Publications by category
Books
Belcher CM (2013). Fire Phenomena and the Earth System: an Interdisciplinary Guide to Fire Science., Wiley.
Journal articles
New SL, Belcher C, Hudspith VA, Gallego-Sala AV (In Press). Holocene fire history: can evidence of peat burning be found in the palaeo-archive?.
Mires and Peat,
18, 1-11.
Abstract:
Holocene fire history: can evidence of peat burning be found in the palaeo-archive?
Smouldering wildfires in peatlands have the potential to release substantial amounts of the carbon currently sequestered in these ecosystems. However, past studies of Holocene fire history in peatlands have given little consideration to the identification of evidence left behind after peat burning, or to charring of the peat matrix. In this study, modern peat samples from peatlands across the globe were charred in order to assess the identifiable characteristics of charred peat. On this basis we believe that charred aggregates of partially decayed organics which can be identified in cores provide clear evidence that the peat matrix itself burned. A range of
charred morphotypes could be found throughout a 2 m peat core from
and we are able to identify charred partially decayed aggregates that appeared to correspond with peaks in fire activity on the bog. These may reflect periods when surface fires ignited the peat surface below, or when the radiant heat from surface fires was sufficient to pyrolyse the surface peat. We conclude that it is possible to find evidence of peat burning in the palaeo-archive, and that future studies should begin to document the occurrence of charred particles so that the discipline can begin to build a picture of possible past peat fire
activity.
Abstract.
Belcher CM (In Press). The influence of leaf morphology on litter flammability and
its utility for interpreting palaeofire. Philosophical Transactions of the Royal Society of London: Biological Sciences
Linley GD, Jolly CJ, Doherty TS, Geary WL, Armenteras D, Belcher CM, Bliege Bird R, Duane A, Fletcher M-S, Giorgis MA, et al (2022). What do you mean, 'megafire'?.
GLOBAL ECOLOGY AND BIOGEOGRAPHY,
31(10), 1906-1922.
Author URL.
Belcher CM, New SL, Gallagher MR, Grosvenor MJ, Clark K, Skowronski NS (2021). Bark charcoal reflectance may have the potential to estimate the heat delivered to tree boles by wildland fires.
INTERNATIONAL JOURNAL OF WILDLAND FIRE,
30(5), 391-397.
Author URL.
Denis EH, Maibauer BJ, Bowen GJ, Jardine PE, Harrington GJ, Baczynski AA, McInerney FA, Collinson ME, Belcher CM, Wing SL, et al (2021). Decreased soil carbon in a warming world: Degraded pyrogenic carbon during the Paleocene-Eocene Thermal Maximum, Bighorn Basin, Wyoming.
Earth and Planetary Science Letters,
566Abstract:
Decreased soil carbon in a warming world: Degraded pyrogenic carbon during the Paleocene-Eocene Thermal Maximum, Bighorn Basin, Wyoming
Global warming will likely perturb carbon storage and cycling throughout many components of the exogenic carbon cycle, but its net impact on the long-term fate of organic carbon stabilized in soils is unclear. Abrupt warming during the Paleocene-Eocene Thermal Maximum (PETM) profoundly altered vegetation and hydrologic patterns globally. To assess the consequences for soil carbon in a mid-latitude region we measured total organic carbon (%TOC), polycyclic aromatic hydrocarbons (PAHs), charcoal, and sporomorphs (pollen and spores) at two paleo-floodplain depositional sites in the Bighorn Basin, Wyoming, USA. At both sites %TOC, PAHs, charcoal, and sporomorphs declined during the PETM. The decline in pyrogenic carbon, which is more severe than the decline in %TOC, is consistent with isotopic and fossil evidence for degradation of labile organic compounds and preservation of highly refractory allochthonous organic carbon. The severe loss of less-labile contemporaneous PETM (autochthonous) soil carbon, illustrated by the fate of pyrogenic carbon, indicates intensified rates of organic matter decay during the PETM. Because of the highly degraded signature of organic matter in these PETM sections, it is difficult to discern if less pyrogenic carbon is in part a consequence of less fire occurrence during the PETM. We propose that in this mid-latitude region of the western USA increased soil carbon oxidation hindered soil carbon sequestration during this period of hotter climate with more seasonal precipitation.
Abstract.
Solofondranohatra CL, Vorontsova MS, Dewhirst RA, Belcher CM, Cable S, Jeannoda V, Lehmann CER (2021). Shade alters the growth and architecture of tropical grasses by reducing root biomass.
Biotropica,
53(4), 1052-1062.
Abstract:
Shade alters the growth and architecture of tropical grasses by reducing root biomass
Tropical grassy biomes have variable tree cover and are often characterized by a flammable grassy ground layer where the dominating grass species have strategies to persist and proliferate with frequent fire. However, there is limited understanding of how grass growth and flammability traits respond to light availability. We experimentally grew 14 grass species characteristic of the Malagasy Central Highlands for one year with four treatments of light exclusion ranging from 0 – 60%. Eight plant functional traits and four leaf flammability traits were measured: plant height, bulk density, aboveground biomass, belowground biomass, ratio of root to shoot biomass, specific leaf area, leaf length, leaf width, leaf heat release capacity, temperature of maximum decomposition, total heat release and peak heat release rate. Belowground biomass, the ratio of root to shoot biomass, and bulk density were all negatively affected by decreasing light availability. Surprisingly, aboveground biomass showed no significant change with changing light availability, although there was a trend toward shorter plants in low light. At a leaf level, declining light availability increased specific leaf area, leaf length, and leaf width. In terms of leaf flammability, of the four traits measured, unexpectedly, only leaf total heat release was significantly positively related to declining light availability. These results suggest field alterations in grass flammability may be primarily related to plant architecture and microclimates. The shifts in allometry and substantial reduction in belowground biomass suggest that grasses would be rapidly lost from shaded environments with a diminished competitive capacity to resprout.
Abstract.
Belcher CM, Mills BJW, Vitali R, Baker SJ, Lenton TM, Watson AJ (2021). The rise of angiosperms strengthened fire feedbacks and improved the regulation of atmospheric oxygen.
Nature Communications,
12(1).
Abstract:
The rise of angiosperms strengthened fire feedbacks and improved the regulation of atmospheric oxygen
The source of oxygen to Earth’s atmosphere is organic carbon burial, whilst the main sink is oxidative weathering of fossil carbon. However, this sink is to insensitive to counteract oxygen rising above its current level of about 21%. Biogeochemical models suggest that wildfires provide an additional regulatory feedback mechanism. However, none have considered how the evolution of different plant groups through time have interacted with this feedback. The Cretaceous Period saw not only super-ambient levels of atmospheric oxygen but also the evolution of the angiosperms, that then rose to dominate Earth’s ecosystems. Here we show, using the COPSE biogeochemical model, that angiosperm-driven alteration of fire feedbacks likely lowered atmospheric oxygen levels from ~30% to 25% by the end of the Cretaceous. This likely set the stage for the emergence of closed-canopy angiosperm tropical rainforests that we suggest would not have been possible without angiosperm enhancement of fire feedbacks.
Abstract.
Losiak A, Joeleht A, Plado J, Szyszka M, Kirsimae K, Wild EM, Steier P, Belcher CM, Jazwa AM, Helde R, et al (2020). Determining the age and possibility for an extraterrestrial impact formation mechanism of the Ilumetsa structures (Estonia).
METEORITICS & PLANETARY SCIENCE,
55(2), 274-293.
Author URL.
Dewhirst RA, Smirnoff N, Belcher CM (2020). Pine species that support crown fire regimes have lower leaf-level terpene contents than those native to surface fire regimes.
Fire,
3(2), 1-19.
Abstract:
Pine species that support crown fire regimes have lower leaf-level terpene contents than those native to surface fire regimes
Fire is increasingly being recognised as an important evolutionary driver in fire-prone environments. Biochemical traits such as terpene (volatile isoprenoid) concentration are assumed to influence plant flammability but have often been overlooked as fire adaptations. We have measured the leaf-level flammability and terpene content of a selection of Pinus species native to environments with differing fire regimes (crown fire, surface fire and no fire). We demonstrate that this biochemical trait is associated with leaf-level flammability which likely links to fire-proneness and we suggest that this contributes to post-fire seedling survival. We find that surface-fire species have the highest terpene abundance and are intrinsically the most flammable, compared to crown-fire species. We suggest that the biochemical traits of surface fire species may have been under selective pressure to modify the fire environment at the leaf and litter scale to moderate fire spread and intensity. We indicate that litter flammability is driven not only by packing ratios and bulk density, but also by terpene content.
Abstract.
Hudspith VA, Belcher CM (2020). Some semifusinite in coal may form during diagenesis, not wildfires.
International Journal of Coal Geology,
218Abstract:
Some semifusinite in coal may form during diagenesis, not wildfires
Semifusinite can be an important component of coals and has previously been interpreted to represent partially charred material produced in palaeowildfires. Low reflecting semifusinite is well known for its chemically reactive properties, good burning behaviour, and for its reflectance to increase with coal rank. Yet, when inertinite in coal and sediments is used to interpret palaeowildfire history, the diagenetic history of the basin is rarely considered. Here, we sought to explore whether the low temperature heating that would occur during diagenesis over geological timescales is sufficient to produce semifusinite. Considering the interpretation that semifusinite represents partially charred material, we reheated thermally degraded, but not charred, wood at 100 °C and 200 °C for 24 h. Through prolonged heating at low temperatures, the previously thermally altered but non-charred wood increased in reflectance to such an extent that it would be classified as semifusinite. This finding suggests that not all semifusinite necessarily has a wildfire origin and calls into question its utility in interpreting palaeowildfire activity.
Abstract.
Crawford AJ, Belcher CM (2020). Volumetric measurement of fossil charcoal: Principles, applications and potential.
Holocene,
30(10), 1481-1487.
Abstract:
Volumetric measurement of fossil charcoal: Principles, applications and potential
Quantifying sedimentary charcoal content by estimation of volume from two-dimensional images is a relatively new and little-used method, but has the potential to improve the accuracy of fire histories. It requires a power transformation of area data, and multiplication by a coefficient to account for particle shape. The latter step has been routinely overlooked, or considered unnecessary, with volume estimates made simply by power transformation of the area data. Some researchers have used the method on the basis of the power transformation only, and others have rejected it as unnecessary on the same basis. However, the assumption that the shape coefficient can be ignored is likely to introduce very large errors, resulting in overestimation of charcoal volume. The magnitude of the error is indicated by a limited amount of empirical data obtained from volumetric measurement of individual charcoal particles, and accurate use of the method would require considerable further work to extend this data set. In a sedimentary sequence where particle morphology varies with depth, the errors identified could seriously distort the fire history produced. However, as such variation is easily identified, the method can still improve charcoal quantification where morphology is stationary.
Abstract.
Boulton CA, Belcher CM (2019). A novel approach for predicting the probability of ignition of palaeofires using fossil leaf assemblages.
Palaeontology,
62(5), 715-730.
Abstract:
A novel approach for predicting the probability of ignition of palaeofires using fossil leaf assemblages
Many metrics are used to predict and manage wildfires today but it is difficult to directly apply these to past wildfires histories. Developing an approach that enables estimation of these fire metrics in the past would provide significant power in our ability to compare past fire risk with that of the modern day. We use the Climate Leaf Analysis Multivariate Program (CLAMP) to estimate warm month mean temperature and annual mean relative humidity for a modern day leaf dataset and establish a novel methodology by which we can generate ‘pseudo-daily’ meteorological parameters to calculate the probability of ignition (p(I)), an aspect of the North American Fire Danger Rating System. We test this methodology on Tortonian aged fossil leaves (11.62–7.25 Ma) from five sites across California, which reveal that the Tortonian was cooler and considerably more humid and that p(I) was lower during this time than in the region today.
Abstract.
Baker SJ, Belcher CM, Barclay RS, Hesselbo SP, Laurin J, Sageman BB (2019). CO2-induced climate forcing on the fire record during the initiation of Cretaceous oceanic anoxic event 2. Geological Society of America Bulletin
Harrison ME, Ottay JB, D’Arcy LJ, Cheyne SM, Anggodo, Belcher C, Cole L, Dohong A, Ermiasi Y, Feldpausch T, et al (2019). Tropical forest and peatland conservation in Indonesia: Challenges and directions. People and Nature, 2(1), 4-28.
Walding NG, Williams HTP, McGarvie S, Belcher CM (2018). A comparison of the US National Fire Danger Rating System (NFDRS) with recorded fire occurrence and final fire size.
International Journal of Wildland Fire,
27(2), 99-113.
Abstract:
A comparison of the US National Fire Danger Rating System (NFDRS) with recorded fire occurrence and final fire size
Most previous research has assessed the ability of the National Fire Danger Rating System (NFDRS) to portray fire activity at either single sites or on small spatial scales, despite it being a nation-wide system. This study seeks to examine the relationships between a set of NFDRS fire danger indices (Fire Danger Ratings, Staffing Level and the Ignition Component) and measures of fire activity (fire occurrence and final fire size) across the entire conterminous US over an 8-year period. We reveal that different regions of the US display different levels of correspondence between each of the fire danger indices and recorded fire activity. Areas in the Southern and Eastern Geographic Area Coordination Centers (GACCs) exhibit weaker correlations than those in the Northwest, Northern Rockies, Great Basin and Northern California GACCs. Peaks in fire occurrence are shown to occur at mid-low values of fire danger whereas final fire sizes increase monotonically with each fire danger index. Our findings appear to align with perceived shifts in management practices currently employed across the US and indicate that the ability of the NFDRS to apportion the resources required to combat large fires is in general well developed.
Abstract.
Archibald S, Lehmann CER, Belcher CM, Bond WJ, Bradstock RA, Daniau A-L, Dexter KG, Ferrestel EJ, Greve M, He T, et al (2018). Biological and geophysical feedbacks with fire in the Earth system. Environmental Research Letters, 13
Hudspith VA, Hadden RM, Bartlett AI, Belcher CM (2018). Does fuel type influence the amount of charcoal produced in wildfires? Implications for the fossil record.
Palaeontology,
61(2), 159-171.
Abstract:
Does fuel type influence the amount of charcoal produced in wildfires? Implications for the fossil record
Charcoal occurrence is extensively used as a tool for understanding wildfires over geological timescales. Yet, the fossil charcoal literature to date rarely considers that fire alone is capable of creating a bias in the abundance and nature of charcoal it creates, before it even becomes incorporated into the fossil record. In this study we have used state-of-the-art calorimetry to experimentally produce charcoal from 20 species that represent a range of surface fuels and growth habits, as a preliminary step towards assessing whether different fuel types (and plant organs) are equally likely to remain as charcoal post-fire. We observe that charcoal production appears to be species specific, and is related to the intrinsic physical and chemical properties of a given fuel. Our observations therefore suggest that some taxa are likely to be overrepresented in fossil charcoal assemblages (i.e. needle-shed conifers, tree ferns) and others poorly represented, or not preserved at all (i.e. broad shoot-shed conifers, weedy angiosperms, shrub angiosperms, some ferns). Our study highlights the complexity of charcoal production in modern fuels and we consider what a bias in charcoal production may mean for our understanding of palaeowildfires.
Abstract.
Doerr SH, Santín C, Merino A, Belcher CM, Baxter G (2018). Fire as a Removal Mechanism of Pyrogenic Carbon from the Environment: Effects of Fire and Pyrogenic Carbon Characteristics.
