Prescribed Burning Campaign

PRESCRIBED BURNING CAMPAIGN

Winter 2020-2021

19 April 2021

Contents 1. WHAT DO FIREFIGHTERS USE FIRE FOR? ...... 3 2. OBJECTIVES OF CONTROLLED BURNING ...... 4 3. WHAT KIND OF VEGETATION DO WE BURN? ...... 7 4. HOW DO WE CARRY OUT A PRESCRIBED BURN? ...... 9 5. BURNING CAMPAIGNS ...... 10 6. THE 2021 WINTER BURNING SEASON ...... 11

1. WHAT DO FIREFIGHTERS USE FIRE FOR?

Fire is a natural element of our ecosystems and, if used wisely, is a valuable tool for reducing the risk of large fires. Most of the forests in Catalonia are naturally endowed with fire defence systems that have developed over thousands of years of evolution. Different types of trees, shrubs and grasses respond differently to the spread of fire, depending on its strength and the time of year.

There are trees, such as the laricio pine, which have evolved to have thick bark to withstand the heat of fires; others, such as the holm oak or the oak, have the capacity to resprout from the stump, and there are still others that are capable of resprouting from the crown, as is the case of the cork oak.

These, along with other adaptations, are known as vital attributes, and, if we know them well, we can use them to protect forests from large forest fires. By choosing when we apply fire in the forest and with what force or intensity, we can affect different plant species, which will respond differently. In this way, for example, we can plan undergrowth clearing (removing the undergrowth and small trees to reduce the risk of fire) using fire in a controlled manner, affecting only those plants whose development we want to control. Indeed, prescribed burning is the most green form of vegetation control, along with extensive livestock grazing.

For firefighters, prescribed burning scenarios also give us the opportunity to work with real fire, making it an ideal practice and training ground for when we have to deal with real fires.

Burning in Aleppo pine forests in El Garraf in the municipality of Olivella at the beginning of March. The aim is to preserve a forest structure that withstood the 1994 fire and is now at risk from further fires. This is a peri-urban forest surrounding the Mas Mestre housing estate. Source: Fire brigade.

2. OBJECTIVES OF CONTROLLED BURNING

Various objectives are pursued through prescribed burning, and it is common to find more than one objective in a given burn, although there is always one that predominates over the others.

Since the start of the Fire Brigade's burning programme in 1999, burns have been classified according to the following main objectives:

 Grass burning: this is humanity's ancient method of securing food for its domestic herbivorous animals. The burning of open grass and scrubland has served to rejuvenate the herbaceous layer and provide better pastures for herds of cows, sheep, horses or goats.

Burning to improve pastures in Bausen (Val d'Aran) at the end of February. Depending on the type of vegetation, the control team uses different hand tools to limit the spread of fire. The fire swatter is the optimal tool for smothering flames on the herbaceous stratum. Source: Fire brigade.

 Burning to conserve and improve habitats: certain animal species, such as some birds, reptiles or mammals, need specific vegetation characteristics for shelter, hunting or nesting areas. The lack of natural fires and the abandonment of livestock or forestry activities favour the proliferation of areas of continuous scrub and forests that are too closed and endanger the survival of these species. The use of fire can maintain or restore the natural characteristics of certain habitats and make them viable again.

High intensity fire to achieve a change in the homogeneous forest structure and recover areas of Campeche wood for Bonelli's eagle on the Cal Setró estate in Bonastre (Baix Penedès) during the first week of March 2021. Source: Fire brigade.

 Forest management burns: one of the main problems in the forests of Catalonia that makes them vulnerable to forest fires is the high density of trees and the continuity of undergrowth that they accumulate. Forest management, with tree thinning and undergrowth clearance, aims to reduce this excess biomass and to guide forests towards maturity, reducing the risk of forest burning in the process. The application of direct fire in the undergrowth under planned and controlled conditions achieves this objective by eliminating undergrowth and small trees that have a limited future. The lower branches of the trees are scorched by the heat of the fire that burns the undergrowth and part of the canopy can also be affected without killing the trees. This produces so-called thermal pruning which, in addition, eliminates leaf litter from the canopy and reduces its ability to burn in the event of a forest fire.

