1

Prevention of Large Wildfires using theFire Types Concept

Supported by:

Pau Costa AlcubierreMarc Castellnou Ribau

Asier Larrañaga Otxoa de EgileorMarta Miralles Bover

Paul Daniel Kraus

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First edition: March 2011.

Editorial Office: Unitat Tècnica del GRAF, Divisió de Grups Operatius Especials.Direcció General de Prevenció, Extinció d'Incendis i Salvaments.Departament d’Interior. Generalitat de Catalunya.

Contact: utgraf@gencat.cat Carretera de la Universitat Autònoma s/n, 08290 Cerdanyola del Vallès, Barcelona, Spain

Author cover photo: Marcel·lí Fons. Navàs 2007, Catalunya. Spain.

Disclaimer: This handbook was prepared for the project FireParadox under EU Sixth Framework Programme. The content ofthis publication is the sole responsibility of the authors and doesnot necessarily reflect the views of the European Union or theEuropean Forest Institute.

Legal deposit :B-17311-2011ISBN: 978-84-694-1457-6

Certificat digital:UT GRAF

Bombers de la Generalitat de Catalunya. utgraf@gencat.cat

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AuthorsPau Costa Alcubierre, Asier Larrañaga Otxoa de Egileor, Marc Castellnou Ribau and Marta MirallesBover(Forest Engineers, Bombers de la Generalitat de Catalunya, GRAF); Paul Daniel Kraus, (FireEcologist, Fire Ecology Research Group, MPI Chemistry, Germany).

AcknowledgementsWe would like to thank all fire specialists of GRAF (Grup de Recolzament d’Actuacions Forestals) fromCatalonian Fire Service (Bombers de la Generalitat de Catalunya) who have participated directly orindirectly in the preparation of this handbook.

We are especially grateful to all persons and institutions who kindly have provided illustrations andvarious other materials for the compilation of this handbook, in particular to Míriam Piqué (CentreTecnològic Forestal de Catalunya, Catalonia), Paulo Fernandes (Universidade de Trás-os-Montes eAlto Douro, Vila Real, Portugal), Josep Piñol (Centre de Recerca Ecològica i Aplicacions Forestals,Catalonia), Eric Rigolot (Institut National de la Recherche Agronomique, France), Steve Gibson(Northumberland Fire and Rescue Service, England), Mónica Bardají and Jaime Sendra (DepartamentoMedio Ambiente. Gobierno de Aragón, Spain), Domingo Molina (Universitat de Lleida, Catalonia),Gerard Grau (Sapeur Pompiers de l’Aude, France), Teresa Cervera (Centre de la Propietat Forestal,Catalonia), David Meya and Carlos Miranda (Departament de Medi Ambient de la Generalitat deCatalunya, Catalonia), Manuel Rainha (Grupo de Análise e Uso do Fogo da AFN, Portugal), MichaelaSpielmann (EFI Central European Regional Office, Germany), Steve Hawkins (Wallowa WhitmanNational Forest, USA), Luis Galiana (Universidad Autonoma de Madrid, Spain).

Contributors

Tim Green (European Forest Institute, Finland), Francisco Cano (Departament de Medi Ambient de laGeneralitat de Catalunya, Catalonia), Fernando Chico (Forest Engineer, Spain), Antonio Salgueiro andPedro Palheiro (Grupo de Análise e Utilização do Fogo da DGRF, Portugal), Eduard Plana (CentreTecnològic Forestal de Catalunya, Catalonia), Andreas Schuck (European Forest Institute, CentralEuropean Regional Office), Albert Alemany (Bombers de la Generalitat de Catalunya, Catalonia).

EditionJordi Vendrell (Geographer, Bombers de la Generalitat de Catalunya, Catalonia), Edgar Nebot, Mariona

Borràs and Helena Ballart (Forest Engineers, Bombers de la Generalitat de Catalunya, Catalonia).

Lay-out

Maria Luïsa Lopo y José Ignacio Solano (Journalists of Àrea d’Informació i Comunicació delsBombers de la Generalitat de Catalunya, Catalonia).

