@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-7472, title = {Causes and consequences of Eastern Australia{\textquoteright}s 2019{\textendash}20 season of mega-fires: A broader perspective}, journal = {Global Change Biology}, volume = {26}, year = {2020}, month = {04/2020}, pages = {pp. 3756-3758}, abstract = {

Climates{\textemdash}especially seasonal and long-term droughts{\textemdash}and fuel loads combine to determine risks of wildfires across much of Australia. Here we illustrate how long-term accumulations of fuel combined with a serious drought to drive the behaviour and extent of recent fires in South-eastern Australia.

This article is a commentary on Nolan et al. 26,\ 1039{\textendash}1041. See also the response to this letter by Bradstock et al. 26,\ e8{\textendash}e9.

}, keywords = {Bushfire, climate, Fire behaviour}, doi = { https://doi.org/10.1111/gcb.15125}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15125}, author = {Adams, Mark A. and Majid Shadmanroodposhti and Mathias Neumann} } @article {bnh-7471, title = {Diminishing CO2-driven gains in water-use efficiency of global forests}, journal = {Nature Climate Change}, volume = {10}, year = {2020}, month = {04/2020}, pages = {466{\textendash}471}, abstract = {

There is broad consensus that, via changes in stomatal conductance, plants moderate the exchanges of water and carbon between the biosphere and atmosphere, playing a major role in global hydroclimate. Tree rings record atmospheric CO2\ concentration (ca) and its isotopic composition (13C/12C){\textemdash}mediated by stomatal and photosynthetic influences{\textemdash}that can be expressed in terms of intrinsic water-use efficiency (W). Here, we compile a global\ W\ dataset based on 422 tree-ring isotope series and report that\ W\ increased with\ ca\ over the twentieth century, but the rates of increase (dW/dca) declined by half. Angiosperms contributed more than gymnosperms to the slowdown, and in recent decades, dW/dca\ for angiosperms was close to zero. dW/dca\ varies widely across climatic regions and reflects pauses in emissions during the Great Depression and after World War II. There is strong spatial variability in climate forcing via an increasing\ W, which is weakening globally with time.

}, keywords = {Biogeochemistry, Climate and Earth system modelling, Ecophysiology, hydrology}, doi = {https://doi.org/10.1038/s41558-020-0747-7}, url = {https://www.nature.com/articles/s41558-020-0747-7}, author = {Adams, Mark A. and Buckley, TN and Turnbull, Tarryn L.} } @article {bnh-7484, title = {Plasticity of leaf respiratory and photosynthetic traits in Eucalyptus grandis and E. regnans grown under variable light and nitrogen availability}, journal = {Frontiers in Forests and Global Change}, year = {2020}, month = {02/2020}, abstract = {

Plant growth strategies are adapted to resource availability in native habitat(s), and thus reflected in traits such as photosynthetic and respiratory capacities of leaves. We explored acclimation of such traits to contrasting light and nitrogen supply for Flooded Gum (Eucalyptus grandis) and Mountain Ash (E. regnans) saplings growing under warm-temperate conditions. We focused on respiration parameters that are not routinely measured, but could expand our mechanistic understanding of trait correlation networks [interdependencies between leaf mass per area (LMA), foliar nitrogen concentration (Nmass), photosynthetic capacity (mass- based Amax) and respiration (R)]. We measured temperature responses of leaf R via calorimetric methods, in order to derive three respiration parameters that are useful to characterize capacity and flux mode of respiratory oxygen reduction in mature source leaves and young sink leaves. Subtropical\ E. grandis\ saplings produced 3-fold more biomass than\ E. regnans, and responded more strongly to enhanced supplies of nitrogen, in particular under semi-shade conditions. Acclimation of LMA to growth irradiance was more plastic in\ E. grandis, but light treatment had no effect on Nmass\ and mass-based Amax\ in this species. In\ E. regnans, growth under abundant nitrogen and full sunlight caused significant increases in foliar Nmass{\textendash}albeit not matched by relatively modest increases in mass-based Amax. Cool-temperate\ E. regnans\ saplings appeared to allocate a substantial share of leaf-N to protective functions upon exposure to full sunlight. Foliar nitrogen was used more effectively for the production of new foliage in\ E. grandis, owing to better coordination with foliar capacity and flux mode of mitochondrial oxygen reduction. Most of the variation in three respiration parameters can be explained by a few physiological/anatomical variables, responding to variation in absolute and relative demand for ATP, reducing power and anabolic intermediates. These demands strongly depended on leaf developmental stage and also varied between species and treatments. Our approach opens a path to improved process- based understanding of respiratory flux control, which could facilitate predictions of plant respiration in a changing environment.

}, keywords = {Eucalyptus forest, forest}, doi = { https://doi.org/10.3389/ffgc.2020.00005}, url = {https://www.frontiersin.org/articles/10.3389/ffgc.2020.00005/full}, author = {Jorg Kruse and Turnbull, Tarryn L. and Heinz Rennenberg and Adams, Mark A.} } @article {bnh-5094, title = {Can a growth model be used to describe forest carbon and water balance after fuel reduction burning in temperate forests?}, journal = {Science of the Total Environment}, volume = {615}, year = {2018}, month = {02/2018}, pages = {1000-1009}, chapter = {1000}, abstract = {

Empirical evidence from Australia shows that fuel reduction\ burningsignificantly reduces the incidence and extent of unplanned fires. However, the integration of environmental values into\ fire management\ operations is not yet well-defined and requires further research and development.