 Burning to protect isolated urban centres: the dispersion of small urban centres throughout the rural areas of Catalonia has generated a landscape in which some villages, generally in mountainous regions, have seen how, with the abandonment of traditional agricultural activities around the centres, the distance between the forest and the houses has been reduced to almost zero, putting people and property at risk in the event of a forest fire. Reclaiming open spaces through prescribed burns with a low vegetation fuel load on the outer edge of these villages improves its defence capacity in the event of a forest fire.

Reducing the biomass load in the most fire-prone parts of small inhabited areas, such as Sant Salvador in El Pallars Jussà, improved the Fire Brigade's defence capacity in the event of a major forest fire in February 2021. Source: Fire brigade.  Strategic spot burns to control large fires: we try to learn from the fires of the past to anticipate how the fires of the future will move. On the basis of the fire analysis, we try to determine the areas where fires can be dealt with in the future. These so-called 'strategic points' need to be safe for fire control manoeuvres, which is why prescribed burning helps us to reduce biomass load and improve forest conditions.

The wind fires in Cap de Creus are as strong as the Tramontane wind and repeat their pattern of movement periodically. Preparing the vegetation by maintaining a cork oak forest with sparse undergrowth is part of the objective of this burning at a strategic point on the road between Roses and Cadaqués (L'Alt Empordà). February is a good month for this type of habitat, taking advantage of the hibernation period of the tortoise. Source: Fire brigade.

 Training burns: constant training and practice are part of the day-to-day life of any emergency response service. The burnings serve as a practice and training ground for the fire brigade, in a real fire scenario but under safe and controlled conditions. The entry of new firefighters requires the creation of training practices so that they can learn how to work in realistic scenarios. The burnings allows aspiring firefighters to gain knowledge by experiencing fire at close quarters, observing and analysing the fundamental factors that explain the spread of fires seen on a small scale.

The trainers prepare the students of the last graduating class of the GRAF (Forest Action Group) speciality of Firefighters before performing the burning of Vilaseca in Castellnou de Bages. Source: Fire brigade.  Burning for research projects: any action we carry out on ecosystems generates an impact with effects that last for a greater or lesser period of time, or that may even become irreversible, depending on the intensity and recurrence with which they occur. This is not a new phenomenon, and in nature it already occurs with events such as floods, snowfalls, windstorms, etc. Any human action also generates changes and impacts, and knowing the extent and subsequent processes that nature will employ in response becomes a core element that must be incorporated in order to manage and conserve habitats. Research is

the primary means of furthering this knowledge and the findings will need to be incorporated in order to address future fire issues. The burnings are an opportunity for scientists to conduct trials where they can measure the impact of fire and how nature responds.

3. WHAT KIND OF VEGETATION DO WE BURN?

The type of vegetation being burned is an important factor in planning the burn and determining the impact we will achieve through the use of fire. The method of burning, selecting the best days to burn and the human and material equipment to be used can be very different if we are burning a pasture or ground with plant remains under a mature pine forest that we want to preserve.

Although the diversity of habitats and types of plant populations is very wide in Catalonia, with a large number of species mixed in different groupings, we classify the type of vegetation into six main groups:

 Grasslands and reedbeds

Burning of open space populated mainly by the herbaceous stratum with a heavy load of old and dry grass. Fire removes dry biomass and activates the regeneration mechanism of new grass.

February in El Pallars Jussà. Source: Fire brigade.

 Grassland under woodland The maintenance of forests with a herbaceous stratum reduces the risk of fire spreading by canopy in the event of a fire, as is the case of this burn in Sant Carles de la Ràpita (El Montsià) on 16 March 2021. Maintaining this type of forest structure can be a good option for peri-urban forests that present serious civil protection problems in the event of fire. Source: Fire brigade.

 Shrubland

Reducing high biomass loads in continuous areas of scrubland, as in the case of El Montgrí (El Baix Empordà), makes it possible to generate a mosaic landscape with more biodiversity and a greater defensive capacity in the event of fire. Burning must incorporate environmental aspects, as in the case of the image on the right, where you can see the small islands of scrubland that will not be burned in order to ensure shelter for certain types of fauna. February 2021. Source: Fire brigade.