Frontiers in Earth Science,
6Abstract:
Fire as a Removal Mechanism of Pyrogenic Carbon from the Environment: Effects of Fire and Pyrogenic Carbon Characteristics
Pyrogenic carbon (PyC, charcoal) is produced during vegetation fires at a rate of ~116–385 Tg C yr−1 globally. It represents one of the most degradation-resistant organic carbon pools, but its long-term fate and the processes leading to its degradation remain subject of debate. A frequently highlighted potential loss mechanism of PyC is its consumption in subsequent fires. However, only three studies to date have tested this hypothesis with reported losses of 300°C. Mass losses also showed a significant negative correlation (r = −0.38, p = 0.05) with thermal recalcitrance (T50) determined using Differential Scanning Calorimetry (DSC) and Tmax with charcoal reflectance (Ro) determined after the fires (r = 0.46, p = 0.05). Losses in the high-intensity fire were significantly higher (p = 0.05) than in the low-intensity fire, but the latter had a higher rate of conversion of fuel to PyC. Our results demonstrate that exposure to fire can indeed be a significant removal mechanism for PyC that remains exposed on the ground after a previous fire. The losses found, however, are likely to represent an extreme upper range as most PyC produced in a fire would not remain exposed on the ground surface by the time the next fire occurs. Our data also demonstrate, for real wildfire conditions, the (i) contrasting resistance of different PyC types to combustion and (ii) contrasting net PyC losses between different fire intensities. The DSC and reflectance (Ro) results support the usefulness of these analyses in reflecting thermal degradation resistance and temperature exposure under actual wildfire conditions.
Abstract.
Crawford AJ, Baker SJ, Belcher CM (2018). Fossil charcoals from the Lower Jurassic challenge assumptions about charcoal morphology and identification.
Palaeontology,
61(1), 49-56.
Abstract:
Fossil charcoals from the Lower Jurassic challenge assumptions about charcoal morphology and identification
Charcoal morphometry is increasingly employed in the analysis of Quaternary sediments, but has not been applied in studies of earlier sediments. We present findings relating to charcoal morphometry and morphotypes in a Toarcian sequence, which contains a preponderance of highly elongate forms, and morphometric values well outside expected ranges. SEM imaging reveals elongate particles of two distinct kinds. One originates in conifer xylem, and may be associated with formation at high levels of heating. It is proposed that the other may derive from tree ferns, or from plants with similar growth forms. Our results show the importance of recognizing the wide morphological variation that exists in sedimentary charcoal. Failing to do so may result in serious errors in its identification, interpretation and quantification.
Abstract.
Cardoso AW, Oliveras I, Abernethy KA, Jeffery KJ, Lehmann D, Edzang Ndong J, McGregor I, Belcher CM, Bond WJ, Malhi YS, et al (2018). Grass Species Flammability, Not Biomass, Drives Changes in Fire Behavior at Tropical Forest-Savanna Transitions.
Frontiers in Forests and Global Change,
1Abstract:
Grass Species Flammability, Not Biomass, Drives Changes in Fire Behavior at Tropical Forest-Savanna Transitions
Forest-savanna mosaics are maintained by fire-mediated positive feedbacks; whereby forest is fire suppressive and savanna is fire promoting. Forest-savanna transitions therefore represent the interface of opposing fire regimes. Within the transition there is a threshold point at which tree canopy cover becomes sufficiently dense to shade out grasses and thus suppress fire. Prior to reaching this threshold, changes in fire behavior may already be occurring within the savanna. Such changes are neither empirically described nor their drivers understood. Fire behavior is largely driven by fuel flammability. Flammability can vary significantly between grass species and grass species composition can change near forest-savanna transitions. This study measured fire behavior changes at eighteen forest-savanna transition sites in a vegetation mosaic in Lopé National Park in Gabon, central Africa. The extent to which these changes could be attributed to changes in grass flammability was determined using species-specific flammability traits. Results showed simultaneous suppression of fire and grass biomass when tree canopy leaf area index (LAI) reached a value of 3, indicating that a fire suppression threshold existed within the forest-savanna transition. Fires became less intense and less hot prior to reaching this fire suppression threshold. These changes were associated with higher LAI values, which induced a change in the grass community, from one dominated by the highly flammable Anadelphia afzeliana to one dominated by the less flammable Hyparrhenia diplandra. Changes in fire behavior were not associated with changes in total grass biomass. This study demonstrated not only the presence of a fire suppression threshold but the mechanism of its action. Grass composition mediated fire-behavior within the savanna prior to reaching the suppression threshold, and grass species composition was mediated by tree canopy cover which was in turn mediated by fire-behavior. These findings highlight how biotic and abiotic controls interact and amplify each other in this mosaicked landscape to facilitate forest and savanna co-existence.
Abstract.
Haworth M, Belcher CM, Killi D, Dewhirst RA, Materassi A, Raschi A, Centritto M (2018). Impaired photosynthesis and increased leaf construction costs may induce floral stress during episodes of global warming over macroevolutionary timescales.
SCIENTIFIC REPORTS,
8 Author URL.
Haworth M, Belcher CM, Killi D, Dewhirst RA, Materassi A, Raschi A, Centritto M (2018). Impaired photosynthesis and increased leaf construction costs may induce floral stress during episodes of global warming over macroevolutionary timescales (vol 8, 6206, 2018).
SCIENTIFIC REPORTS,
8 Author URL.
New SL, Hudspith VA, Belcher CM (2018). Quantitative charcoal reflectance measurements better link to regrowth potential than ground-based fire-severity assessments following a recent heathland wildfire at Carn Brea, Cornwall, UK.
International Journal of Wildland Fire,
27(12), 845-850.
Abstract:
Quantitative charcoal reflectance measurements better link to regrowth potential than ground-based fire-severity assessments following a recent heathland wildfire at Carn Brea, Cornwall, UK
Charcoal has recently been suggested to retain information about the fire that generated it. When looked at under a microscope, charcoals formed by different aspects of fire behaviour indicate different ability to reflect the amount of light when studied using the appropriate technique. It has been suggested that this method, charcoal reflectance (Ro), might be able to provide a quantitative fire severity metric that can be used in conjunction with or instead of standard qualitative fire severity scores. We studied charcoals from a recent heathland wildfire in Carn Brea, Cornwall, UK, and assessed whether charcoal reflectance (Ro) can be linked to standard qualitative fire severity scores for the burned area. We found that charcoal reflectance was greater at sites along the burned area that had been scored as having a higher qualitative fire severity. However, there were clear instances where the quantitative charcoal reflectance measurements were able to better indicate damage and regrowth potential than qualitative scoring alone. We suggest measuring the reflectance of charcoals may not only be able to provide quantitative information about the spatial distribution of heat across a burned area post fire but that this approach is able to provide improvement to fire severity assessment approaches.
Abstract.
Belcher CM, New SL, Santín C, Doerr SH, Dewhirst RA, Grosvenor MJ, Hudspith VA (2018). What can charcoal reflectance tell us about energy release in wildfires and the properties of pyrogenic carbon?.
Frontiers in Earth Science,
6Abstract:
What can charcoal reflectance tell us about energy release in wildfires and the properties of pyrogenic carbon?
Here, we explore how charcoal formation under different heating regimes and circumstances leads to chars of different physical properties. In order to do this, we have undertaken (1) carefully controlled laboratory experiments that replicate the different heating regimes that might be experienced during a wildfire and (2) two experimental wildfires where heat variations were monitored across the burn from which resulting charcoal has been studied. The charcoal properties were assessed using charcoal reflectance that measures the light reflected back from the charcoals structure and which links to changes in its structural properties. We find that increased total heat released during combustion positively correlates with increased charcoal reflectance and that this is evidenced from both our laboratory experiments and experimental wildfires. Charcoals that related to lower total heat release were found to have more lignin remaining than those subjected to greater heating indicating that charcoals formed in lower energy regimes are likely to be more susceptible to post-fire degradation. We conclude that charcoal reflectance may make a useful metric with which to determine the distribution of energy delivery across a burned area and that this may be utilized to inform both variations in fire severity and enable the prediction of long-term C budgeting for different types of wildfire.
Abstract.
Belcher CM, Hudspith VA (2017). Changes to Cretaceous surface fire behaviour influenced the spread of the early angiosperms.
New Phytologist,
213(3), 1521-1532.
Abstract:
Changes to Cretaceous surface fire behaviour influenced the spread of the early angiosperms
Angiosperms evolved and diversified during the Cretaceous period. Early angiosperms were short-stature weedy plants thought to have increased fire frequency and mortality in gymnosperm forest, aiding their own expansion. However, no explorations have considered whether the range of novel fuel types that diversified throughout the Cretaceous also altered fire behaviour, which should link more strongly to mortality than fire frequency alone. We measured ignitability and heat of combustion in analogue Cretaceous understorey fuels (conifer litter, ferns, weedy and shrubby angiosperms) and used these data to model palaeofire behaviour. Variations in ignition, driven by weedy angiosperms alone, were found to have been a less important feedback to changes in Cretaceous fire activity than previously estimated. Our model estimates suggest that fires in shrub and fern understories had significantly greater fireline intensities than those fuelled by conifer litter or weedy angiosperms, and whilst fern understories supported the most rapid fire spread, angiosperm shrubs delivered the largest amount of heat per unit area. The higher fireline intensities predicted by the models led to estimates of enhanced scorch of the gymnosperm canopy and a greater chance of transitioning to crown fires. Therefore, changes in fire behaviour driven by the addition of new Cretaceous fuel groups may have assisted the angiosperm expansion.
Abstract.
Baker SJ, Hesselbo SP, Lenton TM, Duarte LV, Belcher CM (2017). Charcoal evidence that rising atmospheric oxygen terminated Early Jurassic ocean anoxia. Nature Communications
Hudspith VA, Belcher CM, Barnes J, Dash CB, Kelly R, Hu FS (2017). Charcoal reflectance suggests heating duration and fuel moisture affected burn severity in four Alaskan tundra wildfires.
INTERNATIONAL JOURNAL OF WILDLAND FIRE,
26(4), 306-316.
Author URL.
Prat-Guitart N, Belcher CM, Thompson DK, Burns P, Yearsley JM (2017). Fine-scale distribution of moisture in the surface of a degraded blanket bog and its effects on the potential spread of smouldering fire.
Ecohydrology,
10(8).
Abstract:
Fine-scale distribution of moisture in the surface of a degraded blanket bog and its effects on the potential spread of smouldering fire
During rain-free periods, the water table in peatlands falls and the moisture content (MC) of top 10 cm, including the moss layer, depends upon the hydrophysical properties and the responses of the local composition of species to water deficit. Thus, the ecosystem becomes vulnerable to surface peat fires. The spread of such fires is often irregular; however, there is little understanding of how the fine-scale variation of peat MC can affect the spread of smouldering fire. We analyse the fine-scale distribution of surface MC from a degraded blanket bog (i.e. horizontal intervals of 10 cm), thus indirectly analysing the effect of fine-scale MC distribution on peat fire spread. We determine the relationship of vegetation and microtopography to the spatial distribution of near surface MC and the moisture gradient around patches of dry peat (less than 250% MC, moisture content in a dry mass basis). We found that the MC of the surface peat was distributed in clusters with dry patches (less than 250% MC) averaging 40 ± 15 cm in size. The MC gradient surrounding dry patches was 10 ± 7% MC∙cm−1. A mixed-effects model showed that dry patches were associated with lawns (of feather moss or Sphagnum) and hummocks of feather moss. Our model showed that wet patches were associated with both hummocks and hollows of Sphagnum. Therefore, the characterization of the surface MC in a fine-scale is critical if we are to understand the spread of fires in peatlands.
Abstract.
Hudspith VA, Belcher CM (2017). Fire biases the production of charred flowers: Implications for the Cretaceous fossil record.
Geology,
45(8), 727-730.
Abstract:
Fire biases the production of charred flowers: Implications for the Cretaceous fossil record
The radiation of angiosperm lineages during the Cretaceous Period (145.5-65.5 Ma) initiated one of the greatest floral turnovers to have occurred on our planet. Much of our understanding of the floral biology and diversity of these early angiosperms derives from exceptionally preserved charcoalified and coalified Cretaceous fossil floras. Although fire played an integral role in the production of charred early angiosperm flowers, research has not considered whether the fire is capable of creating a bias in the nature of the charcoalified flowers that are produced. Here we use calorimetry to experimentally produce morphologically variable charcoalified flowers. Our findings indicate that combustion behavior, floral structure, the number of flowers, and their arrangement (inflorescence) all affect the number of charred flowers that are produced. These observations suggest that charred flowers are not equally likely to be represented in Cretaceous charcoal assemblages, and some species may be missing from the fossil record entirely. This may in turn alter our understanding of early angiosperm evolution and the fossil record of fire.
Abstract.
Hudspith VA, Belcher CM (2017). Observations of the structural changes that occur during charcoalification: implications for identifying charcoal in the fossil record.
Palaeontology,
60(4), 503-510.
Abstract:
Observations of the structural changes that occur during charcoalification: implications for identifying charcoal in the fossil record
All of our current understanding of fossil charcoal structure comes from observations of modern wood charcoal produced in furnaces. These charcoals consistently show cell wall homogenization after prolonged heating (>325°C) and this is therefore considered to be a key identifying feature of fossil charcoal. Yet furnaces are unable to replicate the full combustion processes that occur during a wildfire. Here, for the first time, we have studied the microscopic structural evolution of charcoal produced using calorimetry, wherein the wood is ignited under controlled conditions and the heat release rate and other parameters measured, and the resulting charcoal studied using reflected light microscopy. We show that homogenization of cell walls is actually only a short-lived phase of charcoal formation that occurs during the early heating stages as the pyrolysis front traverses through the wood. Cell wall homogenization is then rapidly overprinted by the thinning, distortion and breakdown of cell walls, and a notable visual increase in reflectance. Our preliminary study therefore suggests that we need to first improve our understanding of charcoal formation in order to better understand the fossil record of wildfires.
Abstract.
Mills BJW, Belcher CM, Lenton TM, Newton RJ (2016). A modeling case for high atmospheric oxygen concentrations during the Mesozoic and Cenozoic.
Geology,
44(12), 1023-1026.
Abstract:
A modeling case for high atmospheric oxygen concentrations during the Mesozoic and Cenozoic
Changes in atmospheric oxygen concentration over Earth history are commonly related to the evolution of animals and plants. But there is no direct geochemical proxy for O2 levels, meaning that estimations rely heavily on modeling approaches. The results of such studies differ greatly, to the extent that today's atmospheric mixing ratio of 21% might be either the highest or lowest level during the past 200 m.y. Long term oxygen sources, such as the burial in sediments of reduced carbon and sulfur species, are calculated in models by representation of nutrient cycling and estimation of productivity, or by isotope mass balance (IMB)-a technique in which burial rates are inferred in order to match known isotope records. Studies utilizing these different techniques produce conflicting estimates for paleoatmospheric O2, with nutrient-weathering models estimating concentrations close to, or above, that of the present day, and IMB models estimating low O2, especially during the Mesozoic. Here we reassess the IMB technique using the COPSE biogeochemical model. IMB modelling is confirmed to be highly sensitive to assumed carbonate δ13C, and when this input is defined following recent compilations, predicted O2 is significantly higher and in reasonable agreement with that of non-IMB techniques. We conclude that there is no model-based support for low atmospheric oxygen concentrations during the past 200 m.y. High Mesozoic O2 is consistent with wildfire records and the development of plant fire adaptions, but links between O2 and mammal evolution appear more tenuous.
Abstract.
Prat-Guitart N, Rein G, Hadden RM, Belcher CM, Yearsley JM (2016). Effects of spatial heterogeneity in moisture content on the horizontal spread of peat fires.
Sci Total Environ,
572, 1422-1430.
Abstract:
Effects of spatial heterogeneity in moisture content on the horizontal spread of peat fires.
