree Protection Zone boundaries, and further specifications to protect the above-ground canopies as well as critical root zones of City trees must be prepared by the project arborist in consultation with the applicant, the General Contractor, and the Parks Board prior to demolition and construction.

As further tree protetction requirements will be prescribed once the actual root distribution of retention trees is determined, root mapping prior to construction is strongly recommended to avoid delays during development.

Introduction Background Green Crown Arborworks was contracted by Prima Properties as the project arborist for a rezoning inquiry for 1157 Burrard St. (Figure 1) as required by the City of Vancouver.

This report includes an inventory and assessment of protected trees onsite and specifies requirements to ensure the protection of trees recommended for retention on and adjacent to the property during predicted development activities, should the proposed rezoning be approved.

Figure 1. 1157 Burrard St.


Assignment My assignment was to provide an arborist as required by the City of Vancouver for a rezoning inquiry following Section 7.2 of the City of Vancouver Protection of Trees By-law No. 9958, based on the information provided to me about the proposed project.

Limits of Assignment Tree management requirements, potential effects of the proposed development on trees, and project clearance and access requirements were developed or predicted based only on my observations during site visits and drawings and descriptions of proposed activities and historical information made available to me by the applicant.

My evaluation of the trees was conducted from ground level without any excavation or invasive sampling of tissues. This report provides no guarantee of health of or safety associated with the assessed trees nor does it represent legal advice.

A Tree Risk Assessment was not requested for this assignment, and was therefore not performed. The arborist shall in no way be held liable for any damages resulting from tree or branch failure, or any damage otherwise caused by trees on or near the property.

Trees were examined after fall leaf senescence had begun. As such, I was not able to assess foliar health, leaf density, and/or the presence of recently dead branches on deciduous trees.

Purpose and use of the Report This report documents recommendations for the management of existing protected trees on and adjacent to the property. Upon approval of the report and included recommendations by the Planning Department, the management requirements specified herein must be met by the developer unless stated otherwise in a report amendment or site visit summary by the project arborist.

Methods A site survey and preliminary drawings of the proposed project were provided to me by Merrick Architecture on November 13, 2018. I visited the site on November 21 to assess protected trees on and adjacent to the property.

During the site visit, I assessed protected trees in relation to the proposed development activities as described to me, which were identified, photographed, assessed for health, vitality, structure, and general landscape value, and measured for height and DBH (Diameter at Breast Height, as measured at 1.4 m above grade). I determined which trees could not be reasonably retained given the proposed development activities, and which trees would require special management consideration for the project as proposed. Tree Protection Zone (TPZ) dimensions and additional tree protection requirements were determined based on tree size, species, vitality, and predicted root distribution, as well as site access requirements.

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Observations The property is currently in use as a community garden. Two permit-sized trees exist on the property. Additionally, two boulevard trees on City property require consideration for the project as proposed.

Basic tree data, including ratings for health, structure, and landscape value for all protected trees on 1157 Burrard St. are summarized in Table 1 below, and those for trees on City property are summarized in Table 2. Approximate tree locations are illustrated in Appendix A.

For trees with multiple stems as measured at 1.4 m above grade, DBH measurements are given for the three largest stems.

Table 1: Tree data for protected trees on 1157 Burrard St.

Tree # Species DBH

(cm) Height

(m)

Crown Spread

(m)

Health Structure Landscape Value

0=Poor/Low 10=Excellent/High 1 Birch (Betula spp.) 9,6,5 4.8 2.4 8 6 6 2 Honey locust (Gleditsia tricanthos) 25 10.9 6.7 8 7 7

Table 2: Tree data for protected trees on City property.

Tree # Species DBH

(cm) Height

(m)

Crown Spread

(m)

Health Structure Landscape Value

0=Poor/Low 10=Excellent/High 3 Honey locust (Gleditsia tricanthos) 41 11.8 5.5 7 10 10 4 Honey locust (Gleditsia tricanthos) 44 14.7 6.8 8 10 10

Trees within property Tree #1

Tree #1 is a young birch (Betula spp.), likely a volunteer grown from seed, with DBH of the three largest stems of 9, 6, and 5 cm, height of 4.8 m, and crown spread of 2.4 m, located at the southwest edge of the community garden (Figure 2). The tree is healthy and has moderate form, with the primary lower scaffold limb growing at a poor angle of attachment, and a large heading cut in one of the upper limbs. The crown asymmetrical, with the majority of growth extending over the sidewalk to the southwest.

