CONCRETE JUNGLE FORESTRY LTD.

Urban & Wildland Forest Assessment & Mapping

Concrete Jungle Forestry Ltd.

297 View Royal Avenue

March 28, 2023 Ryzuk Geotechnical; Proposed Foreshore Stabilization Works Douglas-fir Holding Root Arborist Opinion

Donald Skinner
May 1, 2023

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May 1, 2023

Leanne Howes
297 View Royal Avenue
Victoria BC, V9B 1B3

Re: 297 View Royal Avenue; March 28, 2023 Ryzuk Geotechnical; Proposed Foreshore Stabilization Works Douglas-fir Holding Root Arborist Opinion.

Introduction:

ISA Certified Arborist Donald Skinner of Concrete Jungle Forestry Ltd. (CJF) has been asked to provide a tree impact opinion on Ryzuk Geotechnical’s proposed foreshore stabilization works methodology and impacted Douglas-fir holding root retention.

As CJF understands it, primary stabilization changes since May 2022:

• Use of marine grade gabion basket.
• Use of Flex MSE landscaping wall to cradle Douglas-fir No.491 +/-35cm diameter holding root shown in Ryzuk Proposed Foreshore Stabilization Site Plan drawing (Appendix 1).

Exposed root parent tree located on neighbouring 299 View Royal Avenue just above concrete seawall¹. Douglas-fir No.491 ongoing structural collapse described in CJF July 7, 2022 15m Natural Watercourse Shoreline DPA New Landscape, Tree Protection Plan arborist report. Retaining functional Appendix 1 exposed holding root(s) critical to ensuring tree 491 remains vertical as long as possible.

Proposed Slope Stabilization Works Tree Impact:

Appendix 1 identified +/-35cm diameter Douglas-fir holding root runs north to south across the foreshore slope (Image 1). CJF confident:

• Slope toe gabion baskets will not critically impact holding root structure / function.
• Reduced number of inflexible gabion walls between slope toe and second tier (Appendix 1 March 2023 Ryzuk slope stabilization) benefit functional root retention.
• Field fit Flex MSE landscaping wall² will cradle Douglas-fir No.491 holding root exposed west face without critically impacting structure / function.
• MSE wall soil bags more easily re-set / replaced in future should holding root shift with increased parent tree trunk lean over Limekiln Bay.
• Beach access stairway / gabion walls / gravel landings south / west of root can be constructed without critical impact to holding root structure / function.

CJF’s July 7, 2022 report identified second smaller diameter horizontal holding root upslope of the +/-35cm root (CJF added approximate location to Appendix 1 and root shown in Image 2). Root holding function suspect due to decayed structure / fractured distal end. CJF confident:

• Retention possible with:
  • Upslope gabion wall field fit around root end.
  • Possible use of MSE bags to support exposed south side.
• Decayed / fractured root unimpacted by beach access stairs or gravel landings south / west of +/-35cm holding root.

CJF opinion:

• March 2023 Ryzuk slope stabilization reduces Douglas-fir root impact / benefits long-term retention.
• Arborist oversight of slope stabilization works near +/-35cm and decayed / fractured holding roots required.

End Letter:

Sincerely

Donald Skinner M.Sc.
Registered Professional Biologist (#827).
I.S.A. Certified Arborist (# PN5907A).
I.S.A. Tree Risk Assessment Qualified.

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¹ Image 2.
² Vegetated Geomodular Wall System for walls or erosion control - Flex MSE

Image 1: 299 View Royal Avenue Douglas-fir No.491 +/-35cm diameter holding root, August 21, 2021.

Image 2: 299 View Royal Avenue Douglas-fir No.491 decayed / fractured holding root, June 26, 2022.