The gravimetric moisture content of peat is the main factor limiting the ignition and spread propagation of smouldering fires. Our aim is to use controlled laboratory experiments to better understand how the spread of smouldering fires is influenced in natural landscape conditions where the moisture content of the top peat layer is not homogeneous. In this paper, we study for the first time the spread of peat fires across a spatial matrix of two moisture contents (dry/wet) in the laboratory. The experiments were undertaken using an open-top insulated box (22×18×6cm) filled with milled peat. The peat was ignited at one side of the box initiating smouldering and horizontal spread. Measurements of the peak temperature inside the peat, fire duration and longwave thermal radiation from the burning samples revealed important local changes of the smouldering behaviour in response to sharp gradients in moisture content. Both, peak temperatures and radiation in wetter peat (after the moisture gradient) were sensitive to the drier moisture condition (preceding the moisture gradient). Drier peat conditions before the moisture gradient led to higher temperatures and higher radiation flux from the fire during the first 6cm of horizontal spread into a wet peat patch. The total spread distance into a wet peat patch was affected by the moisture content gradient. We predicted that in most peat moisture gradients of relevance to natural ecosystems the fire self-extinguishes within the first 10cm of horizontal spread into a wet peat patch. Spread distances of more than 10cm are limited to wet peat patches below 160% moisture content (mass of water per mass of dry peat). We found that spatial gradients of moisture content have important local effects on the horizontal spread and should be considered in field and modelling studies.
Abstract.
Author URL.
Roos CI, Scott AC, Belcher CM, Chaloner WG, Aylen J, Bird RB, Coughlan MR, Johnson BR, Johnston FH, McMorrow J, et al (2016). Living on a flammable planet: Interdisciplinary, cross-scalar and varied cultural lessons, prospects and challenges.
Philosophical Transactions of the Royal Society B: Biological Sciences,
371(1696).
Abstract:
Living on a flammable planet: Interdisciplinary, cross-scalar and varied cultural lessons, prospects and challenges
Living with fire is a challenge for human communities because they are influenced by socio-economic, political, ecological and climatic processes at various spatial and temporal scales. Over the course of 2 days, the authors discussed how communities could live with fire challenges at local, national and transnational scales. Exploiting our diverse, international and interdisciplinary expertise, we outline generalizable properties of fire-adaptive communities in varied settings where cultural knowledge of fire is rich and diverse. At the national scale, we discussed policy and management challenges for countries that have diminishing fire knowledge, but for whom global climate change will bring new fire problems. Finally, we assessed major fire challenges that transcend national political boundaries, including the health burden of smoke plumes and the climate consequences of wildfires. It is clear that to best address the broad range of fire problems, a holistic wildfire scholarship must develop common agreement in working terms and build across disciplines. We must also communicate our understanding of fire and its importance to the media, politicians and the general public.
Abstract.
Prat-Guitart N, Rein G, Hadden RM, Belcher CM, Yearsley JM (2016). Propagation probability and spread rates of self-sustained smouldering fires under controlled moisture content and bulk density conditions.
INTERNATIONAL JOURNAL OF WILDLAND FIRE,
25(4), 456-465.
Author URL.
Belcher CM, Hudspith VA (2016). The formation of charcoal reflectance and its potential use in post-fire assessments.
International Journal of Wildland Fire,
25(7), 775-779.
Abstract:
The formation of charcoal reflectance and its potential use in post-fire assessments
Charcoal has an exceptional ability to reflect light when viewed using reflectance microscopy. The amount of light reflected is variable depending on the differential ordering of graphite-like phases within the charcoal itself. It has been suggested that this relates to the temperature of formation, whereby higher formation temperatures result in high charcoal reflectance. However, this explanation is derived from oven-based chars that do not well represent the natural combustion process. Here, we have experimentally created charcoals using a cone calorimeter, in order to explore the development of charcoal reflectance during pre-ignition heating and peak heat-release rate, through to the end of flaming and the transition to char oxidation. We find that maximum charcoal reflectance is reached at the transition between pyrolysis and char oxidation, before its conversion to mineral ash, and indicates that our existing understanding of reflectance is in error. We suggest that charcoal reflectance warrants additional study as it may provide a useful quantitative addition to ground-based fire severity surveys, because it may allow exploration of surface heating after the main fire front has passed and the fire transitions to smouldering phases.
Abstract.
Scott AC, Chaloner WG, Belcher CM, Roos CI (2016). The interaction of fire and mankind. Philosophical Transactions of the Royal Society B: Biological Sciences, 371(1696).
Scott AC, Chaloner WG, Belcher CM, Roos CI (2016). The interaction of fire and mankind: Introduction.
Philosophical Transactions of the Royal Society B: Biological Sciences,
371(1696).
Abstract:
The interaction of fire and mankind: Introduction
Fire has been an important part of the Earth system for over 350 Myr. Humans evolved in this fiery world and are the only animals to have used and controlled fire. The interaction of mankind with fire is a complex one, with both positive and negative aspects. Humans have long used fire for heating, cooking, landscape management and agriculture, as well as for pyrotechnologies and in industrial processes over more recent centuries. Many landscapes need fire but population expansion into wildland areas creates a tension between different interest groups. Extinguishing wildfires may not always be the correct solution. A combination of factors, including the problem of invasive plants, landscape change, climate change, population growth, human health, economic, social and cultural attitudes that may be transnational make a reevaluation of fire and mankind necessary. The Royal Society meeting on Fire and mankind was held to address these issues and the results of these deliberations are published in this volume.
Abstract.
He T, Belcher CM, Lamont BB, Lim SL (2015). A 350-million-year legacy of fire adaptation among conifers.
Journal of EcologyAbstract:
A 350-million-year legacy of fire adaptation among conifers
© 2015 British Ecological Society. Current phylogenetic evidence shows that fire began shaping the evolution of land plants 125 Ma, although the fossil charcoal record indicates that fire has a much longer history (>350 Ma). Serotiny (on-plant seed storage) is generally accepted as an adaptation to fire among woody plants. We developed a conceptual model of the requirements for the evolution of serotiny, and propose that serotiny is only expressed in the presence of a woody rachis as supporting structure, compact scales covering seeds as protective structure, seed wing as dispersal structure, and crown fire as the agent of selection and mechanism for seed release. This model is strongly supported by empirical data for modern ecosystems. We reconstructed the evolutionary history of intrinsic structural states required for the expression of serotiny in conifers, and show that these were diagnostic for early ('transitional') conifers from 332 Ma (late-Carboniferous). We assessed the likely flammable characteristics of early conifers and found that scale-leaved conifers burn rapidly and with high intensity, supporting the idea that crown fire regimes may have dominated early conifer ecosystems. Synthesis. Coupled with strong evidence for frequent fire throughout the Permian-Carboniferous and fossil evidence for other fire-related traits, we conclude that many early conifers were serotinous in response to intense crown fires, indicating that fire may have had a major impact on the evolution of plant traits as far back as 350 Ma.
Abstract.
Belcher CM, Hadden RM, Rein G, Morgan JV, Artemieva N, Goldin T (2015). An experimental assessment of the ignition of forest fuels by the thermal pulse generated by the cretaceous–palaeogene impact at chicxulub.
Journal of the Geological Society,
172(2), 175-185.
Abstract:
An experimental assessment of the ignition of forest fuels by the thermal pulse generated by the cretaceous–palaeogene impact at chicxulub
A large extraterrestrial body hit the Yucatán Peninsula at the end of the Cretaceous period. Models suggest that a substantial amount of thermal radiation was delivered to the Earth’s surface by the impact, leading to the suggestion that it was capable of igniting extensive wildfires and contributed to the end-Cretaceous extinctions. We have reproduced in the laboratory the most intense impact-induced heat fluxes estimated to have reached different points on the Earth’s surface using a fire propagation apparatus and investigated the ignition potential of forest fuels. The experiments indicate that dry litter can ignite, but live fuels typically do not, suggesting that any ignition caused by impact-induced thermal radiation would have been strongly regional dependent. The intense, but short-lived, pulse downrange and at proximal and intermediate distances from the impact is insufficient to ignite live fuel. However, the less intense but longer-lasting thermal pulse at distal locations may have ignited areas of live fuels. Because plants and ecosystems are generally resistant to single localized fire events, we conclude that any fires ignited by impact-induced thermal radiation cannot be directly responsible for plant extinctions, implying that heat stress is only part of the end-Cretaceous story.
Abstract.
Crawford AJ, Belcher CM (2015). Area–volume relationships for fossil charcoal and their relevance for fire history reconstruction.
The Holocene,
26(5), 822-826.
Abstract:
Area–volume relationships for fossil charcoal and their relevance for fire history reconstruction
Sedimentary charcoal is a widely used tool for reconstructing past fire histories. These fossil charcoals are normally quantified as the number or area of particles present in a sediment sample, but it is not known how well either measure is correlated with their volume. Areal measurements are often treated as the true measure of quantity, which may introduce bias to fire histories. The relationship of measured area to volume is a function of shape, and if this relationship can be understood, areal measurements may be adjusted to better reflect volume. We show that particle elongation may be particularly important when making such adjustments. We also establish a high degree of correlation between volume and area in a mid-Holocene mesocharcoal assemblage, which indicates that the bias may be small in similar cases.
Abstract.
Hudspith VA, Belcher CM, Kelly R, Hu FS (2015). Charcoal reflectance reveals early holocene boreal deciduous forests burned at high intensities.
PLoS One,
10(4).
Abstract:
Charcoal reflectance reveals early holocene boreal deciduous forests burned at high intensities.
Wildfire size, frequency, and severity are increasing in the Alaskan boreal forest in response to climate warming. One of the potential impacts of this changing fire regime is the alteration of successional trajectories, from black spruce to mixed stands dominated by aspen, a vegetation composition not experienced since the early Holocene. Such changes in vegetation composition may consequently alter the intensity of fires, influencing fire feedbacks to the ecosystem. Paleorecords document past wildfire-vegetation dynamics and as such, are imperative for our understanding of how these ecosystems will respond to future climate warming. For the first time, we have used reflectance measurements of macroscopic charcoal particles (>180μm) from an Alaskan lake-sediment record to estimate ancient charring temperatures (termed pyrolysis intensity). We demonstrate that pyrolysis intensity increased markedly from an interval of birch tundra 11 ky ago (mean 1.52%Ro; 485°C), to the expansion of trees on the landscape ~10.5 ky ago, remaining high to the present (mean 3.54%Ro; 640°C) irrespective of stand composition. Despite differing flammabilities and adaptations to fire, the highest pyrolysis intensities derive from two intervals with distinct vegetation compositions. 1) the expansion of mixed aspen and spruce woodland at 10 cal. kyr BP, and 2) the establishment of black spruce, and the modern boreal forest at 4 cal. kyr BP. Based on our analysis, we infer that predicted expansion of deciduous trees into the boreal forest in the future could lead to high intensity, but low severity fires, potentially moderating future climate-fire feedbacks.
Abstract.
Author URL.
Simpson KJ, Ripley BS, Christin P, Belcher CM, Lehmann CER, Thomas GH, Osborne CP (2015). Determinants of flammability in savanna grass species. Journal of Ecology, 104(1), 138-148.
Hudspith VA, Rimmer SM, Belcher CM (2015). Latest Permian chars may derive from wildfires, not coal combustion: REPLY. Geology Forum, 43(5), p. e363-p. e363.
Mander L, Baker SJ, Belcher CM, Haselhorst DS, Rodriguez J, Thorn JL, Tiwari S, Urrego DH, Wesseln CJ, Punyasena SW, et al (2014). Accuracy and consistency of grass pollen identification by human analysts using electron micrographs of surface ornamentation.
Appl Plant Sci,
2(8).
Abstract:
Accuracy and consistency of grass pollen identification by human analysts using electron micrographs of surface ornamentation.
PREMISE OF THE STUDY: Humans frequently identify pollen grains at a taxonomic rank above species. Grass pollen is a classic case of this situation, which has led to the development of computational methods for identifying grass pollen species. This paper aims to provide context for these computational methods by quantifying the accuracy and consistency of human identification. • METHODS: We measured the ability of nine human analysts to identify 12 species of grass pollen using scanning electron microscopy images. These are the same images that were used in computational identifications. We have measured the coverage, accuracy, and consistency of each analyst, and investigated their ability to recognize duplicate images. • RESULTS: Coverage ranged from 87.5% to 100%. Mean identification accuracy ranged from 46.67% to 87.5%. The identification consistency of each analyst ranged from 32.5% to 87.5%, and each of the nine analysts produced considerably different identification schemes. The proportion of duplicate image pairs that were missed ranged from 6.25% to 58.33%. • DISCUSSION: the identification errors made by each analyst, which result in a decline in accuracy and consistency, are likely related to psychological factors such as the limited capacity of human memory, fatigue and boredom, recency effects, and positivity bias.
Abstract.
Author URL.
Crawford AJ, Belcher CM (2014). Charcoal morphometry for paleoecological analysis: the effects of fuel type and transportation on morphological parameters.
Appl Plant Sci,
2(8).
Abstract:
Charcoal morphometry for paleoecological analysis: the effects of fuel type and transportation on morphological parameters.
PREMISE OF THE STUDY: Charcoal particles preserved in sediments are used as indicators of paleowildfire. Most research focuses on abundance as an indicator of fire frequency, but charcoals also convey information about the vegetation from which they are derived. One potential source of information is their morphology, which is influenced by the parent material, the nature of the fire, and subsequent transportation and burial. • METHODS: We charcoalified 26 materials from a range of plant taxa, and subjected them to simulated fluvial transport by tumbling them with water and gravel. We photographed the resulting particles, and used image analysis software to measure morphological parameters. • RESULTS: Leaf charcoal displayed a logarithmic decrease in area, and a logarithmic increase in circularity, with transportation time. Trends were less clear for stem or wood charcoal. Grass charcoal displayed significantly higher aspect ratios than other charcoal types. • CONCLUSIONS: Leaf charcoal displays more easily definable relationships between morphological parameters and degree of breakdown than stem or wood charcoal. The aspect ratios of fossil mesocharcoal can indicate the broad botanical source of an assemblage. Coupled to estimates of charcoal abundance, this will improve understanding of the variation in flammability of ancient ecosystems.
Abstract.
Author URL.
Hudspith VA, Belcher CM, Yearsley JM (2014). Charring temperatures are driven by the fuel types burned in a peatland wildfire.
Frontiers in Plant Science,
5(DEC).
Abstract:
Charring temperatures are driven by the fuel types burned in a peatland wildfire
Peatlands represent a globally important carbon store; however, the human exploitation of this ecosystem is increasing both the frequency and severity of fires on drained peatlands. Yet, the interactions between the hydrological conditions (ecotopes), the fuel types being burned, the burn severity, and the charring temperatures (pyrolysis intensity) remain poorly understood. Here we present a post-burn assessment of a fire on a lowland raised bog in Co. Offaly, Ireland (All Saints Bog). Three burn severities were identified in the field (light, moderate, and deeply burned), and surface charcoals were taken from 17 sites across all burn severities. Charcoals were classified into two fuel type categories (either ground or aboveground fuel) and the reflectance of each charcoal particle was measured under oil using reflectance microscopy. Charcoal reflectance shows a positive relationship with charring temperature and as such can be used as a temperature proxy to reconstruct minimum charring temperatures after a fire event. Resulting median reflectance values for ground fuels are 1.09 ± 0.32%Romedian, corresponding to estimated minimum charring temperatures of 447°C ± 49°C. In contrast, the median charring temperatures of aboveground fuels were found to be considerably higher, 646°C ± 73°C (3.58 ± 0.77%Romedian). A mixed-effects modeling approach was used to demonstrate that the interaction effects of burn severity, as well as ecotope classes, on the charcoal reflectance is small compared to the main effect of fuel type. Our findings reveal that the different fuel types on raised bogs are capable of charring at different temperatures within the same fire, and that the pyrolysis intensity of the fire on all Saints Bog was primarily driven by the fuel types burning, with only a weak association to the burn severity or ecotope classes.