WAVES, a plant growth model that incorporates Soil-Vegetation-Atmosphere Transfer, was used to simulate the hydrological and\ ecological effects\ of three fuel management scenarios on a\ forest ecosystem. WAVES was applied using inputs from a set of forest plots for one year after three potential scenarios: (1) all litter removed, (2) all litter and 50\% of the\ understorey\ removed, (3) all litter and understorey removed. Modelled outputs were compared with sites modelled with no-fuel reduction treatment (Unburnt).

The key change between unburnt and fuel reduced forests was a significant increase in soil moisture after fire. Predictions of the recovery of aboveground carbon as plant biomass were driven by model structure and thus variability in available light and soil moisture at a local scale. Similarly, effects of fuel reduction burning on\ water processes\ were mainly due to changes in vegetation interception capacity (i.e. regrowth) and soil evaporation. Predicted effects of fuel reduction burning on total\ evapotranspiration\ (ET) {\textendash} the major component of\ water balance\ {\textendash} were marginal and not significant, even though a considerable proportion of ET had effectively been transferred from understorey to overstorey. In common with many plant growth models, outputs from WAVES are dictated by the assumption that overstorey trees continue to grow irrespective of their age or stage of maturity. Large areas of eucalypt forests and woodlands in SE Australia are well beyond their aggrading phase and are instead over-mature. The ability of these forests to rapidly respond to greater availability of water remains uncertain.

}, doi = {https://doi.org/10.1016/j.scitotenv.2017.09.315}, url = {https://www.sciencedirect.com/science/article/pii/S0048969717326669?via\%3Dihub}, author = {Gharun, Mana and Malcolm Possell and R. Willem Vervoort and Adams, Mark A. and Bell, Tina} } @article {bnh-4118, title = {Improving forest sampling strategies for assessment of fuel reduction burning}, journal = {Forest Ecology and Management}, volume = {392}, year = {2017}, month = {05/2017}, pages = {78-89}, chapter = {78}, abstract = {

Land managers\ typically make\ post hoc\ assessments of the effectiveness of fuel reduction burning (FRB), but often lack a rigorous sampling framework. A general, but untested, assumption is that variability in soil and fuel properties increases from small (\~{}1\ m) to large spatial scales (\~{}10{\textendash}100\ km). Based on a recently published field-based sampling scheme, we addressed the following questions: (i) How much variability is captured in measurements collected at different spatial scales? (ii) What is the optimal number of sampling plots required for statistically robust characterisation of burnt areas? (iii) How can land managers improve their assessment of the effectiveness of FRB? We found that measurement variability does not increase with scale for all fuel components. Results showed that\ coarse woody debris\ is as variable at the small scale (plot, m) as it is at the landscape scale (km). For certain fuel components, such as litter biomass (in unburnt areas),\ overstorey\ biomass and leaf area, and\ soil properties\ such as total carbon and total nitrogen, samples taken at the small (plot) scale were indicative of variation at the larger scale of an individual FRB and more broadly across the landscape.

We then tested the hypothesis that site stratification can reduce variability between sampling plots and as a consequence will reduce the required number of sampling plots. To test this hypothesis we used Landsat Normalized Difference Vegetation Index (NDVI) across areas treated with FRB and compared the number of sampling plots required to estimate mean fuel biomass with and without stratification. Stratification of burnt areas using remotely sensed vegetation indices reduced the number of sampling plots required. We provide a model of green biomass from Landsat NDVI and make recommendations on how sampling schemes can be improved for assessment of fuel reduction burning.

}, doi = {https://doi.org/10.1016/j.foreco.2017.03.001}, url = {http://www.sciencedirect.com/science/article/pii/S0378112716310751?via\%3Dihub}, author = {Gharun, Mana and Malcolm Possell and Jenkins, Meaghan E. and Lai Fan Poon and Bell, Tina and Adams, Mark A.} } @article {bnh-4117, title = {Optimisation of fuel reduction burning regimes for carbon, water and vegetation outcomes}, journal = {Journal of Environmental Management}, volume = {203}, year = {2017}, month = {12/2017}, pages = {157-170}, chapter = {157}, abstract = {

Fire plays a critical role in biodiversity, carbon balance, soil erosion, and nutrient and hydrological cycles. While empirical evidence shows that fuel reduction burning can reduce the incidence, severity and extent of unplanned fires in Australia and elsewhere, the integration of environmental values into fire management operations is not well-defined and requires further research and development. In practice, the priority for fuel reduction burning is effective mitigation of risk to life and property. Environmental management objectives, including maintenance of high quality water, reduction of CO2\ emissions and conservation of biodiversity can be constrained by this priority. We explore trade-offs between fuel reduction burning and environmental management objectives and propose a framework for optimising fuel reduction burning for environmental outcomes.