The tree’s landscape value was rated as moderate, due to its diminutive size and functional replaceability.

Tree #2

Tree # 2 is an early-mature honey locust (Gleditsia tricanthos) near the eastern corner of the property, likely grown as a volunteer from seed or sucker from the adjacent street tree (Tree #3), with a DBH of 25 cm, a height of 10.9 m, and a crown spread of 6.7 m (Figure 3). The tree is healthy, with good shoot extension, and has moderately good form.

The crown is asymmetrical, with a strong lean to the northwest (Figures 4 & 5). The lean is likely at least partially phototropic, growing away from the shade of Tree #3, and growth has corrected to vertical in the upper fifth of the tree’s height. The gap between the canopies of the two adjacent trees suggests that there may have also been a


partial root plate rotation early in the tree’s life, but no significant root plate heaving is visible to the southeast of the tree and some taper is visible at the root collar (Figure 6); as such the tree appears to be structurally stable.

The tree’s landscape value was rated as moderately high: with benefits due to its size and the high suitability of the species in dense urban areas, but with less than ideal form.

Trees on city property Tree #3

Tree #5 is a mature honey locust boulevard tree on Burrard St. near the western corner of the property (Figures 7 & 8), with a DBH of 41 cm, a height of 11.8 m, and a crown spread of 5.5 m. The tree has excellent form. Shoot growth in the upper canopy appears restricted, compared to adjacent trees of the same species, which is likely due to a combination of the tree’s maturity and difficult growing conditions at the edge of the busy street.

The tree’s landscape value was rated as very high due to its size and age, and because of the high suitability of the species in dense urban areas.

Tree #4

Tree #4 is a mature honey locust boulevard tree on Burrard St. to the southeast of the property (Figure 9), with a DBH of 44 cm, a height of 14.7 m, and a crown spread of 6.8 m. The tree has excellent form. Though likely planted at the same time as Tree #3, Tree #4 is considerably larger, with much greater shoot extension. It likely has greater access to good soil than its neighbour.

The tree’s landscape value was rated as very high due to its size and age, and because of the high suitability of the species in dense urban areas.

Figure 2. Tree #1, viewed from south. Figure 3. Tree #2. Viewed from west.

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Figure 4. Tree #2. Viewed from southwest. Figure 5. Tree # 2. Viewed from northeast.

Figure 6. Tree #2. Root collar. Viewed from northeast. Figure 7. Tree #3. Viewed from north.


Figure 8. Tree #3. Viewed from southwest. Figure 9. Tree #4. Viewed from southwest.

Discussion For the proposed development, both trees within the subject property are recommended for removal. The two assessed street trees are recommended for retention and will require protection measures for the project as proposed.

Both trees within the property were likely established as volunteers from seed or root suckers. Tree #1 has only moderate landscape value and is easily replaceable due to its diminutive size. While Tree #2 has moderately high landscape value, its root roller lies within the crown spread of Tree #3 and the majority of its asymmetrical canopy is within the proposed building space. Both trees are recommended for removal for the construction of the proposed underground parking.

The two street trees will require special consideration for protection as the project evolves. Due to public access requirements for roads, sidewalks, and bike lanes, specified tree protection fencing dimensions alone cannot adequately protect the upper crowns or critical root zones. As such, if the project moves forward, early and ongoing consultation between the general contractor, the project arborist, and the Parks Board will be required to refine tree protection requirements to reflect project logistics and construction methodology.

The recommended curb clearance of 60 cm for TPZ fencing for street trees is not appropriate for this project, as the root collars of all assessed street trees are within that distance. As such, TPZ fencing was specified to extend to 30 cm from the outer curb along Burrard St., as that section of road is signed as ‘no stopping’, and presumably clearance for opening car doors will not be required adjacent to those trees.