Abstract.
Hudspith VA, Rimmer SM, Belcher CM (2014). Latest Permian chars may derive from wildfires, not coal combustion.
Geology,
42(10), 879-882.
Abstract:
Latest Permian chars may derive from wildfires, not coal combustion
The Permian-Triassic boundary extinction event was the largest biological crisis of the Phanerozoic. One of the principle triggers for the mass extinction is thought to be greenhouse warming resulting from the release of CH4 from basalt-coal interaction during the extensive Siberian Traps (Russia) eruptions. Observations of organic matter interpreted to be coal combustion products (fly ash) in latest Permian marine sediments have been used to support this hypothesis. However, this interpretation is dependent upon vesicular chars being fly ash (coal combustion derived) and not formed by alternative mechanisms. Here we present reflectance microscopy images of vesicular chars from Russian Permian coals, and chars from modern tundra, peatland, and boreal forest fires, to demonstrate that despite a difference in precursor fuels, wildfires are capable of generating vesicular chars that are morphologically comparable to end-Permian fly ash. These observations, coupled with extensive global evidence of wildfires during this time interval, call into question the contribution of coal combustion to the end- Permian extinction event.
Abstract.
Zaccone C, Rein G, D'Orazio V, Hadden RM, Belcher CM, Miano TM (2014). Smouldering fire signatures in peat and their implications for palaeoenvironmental reconstructions.
Geochimica et Cosmochimica Acta,
137, 134-146.
Abstract:
Smouldering fire signatures in peat and their implications for palaeoenvironmental reconstructions
Peatland ecosystems are valued as natural archives of past climatic and vegetation changes and as such their study is essential for palaeoenvironmental reconstructions over millennia. Fires in peatlands are dominated by smouldering combustion which is the self-sustained, slow, low temperature, flameless form of burning. Most studies on peat fires to date have focused on ignition conditions, C losses or atmospheric emissions, but there is a significant gap in the understanding of the evolution of organic matter (OM) following smouldering. A key feature of smouldering fires is that they consume most of the pyrogenic char produced. Consequently, it may be that most smouldering fires are simply not visible using standard palaeontological techniques. Here we present the possibility of identifying palaeofires by following their physical and chemical signature along a peat profile. We have undertaken laboratory experiments on Sphagnum peat columns and measured physical, chemical and spectroscopic changes of OM features induced by smouldering on samples of varying moisture content. We reveal that there is a higher production of aromatic and condensed molecules, an increase of the total N and a decrease of the C/N ratio, besides significant variations of pH, electrical conductivity and ash content. Several of these changes have, in previous studies, been taken to be indicative of alterations in atmospheric dust deposition and climate-driven changes (e.g. vegetation, water table fluctuation, decomposition and mineralization processes), but are also produced by smouldering fires. Our results imply that smouldering fires should therefore also be considered in climatic and floral reconstructions drawn from peat cores and that these additional physical and chemical changes may serve to enhance our understanding of palaeofire histories. © 2014 the Authors.
Abstract.
Hesselbo SP, Bjerrum CJ, Hinnov LA, MacNiocaill C, Miller KG, Riding JB, van de Schootbrugge B, Mochras Revisited Science Team (2013). Mochras borehole revisited: a new global standard for Early Jurassic earth history. Scientific Drilling, 16, 81-91.
Belcher CM, Punyasena SW, Sivaguru M (2013). Novel application of confocal laser scanning microscopy and 3D volume rendering toward improving the resolution of the fossil record of charcoal.
PLoS One,
8(8).
Abstract:
Novel application of confocal laser scanning microscopy and 3D volume rendering toward improving the resolution of the fossil record of charcoal.
Variations in the abundance of fossil charcoals between rocks and sediments are assumed to reflect changes in fire activity in Earth's past. These variations in fire activity are often considered to be in response to environmental, ecological or climatic changes. The role that fire plays in feedbacks to such changes is becoming increasingly important to understand and highlights the need to create robust estimates of variations in fossil charcoal abundance. The majority of charcoal based fire reconstructions quantify the abundance of charcoal particles and do not consider the changes in the morphology of the individual particles that may have occurred due to fragmentation as part of their transport history. We have developed a novel application of confocal laser scanning microscopy coupled to image processing that enables the 3-dimensional reconstruction of individual charcoal particles. This method is able to measure the volume of both microfossil and mesofossil charcoal particles and allows the abundance of charcoal in a sample to be expressed as total volume of charcoal. The method further measures particle surface area and shape allowing both relationships between different size and shape metrics to be analysed and full consideration of variations in particle size and size sorting between different samples to be studied. We believe application of this new imaging approach could allow significant improvement in our ability to estimate variations in past fire activity using fossil charcoals.
Abstract.
Author URL.
Belcher CM (2013). Preface. Fire Phenomena and the Earth System: an Interdisciplinary Guide to Fire Science
Hadden RM, Rein G, Belcher CM (2013). Study of the competing chemical reactions in the initiation and spread of smouldering combustion in peat.
Proceedings of the Combustion Institute,
34(2), 2547-2553.
Abstract:
Study of the competing chemical reactions in the initiation and spread of smouldering combustion in peat
Smouldering combustion of natural fuel layers such as peatlands leads to the largest fires on Earth and posses a possible positive feedback mechanism to climate change. In this paper, we use an experimental methodology to study the smouldering combustion of samples of peat under a wide range burning conditions. Vertical samples (30 mm deep and 125 mm in diameter) are ignited by radiation on the top free surface and the smouldering front propagates downward against a forced flow of oxidizer. By varying the oxygen concentration ([O2]) and the ignition conditions we investigate the competing pyrolysis and oxidation reactions. A reaction framework with two regimes is consistently observed. The measurements show that a char species is formed by the competing pyrolysis and oxidation reactions in the first regime resulting in net char production and in the second regime char oxidation results in conversion of the char to ash. Lower mass loss rates and the larger residual mass at lower [O2] suggest that a wider smouldering front is required to sustain combustion as the [O 2] is decreased. These results improve our understanding of smouldering phenomena and the role of the competing chemical reactions. © 2012 the Combustion Institute. Published by Elsevier Inc. All rights reserved.
Abstract.
He T, Pausas JG, Belcher CM, Schwilk DW, Lamont BB (2012). Fire‐adapted traits of Pinus arose in the fiery Cretaceous.
New Phytologist,
194(3), 751-759.
Abstract:
Fire‐adapted traits of Pinus arose in the fiery Cretaceous
The mapping of functional traits onto chronograms is an emerging approach for the identification of how agents of natural selection have shaped the evolution of organisms. Recent research has reported fire-dependent traits appearing among flowering plants from 60 million yr ago (Ma). Although there are many records of fossil charcoal in the Cretaceous (65-145Ma), evidence of fire-dependent traits evolving in that period is lacking. We link the evolutionary trajectories for five fire-adapted traits in Pinaceae with paleoatmospheric conditions over the last 250million yr to determine the time at which fire originated as a selective force in trait evolution among seed plants. Fire-protective thick bark originated in Pinus c. 126Ma in association with low-intensity surface fires. More intense crown fires emerged c. 89Ma coincident with thicker bark and branch shedding, or serotiny with branch retention as an alternative strategy. These innovations appeared at the same time as the Earth's paleoatmosphere experienced elevated oxygen levels that led to high burn probabilities during the mid-Cretaceous. The fiery environments of the Cretaceous strongly influenced trait evolution in Pinus. Our evidence for a strong correlation between the evolution of fire-response strategies and changes in fire regime 90-125Ma greatly backdates the key role that fire has played in the evolution of seed plants. © 2012 the Authors. New Phytologist © 2012 New Phytologist Trust.
Abstract.
Bacon KL, Belcher CM, Hesselbo SP, McElwain JC (2011). The Triassic-Jurassic Boundary Carbon-Isoptope Excursions Expressed in Taxonically Identified Leaf Cuticles. PALAIOS, 26, 461-469.
Belcher CM, Yearsley JM, Hadden RM, McElwain JC, Rein G (2010). Baseline Intrinsic Flammability of Earth’s Ecosystems Estimated from Paleoatmospheric Oxygen over the Past 350 Million Years. Proceedings of the National Academy of Sciences, 107, 22448-22453.
Belcher CM (2010). From Fiery Beginnings: Wildfires Facilitated the Spread of Angiosperms in the Cretaceous. New Phytologist(188), 913-915.
Belcher CM, Mander L, Rein G, Jervis FX, Haworth M, Glasspool IJ, Hesselbo SP, McElwain JC (2010). Increased Fire Activity at the Triassic/Jurassic Boundary in Greenland due to Climate-Driven Floral Change. Nature Geoscience, 3, 426-429.
Belcher CM, Finch P, Collinson ME, Scott AC, Grassineau NV (2009). Geochemical Evidence for Combustion of Hydrocarbons During the K-T Impact Event. Proceedings of the National Academy of Sciences, 106, 4112-4117.
Belcher CM (2009). Reigniting the Cretaceous-Palaeogene Firestorm Debate. Geology, 37, 1147-1148.
Harvey MC, Brassell SC, Belcher CM, Montanari A (2008). Combustion of Fossil Organic Matter at the K-P Boundary. Geology, 36, 335-358.
Belcher CM, McElwain JC (2008). Limits for Combustion in Low O2 Redefine Paleoatmospheric Predictions for the Mesozoic. Science, 321, 1197-1200.
Morgan J, Lana C, Kearsley A, Coles B, Belcher CM, Montanari S, Dias E, Barbosa E, Neumann V (2006). Analyses of Shocked Quartz at the Global K-P Boundary Indicate an Origin from a Single, High- Angle, Oblique Impact at Chicxulub. Earth and Planetary Science Letters, 251, 264-279.
Belcher CM, Collinson ME, Scott AC (2005). Constraints on the Thermal Power Released from the Chicxulub Impactor: New Evidence from Multi-Method Charcoal Analysis. Journal of the Geological Society of London, 162, 591-602.
Belcher CM, Collinson ME, Sweet AR, Hildebrand AR, Scott AC (2004). Reply to comment on Fireball Passes and Nothing Burns - the Role of Thermal Radiation in the K-T Event: Evidence from the Charcoal Record of North America by Robertson et al.. Geology, 32, e50-e51.
Belcher CM, Collinson ME, Sweet AR, Hildebrand AR, Scott AC (2003). Fireball Passes and Nothing Burns - the Role of Thermal Radiation in the K-T Event: Evidence from the Charcoal Record of North America. Geology, 31, 1061-1064.
Chapters
Torrence K, Switzer C, Carvel R, Hadden RM, Belcher CM (In Press). Self-sustained smouldering combustion of a coal-waster heap in central Scotland. In Stracher GB, Prakash A, Sokol EV (Eds.) .
Prat-Guitart N, Nugent C, Mullen E, Mitchell FJG, Hawthorne D, Belcher CM, Yearsley JM (2018). History of irish peatland fires. In (Ed) Coal and Peat Fires: a Global Perspective, 452-482.
Prat-Guitart N, Hadden RM, Belcher CM, Rein G, Yearsley JM (2015). Infrared Image Analysis as a Tool for Studying the Horizontal Smoldering Propagation of Laboratory Peat Fires. In (Ed)
Coal and Peat Fires: a Global Perspective, 121-139.
Abstract:
Infrared Image Analysis as a Tool for Studying the Horizontal Smoldering Propagation of Laboratory Peat Fires
Abstract.
Belcher CM, Collinson ME, Scott AC (2013). A 450-Million-Year History of Fire. In Belcher CM (Ed) Fire Phenomena and the Earth System: an interdisciplinary Guide to Fire Science, Wiley, 229-229.
Belcher CM, Mander L (2012). Catastrophe: Extraterrestrial Impacts, Massive Volcanism and the Biosphere. In Henderson-Sellers A, McGuffie K (Eds.) Future Climates of the World, 463-485.
Belcher CM (2006). Impacts and Wildfires - an Analysis of the K-T Event. In Cockell C, Koerberl C, Gilmour I (Eds.) Biological Processes Associated with Impact Events, Springer, 221-243.
Conferences
New SL, Hudspith VA, Belcher CM (2018). Assessing fire severity using charcoal reflectance following a recent heathland wildfire on Carn Brea, Cornwall, UK.
Author URL.
Losiak A, Belcher C, Hudspith V, Bronikowska M, Zhu M, Joeleht A, Plado J, Wilk J (2016). KAALI IMPACT CRATER: IMPACT-PRODUCED CHARCOAL SHEDS LIGHT ON THE PROCESSES ASSOCIATED WITH THE FORMATION OF SMALL CRATERS.
Author URL.
Publications by year
In Press
New SL, Belcher C, Hudspith VA, Gallego-Sala AV (In Press). Holocene fire history: can evidence of peat burning be found in the palaeo-archive?.
Mires and Peat,
18, 1-11.
Abstract:
Holocene fire history: can evidence of peat burning be found in the palaeo-archive?
Smouldering wildfires in peatlands have the potential to release substantial amounts of the carbon currently sequestered in these ecosystems. However, past studies of Holocene fire history in peatlands have given little consideration to the identification of evidence left behind after peat burning, or to charring of the peat matrix. In this study, modern peat samples from peatlands across the globe were charred in order to assess the identifiable characteristics of charred peat. On this basis we believe that charred aggregates of partially decayed organics which can be identified in cores provide clear evidence that the peat matrix itself burned. A range of
charred morphotypes could be found throughout a 2 m peat core from
and we are able to identify charred partially decayed aggregates that appeared to correspond with peaks in fire activity on the bog. These may reflect periods when surface fires ignited the peat surface below, or when the radiant heat from surface fires was sufficient to pyrolyse the surface peat. We conclude that it is possible to find evidence of peat burning in the palaeo-archive, and that future studies should begin to document the occurrence of charred particles so that the discipline can begin to build a picture of possible past peat fire
activity.
Abstract.
Torrence K, Switzer C, Carvel R, Hadden RM, Belcher CM (In Press). Self-sustained smouldering combustion of a coal-waster heap in central Scotland. In Stracher GB, Prakash A, Sokol EV (Eds.) .
Belcher CM (In Press). The influence of leaf morphology on litter flammability and
its utility for interpreting palaeofire. Philosophical Transactions of the Royal Society of London: Biological Sciences
2022
Linley GD, Jolly CJ, Doherty TS, Geary WL, Armenteras D, Belcher CM, Bliege Bird R, Duane A, Fletcher M-S, Giorgis MA, et al (2022). What do you mean, 'megafire'?.
GLOBAL ECOLOGY AND BIOGEOGRAPHY,
31(10), 1906-1922.
Author URL.
2021
Belcher CM, New SL, Gallagher MR, Grosvenor MJ, Clark K, Skowronski NS (2021). Bark charcoal reflectance may have the potential to estimate the heat delivered to tree boles by wildland fires.
INTERNATIONAL JOURNAL OF WILDLAND FIRE,
30(5), 391-397.
Author URL.
Denis EH, Maibauer BJ, Bowen GJ, Jardine PE, Harrington GJ, Baczynski AA, McInerney FA, Collinson ME, Belcher CM, Wing SL, et al (2021). Decreased soil carbon in a warming world: Degraded pyrogenic carbon during the Paleocene-Eocene Thermal Maximum, Bighorn Basin, Wyoming.
