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    Climbers' Corner • Tree Academy
    Monday • Tuesday • Wednesday

    Bark chlorophyll fluorescence: a novel way of measuring vitality in mature urban trees*

    Summary

    *This project was supported by a Jack Kimmel grant

     

    Leaf chlorophyll fluorescence has been used to assess the effects of physiological stress and vitality in trees in urban environments for many years. This presentation describes a method for assessing tree vitality that has been used for plantation trees (Eucalyptus saligna Sm, Sydney Blue Gum) but has not been previously used in urban trees. The tree species tested in this study were street and park trees; Ficus macrophylla (Morton Bay Fig), Platanus xacerifolia (Plane Tree) and Ulmus parvifolia (Chinese Elm). Bark and leaf fluorescence were compared with an urban visual vitality index in autumn and summer. Predawn water potentials were compared with the urban visual vitality index as a way of determining the cause of physiological stress in the plants. Relationships between bark chlorophyll fluorescence readings and urban tree visual vitality were almost non-existent in the Ficus macrophylla and Platanus xacerifolia trees. On the other hand statistical relationships were significant between bark chlorophyll fluorescence and the urban tree vitality index in Ulmus parvifolia. In a reversal of this trend statistical relationships were present between bark chlorophyll fluorescence and pre-dawn water potentials in Ficus macrophylla and Platanus xacerifolia, but were not as consistent within the Ulmus parvifolia trees. Bark chlorophyll fluorescence may become a useful tool for tree vitality assessments, but further work needs to be undertaken to clarify and understand the responses of different species.

    Presenters

    Denise Johnstone is a lecturer in arboriculture at the University of Melbourne, a position she has held for twenty years. She completed her PhD in 2011 and her Master of Forest Science degree by research in 2005. Denise has been involved in the Arboricultural industry for twenty five years, beginning as a contract climber for a small arboricultural company. In the past she has competed in the Australian Tree Climbing Championships and was Vice-President of the Arboricultural Association of Australia for two years. She presented papers at the ISA’s 79th, 81st, 82nd, 83rd, 85th and 87th International Conference and trade show on Tree Risk Assessment, Wood Density, Decay Measurement and Tree vitality, and has had several papers published in Arboriculture & Urban Forestry.

    Patricio Sepulveda completed a Master of Urban Horticulture at the University of Melbourne, Australia in 2012. He completed a research project within his masters that was partically based on the work we will be presenting at this conference. After a period of work as an arboricultural consultant, Patricio left Australia and is now managing trees in Chile.

    Climbers' Corner • Tree Academy
    Monday • Tuesday • Wednesday

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