}, doi = {https://doi.org/10.1016/j.jenvman.2017.07.056}, url = {http://www.sciencedirect.com/science/article/pii/S0301479717307387?via\%3Dihub}, author = {Gharun, Mana and Malcolm Possell and Bell, Tina and Adams, Mark A.} } @article {bnh-3416, title = {Production of pyrogenic carbon during planned fires in forests of East Gippsland, Victoria}, journal = {Forest Ecology and Management}, volume = {373}, year = {2016}, month = {08/2016}, pages = {9-16}, chapter = {9}, abstract = {

Management strategies such as planned burning for fuel reduction can help mitigate the effects of wildfires. The amount of biomass consumed is of interest to fire managers as reduction of fuel loads is imperative to reducing the risk and extent of a wildfire event. Biomass regeneration is also of importance for ecosystem recovery and resilience. Pyrogenic carbon (PyC), a product of combustion during both planned and unplanned fires, plays a key role in global carbon stores and balances. A three-year study of planned burning practices examined fires in Lowland temperate Eucalypt forest of south eastern Australia. We collected data on overstorey, understorey, coarse woody debris, fine litter, PyC and soil across nine sites to determine biomass consumption, PyC production and changes in ecosystem carbon during planned burning. Lowland forest showed significant recovery of combustible biomass (fine litter and understorey) one year after planned fire. Across our sites, PyC was produced at a rate of approximately 5\% of the biomass consumed. The PyC produced is destined to become part of soil and litter carbon and contributes to long-term carbon storage. Planned burning had a short-term (\<1\ year) impact on forest carbon balance, and on reduction risk of wildfire and associated losses of biomass carbon, but no long-term impact, through deposition of PyC and recovery of biomass.

}, doi = {10.1016/j.foreco.2016.04.028}, url = {http://www.sciencedirect.com/science/article/pii/S0378112716301979}, author = {Jenkins, Meaghan E. and Bell, Tina and Lai Fan Poon and Cristina Aponte and Adams, Mark A.} } @article {bnh-3431, title = {Emissions from prescribed fires in temperate forest in south-east Australia: implications for carbon accounting}, journal = {Biogeosciences}, volume = {12}, year = {2015}, month = {01/2015}, abstract = {

We estimated emissions of carbon, as equivalent CO2 (CO2e), from planned fires in four sites in a south-eastern Australian forest. Emission estimates were calculated using measurements of fuel load and carbon content of different fuel types, before and after burning, and determination of fuel-specific emission factors. Median estimates of emissions for the four sites ranged from 20 to 139 Mg CO2e ha-1. Variability in estimates was a consequence of different burning efficiencies of each fuel type from the four sites. Higher emissions resulted from more fine fuel (twigs, decomposing matter, near-surface live and leaf litter) or coarse woody debris (CWD; \> 25 mm diameter) being consumed. In order to assess the effect of declining information quantity and the inclusion of coarse woody debris when estimating emissions, Monte Carlo simulations were used to create seven scenarios where input parameters values were replaced by probability density functions. Calculation methods were (1) all measured data were constrained between measured maximum and minimum values for each variable; (2) as in (1) except the proportion of carbon within a fuel type was constrained between 0 and 1; (3) as in (2) but losses of mass caused by fire were replaced with burning efficiency factors constrained between 0 and 1; and (4) emissions were calculated using default values in the Australian National Greenhouse Accounts (NGA), National Inventory Report 2011, as appropriate for our sites. Effects of including CWD in calculations were assessed for calculation Method 1, 2 and 3 but not for Method 4 as the NGA does not consider this fuel type. Simulations demonstrate that the probability of estimating true median emissions declines strongly as the amount of information available declines. Including CWD in scenarios increased uncertainty in calculations because CWD is the most variable contributor to fuel load. Inclusion of CWD in scenarios generally increased the amount of carbon lost. We discuss implications of these simulations and how emissions from prescribed burns in temperate Australian forests could be improved.

}, doi = {10.5194/bg-12-257-2015}, url = {http://www.biogeosciences.net/12/257/2015/bg-12-257-2015-discussion.html}, author = {Malcolm Possell and Jenkins, Meaghan E. and Bell, Tina and Adams, Mark A.} } @article {bnh-3409, title = {Fire eases imbalances of nitrogen and phosphorus in woody plants}, journal = {Ecosystems}, volume = {18}, year = {2015}, month = {08/2015}, pages = {769-779}, chapter = {769}, abstract = {

Fires are widespread and can result in large nutrient losses from ecosystems simultaneous with pulses in nitrogen (N) and phosphorus (P) that can increase their availability to plants. Plant growth is frequently limited by N and P, and fire has the potential to enhance or moderate the magnitude of N and P limitation in plants with important consequences for long-term net primary productivity and global carbon cycling. We used meta-analysis to explore fire effects on N and P concentrations in aboveground plant biomass among a variety of plants and plant communities worldwide. We show that across all observations, fire enhanced N concentration in plants when N/P ratios in biomass were low, and enhanced P concentration in plants when biomass N/P ratios were high. P concentration increased particularly in woody plants. Furthermore, responses of the N/P ratio in woody plants were more flexible than in herbaceous plants so that fire eased N and P imbalances only in woody plants. Our results suggest that these changes in plant N and P in response to fire may help sustain net primary productivity and persistence of woody plants in fire-affected ecosystems worldwide.

