Carbon stocks and stability are diminished by short-interval wildfires in fire-tolerant eucalypt forests

2022 ◽  
Vol 505 ◽  
pp. 119919
Author(s):  
Thomas A. Fairman ◽  
Craig R. Nitschke ◽  
Lauren T. Bennett
2016 ◽  
Vol 25 (8) ◽  
pp. 831 ◽  
Author(s):  
Thomas A. Fairman ◽  
Craig R. Nitschke ◽  
Lauren T. Bennett

In temperate Australia, wildfires are predicted to be more frequent and severe under climate change. This could lead to marked changes in tree mortality and regeneration in the region’s predominant eucalypt forests, which have been burned repeatedly by extensive wildfires in the period 2003–14. Recent studies have applied alternative stable state models to select ‘fire sensitive’ forest types, but comparable models have not been rigorously examined in relation to the more extensive ‘fire tolerant’ forests in the region. We review the effects of increasing wildfire frequency on tree mortality and regeneration in temperate forests of Victoria, south-eastern Australia, based on the functional traits of the dominant eucalypts: those that are typically killed by wildfire to regenerate from seed (‘obligate seeders’) and those that mostly survive to resprout (‘resprouters’). In Victoria, over 4.3 million ha of eucalypt forest has been burned by wildfire in the last decade (2003–14), roughly equivalent to the cumulative area burned in the previous 50 years (1952–2002; 4.4 million ha). This increased wildfire activity has occurred regardless of several advancements in fire management, and has resulted in over 350 000 ha of eucalypt forest being burned twice or more by wildfire at short (≤11 year) intervals. Historical and recent evidence indicates that recurrent wildfires threaten the persistence of the ‘fire sensitive’ obligate seeder eucalypt forests, which can facilitate a shift to non-forest states if successive fires occur within the trees’ primary juvenile period (1–20 years). Our review also highlights potential for structural and state changes in the ‘fire tolerant’ resprouter forests, particularly if recurrent severe wildfires kill seedlings and increase tree mortality. We present conceptual models of state changes in temperate eucalypt forests with increasing wildfire frequency, and highlight knowledge gaps relating to the development and persistence of alternative states driven by changes in fire regimes.


2021 ◽  
Vol 5 (1) ◽  
pp. 19
Author(s):  
Cátia Magro ◽  
Marcelo Morais ◽  
Paulo A. Ribeiro ◽  
Susana Sério ◽  
Pedro Vieira ◽  
...  

Recent research on volatile organic compounds (VOC) released by the heated vegetation has shown that, under specific conditions (e.g., extreme heat, humidity, wind, and topography), VOC might foster wildfire ignition sources and explain sudden changes in fire behavior, particularly in the most susceptible and flammable forests (eucalypt forests). This work aims to develop an electronic nose (e-nose) based on a sensor’s array to monitor the concentration of eucalyptol, the major VOC compound of the Eucalyptus globulus tree. The detection of this target compound was achieved by measuring the impedance spectra of layer-by-layer developed thin films based on polyethyleneimine, poly(allylamine hydrochloride), and graphene oxide, by injecting the analyte into a custom-made vacuum chamber system. The obtained results were analyzed by the principal component analysis method. The developed e-nose sensor was able to distinguish different concentrations in a range from 411 to 1095 ppm.


2019 ◽  
Vol 231 ◽  
pp. 59-65 ◽  
Author(s):  
Thomas A. Fairman ◽  
Lauren T. Bennett ◽  
Craig R. Nitschke
Keyword(s):  

2004 ◽  
Vol 36 (11) ◽  
pp. 1707-1717 ◽  
Author(s):  
Anders Michelsen ◽  
Michael Andersson ◽  
Michael Jensen ◽  
Annelise Kjøller ◽  
Menassie Gashew

2012 ◽  
Vol 21 (6) ◽  
pp. 629 ◽  
Author(s):  
R. A. Bradstock ◽  
M. M. Boer ◽  
G. J. Cary ◽  
O. F. Price ◽  
R. J. Williams ◽  
...  

Prescribed fire can potentially reduce carbon emissions from unplanned fires. This potential will differ among ecosystems owing to inherent differences in the efficacy of prescribed burning in reducing unplanned fire activity (or ‘leverage’, i.e. the reduction in area of unplanned fire per unit area of prescribed fire). In temperate eucalypt forests, prescribed burning leverage is relatively low and potential for mitigation of carbon emissions from unplanned fires via prescribed fire is potentially limited. Simulations of fire regimes accounting for non-linear patterns of fuel dynamics for three fuel types characteristic of eucalypt forests in south-eastern Australia supported this prediction. Estimated mean annual fuel consumption increased with diminishing leverage and increasing rate of prescribed burning, even though average fire intensity (prescribed and unplanned fires combined) decreased. The results indicated that use of prescribed burning in these temperate forests is unlikely to yield a net reduction in carbon emissions. Future increases in burning rates under climate change may increase emissions and reduce carbon sequestration. A more detailed understanding of the efficacy of prescribed burning and dynamics of combustible biomass pools is required to clarify the potential for mitigation of carbon emissions in temperate eucalypt forests and other ecosystems.