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Index

Introduction to the handbook........................... 7

Handbook

1 The paradigm of large wildfires in Europe....... 8

1.1. Fire as a tool to mitigate the problem

of large wildfires................................ 8

1.2. Land use change and landscape evo-

lution as a main driver for the large

wildfire phenomenon.................... 10

1.3. Why do large wildfires overcome our

suppression capacity?...................13

2 Planning for the limitation of fire spread

potential......................................................14

2.1. Reducing fire spread potential.

Extensive fuel management........... 14

2.2. Slowing down fire spread.

Anticipating and preparing suppres-

sion opportunities..........................16

2.3. Adapting forest fire prevention to cur-

rent large wildfires.........................17

3 The Fire Types Concept as a support tool.......22

3.1. The Fire Types Concept as a planning

element. Planning levels and fields of

application.....................................23

3.2. Contributions to pre-suppression;

Model Fires and Strategic

Management Points (SMPs)...........24

3.3. Contributions to prevention. Limiting

the extent of large wildfires............25

3.4. Contributions to forest manage-

ment..............................................27

4 Final considerations.......................................28

5 References....................................................29

Appendices

1) Fire as a landscape management tool.........32

1a) Ecology of fire....................................32

1a1) Characterisation of fire regimes..33

5

1a2) Vulnerability depending on stand

structure..................................36

1a3) Natural Fire Rotation (NFR) and

Homogeneous Fire Regime Zones

(HRZ).......................................38

1b) Traditional fire use..............................40

1b1) Living with fires as a model for

current landscapes..................40

1b2) Current situation.....................42

1c) The use of fire as a management

tool.....................................................44

1c1) The role of fire for stand struc-

ture..........................................44

1c2) Integration of fire into forest

management-prescribed burn-

ing....................................45

2) Generations of large wildfires. Interaction of

landscape, land use, prevention/suppression

systems and types of wildfires. The

Catalonian example....................................52

3) Proposed treatments for each fire spread

type...........................................................58

3a) Methodology for the development and

application of the Fire Types Concept.

The Catalonian example......................58

3a1) Methodology. . . . . . . . . . . . . . . .58

3a2) Basic factors for fire spread.......63

3a3) Spread schemes for each Fire

Type........................................65

3b) Proposed treatments for each fire

spread type........................................75

3b1) Identification of Strategic

Management Points (SMPs)....75

3b2) Creating Strategic Management

Points .....................................75

3b3) Proposed treatments for each

fire spread type........................76

3b4) Validation of pre-defined oppor-

tunities....................................79

Glossary..........................................................83

Index

To Pau Costa Alcubierre, who never stopped fighting for his greatest dream.

Without your enthusiasm this handbook would have neverbecome reality.

To Jaume Arpa, Jordi Moré, Ramon Espinet and David Duaigües, for always leading the way ahead.

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Introduction to thehandbook

This handbook, entitled Prevention ofLarge Wildfires using the Fire TypesConcept, is an attempt to introduce themethodology of the Fire Types Concept asa prevention and pre-suppression tool.The scope of this handbook includes theintegration of fire use into forest planningand the prevention of large wildfires.

The purpose of the handbook is to providethe knowledge for the integration of fireinto forest planning and wildfire preven-tion so that it can be used as a tool tocomplement and support forest policies.The handbook seeks to provide aEuropean perspective on fire preventionconsidering the different fire regimes andvegetation structures as well as the het-erogeneous socioeconomic conditions inEurope.

The structure of the handbook consists ofthe main text that describes the context ofits field of application and a series ofappendices where more technical informa-tion can be found. The first part of the doc-ument gives an overview on the currentstate of European forests and the evolutionof large wildfires related to the socioeco-nomic processes in the second half of the20th century. The causes of the increase inthe occurrence of large wildfires areexplained, with a focus given on land usechanges and policies to increase suppres-sion capacity.

In the second and third parts, strategies arerecommended to minimise the effects oflarge wildfires, to reduce their intensity andto improve the safety of firefighting per-sonnel. The second part explains the Fire

Type Concept, spread patterns and thedetailed determination of a Fire Type. Thethird part describes these concepts andtheir applicability when it comes to land-scape planning to establish strategic man-agement points.

The appendices that complete the hand-book go into greater depth on: (1) the useof fire as a landscape management tool,based on fire ecology and historical fireuse, (2) fire prevention strategies consider-ing the fire generations and (3) recom-mended strategies and tactics for each firespread type.

References to literature used in the hand-book are numbered, whereas letters areused for terminology explained in the glos-sary to improve readability of the handbook.

