Bartlett Tree Experts: Tree Protection Plan Report

Table of Contents

• Introduction ....................................................................................................................................................................1
• Assignment ....................................................................................................................................................................1
• Limits of the Assignment................................................................................................................................................1
• Town of View Royal Bylaw Regulations.........................................................................................................................2
• Methods .........................................................................................................................................................................2
• Observations..................................................................................................................................................................3
• Responsibilities of Project Arborist.................................................................................................................................3
• Tree Impacts ..................................................................................................................................................................4
• Tree Preservation Guidelines.........................................................................................................................................6
  • Design Recommendations.........................................................................................................................................6
  • Tree Protection Zone.................................................................................................................................................7
  • Pre-construction Treatments and Recommendations................................................................................................8
  • Recommendations for Tree Protection during Construction ......................................................................................8
  • Maintenance of Impacted Trees ................................................................................................................................9
• Appendix I – Site Map..................................................................................................................................................11
• Appendix II – Site Plan.................................................................................................................................................12
• Appendix III – Tree Inventory Table .............................................................................................................................13
• Appendix III – Photographs..........................................................................................................................................15

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Summary

The homeowner Mr. Brian Richards will be building an addition to the west side of his home within the driveway on the property at 335 Stewart Avenue. This two story structure will require footings be excavated along the perimeter of the addition. No utility upgrades are required as the sewer, hydro, and water lines were installed prior to the project with the initial house built twelve years ago. As part of the design review process, the Town of View Royal requested a tree protection plan. Mr. Richards asked Bartlett Tree Experts to perform a tree inventory and prepare a Tree Protection Plan for the property as part of the application to the municipality. Bartlett Tree Experts Field Consulting Arborist Peter McAra was assigned to conduct the assessment.

The Site Plan includes building an addition within the current crushed gravel driveway adjacent to the west side of the home. The two story addition is to be 8.25 m wide and 21.25 m long. The construction would require excavation of the footings for the structure be dug to a depth of approximately 0.4 m to 0.6 m below grade. The difference in depth is dependent on the grade on the terrain to ensure the building will be level. It is recommended that the footing perimeter for the west wall be excavated with the use of a hydro-vacuum truck to minimize the impacts to the nearby trees and particularly the protected Douglas maple (Acer glabrum) #720. This tree may also require clearance pruning to lift the canopy on the east side of the tree to accommodate the two story building construction. Impacts to each tree are discussed below and listed in the Tree Inventory (Appendix III). Based on my evaluation of the plans:

• 41 trees will be preserved.

To help protect the preserved trees from excessive construction impacts, I recommend following the Tree Preservation Guidelines found within this report.

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Introduction

In September 2022, the homeowner Mr. Brian Richards retained Bartlett Tree Experts to perform a tree inventory and prepare a Tree Protection Plan Report for his property at 335 Stewart Avenue in the municipality of View Royal, BC. The intended purpose of this report is to provide recommendations based on the impacts to the trees from my interpretations of the site plans provided, as part of the submission to the Town of View Royal.

Assignment

This report communicates the potential impacts to trees from construction to the municipality and to the client. The Town of View Royal requires a Tree Protection Plan as part of their design review process. The report is designed to provide the design team with the tree related details they will need to prepare a Tree Preservation Plan to meet that requirement, including:

• observations of the health and structural condition of the trees,
• evaluation of the impacts to trees based on development plans, and
• guidelines for tree preservation throughout the development process

Limits of the Assignment

The tree assessment was performed from the ground for visual conditions. This tree inventory was not a tree risk assessment. As such, no trees were assessed for risk in accordance with industry standards, nor are there any tree risk ratings or risk mitigation recommendations provided within this report.

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

Illustrations, 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.

Information contained in this report covers only those items that were examined and reflects the condition of those items at the time of inspection. There is no warranty or guarantee, expressed or implied, that problems or deficiencies of the plans of the property in question may not arise in the future.