Earth and Planetary Science Letters,
566Abstract:
Decreased soil carbon in a warming world: Degraded pyrogenic carbon during the Paleocene-Eocene Thermal Maximum, Bighorn Basin, Wyoming
Global warming will likely perturb carbon storage and cycling throughout many components of the exogenic carbon cycle, but its net impact on the long-term fate of organic carbon stabilized in soils is unclear. Abrupt warming during the Paleocene-Eocene Thermal Maximum (PETM) profoundly altered vegetation and hydrologic patterns globally. To assess the consequences for soil carbon in a mid-latitude region we measured total organic carbon (%TOC), polycyclic aromatic hydrocarbons (PAHs), charcoal, and sporomorphs (pollen and spores) at two paleo-floodplain depositional sites in the Bighorn Basin, Wyoming, USA. At both sites %TOC, PAHs, charcoal, and sporomorphs declined during the PETM. The decline in pyrogenic carbon, which is more severe than the decline in %TOC, is consistent with isotopic and fossil evidence for degradation of labile organic compounds and preservation of highly refractory allochthonous organic carbon. The severe loss of less-labile contemporaneous PETM (autochthonous) soil carbon, illustrated by the fate of pyrogenic carbon, indicates intensified rates of organic matter decay during the PETM. Because of the highly degraded signature of organic matter in these PETM sections, it is difficult to discern if less pyrogenic carbon is in part a consequence of less fire occurrence during the PETM. We propose that in this mid-latitude region of the western USA increased soil carbon oxidation hindered soil carbon sequestration during this period of hotter climate with more seasonal precipitation.
Abstract.
Solofondranohatra CL, Vorontsova MS, Dewhirst RA, Belcher CM, Cable S, Jeannoda V, Lehmann CER (2021). Shade alters the growth and architecture of tropical grasses by reducing root biomass.
Biotropica,
53(4), 1052-1062.
Abstract:
Shade alters the growth and architecture of tropical grasses by reducing root biomass
Tropical grassy biomes have variable tree cover and are often characterized by a flammable grassy ground layer where the dominating grass species have strategies to persist and proliferate with frequent fire. However, there is limited understanding of how grass growth and flammability traits respond to light availability. We experimentally grew 14 grass species characteristic of the Malagasy Central Highlands for one year with four treatments of light exclusion ranging from 0 – 60%. Eight plant functional traits and four leaf flammability traits were measured: plant height, bulk density, aboveground biomass, belowground biomass, ratio of root to shoot biomass, specific leaf area, leaf length, leaf width, leaf heat release capacity, temperature of maximum decomposition, total heat release and peak heat release rate. Belowground biomass, the ratio of root to shoot biomass, and bulk density were all negatively affected by decreasing light availability. Surprisingly, aboveground biomass showed no significant change with changing light availability, although there was a trend toward shorter plants in low light. At a leaf level, declining light availability increased specific leaf area, leaf length, and leaf width. In terms of leaf flammability, of the four traits measured, unexpectedly, only leaf total heat release was significantly positively related to declining light availability. These results suggest field alterations in grass flammability may be primarily related to plant architecture and microclimates. The shifts in allometry and substantial reduction in belowground biomass suggest that grasses would be rapidly lost from shaded environments with a diminished competitive capacity to resprout.
Abstract.
Belcher CM, Mills BJW, Vitali R, Baker SJ, Lenton TM, Watson AJ (2021). The rise of angiosperms strengthened fire feedbacks and improved the regulation of atmospheric oxygen.
Nature Communications,
12(1).
Abstract:
The rise of angiosperms strengthened fire feedbacks and improved the regulation of atmospheric oxygen
The source of oxygen to Earth’s atmosphere is organic carbon burial, whilst the main sink is oxidative weathering of fossil carbon. However, this sink is to insensitive to counteract oxygen rising above its current level of about 21%. Biogeochemical models suggest that wildfires provide an additional regulatory feedback mechanism. However, none have considered how the evolution of different plant groups through time have interacted with this feedback. The Cretaceous Period saw not only super-ambient levels of atmospheric oxygen but also the evolution of the angiosperms, that then rose to dominate Earth’s ecosystems. Here we show, using the COPSE biogeochemical model, that angiosperm-driven alteration of fire feedbacks likely lowered atmospheric oxygen levels from ~30% to 25% by the end of the Cretaceous. This likely set the stage for the emergence of closed-canopy angiosperm tropical rainforests that we suggest would not have been possible without angiosperm enhancement of fire feedbacks.
Abstract.
2020
New S (2020). Charcoal reflectance: a quantitative approach to understanding the impact of fire on an ecosystem.
Abstract:
Charcoal reflectance: a quantitative approach to understanding the impact of fire on an ecosystem
This thesis develops the charcoal reflectance method into a novel metric with which to assess fire severity and begin to explore the relationship between this and the amount of energy that has been delivered across a burned area.
The ability to better understand the effects of fires on ecosystems is critical for future policy and management strategies especially as in some regions of the Earth fire is predicted to become a more prevalent and catastrophic disturbance.
Charcoal is a key product of wildfire, resulting from the incomplete combustion of fuel. During the creation of charcoal, the energy from the fire alters the atomic structure of the plant material and it is eventually re-ordered to a more graphite-like structure. This re-ordering of cells alters the reflective properties of the charcoal i.e. there is an increase in the quantifiable amount of light reflected from the surface of the charcoal thus allowing researchers to study the reflectance properties of charcoal. It has been suggested that the properties of charcoal may be capable of capturing evidence of the heat distribution throughout a wildfire. As such charcoal may be able to provide a means with which to assess fire severity and the amount of energy that has been applied to fuel to create charcoal.
At present, there are two main tools by which fire severity is assessed: Qualitative fire severity scores taken at the ground-level, and quantitative satellite-based approaches. In this thesis, I examine how well charcoal reflectance compares to existing fire severity metrics whilst developing it into a post-fire assessment tool that has the potential to assist in future policy and management decisions, and in predictions of carbon budgeting for ecosystems.
Abstract.
Losiak A, Joeleht A, Plado J, Szyszka M, Kirsimae K, Wild EM, Steier P, Belcher CM, Jazwa AM, Helde R, et al (2020). Determining the age and possibility for an extraterrestrial impact formation mechanism of the Ilumetsa structures (Estonia).
METEORITICS & PLANETARY SCIENCE,
55(2), 274-293.
Author URL.
Dewhirst RA, Smirnoff N, Belcher CM (2020). Pine species that support crown fire regimes have lower leaf-level terpene contents than those native to surface fire regimes.
Fire,
3(2), 1-19.
Abstract:
Pine species that support crown fire regimes have lower leaf-level terpene contents than those native to surface fire regimes
Fire is increasingly being recognised as an important evolutionary driver in fire-prone environments. Biochemical traits such as terpene (volatile isoprenoid) concentration are assumed to influence plant flammability but have often been overlooked as fire adaptations. We have measured the leaf-level flammability and terpene content of a selection of Pinus species native to environments with differing fire regimes (crown fire, surface fire and no fire). We demonstrate that this biochemical trait is associated with leaf-level flammability which likely links to fire-proneness and we suggest that this contributes to post-fire seedling survival. We find that surface-fire species have the highest terpene abundance and are intrinsically the most flammable, compared to crown-fire species. We suggest that the biochemical traits of surface fire species may have been under selective pressure to modify the fire environment at the leaf and litter scale to moderate fire spread and intensity. We indicate that litter flammability is driven not only by packing ratios and bulk density, but also by terpene content.
Abstract.
Hudspith VA, Belcher CM (2020). Some semifusinite in coal may form during diagenesis, not wildfires.
International Journal of Coal Geology,
218Abstract:
Some semifusinite in coal may form during diagenesis, not wildfires
Semifusinite can be an important component of coals and has previously been interpreted to represent partially charred material produced in palaeowildfires. Low reflecting semifusinite is well known for its chemically reactive properties, good burning behaviour, and for its reflectance to increase with coal rank. Yet, when inertinite in coal and sediments is used to interpret palaeowildfire history, the diagenetic history of the basin is rarely considered. Here, we sought to explore whether the low temperature heating that would occur during diagenesis over geological timescales is sufficient to produce semifusinite. Considering the interpretation that semifusinite represents partially charred material, we reheated thermally degraded, but not charred, wood at 100 °C and 200 °C for 24 h. Through prolonged heating at low temperatures, the previously thermally altered but non-charred wood increased in reflectance to such an extent that it would be classified as semifusinite. This finding suggests that not all semifusinite necessarily has a wildfire origin and calls into question its utility in interpreting palaeowildfire activity.
Abstract.
Crawford AJ, Belcher CM (2020). Volumetric measurement of fossil charcoal: Principles, applications and potential.
Holocene,
30(10), 1481-1487.
Abstract:
Volumetric measurement of fossil charcoal: Principles, applications and potential
Quantifying sedimentary charcoal content by estimation of volume from two-dimensional images is a relatively new and little-used method, but has the potential to improve the accuracy of fire histories. It requires a power transformation of area data, and multiplication by a coefficient to account for particle shape. The latter step has been routinely overlooked, or considered unnecessary, with volume estimates made simply by power transformation of the area data. Some researchers have used the method on the basis of the power transformation only, and others have rejected it as unnecessary on the same basis. However, the assumption that the shape coefficient can be ignored is likely to introduce very large errors, resulting in overestimation of charcoal volume. The magnitude of the error is indicated by a limited amount of empirical data obtained from volumetric measurement of individual charcoal particles, and accurate use of the method would require considerable further work to extend this data set. In a sedimentary sequence where particle morphology varies with depth, the errors identified could seriously distort the fire history produced. However, as such variation is easily identified, the method can still improve charcoal quantification where morphology is stationary.
Abstract.
2019
Boulton CA, Belcher CM (2019). A novel approach for predicting the probability of ignition of palaeofires using fossil leaf assemblages.
Palaeontology,
62(5), 715-730.
Abstract:
A novel approach for predicting the probability of ignition of palaeofires using fossil leaf assemblages
Many metrics are used to predict and manage wildfires today but it is difficult to directly apply these to past wildfires histories. Developing an approach that enables estimation of these fire metrics in the past would provide significant power in our ability to compare past fire risk with that of the modern day. We use the Climate Leaf Analysis Multivariate Program (CLAMP) to estimate warm month mean temperature and annual mean relative humidity for a modern day leaf dataset and establish a novel methodology by which we can generate ‘pseudo-daily’ meteorological parameters to calculate the probability of ignition (p(I)), an aspect of the North American Fire Danger Rating System. We test this methodology on Tortonian aged fossil leaves (11.62–7.25 Ma) from five sites across California, which reveal that the Tortonian was cooler and considerably more humid and that p(I) was lower during this time than in the region today.
Abstract.
Baker SJ, Belcher CM, Barclay RS, Hesselbo SP, Laurin J, Sageman BB (2019). CO2-induced climate forcing on the fire record during the initiation of Cretaceous oceanic anoxic event 2. Geological Society of America Bulletin
Pointer R (2019). Fire & Global Change During Key Intervals of the Late Triassic & Early Jurassic with a Focus on the Central Polish Basin.
Abstract:
Fire & Global Change During Key Intervals of the Late Triassic & Early Jurassic with a Focus on the Central Polish Basin
Core from modern-day Poland recovering fluvial and paralic strata provides an excellent record of climatic and environmental changes in the Central Polish Basin during two key intervals of the Early Jurassic. Thick successions of Rhaetian-Hettangian and Pliensbachian-Toarcian age are examined using a number of techniques in order to understand the wildfire activity history, carbon-cycle interactions, and organic matter composition of sediments at two sites in the Central Polish Basin. Physical and geochemical proxies for wildfire activity show evidence of increased wildfire activity both prior to and after the Toarcian Oceanic Anoxic Event (OAE) at the Kazewy-1 site, with suppression of wildfire activity during the negative carbon-isotope excursion of the OAE. Correlation with published wildfire activity proxy records from additional sites in the Tethyan realm shows that this pattern was not limited to the Central Polish Basin, but is part of a wider, regional change. Additionally, new wildfire activity proxy records show increased wildfire activity across the Triassic-Jurassic Boundary at the Kaszewy-1 and Niekłań PIG-1 sites in the Central Polish Basin, correlating with other contemporaneous proxy records from Denmark and Greenland. New carbon-isotope records generated from terrestrial organic matter from the Niekłań PIG-1 core show trends towards heavier δ¹³C values immediately after the Triassic-Jurassic Boundary, providing evidence of a perturbation to the carbon-cycle at this time. Exploratory investigation of sediments from the Kaszewy-1 core provides a new record of BIT indices of Early Jurassic sediments, surpassing the oldest-known use of this terrestrial organic matter input proxy. Additionally, a newly-developed technique is used to investigate carbon-isotope variability in fossil terrestrial organic matter across the Toarcian Oceanic Anoxic Event carbon-isotope excursions. A new record of individual phytoclast δ¹³C values demonstrates that, despite δ¹³C variability between phytoclasts from a single horizon, larger overall trends in δ¹³C values can be identified from single phytoclast δ¹³C measurements.Core from modern-day Poland recovering fluvial and paralic strata provides an excellent record of climatic and environmental changes in the Central Polish Basin during two key intervals of the Early Jurassic. Thick successions of Rhaetian-Hettangian and Pliensbachian-Toarcian age are examined using a number of techniques in order to understand the wildfire activity history, carbon-cycle interactions, and organic matter composition of sediments at two sites in the Central Polish Basin. Physical and geochemical proxies for wildfire activity show evidence of increased wildfire activity both prior to and after the Toarcian Oceanic Anoxic Event (OAE) at the Kazewy-1 site, with suppression of wildfire activity during the negative carbon-isotope excursion of the OAE. Correlation with published wildfire activity proxy records from additional sites in the Tethyan realm shows that this pattern was not limited to the Central Polish Basin, but is part of a wider, regional change. Additionally, new wildfire activity proxy records show increased wildfire activity across the Triassic-Jurassic Boundary at the Kaszewy-1 and Niekłań PIG-1 sites in the Central Polish Basin, correlating with other contemporaneous proxy records from Denmark and Greenland. New carbon-isotope records generated from terrestrial organic matter from the Niekłań PIG-1 core show trends towards heavier δ¹³C values immediately after the Triassic-Jurassic Boundary, providing evidence of a perturbation to the carbon-cycle at this time. Exploratory investigation of sediments from the Kaszewy-1 core provides a new record of BIT indices of Early Jurassic sediments, surpassing the oldest-known use of this terrestrial organic matter input proxy. Additionally, a newly-developed technique is used to investigate carbon-isotope variability in fossil terrestrial organic matter across the Toarcian Oceanic Anoxic Event carbon-isotope excursions. A new record of individual phytoclast δ¹³C values demonstrates that, despite δ¹³C variability between phytoclasts from a single horizon, larger overall trends in δ¹³C values can be identified from single phytoclast δ¹³C measurements.
Abstract.
Harrison ME, Ottay JB, D’Arcy LJ, Cheyne SM, Anggodo, Belcher C, Cole L, Dohong A, Ermiasi Y, Feldpausch T, et al (2019). Tropical forest and peatland conservation in Indonesia: Challenges and directions. People and Nature, 2(1), 4-28.
2018
Walding NG, Williams HTP, McGarvie S, Belcher CM (2018). A comparison of the US National Fire Danger Rating System (NFDRS) with recorded fire occurrence and final fire size.
International Journal of Wildland Fire,
27(2), 99-113.