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1. The paradigm of large wildfires in Europe

1.1. Fire as a tool to mitigate the problem of large wildfiresIn Mediterranean Europe thelast few decades have beencharacterised by dramatic landuse changes. The abandon-ment of farmland and reducedgrazing have led to an increasein wildland areas. Thesechanges in the landscape havecontributed to a more aggres-sive spread of large wildfires(LWF) all over Europe(18).

Currently, in theMediterranean region wildfireslarger than 50 ha representmore than 75% of the areaburned, although they repre-sent only 2.6% of the totalnumber of wildfires(24). Overthe last few years, the occur-rence of large wildfireepisodes with extreme firebehaviour has affected differ-ent regions of Europe: Portugal(2003 and 2005), south-easternFrance (2003), Spain (2006 and2009), and Greece (2000, 2007and 2009)(8) , see Graph 1.

The response of mostEuropean societies to this prob-lem has generally been tostrengthen fire suppressionpolicies(9) with the overall aimto increase their fire suppres-sion capacity. However, theselarge wildfire episodes haveclearly shown the limitations ofthe suppression systems(20)

which have been overwhelmedby fire fronts of very high inten-sity and fire spread. Preventionand suppression systems withlarge budgets began to recog-nise that they became victimsof their own success: the heavyinvestment reduced fires ofmedium and low intensity,while the more intense wild-fires continued to spreadunhindered through the land-scape, remaining beyond thesuppression capacity.Additionally, the reduction oflow- and medium-intensity dis-turbances paradoxicallyensured the persistence of

high-intensity wildfires(6),which resembles the applica-tion of a negative selection toour wildfires.

This strategy to improve andincrease suppression resourceshas resulted in a scenario witha rather constant area burned

over the years and with onlyfew years where several thou-sands of hectares are affectedby large wildfires. The problemis thus concentrated in yearswith droughts and/or adverseweather conditions that mayproduce combustion processeswith extreme fire behaviour.

Graph 1. Area burned (thousands of hectares) by large wild-fires during the period 2000-2006 in different European coun-tries. Source: European Forest Fire Information System (EFFIS).

9european paradigm

Despite the high investment in fire sup-pression efforts, wildfires are becominglarger and more intensive, with fasterspread rates(8), which offers only fewopportunities for the suppression sys-tems, see Figure 1.

Fig. 1. Patterns of wildfires inCatalonia over the last 50 years. Thesurface affected by fire at least once in thisperiod is shown in orange. 94.6% of thatarea was burnt by fires larger than 100hectares. Consequently, not fire in generalcan be considered the main ecosystemdriver but only those fires with the highestintensities are forming ecosystems. Source:Bombers de la Generalitat de Catalunya.

Fire is a widespread phenomenon in manyEuropean ecosystems and it has alwayscoexisted with human activity, see appen-dix 1a, as either natural ignition from drylightning storms or as a tool in agricultureand silvo-pastoral systems(9).

Fire has traditionally been used for thereduction of plant residue, improving ofgrazing conditions, removal of moribundplant material and improved regenerationof plant species requiring open habi-tats(16). Despite these widespread tradi-

tional uses of fire, the fire culture inEurope has been lost as a consequence ofthe rural exodus that occurred during thesecond half of the 20th century, and theperception of this element has changedfrom being a tool to being a threat(19).Appendix 1b gives more detailed informa-tion concerning the traditional uses of firein Europe.

Fire is a natural element of Mediterraneanecosystems, and large wildfires are noparticular single events but part of a

defined disturbance regime. For that rea-son the challenge that needs to be facedfrom both a prevention and suppressionpoint of view, is to anticipate and reducethe spread potential of large wildfires, aswell as potential risk for lives, propertyand land use systems.

The main focus of this handbook will be: toidentify tools to reduce spread potential.Factors that determine extreme fire beha-viour are analysed and then appropriatepreventive strategies are determined.

10 european paradigm

1.2. Land use change and landscape evolution as a maindriver for the large wildfire phenomenon

An analysis of the importance of the deter-mining parameters of fire behaviour is ne-cessary to understand the problem: topo-graphy, weather and fuel (biomass).

TopographyIn the time scale analysed (<100 years), itcan be said that topography as a factorhas remained unchanged, and is thereforeconsidered not very important.