 Shrubland under woodland

This burning at the end of February in Navàs (El Bages) aims to reduce the risk of canopy spread in a Aleppo pine forest located in a strategic point of the River Cardener. Mastic, rosemary, gorse or juniper form a continuous canopy under the Aleppo pine. When the height of this stratum exceeds a certain limit, the fire can easily climb and spread through the forest canopy. Controlled burning makes it possible to maintain a low-risk structure for 7 to 10 years. Source: Fire brigade.

 Remains of thinnings or cuttings These burns are aimed at eliminating large accumulations of fuel after massive tree falls due to extreme meteorological phenomena such as windstorms or snowfalls, or due to the action of clearings to generate an agricultural mosaic in forest areas.

 Remnants of thinning under trees

Burning debris after silvicultural thinning treatment achieves two complementary objectives. Thinning allows forest growth to be concentrated in a smaller group of trees, accelerating the process towards the transformation of a forest with larger, mature trees.

The burning of the remains, as in this case in Oristà (Osona), ensures low combustibility of the forest in this process, improving fire resistance. Source: Fire brigade.

4. HOW DO WE CARRY OUT A PRESCRIBED BURN?

Executing a prescribed burn involves teamwork, with each player contributing a specific role that requires commitment and responsibility. These characteristics are inherent to each firefighting activity and therefore are used to maintain the appropriate level of training. The roles and functions deployed in the execution of a burn are the same as those used in an extinguishing manoeuvre in a real fire situation, following an organisational scheme that defines who does what and how various components relate to each other in order to achieve a common objective. The burnings are organised into five main phases:

 Planning: related to the location of the burn, the determination of the main objectives and the drafting of the burning plan, which is the technical document that sets out the what, the who and the how of the execution of the burn.

 Preparation of burn plots: before starting a fire in the forest, it must be ensured that the burn will not spread beyond the established limits; this requires the determination of control or defence lines, which are created with manual or mechanical tools. On certain occasions, preparation work may include clearing or pruning to ensure the preservation of certain species or specific specimens (e.g. singular trees).

− Execution: this is the main day of the burn, when all the teams that are part of the burn come together:

− Control team: in charge of ensuring that burning does not exceed the established limits.

− Ignition team: in charge of applying the fire in the appropriate way to achieve the established objectives and without jeopardising the safety and control of the burn.

− Lookout: responsible for monitoring the weather and the overall view of the burn. They should observe and anticipate changes that may influence the evolution of the fire and alert the burn team.

− Control chief and ignition chief: responsible for the two teams mentioned above, which must be coordinated throughout the burn so that the ignition team's activity never exceeds the capacity of the control team's control.

− Burn manager: the person in charge of the burn, who must ensure that the objectives sought through the application of fire are achieved, always within the established safety framework.

 Rearguard: once the execution phase is over, the burned plot may have hot spots, with areas of organic mulch burning after the fire has passed through or old vines burning for hours or days. It is important to ensure that the burnt plot is safely cooled and that interior hot spots do not have the potential to re-ignite outside the plot. In this phase, the aim is to use hand tools to accelerate cooling of the hot spots and to monitor the perimeter in the same way as in an actual forest fire.

 Monitoring: once the active phase of the burning is over, a period begins in which monitoring actions are established to assess and quantify the effects and impact of the fire on the ecosystem. Periodic visits to collect data on and take photos of the evolution of the type and quantity of vegetation that recovers across the burned area serve to establish knowledge on the effects of the fire and help to improve the planning of new burns.

5. BURNING CAMPAIGNS

Although there can be good days for burning throughout most of the year, burning activity is concentrated around two main periods: winter and late summer/autumn.

 Winter burning: this is the most convenient period to apply fire because the vegetation is in vegetative standstill (without important physiological activity due to low temperatures); grasses and bushes burn well, but the weather is usually favourable to bring the burns under control in an 'easy' way. The above-ground parts of weeds and bushes are burned and we activate the natural response of all those plants that resprout from the root. As the temperature is usually low, fire damage to the tree canopy can be easily controlled. February and March offer the most days suitable for burning, since in January the days are still too short for the few hours of burning required.