Abstract:
A comparison of the US National Fire Danger Rating System (NFDRS) with recorded fire occurrence and final fire size
Most previous research has assessed the ability of the National Fire Danger Rating System (NFDRS) to portray fire activity at either single sites or on small spatial scales, despite it being a nation-wide system. This study seeks to examine the relationships between a set of NFDRS fire danger indices (Fire Danger Ratings, Staffing Level and the Ignition Component) and measures of fire activity (fire occurrence and final fire size) across the entire conterminous US over an 8-year period. We reveal that different regions of the US display different levels of correspondence between each of the fire danger indices and recorded fire activity. Areas in the Southern and Eastern Geographic Area Coordination Centers (GACCs) exhibit weaker correlations than those in the Northwest, Northern Rockies, Great Basin and Northern California GACCs. Peaks in fire occurrence are shown to occur at mid-low values of fire danger whereas final fire sizes increase monotonically with each fire danger index. Our findings appear to align with perceived shifts in management practices currently employed across the US and indicate that the ability of the NFDRS to apportion the resources required to combat large fires is in general well developed.
Abstract.
New SL, Hudspith VA, Belcher CM (2018). Assessing fire severity using charcoal reflectance following a recent heathland wildfire on Carn Brea, Cornwall, UK.
Author URL.
Archibald S, Lehmann CER, Belcher CM, Bond WJ, Bradstock RA, Daniau A-L, Dexter KG, Ferrestel EJ, Greve M, He T, et al (2018). Biological and geophysical feedbacks with fire in the Earth system. Environmental Research Letters, 13
Hudspith VA, Hadden RM, Bartlett AI, Belcher CM (2018). Does fuel type influence the amount of charcoal produced in wildfires? Implications for the fossil record.
Palaeontology,
61(2), 159-171.
Abstract:
Does fuel type influence the amount of charcoal produced in wildfires? Implications for the fossil record
Charcoal occurrence is extensively used as a tool for understanding wildfires over geological timescales. Yet, the fossil charcoal literature to date rarely considers that fire alone is capable of creating a bias in the abundance and nature of charcoal it creates, before it even becomes incorporated into the fossil record. In this study we have used state-of-the-art calorimetry to experimentally produce charcoal from 20 species that represent a range of surface fuels and growth habits, as a preliminary step towards assessing whether different fuel types (and plant organs) are equally likely to remain as charcoal post-fire. We observe that charcoal production appears to be species specific, and is related to the intrinsic physical and chemical properties of a given fuel. Our observations therefore suggest that some taxa are likely to be overrepresented in fossil charcoal assemblages (i.e. needle-shed conifers, tree ferns) and others poorly represented, or not preserved at all (i.e. broad shoot-shed conifers, weedy angiosperms, shrub angiosperms, some ferns). Our study highlights the complexity of charcoal production in modern fuels and we consider what a bias in charcoal production may mean for our understanding of palaeowildfires.
Abstract.
Doerr SH, Santín C, Merino A, Belcher CM, Baxter G (2018). Fire as a Removal Mechanism of Pyrogenic Carbon from the Environment: Effects of Fire and Pyrogenic Carbon Characteristics.
Frontiers in Earth Science,
6Abstract:
Fire as a Removal Mechanism of Pyrogenic Carbon from the Environment: Effects of Fire and Pyrogenic Carbon Characteristics
Pyrogenic carbon (PyC, charcoal) is produced during vegetation fires at a rate of ~116–385 Tg C yr−1 globally. It represents one of the most degradation-resistant organic carbon pools, but its long-term fate and the processes leading to its degradation remain subject of debate. A frequently highlighted potential loss mechanism of PyC is its consumption in subsequent fires. However, only three studies to date have tested this hypothesis with reported losses of 300°C. Mass losses also showed a significant negative correlation (r = −0.38, p = 0.05) with thermal recalcitrance (T50) determined using Differential Scanning Calorimetry (DSC) and Tmax with charcoal reflectance (Ro) determined after the fires (r = 0.46, p = 0.05). Losses in the high-intensity fire were significantly higher (p = 0.05) than in the low-intensity fire, but the latter had a higher rate of conversion of fuel to PyC. Our results demonstrate that exposure to fire can indeed be a significant removal mechanism for PyC that remains exposed on the ground after a previous fire. The losses found, however, are likely to represent an extreme upper range as most PyC produced in a fire would not remain exposed on the ground surface by the time the next fire occurs. Our data also demonstrate, for real wildfire conditions, the (i) contrasting resistance of different PyC types to combustion and (ii) contrasting net PyC losses between different fire intensities. The DSC and reflectance (Ro) results support the usefulness of these analyses in reflecting thermal degradation resistance and temperature exposure under actual wildfire conditions.
Abstract.
Crawford AJ, Baker SJ, Belcher CM (2018). Fossil charcoals from the Lower Jurassic challenge assumptions about charcoal morphology and identification.
Palaeontology,
61(1), 49-56.
Abstract:
Fossil charcoals from the Lower Jurassic challenge assumptions about charcoal morphology and identification
Charcoal morphometry is increasingly employed in the analysis of Quaternary sediments, but has not been applied in studies of earlier sediments. We present findings relating to charcoal morphometry and morphotypes in a Toarcian sequence, which contains a preponderance of highly elongate forms, and morphometric values well outside expected ranges. SEM imaging reveals elongate particles of two distinct kinds. One originates in conifer xylem, and may be associated with formation at high levels of heating. It is proposed that the other may derive from tree ferns, or from plants with similar growth forms. Our results show the importance of recognizing the wide morphological variation that exists in sedimentary charcoal. Failing to do so may result in serious errors in its identification, interpretation and quantification.
Abstract.
Cardoso AW, Oliveras I, Abernethy KA, Jeffery KJ, Lehmann D, Edzang Ndong J, McGregor I, Belcher CM, Bond WJ, Malhi YS, et al (2018). Grass Species Flammability, Not Biomass, Drives Changes in Fire Behavior at Tropical Forest-Savanna Transitions.
Frontiers in Forests and Global Change,
1Abstract:
Grass Species Flammability, Not Biomass, Drives Changes in Fire Behavior at Tropical Forest-Savanna Transitions
Forest-savanna mosaics are maintained by fire-mediated positive feedbacks; whereby forest is fire suppressive and savanna is fire promoting. Forest-savanna transitions therefore represent the interface of opposing fire regimes. Within the transition there is a threshold point at which tree canopy cover becomes sufficiently dense to shade out grasses and thus suppress fire. Prior to reaching this threshold, changes in fire behavior may already be occurring within the savanna. Such changes are neither empirically described nor their drivers understood. Fire behavior is largely driven by fuel flammability. Flammability can vary significantly between grass species and grass species composition can change near forest-savanna transitions. This study measured fire behavior changes at eighteen forest-savanna transition sites in a vegetation mosaic in Lopé National Park in Gabon, central Africa. The extent to which these changes could be attributed to changes in grass flammability was determined using species-specific flammability traits. Results showed simultaneous suppression of fire and grass biomass when tree canopy leaf area index (LAI) reached a value of 3, indicating that a fire suppression threshold existed within the forest-savanna transition. Fires became less intense and less hot prior to reaching this fire suppression threshold. These changes were associated with higher LAI values, which induced a change in the grass community, from one dominated by the highly flammable Anadelphia afzeliana to one dominated by the less flammable Hyparrhenia diplandra. Changes in fire behavior were not associated with changes in total grass biomass. This study demonstrated not only the presence of a fire suppression threshold but the mechanism of its action. Grass composition mediated fire-behavior within the savanna prior to reaching the suppression threshold, and grass species composition was mediated by tree canopy cover which was in turn mediated by fire-behavior. These findings highlight how biotic and abiotic controls interact and amplify each other in this mosaicked landscape to facilitate forest and savanna co-existence.
Abstract.
Prat-Guitart N, Nugent C, Mullen E, Mitchell FJG, Hawthorne D, Belcher CM, Yearsley JM (2018). History of irish peatland fires. In (Ed) Coal and Peat Fires: a Global Perspective, 452-482.
Haworth M, Belcher CM, Killi D, Dewhirst RA, Materassi A, Raschi A, Centritto M (2018). Impaired photosynthesis and increased leaf construction costs may induce floral stress during episodes of global warming over macroevolutionary timescales.
SCIENTIFIC REPORTS,
8 Author URL.
Haworth M, Belcher CM, Killi D, Dewhirst RA, Materassi A, Raschi A, Centritto M (2018). Impaired photosynthesis and increased leaf construction costs may induce floral stress during episodes of global warming over macroevolutionary timescales (vol 8, 6206, 2018).
SCIENTIFIC REPORTS,
8 Author URL.
New SL, Hudspith VA, Belcher CM (2018). Quantitative charcoal reflectance measurements better link to regrowth potential than ground-based fire-severity assessments following a recent heathland wildfire at Carn Brea, Cornwall, UK.
International Journal of Wildland Fire,
27(12), 845-850.
Abstract:
Quantitative charcoal reflectance measurements better link to regrowth potential than ground-based fire-severity assessments following a recent heathland wildfire at Carn Brea, Cornwall, UK
Charcoal has recently been suggested to retain information about the fire that generated it. When looked at under a microscope, charcoals formed by different aspects of fire behaviour indicate different ability to reflect the amount of light when studied using the appropriate technique. It has been suggested that this method, charcoal reflectance (Ro), might be able to provide a quantitative fire severity metric that can be used in conjunction with or instead of standard qualitative fire severity scores. We studied charcoals from a recent heathland wildfire in Carn Brea, Cornwall, UK, and assessed whether charcoal reflectance (Ro) can be linked to standard qualitative fire severity scores for the burned area. We found that charcoal reflectance was greater at sites along the burned area that had been scored as having a higher qualitative fire severity. However, there were clear instances where the quantitative charcoal reflectance measurements were able to better indicate damage and regrowth potential than qualitative scoring alone. We suggest measuring the reflectance of charcoals may not only be able to provide quantitative information about the spatial distribution of heat across a burned area post fire but that this approach is able to provide improvement to fire severity assessment approaches.
Abstract.
Belcher CM, New SL, Santín C, Doerr SH, Dewhirst RA, Grosvenor MJ, Hudspith VA (2018). What can charcoal reflectance tell us about energy release in wildfires and the properties of pyrogenic carbon?.
Frontiers in Earth Science,
6Abstract:
What can charcoal reflectance tell us about energy release in wildfires and the properties of pyrogenic carbon?
Here, we explore how charcoal formation under different heating regimes and circumstances leads to chars of different physical properties. In order to do this, we have undertaken (1) carefully controlled laboratory experiments that replicate the different heating regimes that might be experienced during a wildfire and (2) two experimental wildfires where heat variations were monitored across the burn from which resulting charcoal has been studied. The charcoal properties were assessed using charcoal reflectance that measures the light reflected back from the charcoals structure and which links to changes in its structural properties. We find that increased total heat released during combustion positively correlates with increased charcoal reflectance and that this is evidenced from both our laboratory experiments and experimental wildfires. Charcoals that related to lower total heat release were found to have more lignin remaining than those subjected to greater heating indicating that charcoals formed in lower energy regimes are likely to be more susceptible to post-fire degradation. We conclude that charcoal reflectance may make a useful metric with which to determine the distribution of energy delivery across a burned area and that this may be utilized to inform both variations in fire severity and enable the prediction of long-term C budgeting for different types of wildfire.
Abstract.
2017
Belcher CM, Hudspith VA (2017). Changes to Cretaceous surface fire behaviour influenced the spread of the early angiosperms.
New Phytologist,
213(3), 1521-1532.
Abstract:
Changes to Cretaceous surface fire behaviour influenced the spread of the early angiosperms
Angiosperms evolved and diversified during the Cretaceous period. Early angiosperms were short-stature weedy plants thought to have increased fire frequency and mortality in gymnosperm forest, aiding their own expansion. However, no explorations have considered whether the range of novel fuel types that diversified throughout the Cretaceous also altered fire behaviour, which should link more strongly to mortality than fire frequency alone. We measured ignitability and heat of combustion in analogue Cretaceous understorey fuels (conifer litter, ferns, weedy and shrubby angiosperms) and used these data to model palaeofire behaviour. Variations in ignition, driven by weedy angiosperms alone, were found to have been a less important feedback to changes in Cretaceous fire activity than previously estimated. Our model estimates suggest that fires in shrub and fern understories had significantly greater fireline intensities than those fuelled by conifer litter or weedy angiosperms, and whilst fern understories supported the most rapid fire spread, angiosperm shrubs delivered the largest amount of heat per unit area. The higher fireline intensities predicted by the models led to estimates of enhanced scorch of the gymnosperm canopy and a greater chance of transitioning to crown fires. Therefore, changes in fire behaviour driven by the addition of new Cretaceous fuel groups may have assisted the angiosperm expansion.
Abstract.
Baker SJ, Hesselbo SP, Lenton TM, Duarte LV, Belcher CM (2017). Charcoal evidence that rising atmospheric oxygen terminated Early Jurassic ocean anoxia. Nature Communications
Hudspith VA, Belcher CM, Barnes J, Dash CB, Kelly R, Hu FS (2017). Charcoal reflectance suggests heating duration and fuel moisture affected burn severity in four Alaskan tundra wildfires.
INTERNATIONAL JOURNAL OF WILDLAND FIRE,
26(4), 306-316.
Author URL.
Prat-Guitart N, Belcher CM, Thompson DK, Burns P, Yearsley JM (2017). Fine-scale distribution of moisture in the surface of a degraded blanket bog and its effects on the potential spread of smouldering fire.
Ecohydrology,
10(8).
Abstract:
Fine-scale distribution of moisture in the surface of a degraded blanket bog and its effects on the potential spread of smouldering fire
During rain-free periods, the water table in peatlands falls and the moisture content (MC) of top 10 cm, including the moss layer, depends upon the hydrophysical properties and the responses of the local composition of species to water deficit. Thus, the ecosystem becomes vulnerable to surface peat fires. The spread of such fires is often irregular; however, there is little understanding of how the fine-scale variation of peat MC can affect the spread of smouldering fire. We analyse the fine-scale distribution of surface MC from a degraded blanket bog (i.e. horizontal intervals of 10 cm), thus indirectly analysing the effect of fine-scale MC distribution on peat fire spread. We determine the relationship of vegetation and microtopography to the spatial distribution of near surface MC and the moisture gradient around patches of dry peat (less than 250% MC, moisture content in a dry mass basis). We found that the MC of the surface peat was distributed in clusters with dry patches (less than 250% MC) averaging 40 ± 15 cm in size. The MC gradient surrounding dry patches was 10 ± 7% MC∙cm−1. A mixed-effects model showed that dry patches were associated with lawns (of feather moss or Sphagnum) and hummocks of feather moss. Our model showed that wet patches were associated with both hummocks and hollows of Sphagnum. Therefore, the characterization of the surface MC in a fine-scale is critical if we are to understand the spread of fires in peatlands.
Abstract.
Hudspith VA, Belcher CM (2017). Fire biases the production of charred flowers: Implications for the Cretaceous fossil record.
Geology,
45(8), 727-730.
Abstract:
Fire biases the production of charred flowers: Implications for the Cretaceous fossil record
The radiation of angiosperm lineages during the Cretaceous Period (145.5-65.5 Ma) initiated one of the greatest floral turnovers to have occurred on our planet. Much of our understanding of the floral biology and diversity of these early angiosperms derives from exceptionally preserved charcoalified and coalified Cretaceous fossil floras. Although fire played an integral role in the production of charred early angiosperm flowers, research has not considered whether the fire is capable of creating a bias in the nature of the charcoalified flowers that are produced. Here we use calorimetry to experimentally produce morphologically variable charcoalified flowers. Our findings indicate that combustion behavior, floral structure, the number of flowers, and their arrangement (inflorescence) all affect the number of charred flowers that are produced. These observations suggest that charred flowers are not equally likely to be represented in Cretaceous charcoal assemblages, and some species may be missing from the fossil record entirely. This may in turn alter our understanding of early angiosperm evolution and the fossil record of fire.