Weather According to climate scientists, the aver-age weather as well as the distribution ofweather events is subject to a relativelyrapid anthropogenic climate change, moregenerally known as global warming. Mostof the observed temperature increasesince the middle of the 20th century wascaused by increasing concentrations ofgreenhouse gases, which results fromhuman activity such as fossil fuel burningand deforestation. The observed increasein average temperatures over the last 50years (0.13ºC [0.10ºC – 0.16ºC] perdecade)(15) shows a rather unfavourabletrend in terms of occurrence of wildfires,but cannot explain the entire problem. Infact, there were hot and dry years record-ed for the first half of the 20th century thatclearly were not linked to the occurrence

of catastrophic wildfires. Quite on the con-trary, fire seasons today facing thosemeteorological conditions would chal-lenge almost any modern fire suppressionsystem at present. Studies conclude thatthe number and area of wildfires between1968 and 1994 increased due to climatechange(22), however, such statements areonly based on meteorological data, where-as the occurrence of wildfires alsodepends on many other factors.Nevertheless, the role of climate for theincrease of adverse weather episodes(drought and high temperatures) is rele-vant for the development of large wildfireepisodes, particularly where most climatemodels predict even more unfavourableconditions than present ones.

Fuel (biomass)When leaving aside the relative effect ofclimate change in explaining large wildfireepisodes, wildland and forest fuels (i.e.bio- and necromass of an ecosystem con-sumed by fire) become the factor that haschanged most significantly, and this hasalso affected the development of wildfiresshowing extreme fire behaviour(17):

· The main change has occurred in thefuel build-up through the development

of forest and other woodland com-pared to the first half of the 20th centu-ry. The increasing accumulation of finefuels allows fast-moving fires tospread through the landscape withlong distance spotting ahead of the firefront.

· Increasing continuity of forest andother wildland areas on abandonedfarm and pasture land allows the devel-opment of long fire perimeters with dif-ficult access. This is a common phe-nomenon in regions that have sufferedfrom a rural exodus process which isaffecting a good part of the rural areasof the EU with a large wildfire problem,see Graph 2 and 3.

· The current trend leads to forests andother woodlands that are increasing inextent, fuel load and continuity, withvery high densities of low-diametertrees, a situation inevitably developingtowards large wildfire scenarios. Thesteady accumulation of biomass hasnot only increased horizontal continu-ity at surface level, but also vertical andtangential continuity of tree crowns,resulting in vegetation structures thatcan burn at very high intensity(6).

11european paradigm

Graph 3: Evolution of forest area in Francebetween 1825 and 2005 in million hectares.Source: Cinotti (1996)(14).

Graph 2. Evolution of forest area for eachAutonomous Community in Spain between 1980and 1990, in percentage. Source: National ForestInventory (IFN), 2 and 3.

As a consequence, the continuity of for-est and other woodland, together withthe immense accumulation of forestfuels, has led to the appearance of largewildfires with crowning and massivespotting activity. Other aspects contribut-ing to a landscape evolution favouring ascenario with more large wildfires thatare showing extreme fire behaviour, are:

· fire suppression policies have led to areduction of low- and medium-intensi-ty fires in the landscape to the point of

virtual disappearance, allowing fuel toaccumulate: this is known as the sup-pression policy paradox(9, 23).

· the decrease or abandonment ofagro-forestry and silvo-pastoral land-use practices due to a rural exodus,leading to the conversion of pastureand farmland into forest areas.

· the dominance of high-intensity wild-fires is considered a major factor inhomogenising the landscape and

present vegetation structure.

· the socio-economic and political con-text of the forest sector resulting in ageneral decrease in active forest man-agement, see figures 2 and 3.

By linking these two factors (weatherand fuel), we can conclude that largewildfires are generated in situationswhere a major part of the fuel is avail-able and under adverse weather condi-tions.

12 european paradigm

Figure 2 (left) and Figure 3 (right). Comparison between two photos of thesame area (1908-2001) where fuel accumulation can be seen as a result ofthe abandonment of agroforestry activity. Masia Can Tardà (Castellolí,Catalonia). Source: Bombers de la Generalitat de Catalunya.