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Town of View Royal Bylaw Regulations

The Town of View Royal (Protection Bylaw #1069) protects trees that meet the following criteria:

1. Any tree of the following species: a) Garry oak (Quercus garryana) b) Arbutus (Arbutus menziesii) c) Pacific yew (Taxus brevifolia) d) Pacific dogwood (Cornus nuttallii) e) Douglas fir (Pseudotsuga menziesii) f) Grand fir (Abies grandis) g) Big leaf maple (Acer macrophyllum) h) Sitka spruce (Picea sitchensis) i) Western red cedar (Thuja plicata) j) Shore / Contorta pine (Pinus contorta)

2. Any tree with a diameter at breast height (DBH) greater than 30 cm (for multi-stemmed trees diameter is calculated as 100% of the largest and 60% of each additional stem).

3. Any tree with evidence of a nest used by: i) Raptors; as defined in the Wildlife Act, R.S.B.C. 1996 C. 488 ii) Osprey; or iii) A Heron colony

4. Any replacement tree

5. Any tree growing on Town-owned property

6. Any tree planted or retained as a requirement of a subdivision permit, development permit or building permit

7. Any tree protected by a restrictive covenant

Based on these guidelines, three trees from our inventory are protected and cannot be removed without approval from the Town of View Royal. The protected status of each tree is listed in the Tree Inventory (Appendix II).

Methods

Trees were assessed on September 14, 2022. The conditions at the time of assessment were partially cloudy skies and mild temperatures. The assessment included all trees of 10 cm and greater in diameter within may be impacted by the project, and/or any tree included in the surveyor plan provided. The following list of criteria was conducted for the trees and included within our inventory:

1. Affix a sequentially numbered tag to the main trunk of each on site tree;

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2. Identifying the species of tree;
3. Measuring the trunk diameter at 1.4 m above grade;
4. Evaluating the health and structural condition, and assigning an overall condition of Good, Fair, Poor and Dead, based on the following criteria:

• Good: A healthy tree that may have a slight decline in vigor, small amount of twig dieback, minor structural defects that could be corrected;
• Fair: Tree with moderate vigor, moderate twig and small branch dieback, thinning of crown, poor leaf color, moderate structural defects that might be mitigated with regular care;
• Poor: Tree in decline, epicormic growth, extensive dieback of medium to large branches, significant structural defects that cannot be abated;
• Dead: Tree is dead

Observations

41 trees surround the perimeter of the proposed building addition and were included in our inventory. Of the 41 trees, 39 were in good condition and 2 were fair at the date of the site visit (Table 1).

TABLE 1: TREE CONDITION AND ABUNDANCE

Responsibilities of Project Arborist

The duties of the project arborist include:

• Reviewing site plans and establishing tree protection zones.
• Make recommendations in relation to the retention, pruning, removal and protection of bylaw protected trees on site.
• Determining the location of tree protection fencing and plywood and ensuring that they are properly installed prior to construction commencing.
• Supervising all work performed within tree protection zones or within the protected root zones of trees.

Note: it is the responsibility of the contractor to ensure that the project arborist is on site for all work performed within the protected root zones.

I reviewed the Site Plans AO Rev. 6 drawn by W. Schmitz of Compu CAD Consulting Technologists (dated Sept. 2022) to evaluate impacts to trees.

The Site Plan includes building an addition within the current crushed gravel driveway adjacent to the west side of the home. The two story addition is to be 8.25 m wide and 21.25 m long. The construction would require excavation of the footings for the structure be dug to a depth of approximately 0.4 m to 0.6 m below grade. The difference in depth is dependent on the grade of the terrain to ensure the building will be level. Impacts to each tree are discussed below and listed in the Tree Inventory (Appendix III). Based on my evaluation of the plans:

• 41 trees will be preserved.

