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Mrs Sandra Hawthorne

profile_hawthorne_thumb Mrs Sandra N. D. Hawthorne

PhD student

Topic: prediction of the long-term impact of thinning on water yield

University of Melbourne



Predicting the impact of forest disturbance on water yield is crucial in managing and securing future water supply. While the general impacts of large-scale forest disturbance are well-established; predicting the long-term impact of partial disturbance, such as thinning, on individual catchment remains a challenge. Thinning treatment produces a complex forest structure to model, with potentially different structural and water use dynamics between the thinned areas and the remaining vegetation. 

This project aims to extend the capability of a process-based, distributed hydrological model in order to predict the impact of forest thinning on water yield. This might be achieved by modelling the dynamics between vegetation structure and evapotranspiration (ET) of thinned catchments. As most of Melbourne’s water catchments are dominated by mountain ash (Eucalyptus regnans) forests, the following research questions will be considered:

· What is the persistence of water yield increase after thinning?

· What are the long-term structural responses of the remaining vegetation and cleared areas to different thinning regimes, i.e. the amount of regeneration or emergence of understorey?

· What is the ET pattern of this new system? How is this different from untreated catchments?

To answer the above questions, this project investigates the interaction between vegetation structure and ET in thinned catchments, represented by the spatial distribution of leaf area index (LAI). The project will also explore the use of remote sensing to retrieve LAI distribution and vegetation structural profile across the catchment.

My interest in this project originated from my background in the water industry. After graduating with Bachelor of Science and Bachelor of Engineering (Civil) from Monash University, I worked as a water resource engineer at a rural water authority. Through my role, I have learnt that sustainable management of water resource is crucial to ensure reliable water supply. This project enables me to investigate the impact of forest disturbance in the context of water resource management. The use of remote sensing in forest environment is also an area of interest that will play an increasingly important role in ecosystem studies and management.

My supervisors are Dr Patrick Lane and Associate Professor Leon Bren from the School of Forests and Ecosystem Science, University of Melbourne.

My PhD project contributes to Project 4.1 Water Quantity and Quality of the Trees in the Landscape Programme.

To browse other PhD projects available with the Trees in the Landscape Programme, click here.