}, doi = {10.1007/s10021-015-9861-1}, url = {https://link.springer.com/article/10.1007/s10021-015-9861-1}, author = {Dijkstra, F and Adams, Mark A.} } @article {bnh-3413, title = {Mapping spatial and temporal variation in tree water use with an elevation model and gridded temperature data}, journal = {Agricultural and Forest Meteorology}, volume = {200}, year = {2015}, month = {01/2015}, pages = {249-257}, chapter = {249}, abstract = {

Tree water use is a major component of the water balance in forested catchments of semi-arid areas, as more than 80\% of the incoming rainfall may be used by overstory trees. Managers are unable to easily predict water use and thus water yield, for the majority of eucalypt-dominated catchments in south-east Australia, owing to the variety of dominant and co-dominant species, their distributions with respect to landform, and the lack of species- and landform-specific knowledge of the regulation of water use. Moreover, the costs incurred to quantify input variables for available complex, process-based models, generally encourage finding alternative approaches. This study tested the adequacy of using just two easily measured variables for estimating rates of tree water use, using a model derived from data-learning techniques. The inputs are (1) measured daily atmospheric demand for water and (2) potential incoming radiation derived from surface topography and solar declination. Artificial neural networks (ANNs) and genetic programming (GP) models were trained and validated using in situ observations of vapour pressure deficit (VPD) and estimates of potential solar radiation (Qpot), for a period of two years, at each of 10 forest stands across the high country of the states of New South Wales and Victoria. The models were tested using a random 50\% of the collected data that was independent, i.e. not used in model development.

Atmospheric demand was selected because it strongly affects tree water use irrespective of site and species. Potential solar radiation was selected as a proxy for radiation, because it is relatively easy to estimate for any location for which elevation data are available in digital format, and since radiation strongly controls photosynthesis (through stomatal behaviour) and thermal balance.

Genetic programming resulted in models better able to predict rates of sap flux. A selected GP model was able to describe the relationship between tree sap flux, VPD, and potential radiation with good accuracy, and was used to map tree water use across the catchment.

}, doi = {10.1016/j.agrformet.2014.09.027}, url = {http://www.sciencedirect.com/science/article/pii/S0168192314002512}, author = {Gharun, Mana and Turnbull, Tarryn L. and Joseph Henry and Adams, Mark A.} } @article {bnh-3412, title = {Short-term forecasting of water yield from forested catchments after bushfire: a case study from south-east Australia}, journal = {Water}, volume = {7}, year = {2015}, month = {02/2015}, pages = {599-614}, chapter = {599}, abstract = {

Forested catchments in southeast Australia play an important role in supplying water to major cities. Over the past decades, vegetation cover in this area has been affected by major bushfires that in return influence water yield. This study tests methods for forecasting water yield after bushfire, in a forested catchment in southeast Australia. Precipitation and remotely sensed Normalized Difference Vegetation Index (NDVI) were selected as the main predictor variables. Cross-correlation results show that water yield with time lag equal to 1 can be used as an additional predictor variable. Input variables and water yield observations were set based on 16-day time series, from 20 January 2003 to 20 January 2012. Four data-driven models namely Non-Linear Multivariate Regression (NLMR), K-Nearest Neighbor (KNN), non-linear Autoregressive with External Input based Artificial Neural Networks (NARX-ANN), and Symbolic Regression (SR) were employed for this study. Results showed that NARX-ANN outperforms other models across all goodness-of-fit criteria. The Nash-Sutcliffe efficiency (NSE) of 0.90 and correlation coefficient of 0.96 at the training-validation stage, as well as NSE of 0.89 and correlation coefficient of 0.95 at the testing stage, are indicative of potentials of this model for capturing ecological dynamics in predicting catchment hydrology, at an operational level.

}, doi = {10.3390/w7020599}, url = {http://www.mdpi.com/2073-4441/7/2/599}, author = {Gharun, Mana and Mohammad Amzi and Adams, Mark A.} } @article {bnh-3414, title = {Stomatal structure and physiology do not explain differences in water use among montane eucalypts}, journal = {Oecologia}, volume = {177}, year = {2015}, month = {04/2015}, pages = {1171-1181}, chapter = {1171}, abstract = {

Understanding the regulation of water use at the whole-tree scale is critical to advancing the utility of physiological ecology, for example in its role in predictive hydrology of forested catchments. For three eucalypt species that dominate high-elevation catchments in south-eastern Australia, we examined if whole-tree water use could be related to three widely discussed regulators of water use: stomatal anatomy, sensitivity of stomata [i.e. stomatal conductance (gs)] to environmental influences, and sapwood area. While daily tree water use varied sixfold among species, sap velocity and sapwood area varied in parallel. Combined, stomatal structure and physiology could not explain differences in species-specific water use. Species which exhibited the fastest (Eucalyptus delegatensis) and slowest (Eucalyptus pauciflora) rates of water use both exhibited greater capacity for physiological control of\ gs[indicated by sensitivity to vapour pressure deficit (VPD)] and a reduced capacity to limit\ gsanatomically [indicated by greater potential\ gs\ (gmax)]. Conversely,\ gs\ was insensitive to VPD and\ gmax\ was lowest for\ Eucalyptus radiata, the species showing intermediate rates of water use. Improved knowledge of stomatal anatomy will help us to understand the capacity of species to regulate leaf-level water loss, but seems likely to remain of limited use for explaining rates of whole-tree water use in montane eucalypts at the catchment scale.

