A Comparison of 2 Health Assessment Methods for Prunus cerasifera 'Atropurpurea'
Jonathan Leung
Lord Byng Secondary
Floor Location : J 110 V

We compare 2 health assessment methods for Prunus cerasifera ‘Atropurpurea’ (Pissard plum) in the Vancouver Arbutus Ridge area. The first method is a qualitative method called tree condition scoring system used by the City of Vancouver. The second method is a quantitative method which is based on a revised version of the health index formula first proposed in a 2020 VDSF project titled: "A New Health Assessment Method for Prunus cerasifera 'Atropuruprea' on a Neighbourhood Scale in Vancouver." The revised health index formula combines 4 key parameters: live crown ratio (LCR), crown density, crown spread to tree height ratio and surface area defect to tree trunk surface ratio. We examine the relationship between different tree parameters for 30 Pissard plums and find 2 sets of linear relationship. We then measure the 4 parameters for 13 Pissard plums and calculate the health index values using the revised health index formula. We also invite a City of Vancouver arborist to do condition scoring for the same trees. The results of the 2 methods do not correlate with each other. We find out it is difficult to come up with a quantitative method that matches well with the qualitative method used by an experienced arborist. The quantitative method does not factor in any measurement of the root health and root, branch and trunk structures. Tree age is also an important factor in tree health assessment that is missing in the revised health index formula.