Abstract.
Hudspith VA, Belcher CM (2017). Observations of the structural changes that occur during charcoalification: implications for identifying charcoal in the fossil record.
Palaeontology,
60(4), 503-510.
Abstract:
Observations of the structural changes that occur during charcoalification: implications for identifying charcoal in the fossil record
All of our current understanding of fossil charcoal structure comes from observations of modern wood charcoal produced in furnaces. These charcoals consistently show cell wall homogenization after prolonged heating (>325°C) and this is therefore considered to be a key identifying feature of fossil charcoal. Yet furnaces are unable to replicate the full combustion processes that occur during a wildfire. Here, for the first time, we have studied the microscopic structural evolution of charcoal produced using calorimetry, wherein the wood is ignited under controlled conditions and the heat release rate and other parameters measured, and the resulting charcoal studied using reflected light microscopy. We show that homogenization of cell walls is actually only a short-lived phase of charcoal formation that occurs during the early heating stages as the pyrolysis front traverses through the wood. Cell wall homogenization is then rapidly overprinted by the thinning, distortion and breakdown of cell walls, and a notable visual increase in reflectance. Our preliminary study therefore suggests that we need to first improve our understanding of charcoal formation in order to better understand the fossil record of wildfires.
Abstract.
2016
Mills BJW, Belcher CM, Lenton TM, Newton RJ (2016). A modeling case for high atmospheric oxygen concentrations during the Mesozoic and Cenozoic.
Geology,
44(12), 1023-1026.
Abstract:
A modeling case for high atmospheric oxygen concentrations during the Mesozoic and Cenozoic
Changes in atmospheric oxygen concentration over Earth history are commonly related to the evolution of animals and plants. But there is no direct geochemical proxy for O2 levels, meaning that estimations rely heavily on modeling approaches. The results of such studies differ greatly, to the extent that today's atmospheric mixing ratio of 21% might be either the highest or lowest level during the past 200 m.y. Long term oxygen sources, such as the burial in sediments of reduced carbon and sulfur species, are calculated in models by representation of nutrient cycling and estimation of productivity, or by isotope mass balance (IMB)-a technique in which burial rates are inferred in order to match known isotope records. Studies utilizing these different techniques produce conflicting estimates for paleoatmospheric O2, with nutrient-weathering models estimating concentrations close to, or above, that of the present day, and IMB models estimating low O2, especially during the Mesozoic. Here we reassess the IMB technique using the COPSE biogeochemical model. IMB modelling is confirmed to be highly sensitive to assumed carbonate δ13C, and when this input is defined following recent compilations, predicted O2 is significantly higher and in reasonable agreement with that of non-IMB techniques. We conclude that there is no model-based support for low atmospheric oxygen concentrations during the past 200 m.y. High Mesozoic O2 is consistent with wildfire records and the development of plant fire adaptions, but links between O2 and mammal evolution appear more tenuous.
Abstract.
Prat-Guitart N, Rein G, Hadden RM, Belcher CM, Yearsley JM (2016). Effects of spatial heterogeneity in moisture content on the horizontal spread of peat fires.
Sci Total Environ,
572, 1422-1430.
Abstract:
Effects of spatial heterogeneity in moisture content on the horizontal spread of peat fires.
The gravimetric moisture content of peat is the main factor limiting the ignition and spread propagation of smouldering fires. Our aim is to use controlled laboratory experiments to better understand how the spread of smouldering fires is influenced in natural landscape conditions where the moisture content of the top peat layer is not homogeneous. In this paper, we study for the first time the spread of peat fires across a spatial matrix of two moisture contents (dry/wet) in the laboratory. The experiments were undertaken using an open-top insulated box (22×18×6cm) filled with milled peat. The peat was ignited at one side of the box initiating smouldering and horizontal spread. Measurements of the peak temperature inside the peat, fire duration and longwave thermal radiation from the burning samples revealed important local changes of the smouldering behaviour in response to sharp gradients in moisture content. Both, peak temperatures and radiation in wetter peat (after the moisture gradient) were sensitive to the drier moisture condition (preceding the moisture gradient). Drier peat conditions before the moisture gradient led to higher temperatures and higher radiation flux from the fire during the first 6cm of horizontal spread into a wet peat patch. The total spread distance into a wet peat patch was affected by the moisture content gradient. We predicted that in most peat moisture gradients of relevance to natural ecosystems the fire self-extinguishes within the first 10cm of horizontal spread into a wet peat patch. Spread distances of more than 10cm are limited to wet peat patches below 160% moisture content (mass of water per mass of dry peat). We found that spatial gradients of moisture content have important local effects on the horizontal spread and should be considered in field and modelling studies.
Abstract.
Author URL.
Losiak A, Belcher C, Hudspith V, Bronikowska M, Zhu M, Joeleht A, Plado J, Wilk J (2016). KAALI IMPACT CRATER: IMPACT-PRODUCED CHARCOAL SHEDS LIGHT ON THE PROCESSES ASSOCIATED WITH THE FORMATION OF SMALL CRATERS.
Author URL.
Roos CI, Scott AC, Belcher CM, Chaloner WG, Aylen J, Bird RB, Coughlan MR, Johnson BR, Johnston FH, McMorrow J, et al (2016). Living on a flammable planet: Interdisciplinary, cross-scalar and varied cultural lessons, prospects and challenges.
Philosophical Transactions of the Royal Society B: Biological Sciences,
371(1696).
Abstract:
Living on a flammable planet: Interdisciplinary, cross-scalar and varied cultural lessons, prospects and challenges
Living with fire is a challenge for human communities because they are influenced by socio-economic, political, ecological and climatic processes at various spatial and temporal scales. Over the course of 2 days, the authors discussed how communities could live with fire challenges at local, national and transnational scales. Exploiting our diverse, international and interdisciplinary expertise, we outline generalizable properties of fire-adaptive communities in varied settings where cultural knowledge of fire is rich and diverse. At the national scale, we discussed policy and management challenges for countries that have diminishing fire knowledge, but for whom global climate change will bring new fire problems. Finally, we assessed major fire challenges that transcend national political boundaries, including the health burden of smoke plumes and the climate consequences of wildfires. It is clear that to best address the broad range of fire problems, a holistic wildfire scholarship must develop common agreement in working terms and build across disciplines. We must also communicate our understanding of fire and its importance to the media, politicians and the general public.
Abstract.
Prat-Guitart N, Rein G, Hadden RM, Belcher CM, Yearsley JM (2016). Propagation probability and spread rates of self-sustained smouldering fires under controlled moisture content and bulk density conditions.
INTERNATIONAL JOURNAL OF WILDLAND FIRE,
25(4), 456-465.
Author URL.
Belcher CM, Hudspith VA (2016). The formation of charcoal reflectance and its potential use in post-fire assessments.
International Journal of Wildland Fire,
25(7), 775-779.
Abstract:
The formation of charcoal reflectance and its potential use in post-fire assessments
Charcoal has an exceptional ability to reflect light when viewed using reflectance microscopy. The amount of light reflected is variable depending on the differential ordering of graphite-like phases within the charcoal itself. It has been suggested that this relates to the temperature of formation, whereby higher formation temperatures result in high charcoal reflectance. However, this explanation is derived from oven-based chars that do not well represent the natural combustion process. Here, we have experimentally created charcoals using a cone calorimeter, in order to explore the development of charcoal reflectance during pre-ignition heating and peak heat-release rate, through to the end of flaming and the transition to char oxidation. We find that maximum charcoal reflectance is reached at the transition between pyrolysis and char oxidation, before its conversion to mineral ash, and indicates that our existing understanding of reflectance is in error. We suggest that charcoal reflectance warrants additional study as it may provide a useful quantitative addition to ground-based fire severity surveys, because it may allow exploration of surface heating after the main fire front has passed and the fire transitions to smouldering phases.
Abstract.
Scott AC, Chaloner WG, Belcher CM, Roos CI (2016). The interaction of fire and mankind. Philosophical Transactions of the Royal Society B: Biological Sciences, 371(1696).
Scott AC, Chaloner WG, Belcher CM, Roos CI (2016). The interaction of fire and mankind: Introduction.
Philosophical Transactions of the Royal Society B: Biological Sciences,
371(1696).
Abstract:
The interaction of fire and mankind: Introduction
Fire has been an important part of the Earth system for over 350 Myr. Humans evolved in this fiery world and are the only animals to have used and controlled fire. The interaction of mankind with fire is a complex one, with both positive and negative aspects. Humans have long used fire for heating, cooking, landscape management and agriculture, as well as for pyrotechnologies and in industrial processes over more recent centuries. Many landscapes need fire but population expansion into wildland areas creates a tension between different interest groups. Extinguishing wildfires may not always be the correct solution. A combination of factors, including the problem of invasive plants, landscape change, climate change, population growth, human health, economic, social and cultural attitudes that may be transnational make a reevaluation of fire and mankind necessary. The Royal Society meeting on Fire and mankind was held to address these issues and the results of these deliberations are published in this volume.
Abstract.
2015
He T, Belcher CM, Lamont BB, Lim SL (2015). A 350-million-year legacy of fire adaptation among conifers.
Journal of EcologyAbstract:
A 350-million-year legacy of fire adaptation among conifers
© 2015 British Ecological Society. Current phylogenetic evidence shows that fire began shaping the evolution of land plants 125 Ma, although the fossil charcoal record indicates that fire has a much longer history (>350 Ma). Serotiny (on-plant seed storage) is generally accepted as an adaptation to fire among woody plants. We developed a conceptual model of the requirements for the evolution of serotiny, and propose that serotiny is only expressed in the presence of a woody rachis as supporting structure, compact scales covering seeds as protective structure, seed wing as dispersal structure, and crown fire as the agent of selection and mechanism for seed release. This model is strongly supported by empirical data for modern ecosystems. We reconstructed the evolutionary history of intrinsic structural states required for the expression of serotiny in conifers, and show that these were diagnostic for early ('transitional') conifers from 332 Ma (late-Carboniferous). We assessed the likely flammable characteristics of early conifers and found that scale-leaved conifers burn rapidly and with high intensity, supporting the idea that crown fire regimes may have dominated early conifer ecosystems. Synthesis. Coupled with strong evidence for frequent fire throughout the Permian-Carboniferous and fossil evidence for other fire-related traits, we conclude that many early conifers were serotinous in response to intense crown fires, indicating that fire may have had a major impact on the evolution of plant traits as far back as 350 Ma.
Abstract.
Belcher CM, Hadden RM, Rein G, Morgan JV, Artemieva N, Goldin T (2015). An experimental assessment of the ignition of forest fuels by the thermal pulse generated by the cretaceous–palaeogene impact at chicxulub.
Journal of the Geological Society,
172(2), 175-185.
Abstract:
An experimental assessment of the ignition of forest fuels by the thermal pulse generated by the cretaceous–palaeogene impact at chicxulub
A large extraterrestrial body hit the Yucatán Peninsula at the end of the Cretaceous period. Models suggest that a substantial amount of thermal radiation was delivered to the Earth’s surface by the impact, leading to the suggestion that it was capable of igniting extensive wildfires and contributed to the end-Cretaceous extinctions. We have reproduced in the laboratory the most intense impact-induced heat fluxes estimated to have reached different points on the Earth’s surface using a fire propagation apparatus and investigated the ignition potential of forest fuels. The experiments indicate that dry litter can ignite, but live fuels typically do not, suggesting that any ignition caused by impact-induced thermal radiation would have been strongly regional dependent. The intense, but short-lived, pulse downrange and at proximal and intermediate distances from the impact is insufficient to ignite live fuel. However, the less intense but longer-lasting thermal pulse at distal locations may have ignited areas of live fuels. Because plants and ecosystems are generally resistant to single localized fire events, we conclude that any fires ignited by impact-induced thermal radiation cannot be directly responsible for plant extinctions, implying that heat stress is only part of the end-Cretaceous story.
Abstract.
Crawford AJ, Belcher CM (2015). Area–volume relationships for fossil charcoal and their relevance for fire history reconstruction.
The Holocene,
26(5), 822-826.
Abstract:
Area–volume relationships for fossil charcoal and their relevance for fire history reconstruction
Sedimentary charcoal is a widely used tool for reconstructing past fire histories. These fossil charcoals are normally quantified as the number or area of particles present in a sediment sample, but it is not known how well either measure is correlated with their volume. Areal measurements are often treated as the true measure of quantity, which may introduce bias to fire histories. The relationship of measured area to volume is a function of shape, and if this relationship can be understood, areal measurements may be adjusted to better reflect volume. We show that particle elongation may be particularly important when making such adjustments. We also establish a high degree of correlation between volume and area in a mid-Holocene mesocharcoal assemblage, which indicates that the bias may be small in similar cases.
Abstract.
Hudspith VA, Belcher CM, Kelly R, Hu FS (2015). Charcoal reflectance reveals early holocene boreal deciduous forests burned at high intensities.
PLoS One,
10(4).
Abstract:
Charcoal reflectance reveals early holocene boreal deciduous forests burned at high intensities.
Wildfire size, frequency, and severity are increasing in the Alaskan boreal forest in response to climate warming. One of the potential impacts of this changing fire regime is the alteration of successional trajectories, from black spruce to mixed stands dominated by aspen, a vegetation composition not experienced since the early Holocene. Such changes in vegetation composition may consequently alter the intensity of fires, influencing fire feedbacks to the ecosystem. Paleorecords document past wildfire-vegetation dynamics and as such, are imperative for our understanding of how these ecosystems will respond to future climate warming. For the first time, we have used reflectance measurements of macroscopic charcoal particles (>180μm) from an Alaskan lake-sediment record to estimate ancient charring temperatures (termed pyrolysis intensity). We demonstrate that pyrolysis intensity increased markedly from an interval of birch tundra 11 ky ago (mean 1.52%Ro; 485°C), to the expansion of trees on the landscape ~10.5 ky ago, remaining high to the present (mean 3.54%Ro; 640°C) irrespective of stand composition. Despite differing flammabilities and adaptations to fire, the highest pyrolysis intensities derive from two intervals with distinct vegetation compositions. 1) the expansion of mixed aspen and spruce woodland at 10 cal. kyr BP, and 2) the establishment of black spruce, and the modern boreal forest at 4 cal. kyr BP. Based on our analysis, we infer that predicted expansion of deciduous trees into the boreal forest in the future could lead to high intensity, but low severity fires, potentially moderating future climate-fire feedbacks.
Abstract.
Author URL.
Simpson KJ, Ripley BS, Christin P, Belcher CM, Lehmann CER, Thomas GH, Osborne CP (2015). Determinants of flammability in savanna grass species. Journal of Ecology, 104(1), 138-148.
Prat-Guitart N, Hadden RM, Belcher CM, Rein G, Yearsley JM (2015). Infrared Image Analysis as a Tool for Studying the Horizontal Smoldering Propagation of Laboratory Peat Fires. In (Ed)
Coal and Peat Fires: a Global Perspective, 121-139.
Abstract:
Infrared Image Analysis as a Tool for Studying the Horizontal Smoldering Propagation of Laboratory Peat Fires
Abstract.
Hudspith VA, Rimmer SM, Belcher CM (2015). Latest Permian chars may derive from wildfires, not coal combustion: REPLY. Geology Forum, 43(5), p. e363-p. e363.
2014
Mander L, Baker SJ, Belcher CM, Haselhorst DS, Rodriguez J, Thorn JL, Tiwari S, Urrego DH, Wesseln CJ, Punyasena SW, et al (2014). Accuracy and consistency of grass pollen identification by human analysts using electron micrographs of surface ornamentation.
Appl Plant Sci,
2(8).