}, doi = {10.1007/s00442-015-3252-3}, url = {https://link.springer.com/article/10.1007/s00442-015-3252-3}, author = {Gharun, Mana and Turnbull, Tarryn L. and Sebastian Pfautsch and Adams, Mark A.} } @article {BF-3749, title = {A critical review of the science underpinning fire management in the high altitude ecosystems of south-eastern Australia}, journal = {Forest Ecology and Management}, year = {2013}, month = {1/2013}, abstract = {We reviewed the scope and quality of published literature relevant to management of the risk of fire and accompanying risks to ecological values, in the vegetation types (mostly forests and woodlands, but including grasslands and herbfields) of the High Country (>750m asl) of south-eastern Australia. Our analysis of quality suggests the published science has improved markedly over the past 60years. That said, there is insufficient data on any subject for a formal meta-analysis. Much of the work published in the past may not pass peer-review today and there are few on-going, long-term studies of the effects of management of a standard that might meet this test. Given the limited number of recent studies of higher quality, this raises the question as to an acceptable standard of evidence for policy making for future management of native ecosystems. With the exception of grassland, feldmark and herbfield types, available data shows that all High Country vegetation types produce fuel loads >10tha-1 in less than 10years after fire, notwithstanding the different fire risk associated with each fuel type (e.g. grasses vs woody shrubs vs forest litter), suggesting that fuel management will continue to be an issue for land managers. The varied and inconsistent history of past land management makes the interpretation of short-term studies difficult. Highlights of past research include the detailed studies of Costin and co-workers that were exemplary for their time in their use of replicated treatments, adequate controls and significant periods of study (4+ year). Recent studies of effects of fire on water yield and quality that are based on well-replicated studies, again over substantial periods of time, are helping fill knowledge gaps. Many other ecological topics of interest to land managers remain poorly understood, including: long-term vegetation and fuel dynamics, nutrient balance, weed invasions and further aspects of hydrology. If high altitude catchments are to be managed effectively, we must improve our understanding the dynamics of fuel loads, vegetation, nutrients and water supply through collection of long-term quantitative data. }, issn = {03781127}, doi = {10.1016/j.foreco.2012.10.042}, author = {Adams, Mark A. and Cunningham, Shaun C. and Taranto, MT} } @article {BF-3122, title = {Differences in water use between mature and post-fire regrowth stands of subalpine Eucalyptus delegatensis R. Baker}, journal = {Forest Ecology and Management}, volume = {270}, year = {2012}, month = {4/2012}, pages = {1 - 10}, abstract = {We estimated plot level water use from sap flux measurements over a 9-month period, in post-fire regrowth and mature plots of Eucalyptus delegatensis R. Baker (Alpine ash) in high elevation catchments near Falls Creek, Victoria, Australia, seven years after a major stand-replacing bushfire. Water use was more than double (460 {\textpm} 100 mm year-1 more) in regrowth as compared to mature plots, whereas sap flux was similar between age classes. This difference in water use reflected 72\% greater sapwood area index and 35\% greater leaf area index in regrowth than in mature plots. A small part of the difference in water use can be attributed to nocturnal transpiration, which was greater in regrowth than in mature plots (10.3 {\textpm} 0.8\% vs 7.3 {\textpm} 0.8\% of diel totals). As evaporative demand was 41\% greater in mature than in regrowth plots, these data suggest mean transpiration rate and stomatal conductance per unit leaf area were approximately 1.6 and 2.3 times greater, respectively, in the regrowth. However, mid-day leaf water potential and photosynthetic capacity were similar in both age classes. Evaporative demand was the primary environmental driver of water use in all cases, whereas soil moisture was not a strong driver of either water use or canopy conductance (estimated as sap flux/evaporative demand). Together, our results suggest (a) stand water use rapidly recovers after fire in these high elevation forests and quickly surpasses rates in mature stands, confirming projections by Kuczera (1987) for lower-elevation Mountain Ash (E. regnans) forests and highlighting the potential impact of tree water use on water yield in the first decade of forest regeneration after fires, and (b) stomatal conductance and sapwood area/leaf area ratio are both less in tall, older Alpine ash trees, whereas leaf water status and photosynthetic capacity appear to be sustained {\textendash} consistent with predictions from optimisation theory but not Pipe-Model Theory.}, issn = {03781127}, doi = {10.1016/j.foreco.2012.01.008}, author = {Buckley, TN and Turnbull, Tarryn L. and Sebastian Pfautsch and Gharun, Mana and Adams, Mark A.} } @article {BF-3185, title = {Simple models for stomatal conductance derived from a process model: cross-validation against sap flux data.}, journal = {Plant, Cell \& Environment}, year = {2012}, month = {04/2012}, pages = {no - no}, abstract = {Representation of stomatal physiology in models of plant-atmosphere gas exchange is minimal, and direct application of process-based models is limited by difficulty of parameter estimation. We derived simple models of stomatal conductance from a recent process-based model, and cross-validated them against measurements of sap flux (176-365 days in length) in 36 individual trees of two age classes for two Eucalyptus species across seven sites in the mountains of southeastern Australia. The derived models-which are driven by irradiance and evaporative demand and have 2-4 parameters that represent sums and products of biophysical parameters in the process model-reproduced a median 83-89\% of observed variance in half-hourly and diurnally averaged sap flux, and performed similarly whether fitted using a random sample of all data or using one month of data from spring or autumn. Our simple models are an advance in predicting plant water use because their parameters are transparently related to reduced processes and properties, enabling easy accommodation of improved knowledge about how those parameters respond to environmental change and differ among species.