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We know it's been a while since we blogged - but we've all been so busy in the lab !

The WildFIRE Lab heads North!

In October 2016 the WildFIRE Lab headed north in search of charcoal.

The majority of research undertaken as part of the WildFIRE lab is done so in the lab itself using specialised equipment to burn vegetation, wood etc to help us better understand wildfires. Therefore, any opportunity to study a real-world fire is great for the lab and when possible we go out to assess the damage caused by these fires and collect charcoal for analysis.

On the 11th of June 2015 a fire occurred on Winter Hill, Bolton, UK. Winter Hill is a heathland dominated by moss, heather and grass, the 2015 fire covered an area of one kilometre by 500 metres burning much of the surrounding vegetation. Drone footage capturing the aftermath of the fire shows the extent of fire damage to the heathland. Luckily the WildFIRE Lab’s resident fire chaser, Dr Victoria Hudspith, was in the area and managed to head to the site after the fire had been extinguished. Fire severity across the burn scar was assessed and charcoal samples collected.

On the 19th of October 2016 Dr Mark Grosvenor, Dr Victoria Hudspith and Stacey New ventured back to Winter Hill to assess vegetation regrowth on the fire scar and collect any charcoal that may have remained from the fire. The same sites from which charcoal had been collected the previous year were revisited allowing us to assess the level of vegetation regrowth and collect some more charcoal, always a good thing!

 


The charcoal that Dr Hudspith collected in June 2015 and the charcoal that was collected in October 2016 will be analysed by Stacey as part of her PhD research looking at the effect of wildfires in temperate ecosystems. The primary technique used in Stacey’s research

is reflected light microscopy; the charcoal is embedded in resin and reflectance measurements taken using a reflectance microscope, this method allows researchers to gain quantitative information about charcoal.

The main aim of sample collection at Winter Hill was to provide a spatial assessment of reflectance across a site, to assess vegetation regrowth and to attempt to link both of these to fire severity.  Ultimately, fire on heathlands like Winter Hill although costly and damaging to the environment enable researchers to gain a valuable insight into the behaviour of real-world wildfires.

 

Stop Press - What Didn't Kill the Dinosaurs?

New research led by the U. Exeter wildFIRE Lab in collaboration with BRE Centre for Fire Safety Engineering and Imperial College London proves the theory that Global Firestorms didn't kill the dinosaurs.

The research featured on BBC Spotlight, BBC Radio and the media continues the hot debate as to what killed 80% off all life on Earth at the End of the Cretaceous?

Until the 1980s this catastrophic loss of life was a mystery, but then scientists found a clue - trace abundances of the element iridium in rocks of this age. Iridium falls to Earth with extraterrestrial objects. This key finding suggested that there was a major extraterrestrial collision with the planet and that this could be responsible for the mass kill of species.

Ten years later scientists found the 65 million year old, 180km wide, Chicxulub crater on the Yucatan Peninsula in Mexico finally providing the smoking gun that could explain the apparent chaos that ensued at the end of the Cretaceous. A 180km wide crater suggests that an approximately 10km wide asteroid or comet hit the Earth. The impact of such a large object would have released a huge amount of energy. The asteroid itself was vaporised as it smashed into the Earth and in doing so vaporised and blasted out particles of the rock that it hit. A huge glowing ball of hot rock and vapour rushed up from the impact site at huge speeds ejecting it way above the atmosphere up into space. As it hit the cold of space it decelerated, cooled and rained back through the atmosphere re-solidifying forming rock spherules. As these fell through the atmosphere they were subject to frictional-drag which caused them to become super heated. As these particles rain down through the atmosphere they delivered a thermal pulse to the ground.

This heat pulse has widely been suggested to have ignited global wildfires and has been cited as a possible cause of extinction on land. But how do you go about estimating the amount of heat generated from an impact? And how do you go about testing whether the heat pulse could start a wildfire?

