Arborist Report – Prince Robert Ridge

Re: 347-349 Old Island Highway – Prince Robert Ridge

During our February 27, 2012 site visit, we inspected a 42/62 cm arbutus tree located in the driveway right-of-way for 347-349 Island Highway, and reviewed the site drawings for the proposed development of this property. We attached an engraved numbered metal tag (tag #349) to the lower trunk of this tree, for ease of identification in the field. Our previous report, dated November 06, 2009, identified risk issues associated with a structural weakness at the main union of this tree’s co-dominant stems. This weakness has been addressed in the short term by heavily pruning and reducing the size of the canopy height and spread; however, the tree will require cyclical pruning in future years to retain this reduced canopy size, should it survive.

The site plans, that were supplied and reviewed by us, located this tree in the centre of the access driveway, where it cannot be retained. The access roadways, driveway areas and front yard setbacks on lots are the locations where typically the highest impacts on a development site occur and where tree retention is the most difficult and least successful. Arbutus is a species of tree that is not considered to be tolerant to these development impacts and frequently declines and dies following the site development, regardless of the measures taken in an attempt to retain it. In this proposal, most of the tree’s critical root system would be covered by a paved surface, and all of the required underground services would pass through this root zone.

Furthermore, during our site visit we observed bedrock on the soil surface near the tree indicating that explosive blasting will probably be necessary to establish driveway and road grades and to attain a sufficient depth of cover for the underground services. It may also be difficult to prune the canopy to a height that would permit adequate clearance for larger trucks (i.e. fire, moving, delivery) while leaving sufficient foliage retained for the tree’s transpiration, respiration and photosynthetic processes.

We have identified an area measuring a radial distance of 9 metres out from the trunk of the tree that will contain the majority of the tree’s critical root structures. In our opinion, it will be very difficult to design and locate a layout for the road, driveway and underground services while still having a reasonable expectation that the tree will survive these development impacts.

In order to retain this tree, our recommendations would be that:

1. The access road be terminated a minimum distance of 5-7 metres out from the east side of the tree trunk.
2. The lots be accessed by a common driveway located on the north side of the tree trunk with its closest edge located a minimum distance of 2 metres from the base of the tree trunk. The driveway would have to be designed so that it floats over the root system with no excavation below the existing surface grade within this root system.
3. That there be no underground services, blasting or other soil disturbance within an area of the critical root system extending a minimum radial distance of 7 metres out from the base of the trunk, in all directions.

Please do not hesitate to call us at 250-479-8733 should you have any further questions. Thank you.

Yours truly,

Tom Talbot & Graham Mackenzie ISA Certified, & Consulting Arborists

Disclosure Statement

Arborists are professionals who examine trees and use their training, knowledge and experience to recommend techniques and procedures that will improve the health and structure of individual trees or group of trees, or to mitigate associated risks.

Trees are living organisms, whose health and structure change, and are influenced by age, continued growth, climate, weather conditions, and insect and disease pathogens. Indicators of structural weakness and disease are often hidden within the tree structure or beneath the ground. It is not possible for an arborist to identify every flaw or condition that could result in failure nor can he/she guarantee that the tree will remain healthy and free of risk.

Remedial care and mitigation measures recommended are based on the visible and detectable indicators present at the time of the examination and cannot be guaranteed to alleviate all symptoms or to mitigate all risk posed.