Tree Impacts

The two Douglas fir trees (#716-717) are located to the northeast of the project area. The trees are expected to have minimal impacts from the excavation of the building footings. I do not anticipate any large structural roots being impacted from the excavation. However, due to the DBH of tree #716, its Protected Root Zone (PRZ) would be within the work limits of the structure. Any roots encountered during the excavation are likely to be the smaller feeder/respiratory roots in my opinion. Severing these roots would be inconsequential to the long term health and viability of the trees.

The five European beech trees (#718-719, 723, and #725-726) have a poor tolerance to construction activity within their critical root zone. These trees were planted approximately eight years ago and are still fairly small. They all appeared to be in good health and structure. The excavation is to take place at the outer limits of the trees PRZ’s. Due to the crushed gravel driveway medium, I don’t anticipate many large structural roots to be present within the area to be excavated for the footings. The roots that may be encountered are likely to be smaller and when pruned could cause temporary stress to the young trees. To help compensate for root damage and loss, reduce stress, and optimize surrounding soil conditions. It is recommended that a soil care regimen be executed once all the construction activities are complete.

The Douglas maple (#720) is a large protected tree within close proximity to the area proposed for excavation. This species has a moderate tolerance to the construction impacts, which are likely to be incurred during the project likely incurred from the project. The excavation of the footings within the trees PRZ would have the least impacts during the fall and winter months. A hydro-vacuum truck would limit the impacts to the tree in my opinion. The hydro-vacuum truck should be able to reduce pressure to approximately 800-1000 psi under the direction of the Project Arborist that shall be monitoring the work. This is to ensure the retained portion of the roots are pruned cleanly and minimal impacts are incurred. The recommendation of fall to winter timing is to limit the amount of root desiccation from being exposed to drought. The tree will most likely require clearance pruning to accommodate the two story building addition. Pruning should also be done in the late fall/early winter as the tree will be dormant with less nutrients flowing through the tissues. This will prevent the tree from excessive weeping from the wounds and also prevent desiccation.

English holly (#721) is adjacent to the maple tree #720. This tree has a good health and structure and the species have a good tolerance to construction activity. The footing excavation would be within the PRZ of the tree. I would anticipate minimal impacts from the construction to this tree as holly are very hardy and the roots incurred are likely to be smaller diameter feeder roots.

Golden rain tree (#722) is a small diameter tree with its PRZ at the edge of the footing excavation. The species has a moderate tolerance to construction activity and I anticipate minimal impacts from the project. This tree sits within the PRZ of the larger maple tree and the excavation would be done with a hydro-vacuum truck to ensure minimal impacts to the tree.

Nootka cypress (#724) have a moderate tolerance to construction. The excavation would be along the outer edge of the trees PRZ and minimal impacts are expected. I don’t anticipate any large structural roots to be encountered during the excavation. Some smaller diameter respiratory roots may require pruning but the long-term viability of the tree should not be compromised if the recommend protection measures are followed.

The row of 27 Arborvitae (#727) shrubs within vicinity to the project are planted within a raised garden bed above the driveway. I do not believe any impacts to the shrubs will be incurred from the project if the design isn’t augmented and the recommended protection measures are followed. The species as a whole have a moderate tolerance to construction with drainage being the primary concern. However the raised bed would prevent any water pooling at the base of the tree. The species is susceptible to Phytopthora sp. infection in poorly drained soils.

The Japanese maple (#728) PRZ is at the edge of the area to be excavated for the footings. I anticipate minimal to no impacts to the tree from the project as the species has a good tolerance to the proposed impacts.

The paperbark maple (#729) species has a moderate tolerance to construction impacts. They tolerate minor root pruning which is potentially to be incurred by the project. The footings would be at the edge of the area to be excavated for the footings. I anticipate minimal to no impacts to the tree as well.

The Katsura tree (#730) as a species have a poor tolerance to construction impacts. The 16 cm DBH tree has a calculated PRZ of 2.9m which would be at the edge of the excavation perimeter. The tree may require moderate root pruning which the tree should tolerate if roots severed are to less than 2 cm in diameter. The tree is in fair health and of good structure in my opinion. Post construction the tree may require fertilization to reduce stress and increase new root growth. Some remedial actions could be taken to improve the health and vitality of the trees. The introduction of premium landscape Biochar through sub-soil injection may help accomplish this. This unique product sequesters carbon and simultaneously benefits soils and plants. It enhances soil fertility while reducing nutrient leaching and ground water contamination. It also increases microbial activity, water retention, stimulates plant growth and reduces insect and disease susceptibility.