New computer modeling techniques have enabled scientists to generate better estimates of the heat pulse resulting from this impact. What they found was that the heat flux wasn’t evenly distributed across the surface of the Earth. Models have shown that a very short lived but high heat pulse was generated near to the impact site but far away (such as all the way in New Zealand), the peak heating was lower but would be delivered for a much longer period.

Live Fuel typically doesn't ignite

Humanity has not been unlucky enough to observe first hand the effects of a large impact so we have to turn to the laboratory in order to study the effect that it might have. In order to do this Earth Scientists have teamed up with Fire Safety Engineers to use state-of-the-art apparatus usually used to test the flammability of furnishings and materials, to recreate the heat pulse from the asteroid impact. This provided, for the first time, the ability to test whether the heat pulse from the impact could start fires in plant material.

Ignition of tinder un-naturally dry fuel

So how likely is the global firestorm hypothesis? The research reveals that the short sharp blast of heat felt closer to the impact could not have ignited live plants but the longer drawn out pulse a long way from the impact may have started fires in some locations, implying that localized fires may have occurred but critically global firestorms were unlikely. More importantly these findings turn our understanding of the effects of the heat pulse on its head as the effects of the heat would have been greater further away from the impact. This means that Earth scientists will have to reassess their understanding of the fossil record of life. Until now they have read the fossil record of this event by assuming that the heat pulse generated was worse close to the crater but now patterns of extinction and survival must be reinterpreted by considering a more severe heat pulse further away. 

Blogged by Claire Belcher

The wildFIRE Lab visit Vancouver for the Geological Society of America Annual Meeting

It was to be the first major conference of the academic year, name badges at the ready and guidebooks in hand; it was time for GSA 2014!

The Geological Society of America (GSA) hosts annual meeting of geologists and Earth scientists to present and discuss recent research, share new insights in their respective fields, and also have a few palaeofire scientist pop along too! This year the venue for the conference was in Vancouver, Canada, with five members of the Palaeofire group venturing across the pond to present some of the wildFIRE Lab's recent research. The visiting group consisted of Dr Claire Belcher, Dr Victoria Hudspith, Alastair (AJ) Crawford and first timer Nick Walding.

The wildFIRE Lab was well represented this year with 6 talks being presented across multiple sessions and a poster being presented on behalf of Stacey New who unfortunately couldn’t join us at the conference. Subject matter ranged from wildfires being both a cause and consequence from environmental change at the Triassic-Jurassic boundary and the Cretaceous-Paleogene boundary; to charcoal morphological changes; to a post-fire assessment of All Saints bog in Ireland through to future climate-driven changes in fire regime.

Dr Claire Belcher kicked off proceedings for the wildFIRE group with her Pardee Keynote Symposium talk entitled; ‘Cause or Consequence? Wildfires at the Jurassic-Triassic and Cretaceous-Paleogene Boundary. This talk explored the mass extinction events at both of these points in time and highlighted the potential role of wildfires as causes or consequences of the major environmental changes seen at these times.

On the following day, the group had a number of presentations in the Technical Session ‘Co-Evolution on Earth’s Surface: Terrestrial Ecosystem and Environmental Interactions’ convened by Jon Wilson and Ellen Currano.  During this session talks were heard from Dr Claire Belcher, Dr Victoria Hudspith, Alastair Crawford, and Nick Walding (full abstracts can be viewed by clicking on peoples names). A special mention also needs to go to guest speaker Albert Simeoni, a collaborator of the wildFIRE group from the BRE Centre for Fire Safety Engineering at the University of Edinburgh, for giving an exciting talk entitled ‘Experimental study of fire behaviour during prescribed fires in New Jersey’ and collaborator Dr Cindy Looy from Berkeley for her talk on the earliest evidence of a fire adaptive trait.

Image: Nick, Claire and Vicky in front of Stacey's poster in the exhibition hall.

Later that day, Dr Claire Belcher presented a poster on Behalf of Stacey New entitled; ‘Tracing the signature of smouldering peat fires in the Holocene’. This research used experimental charred peat particles to assess the likely morphologies of char resulting from the burning of peat, and then applied these findings to peatland cores to assess whether such morphologies can be seen in natural peatlands

On the final day of the conference Dr Victoria Hudspith presented her research into Latest Permian Chars and how they likely derived from wildfires and not coal combustion, and so potentially bringing into question support for the mechanisms involved in the Permian-Triassic extinction events. See her paper in Geology.

