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 11^th 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 19^th 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.

Blogged by Stacey New

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

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

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 19^th and 22^nd 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