Research student profile: Cheryl Poon

Project title

Influence of Black Carbon from Forest fires on Soil Organic Matter

Project overview

Black carbon encompasses the charcoal, charred remains, ash and soot produced during combustion or burning of plant matter and leaf litter. The aim of my project is to study the effects of black carbon (BC) produced during fires (bushfire and prescribed fire) on the decomposition of soil organic matter (SOM). Firstly, I will examine the properties of BC produced during combustion of different types of forest vegetation. Secondly, by measuring the change in rate of soil respiration after addition of BC, we will gain a better understanding of the effects of BC on the carbon cycle.

Black carbon in soil is presumed to be highly resistant to biological decomposition and can therefore act as an important long term carbon sink. This may be of particular importance in a fire-prone country such as Australia where BC is often incorporated into the soil profile and may become a substantial part of the total soil C. However, recent studies have suggested that addition of BC to soil may increase decomposition of SOM, therefore releasing C to the atmosphere.

This project forms part of an ARC Linkage project in collaboration with the Department of Sustainability and Environment, Victoria. My work will provide quantitative data that is needed to understand the role of BC in soil carbon sequestration and the influence of bushfire and prescribed fire on carbon cycling in south-eastern Australian forests.

My project is composed of a combination of field and laboratory work. I will measure the physical (e.g. size fractions, pH), chemical (e.g. total N and C) and biological properties (e.g. microbial biomass) of soil and BC collected from prescribed fires conducted in 2011 and 2012. I will establish a long-term incubation experiment using soil with and without the addition of BC and measure changes in rates of heterotrophic soil respiration over a 2 year period. Short-term incubations (days to months) of soil will be used to examine the effects of addition of other sources of carbon (e.g. simple and complex sugars, decomposed leaf litter), water and nutrients.

The results of my project will provide a better understanding of the role of Australia forests as a source or sink for carbon and how fire may modify this pool. My research has the potential to inform policy-making decisions in Victoria.

Background

I come from Hong Kong and completed a Bachelor of Environmental Science in Geography (Hons) at The University of New South Wales in 2007. After graduation, I worked as a Technical Officer in the Department of Primary Industries in NSW where I participated in projects related to soil carbon and biochar.

I have been granted an Australian Postgraduate Award (Industry).

I have attended the Nature Conservation Council Biennial Bushfire conference in Sydney in 2011. In 2009, I attended the Managing Climate Change Conference on the Gold Coast where I presented a poster titled “The impact of conversion of pasture land to Pinus radiata plantation on soil carbon stocks and dynamics”.

Contact

Email: cheryl.poon@sydney.edu.au


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