@article {bnh-7889, title = {Optimisation of fuel reduction burning regimes for fuel reduction, carbon, water and vegetation outcomes {\textendash} final project report}, number = {648}, year = {2021}, month = {03/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Fire managers often have multiple objectives for a given prescribed burn centred around risk reduction and conservation of biodiversity. The ability to predict the effects of prescribed burning on the capacity of forests to deliver ecosystem services such as clean air, carbon sequestration, and a reliable and high-quality supply of water is becoming increasingly more important.

The body of research detailed in this Synthesis Report represents a concerted effort to understand the effect of prescribed burning on water quantity and carbon losses and gains in forested ecosystems in south-eastern Australia. We collected empirical data from over 100 sampling sites treated with a recent prescribed burn. The sampling strategy we used was consistent over time with target sampling variables included for estimation of overstorey and understorey biomass and direct sampling of surface and near surface fuel loads. Site selection was stratified to accommodate as much site variability as possible and to take full advantage of prescribed burn plans.

Data collected from the field was used in a variety of modelling assignments to capture the effect of prescribed burning on changes in water availability and transformation of carbon pools. Using a mixture of models and empirical sampling and analysis, we showed that there are few risks to long-term carbon and water cycles when prescribed burning is conducted on cycles of 10 or so years. Critical to this analysis is the frequency of bushfires {\textendash} if the inter-fire interval of unplanned fires becomes short (e.g., \<50 years) then ecosystem losses of carbon and reductions in water yield are likely to become semi-permanent features.

Our modelling endeavours ranged from relatively complex process-based models describing water and carbon balances through to simple response surface models. By exploring the transformation of carbon pools in surface fuels during prescribed burning, we developed robust yet simple-to-use models for predicting changes in total carbon and biomass in this fuel fraction. The novel application of FullCAM, a well-established model used for carbon accounting, was tested for its ability to incorporate often subtle changes in forest growth and carbon transformation associated with prescribed burning. We found this model to be relatively sensitive and recommend it to fire managers for applications such as estimation of carbon emissions. Based on our key findings, we advocate for continued research and evidence-based application of prescribed burning as a valuable land management approach.

Data assembled from peer-reviewed publications and researchers worldwide was mined for changing trends in publications concerning prescribed burning, global patterns of litterfall and standing litter, and water use efficiency of forests. These summative studies informed our research direction and chartered our progress.

A considerable number of student projects have been supported during the course of this project contributing to the training of the next generation of researchers and land managers.

}, keywords = {burning regimes, carbon, fuel reduction, optimisation, vegetation, water}, issn = {648}, author = {Bell, Tina and Adams, Mark A. and Mathias Neumann and Danica Parnell and David Pepper and Malcolm Possell} } @article {bnh-7299, title = {Optimisation of fuel reduction burning regimes for fuel reduction, carbon, water and vegetation outcomes: annual report 2019-2020}, number = {606}, year = {2020}, month = {09/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

We have made good progress over the past 12 months and have completed a number of milestones. Fieldwork and analysis of associated samples has ben completed and the data sets generated have formed the basis of our modelling efforts. Research has included: (i) landscape-scale modelling of the effect of prescribed burning on evapotranspiration as the main driver for water use by vegetation; (ii) calibration and testing of FullCAM, a process-based model that can track carbon pools in forests systems, that we have shown is sensitive enough to integrate changes due to prescribed burning; (iii) testing of a fine fuel model that can be used to determine changes in biomass (fuel load) and carbon content in surface fuels without laborious sample collection and analysis; and (iv) use of near infrared spectroscopy to determine fire intensity and severity.

Modelling using FullCAM and the fine fuel model are tools that have very good potential to be adopted by end-user agencies when required to report on carbon emissions resulting from their efforts to manage fuels. For example, the fine fuel model is an easy-to-use tool that can be used as a guide for estimating potential for carbon loss due to prescribed burning. Our recent advances with near infrared spectroscopy of fire residues suggests that the next steps will be to move from a laboratory setting to the field to test the efficacy of hand-held devices. The potential to develop a simple, yet accurate method for determining fire intensity would aid in ground-truthing of fires to replace current methods that are mostly subjective.

Reporting on our progress has taken the form of milestone reports (draft reports and Technical Reports), bi-monthly newsletters directed towards our end-users, and presentations for local, national and international audiences. We have endeavoured to meet regularly with our primary end-user and have continued collaborations with research groups such as CSIRO and local land managers from NSW National Parks and Wildlife Service. As our project ends, we will produce a synthesis of our research and will develop it further for peer-review publications.

}, keywords = {burning regimes, carbon, fuel reduction, vegetation, water}, issn = {606}, author = {Bell, Tina} }