JC: Fire ecology of Rocallaura Fires (Lleida, Spain), June-July 2016

Versión en castellano

Author: Núria Prat, PhD on Environmental Science at University College Dublin. International Projects Manager at Pau Costa Foundation.

The ‘Rocallaura 1’ wildfire took place on June 23rd close to the Rocallaura village (Spain) propagating through a pine forest (Pinus halepensis). Almost one month later, there was a second wildfire, ‘Rocallaura 2’, on July 19th. This second fire was ignited within the perimeter of the Rocallaura 1 fire. This time the fire spread through the pine forest but also through crop fields, olive plantations and finally getting close to the urban areas of Nalec and Rocafort de Vallbona. A total of 817 ha were consumed by those fires.

Both fires took place in mountain Mediterranean forests, in areas were no forestry-management actions were carried out for decades. From the tree scars we can tell that the area did not have a fire since the Spanish Civil War in the 40s. In the last years, winter and summer droughts have affected the area, and in general all the south-west region of Catalonia. As a consequence, before the fire, the fuels were highly available, enabling the spread of the fire during the events.

Walking on the affected area a month and a half after the second wildfire event, we could observe some short-term effects on the ecosystem. We then decided to write this post to share and discuss these effects with all of you. It is important to highlight that the following lines are only observations, which have not been scientifically tested in the area:

  • The fire spread at a variable intensity, causing a diversity of effects on the ecosystem and creating mosaic. We observed that the changes on the fire intensity are imprinted in the landscape. The diversity of fire intensities created a mosaic of burnt patches within the dense and homogeneous forest mass existing before the fires. The subsequent mosaic combines green, burnt areas and crops. The burnt areas are now new spaces for plants colonising from the contiguous unburnt forest. Overall, causing the regeneration of the forest and enhancing species biodiversity.
  • A few fire-adapted strategies from Pinus halepensis were visible in the areas burnt with high and low severity. The area affected by the leading front of the fire was consumed with the highest intensity. In this area trees were completely burnt leaving behind only dead tree trunks, ashes on the soil and open spaces where sunlight could reach the ground. We also observe that this area is now a “nursery” of pine seeds. During the fire, the cones were heated causing the release and spread of the seeds. Since then, the seeds are on the ground mixed with the soil and ashes and ready to germinate.
Forest area burnt with a high intensity. Photo: PCF
Forest area burnt with a high intensity. Photo: PCF

On the right and left flanks, the fire intensity was low. As a result, only a portion of the trees were burnt. In those areas, the fire propagated mainly consuming the understory vegetation. As a consequence, many tree crowns remained, impeding the penetration of the sunlight to the ground’s surface, which in this case is a mixture of soil, ashes and pine needles.

Forest area burnt with a low intensity. Photos: PCF
Forest area burnt with a low intensity. Photos: PCF
  • A layer of ash and char was accumulated on the top soil and it is now protected from erosion under a layer of pine needles. The ash and char bring minerals and nutrients to the soil fostering the accumulation of organic matter. These conditions are observed mainly under the trees burnt with low severity. The fire consumed most of the understory fuel.
Understory of an area burnt with low intensity. The ground is covered by a layer of pine needles. Photo: PCF
Understory of an area burnt with low intensity. The ground is covered by a layer of pine needles. Photo: PCF

Afterwards, the remaining char and ashes were accumulated on top of the soil providing minerals and nutrients for plants. The pine needles felt on the ground afterwards, protect the soil, char and ash particles from erosion processes. If no post-fire management measures are taken to remove the burnt logs, most of the partially consumed material will degrade forming soil organic matter.

Close-up of the ground a month and a half after the second fire. The ashes and carbon remain underneath the pine needles. Photo: PCF
Close-up of the ground a month and a half after the second fire. The ashes and carbon remain underneath the pine needles. Photo: PCF

 

  • The post-fire accumulation of carbon on the soil can potentially contribute to mitigate the effects of climate change. During the fuel combustion, part of the carbon is released to the atmosphere as greenhouse gasses, mainly as CO2 and CO. However, another part is transformed to organic and mineral carbon (char and ashes). Both compounds remain in the ecosystem and contribute to the carbon-sink function of the forest. What is more, some recalcitrant carbon compounds are formed during the combustion of wood and are considered very resistant to degradation (e.g. black carbon), that can remain in the system much longer than green vegetation itself.
  • Despite the lack of rain since the fire, some species start sprouting after a few weeks. Species such as holm oak (Quercus ilex) sprout a month and a half after the fire. This example shows the adaptation of Mediterranean species to forest fires. It should then be considered whether reforestation is necessary after a wildfire, as human intervention will potentially have a higher impact than the ecological fire adaptation developed by Mediterranean plants over millennia.
Example of a holm oak naturally sprouting in the area burnt with a high intensity of Rocallaura 1. Photo: PCF
Example of a holm oak naturally sprouting in the area burnt with a high intensity of Rocallaura 1. Photo: PCF
  • Some bird species take advantage of the fire effects on vegetation and landscape caused by the fire. Birds such as the great spotted woodpecker (Dendrocopos major) or the great tit (Cyanistes caeruleus) usually remain in the burnt areas if the burnt tree trunks are not removed. Since the presence of fungi and insects is usually higher in dead trees, these are areas of food source for insectivorous birds. We observed trunks without bark indicating bird activity in areas were fire intensity was high.

Birds can take advantage of the new mosaic: they can keep living in the green areas and explore the burnt ones. Consequently, protecting green trees from fungi and insect plagues.

The nests of some singular birds, such as the Northern goshawk (Accipiter gentilis) could had been affected by the fires. Nevertheless, since Northern goshawk hunts in open areas, the fire perturbation could cause an increase of the number of this bird in a mid and long term scale.