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As the crowns of both street trees extend slightly beyond the property line, some pruning and training of the outer canopy may be required for building or scaffold clearance. Pruning of any street trees is subject to authorization by, and must be performed by, the Parks Board.

Preexisting vehicle crossings on the sidewalk along Burrard St. likely lie within the root zones of both trees, especially so for Tree #1. Because of the heavily modified soil environment beneath the sidewalk and road near the two street trees, it is not possible to accurately predict the root spread of either tree. As such, TPZ boundary dimensions were prescribed for the duration that the existing sidewalk and adjacent road area remain intact, with the assumption that the existing impermeable surface will provide protection from mechanical root damage. The removal of the existing impermeable surface must be conducted under the supervision of the project arborist, and further tree protection requirements will be developed by the project arborist and/or Parks Board based on the root spread observed as the surface is removed.

Prior to construction, pending approval of the Parks Board and COV Engineering, exploratory excavation (or Ground Penetrating Radar root mapping, if applicable) of the sidewalk and vehicle crossing area along Burrard St. to define the root spread of the two street trees may save time and reduce costs in the long run. Root mapping ahead of time would allow for consistent root protection specifications to be developed earlier in the planning phase, whereas waiting until construction is underway to remove the impermeable surface in this area may result in considerable delays or design changes depending on observed root system orientation and density beyond the pre-defined TPZs.

Management Requirements: Upon project approval, and prior to demolition or construction activities, a site meeting must be scheduled with the Project Arborist, the Parks Board, and the General Contractor to develop further tree protection specifications based on project logistics and construction methodology. After the initial site meeting, or any time as the project evolves, the arborist may require an amendment or addendum to this report to address potential impacts to protected trees, and any tree protection specifications therein must be implemented by the General Contractor.

It is the responsibility of the General Contractor to ensure that the tree protection specifications are followed by all personnel onsite.

Any construction activities or access (e.g. scaffolding, cranes, construction site trailers) required within the canopy space of the street trees is subject to approval by the Park Board and the Project Arborist, and further tree protection requirements or pruning may be specified before such work can occur.

Protection specifications were not provided for the trees recommended for removal in this report. If the removal of any such tree is not approved by the City, management requirements for that tree must be specified in an amendment to this report before development activities can occur on the site.

Preliminary management requirements, including arborist supervision requirements, and Tree Protection Zone (TPZ) fencing dimensions are specified in Table 3. TPZ dimensions and management requirements are illustrated in Appendix B.

All pruning of street trees must be conducted by and approved by the City of Vancouver Board of Parks and Recreation.

TPZ fencing dimensions were specified for the duration that paved sidewalks remain in place. If impermeable ground cover adjacent to any prescribed TPZs is planned for removal, the project arborist must be informed in advance, and new tree protection specifications may be required before the removal of the impermeable surface


can occur. During arborist supervision of existing surface removal, observations of root distribution under such surfaces may be used to develop further tree protection specifications, including new TPZ fencing dimensions.

All tree protection zone barriers must be constructed to the standards of the City of Vancouver for protection of trees on private property, requiring barriers to be:

1. at least 1.2 metres high measured from the ground, 2. meeting the distance requirements, measured 1.4 m above the existing grade of the ground adjoining the

base of the tree, 3. with respect to its construction, consisting of snow fencing fastened securely to metal or wood stakes

spaced no more than one metre apart, or other fencing acceptable to the Chief Building Official or City Engineer.

Absolutely no soil disturbance or storage, dumping, or cleaning of materials is permitted within TPZs.

There is to be absolutely no change to surface grade within TPZs during development activities. Following construction activities, changes to grade within the TPZs to suit the final landscape plan should be designed in consultation with the project arborist.

When roots over 5 cm (2”) are encountered during excavation outside of TPZs, when it is not certain that the roots are from shrubs or trees to be removed, the project arborist must be informed, and, at the discretion of the project arborist, root pruning or further tree protection measures may be required before work can continue.