Tree root systems are generally confined to the uppermost 30-45cm of the soil profile. Construction activities can cause profound changes to the area surrounding a tree’s root system, by virtue of what has to be done for the majority of projects. Access traffic, storage of materials, grading, and trenching can result in soil compaction, crushing or severing of roots, injury to aboveground portions (trunk and branches), and drainage changes.

Cutting of roots reduces a tree’s ability to supply itself with water and nutrients necessary to produce the sugars and carbohydrates necessary for sustaining life. Compaction of the soil reduces air pockets in the soil and makes it more difficult for roots to grow through it. It also slows or even prevents drainage of irrigation or storm water, which can result in excessively wet conditions, leading to root rot. Breakage and injury to a tree’s trunk and branches reduce its aesthetic value, but more importantly, can leave entry points for pests and diseases.

The issues above often do not appear immediately after the area surrounding a tree has been disturbed. It can be years after the project has been completed that stress signs become apparent. Reduced growth, changes in color or leaf size, branch dieback, or even tree death can follow large disturbances.

Tree Preservation Guidelines

Tree preservation is intended to not only foster tree survival during development, but also to promote maintenance of tree health and beauty into the future. Retained trees that are injured or damaged during construction or are insufficiently maintained afterward become a liability rather than an asset. How individual trees respond to disturbances will depend on the extent of excavation and grading, the care with which demolition is undertaken, and the construction methods employed. Coordinating any construction activity inside the Tree Protection Zone (TPZ) can minimize these impacts.

The following recommendations will reduce impacts to trees from development and maintain and improve their health and vitality through the clearing, grading and construction phases.

Design Recommendations

1. Any changes to the plans involving the trees should be reviewed by the consulting arborist with regard to tree impacts. These include, but are not limited to, site plans, improvement plans, utility and drainage plans, grading plans, landscape and irrigation plans, and demolition plans.
2. Tree Preservation Guidelines prepared by the Project Arborist, which include specifications for tree protection during construction, should be included on all plans.

Tree Protection Zone

1. A TREE PROTECTION ZONE shall be identified for each tree to be preserved on the Tree Protection Plan prepared by the project arborist. Tree Protection Zones are shown on Appendix II - Site Plan. PRZ radius distances from the trunk listed in Appendix III - Tree Inventory Data. a. Tree protection fences shall be installed to encompass the TREE PROTECTION ZONE. As detailed in this image below:

b. Fences must be installed prior to beginning of any demolition or construction activities and must remain until the project is complete. c. No grading, excavation, construction or storage or dumping of materials shall occur within the TREE PROTECTION ZONE. Any excavation, grading or digging within a retained tree’s Protected Root Zone (PRZ) must be monitored at the time of work by the Project Arborist. This includes the entire perimeter of the footings for the addition. d. No underground services including utilities, sub-rains, water or sewer shall be placed in the TREE PROTECTION ZONE. These utilities are already in place as the homeowner installed those 12 years prior to the project based on a larger home design that was later altered. Water, hydro and sewer lines will not require upgrading for the project.