Overall the conference was a success for the wildFIRE Lab! This is the first time so many members of the group have presented their research together at a large international conference with our research be well received by the academic community. A shame however that we couldn’t escape the rain of the SW of the UK, Vancouver seemed just as wet!

 

Blogged by Nick Walding





Image: Vicky presenting her Permian Chars research

 

The wildFIRE Lab Visits Sidmouth Science Festival

Sarah Baker and Mark Grosvenor took a little bit of the PalaeoFire Lab to the Super Science Saturday event at the Sidmouth Science Festival in October.

What would be the most obvious aspect of a fire research lab to show off to the general public?  Something on fire of course? Sadly, health and safety probably wouldn’t have been too happy if we had tried to set fire to something inside the Masonic Hall on Sidmouth High Street.  The next best thing to a real fire, had to be our new thermal cameras.

We will be using the thermal cameras in our lab to record the temperature of different part of our experiments (whether it is the flame temperature, ignition temperature, how hot a smouldering piece of wood is, etc).  They work by analysing the infrared spectrum, rather than visible light, and a piece of software false colours the image depending on the intensity of the infrared radiation (i.e. heat) of an object.  It also allows us to pinpoint the temperature of any pixel within the image.

At the science festival, it was the public themselves who decided to be the test subjects.  Without really planning for it, the most interesting thing the public seemed to want to see, was themselves.  Soon after, the ‘thermal selfie’ trend was quickly catching on

We did take a few video clips and images of our cameras working on an actual fire to show how we use them for proper science.  The smaller end of the general public (i.e. children) were simply fascinated by the hidden world of heat, but we hopefully managed to shed a bit of light on how we can study fire and learn about the past and present natural environments.

Image: Thermal person                                                                                            Image: Thermal image of a fire



Claire Belcher also gave the Norman Lockyer Observatory Lecture entitled “Wildfires, The Good, The Bad and The Necessary” as part of Ava Lovelace Day at the Science Festival. The Audience said "Claire Belcher took us on a fascinating tour of fires! Who knew that fires can be both destructive and beneficial and even necessary. We had a fascinating overview of how this works now all over the world and what happened about fires and evolution millions years ago!


Image: Claire is pictured with Dave Bramley, Bob Miles and David Strange at the Norman Lockyer Observatory.














Blogged by Mark Grosvenor and Claire Belcher

First flames from the iCone

No, the iCone isn’t the latest Apple product everyone-is-not-talking-about. Its our latest piece of experimental equipment in the wildFIRE Lab – a cone calorimeter.  We’re the first lab in the UK to have this model and one of just a few in the world.

The logistics of setting up a new lab in an old building can sometimes be problematic.  Firstly the lab needed some renovation work to bring in new gas supplies, fit safety alarms and extract systems.  Then there is the issue of getting large heavy equipment into the building, particularly when there is no step-free access to the lab from the road.  Doors and other obstacles were measured and re-measured.  Thankfully our new iCone calorimeter from FTT [www.fire-testing.com] was in the hands of HRH logistics [http://www.hrhlogistics.co.uk/].  With some ingenious use of the tail lift and some pallets, bridges and ramps were constructed and the iCone made it into the lab intact.


The iCone is a cone calorimeter which will be used to precisely record how different materials burn.  It allows us to monitor and control how different materials burn. 

A sample is placed under a cone shaped heater (hence the name) which can be set to a specific heat flux.  As the sample is exposed to the heat, volatile gases are produced which are then ignited by a spark.  As the sample burns, the changing weight of the material is constantly logged along with the amount of oxygen used and the amount of carbon monoxide/carbon dioxide produced.  The amount of smoke/soot being produced can also be monitored.  All of this information will be used by the wildFIRE Lab researchers to investigate how different vegetation influences the nature of fires.