Project activities must not be conducted in any way so as to damage stems or branches of retention trees. Where there is a risk of tree damage from planned project activities, the project arborist must be informed in advance, and site supervision, preventative or remedial pruning, or other tree protection requirements may be specified at the discretion of the project arborist or the Board of Parks and Recreation.

If further clearance is required for any reason around retention trees, other than specified in this report, pruning for clearance may be possible, if approved by the project arborist and the Board of Parks and Recreation, and must be first specified in an amendment to this report or in a site visit memo by the project arborist.

Site inspection and/or site supervision frequency will be determined by the project arborist based on site activity, the implementation of tree protection requirements, and observed or perceived risk of damage to retention trees. Tree protection requirements specified in site visit summaries must be completed within any time frames specified therein.

Pending issuance of a permit for the proposed development, under section 7.2(e) of the City of Vancouver Protection of Trees By-Law, Green Crown Arborworks may be hired by the owner or project manager to perform, or supervise performance of:

1. pre-construction treatment of trees including root and branch pruning, 2. regular on-site inspections during construction, and will report any offence against this By-law on the site

to the Director of Planning or on a street adjacent to the site to the City Engineer, 3. restorative landscape treatment including soil renovation, 4. selection and planting of any replacement trees required under this By-law, and 5. a post construction inspection of the site, and will prepare a report certified correct by the arborist, for

submission, in a timely manner, to the Director of Planning.

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Table 3. Management requirements Tree

# Species DBH Notes Management Requirements & TPZ Dimensions

1 Birch (Betula spp.)

9,6,5

Young tree. Moderate landscape value. Located within underground parking footprint.

Remove, pending approval from Planning Department.

2 Honey locust (Gleditsia tricanthos)

25

Healthy. Heavy lean and asymmetrical canopy. Moderately high landscape value. Located within underground parking footprint.

Remove, pending approval from Planning Department.


41 City tree. Moderately good health and excellent form.

Retain and protect. TPZ: Erect TPZ Fencing 1.40 m northeast and 3.40 m southwest (measured parallel to Burrard St.) of tree centre, to the northwest of the tree 1.50 m from the outer curb, and to the southeast of the tree 0.30 m northwest from the outer curb. ARBORIST SUPERVISION REQUIRED: Arborist supervision is required for excavation or removal of the existing impermeable surface within an area 3.00 m northeast of tree centre and 6.00 m southwest of tree centre, between the outer curb and the property line (except as conducted by COV under approval of the Parks Board) or for any construction activities within 1.00 m of any above-ground part of any protected tree, until specified otherwise in writing by the project arborist. Arborist supervision is required for any activities occurring within TPZs, and such activities must first be approved by the project arborist. ROOT MAPPING IS RECOMMENDED PRIOR TO CONSTRUCTION: Additional tree protection requirements may be prescribed based on actual root distribution. Root mapping prior to construction may prevent delays or design modification during active development.


Table 3. Management requirements Tree

# Species DBH Notes Management Requirements & TPZ Dimensions


44 City tree. Excellent health and form.

Retain and protect. TPZ: Erect TPZ Fencing 3.40 m northeast and 3.40 m southwest (measured parallel to Burrard St.) of tree centre, to the northwest of the tree 1.50 m from the outer curb, and to the southeast of the tree 0.30 m northwest from the outer curb.

ARBORIST SUPERVISION REQUIRED: Arborist supervision is required for excavation or removal of the existing impermeable surface within an area 6.00 m northeast of tree centre and 6.00 m southwest of tree centre, between the outer curb and the property line (except as conducted by COV under approval of the Parks Board) or for any construction activities within 1.00 m of any above-ground part of any protected tree, until specified otherwise in writing by the project arborist. Arborist supervision is required for any activities occurring within TPZs, and such activities must first be approved by the project arborist. ROOT MAPPING IS RECOMMENDED PRIOR TO CONSTRUCTION: Additional tree protection requirements may be prescribed based on actual root distribution. Root mapping prior to construction may prevent delays or design modification during active development.

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Appendix A: Tree Map

Trees in blue are recommended for retention.

Trees in red are recommended for removal.