}, doi = {10.1111/j.1365-3040.2012.02515.x}, author = {Buckley, TN and Turnbull, Tarryn L. and Adams, Mark A.} } @book {BF-2924, title = {Burning Issues}, year = {2011}, publisher = {CSIRO Publishing}, organization = {CSIRO Publishing}, abstract = {Southern Australia is one of the three most fire-prone areas on Earth. After more than a century of urban growth and valiant efforts to {\textquoteleft}tame{\textquoteright} the bush, recent decades have seen more people moving back onto the fringe or into the middle of this volatile landscape. As this movement has intensified, so has the debate on how to best protect life and property from the ever-present bushfire threat. A long-running drought and a predicted warming climate have ensured that bushfire is a dominant factor in our nation{\textquoteright}s long-term planning. Following the tragic Victorian Black Saturday fires in 2009, a much greater urgency now confronts policy makers, land and fire managers and communities living in bushfire areas. This has led to a call for a single, simple answer on fuel reduction burning to reduce the bushfire risk. Burning Issues explains that this is a complex issue without such a simple answer. The book gives an account of the role of fire in Australia{\textquoteright}s ecosystems, how we have to accept and live with fire, and how we can manage fire both for safety and for diversity. It aims to change people{\textquoteright}s attitudes to fire, and to be influential in encouraging changes in land management by government agencies. }, isbn = {9780643094437}, url = {http://www.publish.csiro.au/nid/201/pid/6421.htm }, author = {Adams, Mark A. and Peter Attiwill} } @article {BF-2587, title = {Respiratory quotients and Q10 of soil respiration in sub-alpine Australia reflect influences of vegetation types}, journal = {Soil Biology and Biochemistry}, year = {2011}, month = {3/2011}, abstract = {Identifying and quantifying attributes that help predict rates of heterotrophic soil respiration is a key issue. Similarly, assessing the temperature sensitivity (Q10) of soil C is critical to establishing if increases in Mean Annual Temperature will serve to further increase atmospheric CO2. Using organic soils from three sub-alpine communities that differ significantly in structure, species composition and productivity, we measured the respiratory quotient (RQ = rates of CO2 efflux/rates of O2 uptake) and temperature sensitivity of heterotrophic respiration during long-term (120 days) incubation. As a directly measurable parameter, RQ is free of empirical assumptions and provides an additional tool that can be used in conjunction with constants derived from fitted Arrhenius or exponential equations, to help understand shifts in microbial use of C substrates and how changes in vegetation might affect soil processes. Q10 did not change significantly over the course of a 120-day incubation for any of our studied soils. RQs varied with vegetation type and were consistently lower in grassland soils than woodland soils. RQs also varied during long-term incubations and declined consistently with time for grassland soils. RQs declined towards the end of the 120-day incubation for woodland soils. The generally low Ea for these soils from sub-alpine vegetation types in Australia, and the fairly rapid decline in RQ during incubation, suggest the likely greater temperature sensitivity of recalcitrant C relative to labile C could provide a strong positive feedback to increases in Mean Annual Temperature.}, doi = {10.1016/j.soilbio.2011.02.017}, author = {Jenkins, Meaghan E. and Adams, Mark A.} } @article {BF-2407, title = {Eucalypt smoke and wildfires: Temperature dependent emissions of biogenic volatile organic compounds}, journal = {International Journal of Mass Spectrometry}, volume = {279}, year = {2009}, month = {01/2009}, pages = {126 - 133}, abstract = {Eucalypt contributions to biogenic sources of volatile organic compounds (VOCs) in Australia are estimated at teragram (Tg = 1012 g) amounts each year. Biogenic VOCs include plant-specific isoprenoids (isoprene and a range of terpenes) and other reactive organic compounds (i.e., acids, aldehydes and ketones). Atmospheric reactions of VOCs are numerous and many have significant environmental impact. Wildfires increase both the amounts of VOCs released and the complexity of their reactions. Proton-transfer reaction mass spectrometry (PTR-MS), gas chromatography mass spectrometry (GCMS) and direct analysis in real time (DART) mass spectrometry were applied to analyze release of VOCs as a function of temperatures ranging from ambient to combustion. PTR-MS enabled trace level analysis of VOCs from a complex forest atmosphere and revealed the release of terpenes associated with leaf damage during a storm. Temperature profile studies revealed ion abundances (i.e., emissions of VOCs) could be correlated with boiling points and vapor pressures of specific compounds. PTR-MS analysis of VOCs resulting from heating fresh leaf (E. grandis) material suggested that emissions of protonated methanol (m/z 33) and protonated acetaldehyde (m/z 45) were greatest at not, vert, similar60 {\textdegree}C while m/z 137 and 153 (associated with a series of terpenes) showed monotonic increases in ion abundance over a wide temperature range from ambient to 200 {\textdegree}C. GCMS analysis of fresh and senescent leaves of E. grandis showed that a series of VOCs (ethylvinylketone, diethylketone, 2-ethylfuran, hexanal and hexenals) are present only in fresh leaves while several terpenes (α and β pinenes, α-phellandrene, eucalyptol, γ-terpinene) were common in both. DART analysis of fresh leaf and stem of E. sideroxylon identified tissue-specific VOCs (e.g., methanol and ethanol were more abundant in stems). PTR-MS combustion studies of senescent leaves (E. grandis) identified two distinct, temperature-dependent VOC compositions. Before the appearance of smoke, the composition of VOCs remained consistent and correlated well with various naturally occurring isoprenoids, as observed in temperature profile studies. Sampling of eucalypt smoke suggested ions (m/z 75, 85, 87, 99, 111 and 125) correlated with protonated mass of oxygenated aldehydes, ketones, furans and substituted benzenes, and were due to pyrolysis of polycarbohydrates (cellulose and lignin) that are common in many types of wood.