Thesis: Understanding the causes and treatment of chlorotic decline of Eucalyptus and Corymbia (Myrtaceae) in an urban managed parkland
Chlorotic decline syndrome (CDS) of two iconic trees, Eucalyptus marginata and Corymbia calophylla, has resulted in the removal of trees within Kings Park and Botanic Garden in Perth, and elsewhere on the Swan Coastal Plain. A significant factor contributing to the decline is reduced plant-availability of manganese (Mn) in the soil due to supply of alkaline irrigation water to turfed areas increasing soil pH.
This research aims to determine the effectiveness of a soil-acidifying amendment as a treatment to manage CDS of eucalypts in urban parkland and restore health to trees. Additionally, the underlying mechanisms of Mn deficiency causing CDS in eucalypts will be studied. The effect of other abiotic stresses coupled with Mn deficiency on the activity of superoxide dismutase in eucalypts will be investigated, and tolerance of three local eucalypt species to high-pH soils resulting in differences in severity of CDS symptoms will be explored.
Why my research is important
Native trees in decline in urban areas are frequently lost from the landscape due to poor understanding of causes and ineffective treatment, which has significant negative social, ecological and economic consequences. This research will add to the limited knowledge available on the physiology and biochemistry of eucalypts with CDS in Australia, and will also inform land managers of effective management of CDS in other urban areas where similar soil and irrigation practices occur (e.g., public parks and reserves or golf courses). Although this study will focus on eucalypts, CDS is evident in numerous species in different environments worldwide. Given that increasing world population and urbanisation will result in more stress factors for trees, the occurrence of urban tree decline and mortality is likely to rise. Therefore, the outcomes of this study will be a valuable contribution to the limited number of published studies detailing decline of trees in the urban landscape.