Pre-construction Treatments and Recommendations

1. The construction superintendents shall meet with the Consulting Arborist before beginning work to review all work procedures, access routes, storage areas, and tree protection measures.
2. Fence all trees to be retained to completely enclose the Tree Protection Zone prior to demolition, grubbing or grading. Fences are to remain until all grading and construction is completed. The trees will require protective tree fencing to be erected around their Protected Root Zones (PRZ). However, due to the vicinity of some trees to the project area, the fencing will not be able to fully protect the entire TPZ as described limitations of space available due to the vicinity to the work being completed. Refer to Site Plan for the illustrated location of fencing installation (Appendix II).
3. Prune trees to be preserved to remove dead branches 5 centimeters and larger in diameter, raise canopies as needed for construction activities. This would most likely be required on the Douglas maple tree #720 for clearance of the two story structure and should be done when the tree is dormant. a. All pruning shall be done by an ISA Certified Arborist® or ISA Certified Tree Worker® in accordance with the Best Management Practices for Pruning (International Society of Arboriculture, 2019) and adhere to the most recent editions of the American National Standard Z133.1 Safety Requirements 2017 for Tree Care Operations and ANSI A300 (Part 1)- Pruning 2017. b. While in the tree the arborist shall perform an aerial inspection to identify any defects, weak branch and trunk attachments and decay not visible from the ground. Any additional work needed to mitigate defects shall be reported to the property owner.

Recommendations for Tree Protection during Construction

1. Hydro-vacuum the perimeter of the excavation within the Douglas maple #720 PRZ to minimize impacts to the tree. This would be best done in the late fall/early winter to minimize desiccation to retained roots from the higher temperatures.
2. Any approved grading, construction, demolition or other work within the TREE PROTECTION ZONE will be monitored by the Project Arborist. As well as other areas described by the Project Arborist which includes any resurfacing of the existing parking lot area at south side of property.
3. All contractors shall conduct operations in a manner that will prevent damage to trees to be preserved.
4. Tree protection devices are to remain until all site work has been completed within the work area. Fences or other protection devices may not be relocated or removed without permission of the Consulting Arborist.
5. Construction trailers, traffic and storage areas must remain outside TREE PROTECTION ZONE at all times.
6. Any root pruning required for construction purposes shall receive the prior approval of and be supervised by the Project Arborist. Roots should be cut with a saw to provide a flat and smooth cut. Removal of roots larger than 3 centimeters in diameter should be avoided.
7. If roots are 3 centimeters and greater in diameter are encountered during site work and must be cut to complete the construction, the Project Arborist must be consulted to evaluate effects on the health and stability of the tree and recommend treatment.
8. Prior to grading or trenching, trees may require root pruning outside the TREE PROTECTION ZONE. Any root pruning required for construction purposes shall receive the prior approval of, and be supervised by, the Project Arborist.
9. If injury should occur to any tree during construction, it should be evaluated as soon as possible by the Project Arborist so that appropriate treatments can be applied.
10. No excess soil, chemicals, debris, equipment or other materials shall be dumped or stored within the TREE PROTECTION ZONE.
11. Any additional tree pruning needed for clearance during construction must be performed by a Certified Arborist and not by construction personnel.

Maintenance of Impacted Trees

Preserved trees will experience a physical environment different from that of the pre-development conditions. As a result, tree health and structural stability should be monitored. Occasional pruning, fertilization, mulch, pest management, replanting and irrigation may be required. In addition, provisions for monitoring both tree health and structural stability following construction must be made a priority. Inspect trees annually and following major storms to identify conditions requiring treatment to manage risk associated with tree failure.

Our procedures included assessing trees for observable defects in structure. This is not to say that trees without significant defects will not fail. Failure of apparently defect-free trees does occur, especially during storm events. Wind forces, for example, can exceed the strength of defect-free wood causing branches and trunks to break. Wind forces coupled with rain can saturate soils, reducing their ability to hold roots, and blow over defect-free trees. Although we cannot predict all failures, identifying those trees with observable defects is a critical component of enhancing public safety.

Furthermore, trees change over time. Our inspections represent the condition of the tree at the time of inspection. As trees age, the likelihood of failure of branches or entire trees increases. Annual tree inspections are recommended to identify changes to tree health and structure. In addition, trees should be inspected after storms of unusual severity to evaluate damage and structural changes. Initiating these inspections is the responsibility of the client and/or tree owner.

If you have any questions about my observations or recommendations, please contact me.

Peter McAra pmcara@bartlett.com