}, doi = {10.1016/j.ijms.2008.10.027}, author = {Maleknia, Simin D. and Bell, Tina and Adams, Mark A.} } @article {BF-2400, title = {Premature Decline of Eucalyptus and Altered Ecosystem Processes in the Absence of Fire in Some Australian Forests}, journal = {The Botanical Review}, volume = {75}, year = {2009}, month = {6/2009}, pages = {191 - 202}, abstract = {We propose a model of {\textquoteleft}premature tree decline{\textquoteright} whereby an absence of fire hastens the mortality of overstorey eucalypts in some forests. This model is relevant to some temperate Australian forests in which fire regimes have shifted from relatively frequent before European settlement to infrequent following settlement. The increased development of midstorey vegetation and litter accumulation has occurred since European settlement in some specific examples of Australian forests and woodlands. Our model proposes that in the long absence of fire: 1. midstorey vegetation reduces the availability of soil water for eucalypts and; 2. Eucalypts have less access to P and/or cations as these elements become locked up in soil, litter and midstorey biomass. We highlight important knowledge gaps and argue that research into ecological burning, for eucalypt health and other values such as biodiversity, is urgently required. }, doi = {10.1007/s12229-009-9027-y}, author = {Close, DC and Davidson, N. J. and Johnson, DW and Abrams, MD and Hart, SC and Lunt, ID and Archibald, RD and Horton, Bryony M. and Adams, Mark A.} } @article {BF-2408, title = {Temperature-dependent release of volatile organic compounds of eucalypts by direct analysis in real time (DART) mass spectrometry}, journal = {Rapid Communications in Mass Spectrometry}, volume = {23}, year = {2009}, month = {08/2009}, pages = {2241 - 2246}, abstract = {A method is described for the rapid identification of biogenic, volatile organic compounds (VOCs) emitted by plants, including the analysis of the temperature dependence of those emissions. Direct analysis in real time (DART) enabled ionization of VOCs from stem and leaf of several eucalyptus species including E. cinerea, E. citriodora, E. nicholii and E. sideroxylon. Plant tissues were placed directly in the gap between the DART ionization source skimmer and the capillary inlet of the time-of-flight (TOF) mass spectrometer. Temperature-dependent emission of VOCs was achieved by adjusting the temperature of the helium gas into the DART ionization source at 50, 100, 200 and 300{\textdegree}C, which enabled direct evaporation of compounds, up to the onset of pyrolysis of plant fibres (i.e. cellulose and lignin). Accurate mass measurements facilitated by TOF mass spectrometry provided elemental compositions for the VOCs. A wide range of compounds was detected from simple organic compounds (i.e. methanol and acetone) to a series of monoterpenes (i.e. pinene, camphene, cymene, eucalyptol) common to many plant species, as well as several less abundant sesquiterpenes and flavonoids (i.e. naringenin, spathulenol, eucalyptin) with antioxidant and antimicrobial properties. The leaf and stem tissues for all four eucalypt species showed similar compounds. The relative abundances of methanol and ethanol were greater in stem wood than in leaf tissue suggesting that DART could be used to investigate the tissue-specific transport and emissions of VOCs}, doi = {10.1002/rcm.4133}, author = {Maleknia, Simin D. and Vail, Teresa M. and Cody, Robert B. and Sparkman, David O. and Bell, Tina and Adams, Mark A.} } @book {BF-2375, title = {Developments in Environmental SciencesWildland Fires and Air PollutionChapter 14 Smoke from Wildfires and Prescribed Burning in Australia: Effects on Human Health and Ecosystems}, volume = {8}, year = {2008}, pages = {289 - 316}, publisher = {Elsevier}, organization = {Elsevier}, abstract = {Much of Australia is seasonally hot and dry, and fuel beds can become very flammable. Biomass burning ranges from annual savanna fires in the north to sporadic but extensive forest fires in the south. In addition, prescribed burning (the controlled application of fire) is being used more frequently as a means of reducing fuel loads, for maintenance of plant and animal biodiversity and in forestry practices. Despite this and in comparison to the Northern Hemisphere, there are few Australian studies of the production or composition of smoke from biomass burning. There is also relatively minimal Australian literature detailing the effect of wildfire smoke on human health and flora and fauna. Most of the literature dealing with smoke and human health issues in Australia outline epidemiological studies that document the incidence of hospital visits and admissions during wildfire events. The causal link between smoke and respiratory illness is yet to be established. The bulk of the publications dealing with ecological effects of smoke are concerned with germination of seed, with little information available on the direct effects of components of smoke on the physiology and biochemistry of plants, animals, invertebrates, or microorganisms. We will outline the knowledge of emissions and effects of smoke from prescribed and wildland fire in Australia on human health and the environment and will indicate potential areas for future research. In addition, a large proportion of the vegetation of Australia is composed of forests dominated by native species of Eucalyptus and Acacia, while large expanses of plantations are dominated by single species of Eucalyptus, and the production of volatile organic compounds (VOCs) by such vegetation is substantial. Thus, we will also outline an emerging research area in which the links among the production of VOCs by native Australian species, environmental conditions, and VOCs found in smoke produced from burning native vegetation are explored.