13european paradigm

1.3. Why do large wildfires overcome our suppressioncapacity?

When called to a wildfire in a forest, thestrategy applied by the vast majority of pre-vention and suppression services is basedon a rapid, hard-hitting initial attack on allignitions, regardless where it occurs and theweather conditions. This strategy is highlyeffective and manages to restrict the major-ity of ignitions to small-scale fires. By con-trast, when the balance between the sup-pression force and the fire behaviour isclearly favourable to the latter, the systemcollapses, showing itself to be inefficient. Itis then that the window for large wildfiresopens.

In this context, a large wildfire can bedefined as a fire that maintains a spreadrate, intensity and flame length that over-comes the capacity of the suppression sys-tem for a reasonably sustained period, andwhich therefore offers few suppressionopportunities.

There are several possibilities how firebehaviour can overcome suppression

capacity, depending on the type of land-scape:

· Growth rates of perimeter length aregreater than the capacity of the contai-ning lines, due to the continuity of thelandscape.

· Rate of spread is greater than suppres-sion progress. Resource deploymentalong the perimeter is slower than therate of perimeter growth. This includesthe speed at which resources are allo-cated and provided with supplies, aswell as the speed at which informationon changes in fire behaviour andchange of plans circulate through thechain of command. Examples: Sardinia(Italy) 2007, Catalonia (Spain) 1986 and2000 and Northumberland (England)2006.

· The suppression system cannot carryout effective operations to the samedegree as under normal circumstances

due to high fire intensities. The highintensity associated with crown firesexceeds suppression capacity and noground force or airborne resource candeal with it. Examples: Spain 1994 or1998.

· Effects on property and people areincreasing the requirement for suppres-sion resources to protect them. At thewildland-urban interface (WUI) there isa negative feedback process whichtranslates into a relative reduction inthe quantity of resources set aside forcontaining the actual wildfire in favourof the quantity of resources given overto protecting property and people.Every piece of property is consideredan emergency. Example: Catalonia2003 and 2007, Greece 2009.

· Simultaneous large wildfires are redu-cing the number of resources availablestill further. Example: California 2003,Portugal 2003, Greece 2007.

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2. Planning for the limitation of firespread potential

At the same pace as the responses tocurrent wildfires are established andthe landscape evolves, the same wild-fires change their fire behaviour, there-by evolving into the next generation ofwildfires. As an example, the successof the investment in suppressing firesburning out of control due to their rateof spread in Catalonia (1986-1993)finally ended in 1994-1998 with largewildfires getting out of control in theform of crown fires.

While the fuel load and its distributionin the landscape remain unchanged,wildfires beyond suppression capacitywhich can neither be prevented norhalted, continue to occur. It is a long-term problem.

In the short term, the only solutionwould be to slow down (if not stop) thespread of a wildfire, preparing oppor-tunities for redirecting, modifying ordelaying the fire spread.

2.1. Reducing fire spread potential.Extensive fuel management

Which fuel load and distribution over the landscape allows fires to burn within capacityfor control? How should the fuel load be reduced or redistributed? The possibility of thesuppression system to controlling a wildfire is determined by the stabilisation capacityalong the perimeter. It is therefore necessary to specify the fire behaviour of that part ofthe perimeter that is beyond suppression capacity, see Figure 4.

Figure 4. Large Wildfire ofthe Solsona region in 1998crossing 200 m of plou-ghed fields and a road indownhill direction. LargeWildfires are characterized bylong distance spotting, start-ing independent fires aheadof the fire front that may joinand interact, and by the cre-ation of their own fire envi-ronment(a). Source: Bombersde la Generalitatde Catalunya.

15planning

Suppression capacityParametrising a large wildfire can becomea complex task, because whether a wildfireis out of control depends not only on thefire behaviour but also on suppressioncapacity (types of suppression tools, longinitial perimeters due to lack of access,resources tied off for protecting peopleand property, etc.).

If different suppression forces are com-pared, fire behaviour thresholds can beestablished – i.e. thresholds for rate ofspread and fire front intensity beyondwhich modern suppression systems beginto have serious problems in controlling anignition. Each suppression system mustknow its suppression capacity thresholds,that are determining the technological lim-its for its ability to fight flames and putthem out, table 1.

The key parameters limiting suppressioncapacity are fire front intensity and rate ofspread. The two factors are often related,but they can be treated independently.

Limiting fire front intensity in largewildfires Fires causing problems because of theirhigh intensity are in most cases related tovegetation structure. When trying to sta-bilise fire fronts capable of maintainingpassive and active crown fires in a sus-tained way for a period of time, the oppor-tunities for attack (indirect, parallel ordirect) decrease in inverse proportion tofuel availability, adverse weather condi-tions and landscape continuity in terms offuel patches.