2019 ◽  
Vol 116 (23) ◽  
pp. 11319-11328 ◽  
Author(s):  
Monica G. Turner ◽  
Kristin H. Braziunas ◽  
Winslow D. Hansen ◽  
Brian J. Harvey

Subalpine forests in the northern Rocky Mountains have been resilient to stand-replacing fires that historically burned at 100- to 300-year intervals. Fire intervals are projected to decline drastically as climate warms, and forests that reburn before recovering from previous fire may lose their ability to rebound. We studied recent fires in Greater Yellowstone (Wyoming, United States) and asked whether short-interval (<30 years) stand-replacing fires can erode lodgepole pine (Pinus contortavar.latifolia) forest resilience via increased burn severity, reduced early postfire tree regeneration, reduced carbon stocks, and slower carbon recovery. During 2016, fires reburned young lodgepole pine forests that regenerated after wildfires in 1988 and 2000. During 2017, we sampled 0.25-ha plots in stand-replacing reburns (n= 18) and nearby young forests that did not reburn (n= 9). We also simulated stand development with and without reburns to assess carbon recovery trajectories. Nearly all prefire biomass was combusted (“crown fire plus”) in some reburns in which prefire trees were dense and small (≤4-cm basal diameter). Postfire tree seedling density was reduced sixfold relative to the previous (long-interval) fire, and high-density stands (>40,000 stems ha−1) were converted to sparse stands (<1,000 stems ha−1). In reburns, coarse wood biomass and aboveground carbon stocks were reduced by 65 and 62%, respectively, relative to areas that did not reburn. Increased carbon loss plus sparse tree regeneration delayed simulated carbon recovery by >150 years. Forests did not transition to nonforest, but extreme burn severity and reduced tree recovery foreshadow an erosion of forest resilience.


1990 ◽  
Vol 78 (1) ◽  
pp. 1-1
Author(s):  
M. J. Brown

From this issue, Clinical Science will increase its page numbers from an average of 112 to 128 per monthly issue. This welcome change — equivalent to at least two manuscripts — has been ‘forced’ on us by the increasing pressure on space; this has led to an undesirable increase in the delay between acceptance and publication, and to a fall in the proportion of submitted manuscripts we have been able to accept. The change in page numbers will instead permit us now to return to our exceptionally short interval between acceptance and publication of 3–4 months; and at the same time we shall be able not only to accept (as now) those papers requiring little or no revision, but also to offer hope to some of those papers which have raised our interest but come to grief in review because of a major but remediable problem. Our view, doubtless unoriginal, has been that the review process, which is unusually thorough for Clinical Science, involving a specialist editor and two external referees, is most constructive when it helps the evolution of a good paper from an interesting piece of research. Traditionally, the papers in Clinical Science have represented some areas of research more than others. However, this has reflected entirely the pattern of papers submitted to us, rather than any selective interest of the Editorial Board, which numbers up to 35 scientists covering most areas of medical research. Arguably, after the explosion during the last decade of specialist journals, the general journal can look forward to a renaissance in the 1990s, as scientists in apparently different specialities discover that they are interested in the same substances, asking similar questions and developing techniques of mutual benefit to answer these questions. This situation arises from the trend, even among clinical scientists, to recognize the power of research based at the cellular and molecular level to achieve real progress, and at this level the concept of organ-based specialism breaks down. It is perhaps ironic that this journal, for a short while at the end of the 1970s, adopted — and then discarded — the name of Clinical Science and Molecular Medicine, since this title perfectly represents the direction in which clinical science, and therefore Clinical Science, is now progressing.


Ob Gyn News ◽  
2011 ◽  
Vol 46 (4) ◽  
pp. 14
Author(s):  
DOUG BRUNK
Keyword(s):  

Author(s):  
Yuhong Jiang

Abstract. When two dot arrays are briefly presented, separated by a short interval of time, visual short-term memory of the first array is disrupted if the interval between arrays is shorter than 1300-1500 ms ( Brockmole, Wang, & Irwin, 2002 ). Here we investigated whether such a time window was triggered by the necessity to integrate arrays. Using a probe task we removed the need for integration but retained the requirement to represent the images. We found that a long time window was needed for performance to reach asymptote even when integration across images was not required. Furthermore, such window was lengthened if subjects had to remember the locations of the second array, but not if they only conducted a visual search among it. We suggest that a temporal window is required for consolidation of the first array, which is vulnerable to disruption by subsequent images that also need to be memorized.


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