Appendix B: Tree Protection Details

Figure 1. Tree Protection Zone dimensions.

Adapted from Underhill Geomatics Ltd. drawings, Sept 24 2018

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Appendix C: Certification of Performance

I, Jason Malysh, certify that:

• I have personally inspected the trees and the property referred to in this report and have stated my findings accurately. I have made assessments based partly on accounts of site history disclosed to me by members of the project team. The extent of the evaluation or appraisal is stated in the attached report and the Limits of Assignment.

• I have no current or prospective interest in the vegetation or the property that is the subject of this report and have no personal interest or bias with respect to the parties involved.

• The analysis, opinions, and conclusions stated herein are my own and are based on current scientific procedures and facts.

• My analysis, opinions and conclusions were developed and this report has been prepared according to commonly accepted arboricultural practices.

• No one provided significant professional assistance to me, except as indicated within the report. • My compensation is not contingent upon the reporting of a predetermined conclusion that favours the

cause of the client or any other party nor upon the results of the assessment, the attainment of stipulated results, or the occurrence of any subsequent events.

I further certify that I am a member in good standing of the American Society of Consulting Arborists and a Board Certified Master Arborist (PN 6582B) with the International Society of Arboriculture.

Signed: ______________________

Date: Decemer 10, 2018


Appendix D: Assumptions & Limiting Conditions

1. This report is intended strictly as an assessment of sampled trees. Any recommendations herein cannot make the arborist liable for any resulting effects on slope or terrain stability, issues of trespass or property ownership, damage or injury, or any legal issues that may arise from actuating said recommendations. It is the duty of the property owner to ensure any actions carried out on or around these trees do not adversely affect the surrounding environment, or other people or property.

2. Any legal description provided to the arborist is assumed to be correct. Any titles and ownerships to any property are assumed to be good and marketable. No responsibility is assumed for matters legal in character. Any and all property is appraised or evaluated as though free and clear, under responsible ownership and competent management.

3. Care has been taken to obtain all information from reliable sources. All data has been verified insofar as possible: however, the arborist can neither guarantee nor be responsible for the accuracy of information provided by others.

4. The arborist shall not be required to give testimony or attend court by reason of this report unless subsequent contractual arrangements are made, including payment of an additional fee for such services as described in the fee schedule and contract of engagement.

5. Loss or alteration of any part of this report invalidates the entire report.

6. Possession of this report or a copy thereof does not imply right of publication or use for any purpose by any other than the person to whom it is addressed, without the prior expressed written or verbal consent of the arborist.

7. Neither all nor any part of the contents of this report, nor copy thereof, shall be conveyed by anyone, including the client, to the public through advertising, public relations, news, sales or other media, without the prior expressed written or verbal consent of the arborist particularly as to value conclusions, identity of the arborist, or any reference to any professional society or institute or to any initialed designation conferred upon the arborist as stated in his qualification.

8. This report and values expressed herein represent the opinion of the arborist, and the arborist’s fee is in no way contingent upon the reporting of a specified value, stipulated results, or the occurrence of a subsequent event, nor upon any finding to be reported.

9. Sketches, diagrams, graphs, and photographs in this report, being intended as visual aids, are not necessarily to scale and should not be construed as engineering or architectural reports or surveys.

10. Unless expressed otherwise: (1) information contained in this report covers only those items that were examined and reflects the condition of those items at the time of inspection; and (2) the inspection is limited to visual examination of accessible items without dissection, excavation, probing, or coring. There is no warranty or guarantee, expressed or implied, that problems or deficiencies of the plants or property in question do not exist or may not arise in the future. By signing below, the client acknowledges that they assume some degree of risk if any trees are left standing within striking distance of people or property. The arborist can only provide an educated estimate whether a tree lies within a client’s threshold of acceptable risk.

I have read and understand the above: Name: ______________________________________

Signed: ____________________________________ Date: _______________________________________

ARBORIST REPORT

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ARBOURIST REPORT - Vancouver · Arborist Report: 1157 Burrard St. - December 2018 Page 3 of 16 Summary This report specifies tree protection requirements for the proposed project