 Late summer and autumn burns: the natural fire pattern in Catalonia is associated with lightning fires typical of summer and autumn storms. This fact tells us that our ecosystems are naturally adapted to summer fires, and that the impact and response of vegetation and wildlife will be closer to nature if we apply fire during this period. Although burning affects the same vegetation strata as in winter, plants will respond differently because they are in a state of physiological activity and at the end of the growing season for each year. Burning during this period will favour plants that disseminate seeds because it will activate the seed bank and they will play a more important role than resprouting plants, which have more difficulty in this period in activating a response. This means that, in the medium term, grass will predominate over scrubland and this type of forest structure is more suited to fire control. We associate summer with the forest fire period because this is the time when drought and heat tend to coincide as key elements in the spread of fire and, consequently, the generation of large fires. Therefore, the drought situation and weather conditions must be well known before

prescribed burning is undertaken during this period, in order to ensure an acceptable level of fire risk. There are many days in late summer and early autumn with lower temperatures and areas with normal drought levels, following the passage of storms that deposit rain in the forests.

Time sequence of images showing the evolution of vegetation from the day of the burn (top left) to almost two years later (bottom centre). The original structure had a high biomass load in the form of scrubland, which also provided vertical continuity between above-ground vegetation and the tree canopy. Two years after burning, herbaceous vegetation predominates, favoured by the timing of the burning, and the risk of this forest burning at high intensity has been significantly reduced. Source: Fire brigade.

6. THE 2021 WINTER BURNING SEASON

This winter's burning campaign began with a scrubland burn at the end of January in El Montgrí (El Baix Empordà) and ended at the end of March in El Bages, with a burn that forms part of a strategic point of the Llobregat in Balsareny.

In total, 49 burns have been carried out, affecting around 162 hectares in 24 different locations.

Grassland burning accounts for more than half of the area burnt, although it only represents 10% of the total number of burns carried out. This year no burning has been carried out for the specific objective of research, although in some areas the prevalence of the pine processionary moth is being assessed between areas treated with burning and those without.

Again, grassland and scrubland burning accounted for most of the burned area. The remaining types are fairly evenly distributed and involve only wooded structures.

Number of burns by Emergency Region (Winter 2021) 20 15 10 5 Quemas 0 REG RELL RETITE REMN REMS REC Val

d'Aran No. of burns carried out carried burns of No. Emergency Region

The distribution of burns by emergency region depends largely on the frequency of good days for burning and the length of the burning periods, depending on the location and characteristics of the habitats that have restrictions due to the bird nesting season from March onwards. Plots in shady areas had little availability for burning until the end of March in Central Catalonia, while other areas in the Pre-Pyrenees and Tarragona, on the other hand, were beginning to exhibit severe fire conditions. Burning activity is also a good indicator of the availability of burnable vegetation and thus can be used to approximate the fire risk in an area.

Number of burnings per county 10 9 8 7 6 5 4 3

No. of burns carried out carried burns of No. 2 1 0

Burns are organised by burning projects with an identifying name. The area per burning project is variable and generally ranges between 1 and 100 hectares, depending on the objective and the location of the plot. When implementing the burning project, the number of burning days to complete the entire project is also variable, and depends very much on the type of vegetation, the terrain and the objective of the burn.

The Puigdorca burning project in Balsareny (El Bages) is part of a Strategic Management Point (PEG) of the Llobregat to limit the spread of western and southern fires that have historically affected Central Catalonia. The project involved 17 hectares requiring six days of burning, which were carried out between February and March. The distribution and frequency of burning in a particular area depends very much on current projects, the total area and the weather windows for each site. Source: Fire brigade.

Area burnt by county. (Winter 2021) 50

Area (ha) Area 20

GRAF Technical Unit Special Task Force Division Directorate General for Fire Prevention, Extinguishing and Rescue Services Firefighters of the Autonomous Community of Catalonia