}, doi = {10.1016/S1474-8177\%2808\%2900014-4}, author = {Bell, Tina and Adams, Mark A.} } @article {BF-2372, title = {Harnessing forest ecological sciences in the service of stewardship and sustainability A perspective from {\textquoteleft}down-under{\textquoteright}}, journal = {Forest Ecology and Management}, volume = {256}, year = {2008}, month = {11/2008}, pages = {1636 - 1645}, abstract = {Australia{\textquoteright}s native forests are predominantly Crown land, managed by the States. Regional Forest Agreements between four of the States and the Federal Government (1997{\textendash}2001) resulted in a 36\% increase in the area of conservation reserves and a 15\% decrease in area of multiple-use (including timber harvesting) forests. The limited acceptance of timber harvesting in native forests, together with the rapid expansion of hardwood plantations, has diverted research focus away from native forests. Recent events including a prolonged drought and two forest fires totaling more than 3 million ha should have stimulated research in native forests on the effects of fire on ecosystem processes, on the management of fire and on management of water catchments; fires, far more than logging, are shaping our native forests in recent times. In particular, the use of prescribed fire to reduce fuels has decreased. We argue that Australian research effort in native eucalypt forests is lacking in two key areas {\textendash} the effects of fire on carbon storage in forests and soils, and on the management of water yield from forested catchments. The results of forest research are variously published in the scientific journals, and increasingly in consultancy reports to governments or a to a range of organizations and industries. The question of who does the harnessing of knowledge coming from the science of forest ecology is compounded by constant changes in both political and management arrangements. If forest science is to assume a greater role in politics and forest management in Australia, scientists must enter the foray, using the fighting words of politics rather than maintaining the protective mantle of neutrality. With research in native forests being continually downgraded at both State and Federal levels, we take a somewhat less than optimistic view about how well ecological sciences will be harnessed in the service of forest stewardship and sustainability in Australia.}, doi = {10.1016/j.foreco.2008.07.024}, author = {Peter Attiwill and Adams, Mark A.} } @article {BF-1096, title = {Impact of volatile organic compounds from wildfires on crop production and quality}, journal = {Aspects of Applied Biology }, number = {88}, year = {2008}, month = {12/01/2008}, pages = {93-97}, author = {Maleknia, Simin D. and Adams, Mark A.} } @book {BF-1095, title = {Smoke from wildfires and prescribed burning in Australia: effects on human health and ecosystems}, series = {Forest Fires and Air Pollution Issues, Developments in Environmental Science Series}, year = {2008}, month = {accepted April 2}, publisher = {Elsevier Ltd}, organization = {Elsevier Ltd}, isbn = {978-0-08-055609-3}, url = {www.elsevier.com/wps/find/bookdescription.cws_home/716396/description$\#$description}, author = {Bell, Tina and Adams, Mark A.} } @article {BF-2363, title = {PTR-MS analysis of reference and plant-emitted volatile organic compounds}, journal = {International Journal of Mass Spectrometry}, volume = {262}, year = {2007}, month = {05/2007}, pages = {203 - 210}, abstract = {Proton transfer reaction-mass spectrometry (PTR-MS) was applied to the analysis of a series of volatile organic compounds (VOCs) that emit from various plants. These include a group of alcohols (methanol, ethanol and butanol), carbonyl-containing compounds (acetic acid, acetone and benzaldehyde), isoprene, acetonitrile, tetrahydrofuran (THF), pyrazine, toluene and xylene and a series of terpenes (p-cymene, camphene, 2-carene, limonene, β-myrcene, α-pinene, β-pinene, γ-tepinene and terpinolene) and oxygen-containing terpenes (1,8-cineole and linalool). These mass spectral data were compared to an electron ionization (EI) database identifying that not all PTR-MS fragments were common to EI. PTR-MS studies of these reference compounds were utilized to identify VOCs emitted from Eucalyptus grandis leaf at a temperature range of 30{\textendash}100 {\textdegree}C. In addition to protonated molecules (M + H)+, abundant proton-bound dimers or trimers were detected for alcohols, acetone, acetonitrile and THF. Abundant fragment ions attributed to the loss of water from these proton-bound clusters were also observed. The stability of butyl (C4H9+ m/z 57) and acetyl (CH3CO+ m/z 43) fragment ions directed the proton-transfer reactions of butanol and acetic acid. Abundant (M + H)+ ions were detected for pyrazine, THF, toluene and xylene, as well as for all terpenes except those containing oxygen. For linalool and 1,8-cineole, the loss of water generated an abundant fragment ion at m/z 137. PTR-MS fragmentation patterns for terpenes were proposed for m/z 81 (C6H9+), 93 (C7H9+), 95 (C7H11+), 107 (C8H11+), 109 (C8H13+), 119 (C9H11+), 121 (C9H13+) and 137 (loss of water for oxygen-containing terpenes; C10H17+). The relative abundances of (M + H)+ and fragments for all terpenes (except linalool) were dependent on the drift tube voltage and the optimum voltage for detection of molecular ions was different for various terpenes.}, doi = {10.1016/j.ijms.2006.11.010}, author = {Maleknia, Simin D. and Bell, Tina and Adams, Mark A.} } @article {BF-1172, title = {Sap flow in Australian subalpine forests \& woodlands suggests nocturnal transpiration contributes significantly to stand water balance and is inversely related to soil moisture.}, journal = {Plant, Cell \& Environment}, year = {2007}, note = {37 pgs}, author = {Buckley, TN and Turnbull, Tarryn L. and Sebastian Pfautsch and Adams, Mark A.} }