In this context of a technological limit fac-ing fire fronts that cannot be dealt withbecause of the high level of crowninvolvement, it is necessary to reduce thetotal fuel load and modify the distributionof fuel loads between the different treestrata.

In order to create forest structures that areresistant to fire spread, and that are allow-ing only fires that burn with intensitiesthat can be dealt with by the suppressionsystems, it is necessary to implement fo-rest management concepts for each typeof structure that are capable of minimisingvulnerability to the development of crownfires.

Forest management guidelines thatinclude the possibility of fire occurrencemust be implemented on a large scalerather than locally in order to achieve aplausible effect on large wildfires. Thisapproach would ensure to succeed ifapplied on landscape level.

Limiting rate of spreadRate of spread overcoming suppressioncapacity is related to different factorsdepending on the type of spread:

· in topographic and convection domi-

nated fires the rate of spread will bedetermined by the spotting distance.The greater the distance, the greaterthe potential to affect large areas inshort time and, therefore, the greaterthe rate of spread. The convectivepotential of a fire is linked to the quan-tity of fuel burning; treatments toreduce fuel loads therefore limit con-vective potential which, at the sametime, limits spotting potential and spot-ting distance, and finally reduces rateof spread. For convection dominatedfires, targeted forest management canbe sufficient to limit fire spread.

· in wind-driven fires the wind speedhas the main direct effect on the wild-fire's general rate of spread. In thiscase, fuel treatments limit the intensityand, to a lesser extent, restrict firespread.

A commitment to forest management thatis oriented towards limiting fire spread isa pre-requisite to manage large wildfires,although its beneficial effects will only beseen in the long term. It is therefore alsonecessary to develop and implementalternative concepts to improve the capac-ities of both prevention and suppressionsystems.

Table 1. Technological limit of the Catalan suppression systems

16 planning

2.2. Slowing down fire spread. Anticipating and preparing suppression opportunities

Any increase in airborne and ground-based suppression resources or even theuse of larger and larger aircraft do still notpermit a direct confrontation with firebehaviour that exceeds the system's sup-pression capacity. At the moment, we canonly slow down rather than prevent thespread of a wildfire, and prepare opportu-nities where the suppression service canredirect, modify and slow down firespread.

For the different fire generations, differentsuppression response strategies havebeen shown useful. These can serve asguidelines when it comes to suggestingpre-suppression tools to slow down firespread:

· Improving road network in terrain withdifficult access (for large wildfiresoccurring in fuel continuity).

· Improving distribution of lookouts,water points, ground-based and air-borne resources according to fire risk,in combination with prescribed burningprogrammes to accumulate experiencein the use of fire for suppression pur-poses (for large wildfires occurring withhigh spread rates).

· Introducing self-protection measures,specialised strike teams and logisticaltools (for large wildfires crossing theWildland Urban Interface, WUI).

· Anticipating suppression opportunities,for all wildfires. The concept of anticipa-tion can be explained best through howa professional tennis player can returnan opponent's serve even though ittravels faster than 200 km/h, by posi-tioning himself on predicting the trajec-tory the ball will follow. He anticipatesthis movement by placing himself inthe best possible position with the rightconditions to be able to return theserve.

For the build up of anticipation capacitywithin suppression systems, new tools topredict fire behaviour had to be devel-oped, such as:

· Identifying spread patterns to identifychanges of the dominant factors inwildfires that create suppression oppor-tunities (developed in the first half ofthe 20th century).

· Use of static area (BEHAVE)(1) and spa-tial (Farsite)(11) fire behaviour simulatorsto predict areas of lower fire intensity.

· Use of simulators based on minimumfire travel paths and time to locate sup-pression opportunities(12, 13).

· CPSL (Campbell Prediction SystemLanguage) analysis to predict wherefire behaviour will change(3).

· Model Fires Concept(5) to identify theexpected Fire Type for each geographi-cal unit, and fire regions(4).

· Planning based on problem fires with alink to fireshed assessment(2).

The use of simulators requires sufficienttime for the processing, precise fuel modeldata and an accurate knowledge of small-and large-scale interaction of weather(largely wind) and topography. The appli-cation of simulators for fire suppression inEurope is limited since the majority of firesoccurring in Mediterranean Europe usuallylasts less than 48hrs.