Abstract:
Accuracy and consistency of grass pollen identification by human analysts using electron micrographs of surface ornamentation.
PREMISE OF THE STUDY: Humans frequently identify pollen grains at a taxonomic rank above species. Grass pollen is a classic case of this situation, which has led to the development of computational methods for identifying grass pollen species. This paper aims to provide context for these computational methods by quantifying the accuracy and consistency of human identification. • METHODS: We measured the ability of nine human analysts to identify 12 species of grass pollen using scanning electron microscopy images. These are the same images that were used in computational identifications. We have measured the coverage, accuracy, and consistency of each analyst, and investigated their ability to recognize duplicate images. • RESULTS: Coverage ranged from 87.5% to 100%. Mean identification accuracy ranged from 46.67% to 87.5%. The identification consistency of each analyst ranged from 32.5% to 87.5%, and each of the nine analysts produced considerably different identification schemes. The proportion of duplicate image pairs that were missed ranged from 6.25% to 58.33%. • DISCUSSION: the identification errors made by each analyst, which result in a decline in accuracy and consistency, are likely related to psychological factors such as the limited capacity of human memory, fatigue and boredom, recency effects, and positivity bias.
Abstract.
Author URL.
Crawford AJ, Belcher CM (2014). Charcoal morphometry for paleoecological analysis: the effects of fuel type and transportation on morphological parameters.
Appl Plant Sci,
2(8).
Abstract:
Charcoal morphometry for paleoecological analysis: the effects of fuel type and transportation on morphological parameters.
PREMISE OF THE STUDY: Charcoal particles preserved in sediments are used as indicators of paleowildfire. Most research focuses on abundance as an indicator of fire frequency, but charcoals also convey information about the vegetation from which they are derived. One potential source of information is their morphology, which is influenced by the parent material, the nature of the fire, and subsequent transportation and burial. • METHODS: We charcoalified 26 materials from a range of plant taxa, and subjected them to simulated fluvial transport by tumbling them with water and gravel. We photographed the resulting particles, and used image analysis software to measure morphological parameters. • RESULTS: Leaf charcoal displayed a logarithmic decrease in area, and a logarithmic increase in circularity, with transportation time. Trends were less clear for stem or wood charcoal. Grass charcoal displayed significantly higher aspect ratios than other charcoal types. • CONCLUSIONS: Leaf charcoal displays more easily definable relationships between morphological parameters and degree of breakdown than stem or wood charcoal. The aspect ratios of fossil mesocharcoal can indicate the broad botanical source of an assemblage. Coupled to estimates of charcoal abundance, this will improve understanding of the variation in flammability of ancient ecosystems.
Abstract.
Author URL.
Hudspith VA, Belcher CM, Yearsley JM (2014). Charring temperatures are driven by the fuel types burned in a peatland wildfire.
Frontiers in Plant Science,
5(DEC).
Abstract:
Charring temperatures are driven by the fuel types burned in a peatland wildfire
Peatlands represent a globally important carbon store; however, the human exploitation of this ecosystem is increasing both the frequency and severity of fires on drained peatlands. Yet, the interactions between the hydrological conditions (ecotopes), the fuel types being burned, the burn severity, and the charring temperatures (pyrolysis intensity) remain poorly understood. Here we present a post-burn assessment of a fire on a lowland raised bog in Co. Offaly, Ireland (All Saints Bog). Three burn severities were identified in the field (light, moderate, and deeply burned), and surface charcoals were taken from 17 sites across all burn severities. Charcoals were classified into two fuel type categories (either ground or aboveground fuel) and the reflectance of each charcoal particle was measured under oil using reflectance microscopy. Charcoal reflectance shows a positive relationship with charring temperature and as such can be used as a temperature proxy to reconstruct minimum charring temperatures after a fire event. Resulting median reflectance values for ground fuels are 1.09 ± 0.32%Romedian, corresponding to estimated minimum charring temperatures of 447°C ± 49°C. In contrast, the median charring temperatures of aboveground fuels were found to be considerably higher, 646°C ± 73°C (3.58 ± 0.77%Romedian). A mixed-effects modeling approach was used to demonstrate that the interaction effects of burn severity, as well as ecotope classes, on the charcoal reflectance is small compared to the main effect of fuel type. Our findings reveal that the different fuel types on raised bogs are capable of charring at different temperatures within the same fire, and that the pyrolysis intensity of the fire on all Saints Bog was primarily driven by the fuel types burning, with only a weak association to the burn severity or ecotope classes.
Abstract.
Hudspith VA, Rimmer SM, Belcher CM (2014). Latest Permian chars may derive from wildfires, not coal combustion.
Geology,
42(10), 879-882.
Abstract:
Latest Permian chars may derive from wildfires, not coal combustion
The Permian-Triassic boundary extinction event was the largest biological crisis of the Phanerozoic. One of the principle triggers for the mass extinction is thought to be greenhouse warming resulting from the release of CH4 from basalt-coal interaction during the extensive Siberian Traps (Russia) eruptions. Observations of organic matter interpreted to be coal combustion products (fly ash) in latest Permian marine sediments have been used to support this hypothesis. However, this interpretation is dependent upon vesicular chars being fly ash (coal combustion derived) and not formed by alternative mechanisms. Here we present reflectance microscopy images of vesicular chars from Russian Permian coals, and chars from modern tundra, peatland, and boreal forest fires, to demonstrate that despite a difference in precursor fuels, wildfires are capable of generating vesicular chars that are morphologically comparable to end-Permian fly ash. These observations, coupled with extensive global evidence of wildfires during this time interval, call into question the contribution of coal combustion to the end- Permian extinction event.
Abstract.
Zaccone C, Rein G, D'Orazio V, Hadden RM, Belcher CM, Miano TM (2014). Smouldering fire signatures in peat and their implications for palaeoenvironmental reconstructions.
Geochimica et Cosmochimica Acta,
137, 134-146.
Abstract:
Smouldering fire signatures in peat and their implications for palaeoenvironmental reconstructions
Peatland ecosystems are valued as natural archives of past climatic and vegetation changes and as such their study is essential for palaeoenvironmental reconstructions over millennia. Fires in peatlands are dominated by smouldering combustion which is the self-sustained, slow, low temperature, flameless form of burning. Most studies on peat fires to date have focused on ignition conditions, C losses or atmospheric emissions, but there is a significant gap in the understanding of the evolution of organic matter (OM) following smouldering. A key feature of smouldering fires is that they consume most of the pyrogenic char produced. Consequently, it may be that most smouldering fires are simply not visible using standard palaeontological techniques. Here we present the possibility of identifying palaeofires by following their physical and chemical signature along a peat profile. We have undertaken laboratory experiments on Sphagnum peat columns and measured physical, chemical and spectroscopic changes of OM features induced by smouldering on samples of varying moisture content. We reveal that there is a higher production of aromatic and condensed molecules, an increase of the total N and a decrease of the C/N ratio, besides significant variations of pH, electrical conductivity and ash content. Several of these changes have, in previous studies, been taken to be indicative of alterations in atmospheric dust deposition and climate-driven changes (e.g. vegetation, water table fluctuation, decomposition and mineralization processes), but are also produced by smouldering fires. Our results imply that smouldering fires should therefore also be considered in climatic and floral reconstructions drawn from peat cores and that these additional physical and chemical changes may serve to enhance our understanding of palaeofire histories. © 2014 the Authors.
Abstract.
2013
Belcher CM, Collinson ME, Scott AC (2013). A 450-Million-Year History of Fire. In Belcher CM (Ed) Fire Phenomena and the Earth System: an interdisciplinary Guide to Fire Science, Wiley, 229-229.
Belcher CM (2013). Fire Phenomena and the Earth System: an Interdisciplinary Guide to Fire Science., Wiley.
Hesselbo SP, Bjerrum CJ, Hinnov LA, MacNiocaill C, Miller KG, Riding JB, van de Schootbrugge B, Mochras Revisited Science Team (2013). Mochras borehole revisited: a new global standard for Early Jurassic earth history. Scientific Drilling, 16, 81-91.
Belcher CM, Punyasena SW, Sivaguru M (2013). Novel application of confocal laser scanning microscopy and 3D volume rendering toward improving the resolution of the fossil record of charcoal.
PLoS One,
8(8).
Abstract:
Novel application of confocal laser scanning microscopy and 3D volume rendering toward improving the resolution of the fossil record of charcoal.
Variations in the abundance of fossil charcoals between rocks and sediments are assumed to reflect changes in fire activity in Earth's past. These variations in fire activity are often considered to be in response to environmental, ecological or climatic changes. The role that fire plays in feedbacks to such changes is becoming increasingly important to understand and highlights the need to create robust estimates of variations in fossil charcoal abundance. The majority of charcoal based fire reconstructions quantify the abundance of charcoal particles and do not consider the changes in the morphology of the individual particles that may have occurred due to fragmentation as part of their transport history. We have developed a novel application of confocal laser scanning microscopy coupled to image processing that enables the 3-dimensional reconstruction of individual charcoal particles. This method is able to measure the volume of both microfossil and mesofossil charcoal particles and allows the abundance of charcoal in a sample to be expressed as total volume of charcoal. The method further measures particle surface area and shape allowing both relationships between different size and shape metrics to be analysed and full consideration of variations in particle size and size sorting between different samples to be studied. We believe application of this new imaging approach could allow significant improvement in our ability to estimate variations in past fire activity using fossil charcoals.
Abstract.
Author URL.
Belcher CM (2013). Preface. Fire Phenomena and the Earth System: an Interdisciplinary Guide to Fire Science
Hadden RM, Rein G, Belcher CM (2013). Study of the competing chemical reactions in the initiation and spread of smouldering combustion in peat.
Proceedings of the Combustion Institute,
34(2), 2547-2553.
Abstract:
Study of the competing chemical reactions in the initiation and spread of smouldering combustion in peat
Smouldering combustion of natural fuel layers such as peatlands leads to the largest fires on Earth and posses a possible positive feedback mechanism to climate change. In this paper, we use an experimental methodology to study the smouldering combustion of samples of peat under a wide range burning conditions. Vertical samples (30 mm deep and 125 mm in diameter) are ignited by radiation on the top free surface and the smouldering front propagates downward against a forced flow of oxidizer. By varying the oxygen concentration ([O2]) and the ignition conditions we investigate the competing pyrolysis and oxidation reactions. A reaction framework with two regimes is consistently observed. The measurements show that a char species is formed by the competing pyrolysis and oxidation reactions in the first regime resulting in net char production and in the second regime char oxidation results in conversion of the char to ash. Lower mass loss rates and the larger residual mass at lower [O2] suggest that a wider smouldering front is required to sustain combustion as the [O 2] is decreased. These results improve our understanding of smouldering phenomena and the role of the competing chemical reactions. © 2012 the Combustion Institute. Published by Elsevier Inc. All rights reserved.
Abstract.
2012
Belcher CM, Mander L (2012). Catastrophe: Extraterrestrial Impacts, Massive Volcanism and the Biosphere. In Henderson-Sellers A, McGuffie K (Eds.) Future Climates of the World, 463-485.
He T, Pausas JG, Belcher CM, Schwilk DW, Lamont BB (2012). Fire‐adapted traits of Pinus arose in the fiery Cretaceous.
New Phytologist,
194(3), 751-759.
Abstract:
Fire‐adapted traits of Pinus arose in the fiery Cretaceous
The mapping of functional traits onto chronograms is an emerging approach for the identification of how agents of natural selection have shaped the evolution of organisms. Recent research has reported fire-dependent traits appearing among flowering plants from 60 million yr ago (Ma). Although there are many records of fossil charcoal in the Cretaceous (65-145Ma), evidence of fire-dependent traits evolving in that period is lacking. We link the evolutionary trajectories for five fire-adapted traits in Pinaceae with paleoatmospheric conditions over the last 250million yr to determine the time at which fire originated as a selective force in trait evolution among seed plants. Fire-protective thick bark originated in Pinus c. 126Ma in association with low-intensity surface fires. More intense crown fires emerged c. 89Ma coincident with thicker bark and branch shedding, or serotiny with branch retention as an alternative strategy. These innovations appeared at the same time as the Earth's paleoatmosphere experienced elevated oxygen levels that led to high burn probabilities during the mid-Cretaceous. The fiery environments of the Cretaceous strongly influenced trait evolution in Pinus. Our evidence for a strong correlation between the evolution of fire-response strategies and changes in fire regime 90-125Ma greatly backdates the key role that fire has played in the evolution of seed plants. © 2012 the Authors. New Phytologist © 2012 New Phytologist Trust.
Abstract.
2011
Bacon KL, Belcher CM, Hesselbo SP, McElwain JC (2011). The Triassic-Jurassic Boundary Carbon-Isoptope Excursions Expressed in Taxonically Identified Leaf Cuticles. PALAIOS, 26, 461-469.
2010
Belcher CM, Yearsley JM, Hadden RM, McElwain JC, Rein G (2010). Baseline Intrinsic Flammability of Earth’s Ecosystems Estimated from Paleoatmospheric Oxygen over the Past 350 Million Years. Proceedings of the National Academy of Sciences, 107, 22448-22453.
Belcher CM (2010). From Fiery Beginnings: Wildfires Facilitated the Spread of Angiosperms in the Cretaceous. New Phytologist(188), 913-915.
Belcher CM, Mander L, Rein G, Jervis FX, Haworth M, Glasspool IJ, Hesselbo SP, McElwain JC (2010). Increased Fire Activity at the Triassic/Jurassic Boundary in Greenland due to Climate-Driven Floral Change. Nature Geoscience, 3, 426-429.
2009
Belcher CM, Finch P, Collinson ME, Scott AC, Grassineau NV (2009). Geochemical Evidence for Combustion of Hydrocarbons During the K-T Impact Event. Proceedings of the National Academy of Sciences, 106, 4112-4117.
Belcher CM (2009). Reigniting the Cretaceous-Palaeogene Firestorm Debate. Geology, 37, 1147-1148.
2008
Harvey MC, Brassell SC, Belcher CM, Montanari A (2008). Combustion of Fossil Organic Matter at the K-P Boundary. Geology, 36, 335-358.
Belcher CM, McElwain JC (2008). Limits for Combustion in Low O2 Redefine Paleoatmospheric Predictions for the Mesozoic. Science, 321, 1197-1200.
2006
Morgan J, Lana C, Kearsley A, Coles B, Belcher CM, Montanari S, Dias E, Barbosa E, Neumann V (2006). Analyses of Shocked Quartz at the Global K-P Boundary Indicate an Origin from a Single, High- Angle, Oblique Impact at Chicxulub. Earth and Planetary Science Letters, 251, 264-279.
Belcher CM (2006). Impacts and Wildfires - an Analysis of the K-T Event. In Cockell C, Koerberl C, Gilmour I (Eds.) Biological Processes Associated with Impact Events, Springer, 221-243.
2005
Belcher CM, Collinson ME, Scott AC (2005). Constraints on the Thermal Power Released from the Chicxulub Impactor: New Evidence from Multi-Method Charcoal Analysis. Journal of the Geological Society of London, 162, 591-602.
2004
Belcher CM, Collinson ME, Sweet AR, Hildebrand AR, Scott AC (2004). Reply to comment on Fireball Passes and Nothing Burns - the Role of Thermal Radiation in the K-T Event: Evidence from the Charcoal Record of North America by Robertson et al.. Geology, 32, e50-e51.
2003
Belcher CM, Collinson ME, Sweet AR, Hildebrand AR, Scott AC (2003). Fireball Passes and Nothing Burns - the Role of Thermal Radiation in the K-T Event: Evidence from the Charcoal Record of North America. Geology, 31, 1061-1064.