The open areas can also restore habitat for species such as the Ortan bunting (Emberiza hortulana), black wheatear (Oenanthe leucura) or the Bonelli’s eagle (Aquila fasciata), especially in areas were the dense forest replaced open spaces in the last decades. Finally, it should be mentioned that several studies indicate that the management of the burnt fuel (e.g. removal of dead tree trunks), could have a higher impact to bird populations than the fire perturbation itself.

Pine trees in the area burnt with a high intensity. The bark of some of the trees have been removed by birds looking for food sources. Photo: PCF
Pine trees in the area burnt with a high intensity. The bark of some of the trees have been removed by birds looking for food sources. Photo: PCF

During the next weeks we will publish a second post talking about the Rocallaura fires and the re-ignition of the fire that took place 26 days after the suppression of the first fire. We will discuss what occurred with the smouldering fire during that month.

We would like to thank Francesc Moncasí for his contribution on the section of fire effects on birds!

Distinción en Incendios Forestales

 

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Today our tasks on wildfire training & internationalisation have been acknowledged by the ISPC (Institute of Public Security of Catalonia). This award is the result of the efforts done by all our members of the wildfire community that contribute to our project. Thanks to all!

Anualmente, el Institut de Seguretat Pública de Catalunya (ISPC) otorga una distinciones con la finalidad de reconocer merecimientos, circunstancias singulares o servicios prestados a aquellas personas que, de manera individual o colectiva, han colaborado con esta entidad en formación, estudio o investigación científica en el ámbito de la seguridad o se han distinguido de forma destacada en estos ámbitos.

Este año, el ISPC ha otorgado esta distinción a la Pau Costa Foundation, entre otros, por el trabajo continuo de colaboración con el ISPC y la Escuela de Bombers i Protecció Civil, realizado con la voluntad de impulsar la investigación, la creación y la difusión del conocimiento relacionado con la gestión de los incendios forestales y su evolución, a partir de capitalizar la experiencia acumulada por los propios servicios operativos de extinción.  Por su apuesta en poner al ISPC y a la Escuela de Bombers i Protecció Civil en contacto con otras escuelas, entidades y servicios de bomberos de Europa para fomentar el intercambio de conocimientos y experiencias, y por promover la mejora en el ámbito de la extinción de los incendios forestales. En resumen, por su compromiso en participar en los programas formativos de los Bomberos de la Generalitat de Catalunya que tienen una repercusión directa en la seguridad de su trabajo y en la mejora del nivel de eficacia en sus actuaciones. 

¡Gracias y Enhorabuena a tod@s los que formáis parte de esta Fundación!

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Art&Fire – Incandescent Memories

Castellano / Català

Homenatge al GRAF anònim (2010) / Josep Serra
Homenatge al GRAF anònim (2010) / Josep Serra

The virtual exhibition INCANDESCENT MEMORIES from the artist Josep Serra i Tarragón (Tarragona, 1970) is inaugurated today. This collection is part of the project ‘Art & Fire’ from the Pau Costa Foundation, a project with the aim to disseminate art on forest fires started four years ago.

The collection is composed by 95 drawings inspired on ‘[…] my first perceptions, my drawings and the Horta de Sant Joan Fire in 2009 […]’ as he mentions in his biography. From today, we will show a drawing of the collection every day through our new media channels on Twitter, and once a week on Facebook. A part of the collection will also be exhibited during the 14th International Wildland Fire Safety Summit and the International Congress on Prescribed Fires taking place between the 31st of January and the 3rd of February of 2017 in Barcelona.

Josep Serra i Tarragón – Tarragona (1970)

I was born 46 years ago in a land where summer fires were perceived as a tragic and intriguing phenomena.

During those years (80-90), my retina was impregnated with yellow-orange, blue lights at dusk, distant spots and convective plumes of smoke filling the skies of the summer time.

Aircrafts loading at the port, the smell of burning wood, acoustic warnings for retardant dropping and men fighting the flames, all those things had an impact to me as a child and teenager.

At that time, I already used drawing as my artistic expression. I saw the world and its morphology in terms of colors, shades, patterns, spectra, perspectives, iterations, etc. rather than a logical and coherent system.

Later, as a doctor from the outside, and artist from the inside, I used mainly charcoal drawing to express my need for communication.

No one could have guessed that the dirt of charcoal in the drawing blocks would end up  connected to the origin: The fire.

It was the documentary “The Great Silence”, broadcasted on the Catalan TV in 2015, that  ignited the latent fuel hidden somewhere in my brain. The awe-inspiring stories told by the same firefighters from the Horta de Sant Joan Fire in 2009 that became the starting point of a growing interest on the dynamics of forest fires that I saw summer after summer as a child.

Although I had already drawn on this subject, my fascination on forest fires accelerated exponentially when I met some of the protagonists of the documentary: Marc Castellnou, Oriol Vilalta and Pepe Pallàs.

The number of artistic creations increased when I discovered that Pau Costa Foundation has an Art Fund (Art & Fire Project). At that moment, I had the strange feeling that this project was waiting for me since its inception.

My obsession with the magical and ancestral look of fires at night was evident from the colors used to illustrate fires, but also from the latest illustrations intending to communicate that there is more beyond the sadness of a burned forest. Apart from the formal beauty I perceived, the intention always was, and it remains, to show the vital continuity of our ecosystems naturally disturbed by the fire regimes.

Surely, without this prodigious encounter between my first perceptions, my drawings and the Horta de Sant Joan Fire in 2009, these creative combustion of products would had never emerged.

Cambrils, 6 Octubre 2016