Tony, the Test Engineer from FTT had 4 days with us to set up the equipment, certify it was giving correct results, and train us to use it.  There are always nervous moments when installing complex pieces of equipment – one missing piece or a malfunctioning component could mean lengthy delays.  You can’t always just pop down the shop to get a replacement bit.  To the relief of everyone, all seemed to be in order.

Even though this is a state of the art semi-automated bit of kit, there was still a lot to take in.  We were all scribbling extra notes on the 70-step set up and calibration process.  Thankfully, after a couple of runs things were making sense and we were getting the hang of how the software worked.

Even though we will only be burning various types of natural material, calibration checks had to be done using plastic (PMMA).  It is amazing how vigorously a solid block of plastic can burn and quite mesmerising the way it boils away on the surface.  After this test, we were then free to experiment with some proper samples including various bits of wood and spruce needles (see image of the spruce ash remaining after a burn).

The training days quickly passed with only time for a brief look at our additional bits of kit – a larger cone heater with a rather big power socket, and an enclosed unit which will allow us to experiment with low-oxygen environments.

Blogged by Mark Grosvenor

Sarah's search for Jurassic charcoals


The presence of fossil charcoal within rocks indicates that wildfires have occurred in Earth’s ancient past. Variations in the amount of charcoal found in rocks are suggested to indicate changes in the frequency of palaeowildfires.

The Peniche coastline in Portugal hosts a unique rock outcrop, which exposes one of the most complete sections of sedimentary rocks of Jurassic age (the rocks are between 201 million years old and 145 million years old !). Throughout this long tract of time major climatic and atmospheric changes are believed to have occurred which likely had the ability to influence the frequency of wildfires.

The sediments deposited here are made up of rocks known as marls (silty-clayey calcium carbonate rich sediments formed by loose clay/silt deposits under the sea) and limestones (hard, calcium carbonate rich rocks formed from ancient skeletal fragments of marine organisms e.g. corals). These sediments indicate that the past environment in which these rocks formed was likely to be a shallow carbonate ramp (nearshore setting). Due to its past nearshore setting, high preservation characteristics and complete record, Peniche offers one of the best places to study variations in fossilised charcoal that were deposited throughout the Early Jurassic period (approximately 174 to 182 million years ago).





Between the 19th and 22nd of May 2014 Sarah Baker, Dr Luis Duarte and field assistant Amir Abbasi ventured to Peniche, collecting samples from the rock section at Praia do Abalo (on the north coast) ready to be analysed for their charcoal content.  Rock samples were chiselled out of the rock section at regular intervals and then bagged. These samples are to be analysed for their charcoal content by Sarah Baker for her PhD thesis in an attempt to assess how fire frequency may have varied throughout the Early Jurassic period (Pliensbachian (182.7 to 190.8 million years old) to the Toarcian (174.1 to 182.7 million years old)).

Blogged by Sarah Baker


Finding fire on the moor

This week (21st May 2014), Alastair Crawford and Mark Grosvenor ventured onto Dartmoor in search of evidence of past fire events. 

Peat bogs provide a great archive of environmental history as they build up through time.  Some bogs can be several meters deep with a layer of living vegetation overlying decomposed bog vegetation – known as peat.  Even though a lot of the bog plants degrade over time, certain macro-fossils (small identifiable things) and micro-fossils (really small identifiable things) can be preserved.  These can include plant fragments, pollen, insect remains, and charcoal.  The length of the record depends on the environmental history of the location – in the UK the oldest peat bogs cover a large proportion of the time period known as the Holocene (since the last ice age).   If environmental conditions are right, a continuous record of history can be preserved which is perfect for researchers like us to examine the earth system. 