In planning, however, simulators allow usto predict general and approximate direc-tions of fire spread, provided there is asource of information available on theinteraction of wind and landscape, thattakes fire behaviour of historical fires inthe area(2, 4, 11) into account and can adjustthe simulation.

17planning

2.3. Adapting forest fire prevention to current large wildfiresApparently though, the use of fire inter-pretation tools alone cannot be consi-dered sufficient to accurately implementplanning in a certain area. It needs ananswer first to the basic questions that areessential to anticipation:

· Probability of having a large wildfire ina specific area

· Expected movement of the fire in thearea

A new tool to master this step is neces-sary to classify, organise and typify wild-fires that occur in a specific area. The basisfor this is the observation that fires underthe same topography and weather condi-tions follow similar spread patterns(5, 10),with only fire intensity changing due tovarying fuel availability (greater accumu-lated drought stress, fuel accumulation,etc.).

Fuel availability depends on form and sizeof a fuel particle and its moisture content.Time lag (b) is related to these two factors.

The qualitative approach to fire spreadpatterns clearly reveals typical spread pat-terns for a region (topographic, wind-driv-en and convection dominated fires), whichshow particular features and geographicalvariation in terms of occurrence. This maygive the idea that each individual wildfireis different and does not follow a certainpattern. However, by using an analyticalapproach it can be seen that reality is

quite different, and that it is possible tosimplify the study of wildfires by estab-lishing a set of different Fire Types.

The Fire Types ConceptWhen analysing historical fires it becomesobvious that under the same topographyand weather (synoptic situation) condi-tions, fire spreads following similarspread schemes, see Figure 5. The FireTypes are derived from the analysis ofcommon factors in these spread schemes,see appendix 3a.

A certain Fire Type does not necessarilyimplicate a certain fire behaviour. It is thedifference in the fuel structure, land use orin ignition points that causes variation infire behaviour. However, the spreadscheme typically is maintained. Also thetypes of suppression opportunities andpoints where fire behaviour changes willbe the same when the relief is taken intoaccount.

The starting point to determine whether aFire Type follows a common spread

scheme is the spread pattern as the domi-nant factor in the wildfire. The concept ofspread patterns refers to the key elementto outline the way in which the firespreads over the terrain. Depending onthe spread pattern, three main types offire can be distinguished, see table 2:

Figure 5. Perimeters of wildfires from1949, 1970, and 2000 in L'Albiol(Catalonia). Compare the three fires followinga similar spread pattern. The differencebetween the ignition points determineswhether a fire will affect one or two crest lines.Source: Bombers de la Generalitat deCatalunya.

Table 2. Classification of fires according to spread pattern and the dominant factors.

The type of spread pattern determines thefire behaviour and the effective suppres-

sion opportunities for the suppressionservices.

18 planning

Note: Wildfires with storm-dominated spread patterns are not included in this table, nor in the whole document because at presentthere exists no knowledge about their management.

Table 3. Fire Types with description of spread scheme and strategies or opportunities for control. Source: Castellnou et al., 2009(7).

Classification of the Fire Types For a region like Catalonia, nine Fire Types have been identified that are based on common spread patterns and classified by charac-teristic factors, table 3 (7). Each of these Fire Types has been linked to specific synoptic weather conditions with a set of meteorologi-cal parameters that determine fire behaviour.

19planning

Zoning of large wildfiresThe relationship between spread patterns,relief and synoptic weather situationallows to classify wildfires by their type ofspread, a fundamental aspect for antici-pating the spread of future fires, but it alsoallows to go a step further.

A geographical region can be divided upaccording to its Fire Types when the effectof the relief is considered a fixed andunchanging factor and that the same syn-optic weather situation may have differenteffects on a region, i.e. causing adversefire weather in some areas (strong winds,low relative humidity, high temperatures,etc.) and leaving other areas with normalmeteorological conditions from a firebehaviour point of view. This step allows

to predict the Fire Types that will occur indifferent areas of a region.

In order to be able to classify and zoneFire Types, historical fires must be docu-mented and analysed by characterising atleast:

· the weather period at synopticlevel(4,21) that determines the character-istic factors

· the type of fire spread pattern and thespread scheme

· the Fire Type· the date and time of day.