Unsurprisingly, in the wildFIRE Lab, we are interested in identifying the charcoal particles in the peat.  Micro-charcoal is dispersed by the wind during burning events (whether natural or started by humans), with a fine covering falling on the surface of the peat.  If the charcoal is not immediately washed away, it is likely to be preserved in the peat as fresh material grows above it.  More and more vegetation grows above it, and compresses the degrading vegetation underneath, but slowly over thousands of years the bog grows, with the charcoal fragments in it.  The ancient peat samples can then be processed (anything from sieving to using acid to digest the plant material) before being analysed under a microscope.  A range of sizes may be present, which can help to tell how far the site of burning was (i.e. large, heavy particles are likely to be blown a shorter distance) and in some cases, it is possible to identify the type of vegetation being burned (such as grass, or wood). 

The samples we collected will be analysed by Alastair for part of his PhD research.  He will be looking at the morphological features of the charcoal.  We collected the samples using what is known as a ‘Russian peat corer’ – it is a chamber on the end of some metal rods which are pushed into the peat (to whatever depth we need) and then rotated to capture the sample.  We take a series of these to piece together the full record.  Another method could be to dig trenches to expose the layers of peat, but the advantage of using a corer is that there is no lasting damage to the bog. 

The samples were taken at Shovel Down, just above Fernworthy Forest on the north eastern edge of Dartmoor.  The site has been investigated before for its environmental history (by Ralph Fyfe and others) so we know there should be charcoal at the site.  Shovel Down is also notable for a series of ceremonial monuments constructed around 4000 years ago including stone circles and standing stones (megaliths).  A number of ancient field boundaries are still visible as stoney ridges (known as ‘reaves’).  Whilst archaeology can provide insight into human activity, the environmental record preserved in the bogs provides another layer of detail about how peoples environment was changing around them, or whether they were altering the landscape themselves. 

For more information on all things bog, check out bogology.org

Blogged by Mark Grosvenor

Conserving priority habitats:

Understanding the impact of fire on All Saints Bog, Ireland

Due to the unpredictable nature of wildfires, it’s not always possible to collect data from an active fire. Fortunately, we are able to get a lot of information about fires by studying the charred remains of plants that are left behind after the fire has passed. These post-burn assessments can be used to help us understand more about fire characteristics. This is particularly important in habitats that are vulnerable to burning, yet considered high conservation priorities, such as All Saints Bog, Offaly County, Ireland. With this in mind, on a cold, damp day in November 2013, Vicky Hudspith, Claire Belcher and Jon Yearsley set out to collect charcoal samples from a recent fire that occurred on the bog.

Site of Burning at All Saints Bog, Ireland

The exceptionally warm and dry July of 2013, provided the perfect conditions for a fire. This fire was of particular concern to conservationists such as the Department of Arts, Heritage and the Gaeltacht (DAHG) and the National Parks & Wildlife Service (NPWS) as the bog has been designated a Special Area of Conservation or Natura 2000 site, and an EU priority habitat, due to the rare patch of birch woodland on the bog. Such sites are uncommon in Ireland and across the EU as a whole. It is imperative that these habitats are protected in order to conserve their unique biodiversity and ecology. However, in a recent monitoring report, the conservation status of All Saints Bog was classified as ‘unfavourable-bad’ due to the impact of active peat-cutting and drainage threatening the bog woodland. Intense peat-cutting has been shown to increase fire frequency, and depending on the intensity and frequency, fires have the potential to alter the vegetation composition on the bog.

Quadrat sampling of charcoals and fire severity scoring 


Claire taking a core through the peat


Before conservation strategies can be made for these priority habitats, it is essential to understand the impact of disturbances, such as fire on this site. As part of a collaborative project between the University of Exeter (Claire Belcher, Angela Gallego-Sala, Victoria Hudspith, Stacey-Louise New), University College Dublin (Jon Yearsley, Nuria Prat-Guitart), NUI Galway/ Denyer Ecology: Ecological Consultancy (Joanne Denyer) and the Department of Arts, Heritage and the Gaeltacht (Ciara Flynn, Noel Bugler, Jim Ryan), we hope to investigate how ecologically damaging these fires on All Saints Bog are, by looking at the previous history of fires on the bog, as well as the severity (amount of organic matter lost), and intensity (temperature) of the 2013 fire.


Blogged by Vicky Hudspith