The Recurrence of Large WildlandFires. Homogeneous Fire RegimeZones

Some extrapolation effort is necessary toenhance the information derived from theanalysis of historical fires that are classi-fied according to the Fire Types Conceptfor an entire region. It is assumed that thesame Fire Type will occur in similar zonesof a region under the same weather condi-tions, see Figures 6 and 7.

Similar zones of a region must have thefollowing characteristics in common thatare determining fire spread:

· Relief· General wind system· Local wind regime during specific

meteorological conditions· Vegetation type· Fire Type

Figure 6. Percentage ofarea burnt by each FireType in differentHomo-geneous fireregime zones (HRZs).Source: Castellnou et al.,2009.

Figure 7. Recurrenceof wildfires based onthe natural fireregime of the last 40years in Catalonia.The map shows the firereturn interval for eacharea. Source: Castellnouet al., 2009.

Figure 6. Figure 7.

20 planning

Suppression opportunitiesOne last field to complete the workingmethodology based on anticipation pro-posed in this handbook must be accom-plished. Once the predictable spread pat-tern of a wildfire in an area and the specif-ic synoptic weather conditions are known,the next step is to identify the suppression

operations that have been successful inorder to characterise the opportunities forsuppressing a certain fire, particularly interms of "where?" and "how?"

The compilation of operational experiencesbecomes the basic tool for developing thissection, characterising the opportunities

with the following data, see Figure 8:

· location and description of the opera-tion

· spread pattern and behaviour of thefire

· type and number of the resourcesinvolved

The Castellnou de Bages Fire, covering 963 ha on 18/07/2005

STABILISING THE HEAD BEFORE IT REACHES THE RAVINE:Descending fire spread along the crest line allows the use ofa backfiring operation on the ravine bottom to prevent the firefrom reaching the next slope in full alignment. Spotting activ-ity 300 metres ahead of the front significantly shortens thetime window for carrying out this operation, and the fire isable to jump the ravine.

Opportunity 1:

STABILISING THE HEAD BEFORE IT JUMPS THE RIVER LLO-BREGAT: the light backwind effect created by the precipicesabove the river is used to set backfires. Resources are concen-trated on the river plain to confine the spotfires falling onstubble fields.

Opportunity 2:

DESCENDING RIGHT FLANK: the right flank begins todescend out of alignment, allowing to anchor it before itreaches the ravine bottom. The length of the flank > 2 km doesnot give sufficient time to stabilise it. Because the flankspreads beyond the ravine it opens up with the backwindfrom the southern crest.

Opportunity 3:

CLOSURE OF THE LEFT FLANK BEFORE THE RAVINE JUNC-TION: the left flank spreads downward, fanned by the generalwind. At the ravine junction it reaches a perpendicular ravineprotected from the general wind that allows it to open up tothe north, generating new runs in full alignment.

Opportunity 4:

Figure 8. Simple diagram of operational dataon strategy and opportunities at a wildfire.Source: Bombers de la Generalitat de Catalunya.

Initial strategy: STABILIZE THE HEAD of the fire before it crosses the Llobre-gat river and ANCHOR THE FLANKS.

21planning

The analysis of past fires also serves for evaluation of the effectiveness of planned pre-vention infrastructures and reconsideration of fundamental aspects of their conceptualdesign, placement and adequacy under observed fire behaviour. Preventive infrastruc-ture in place overcome by fire behaviour is shown in Figure 9.

Figure 9. Example of preven-tive infrastructure overcome byfire behaviour in the RiotintoFire (Huelva) in 2004. Source:Ferrer.

As a conclusion from this section on theworking concepts and methods of antici-pation as a premise for prevention andsuppression of large wildfires, the impor-tance of looking into the past, i.e.analysing historical wildfires from differ-ent points of view should be highlighted:meteorological situation, spread patternsand operational records.

In this handbook it is not possible to gointo more detail, but the working conceptspresented here are considered a neces-sary process for bringing forward appro-

priate prevention and suppression meth-ods for current and future fires.

The classification of Fire Types explainedas an example for a region like Cataloniacan only be a mere attempt to demon-strate a possible typification of wildfiresthat allows to derive different fields ofapplication when it comes to suppressionand prevention of wildfires. This classifica-tion serves as a tool for structuring andorganising both suppression operationsas well as forest management and plan-ning.

22

Implementing the Fire Types Concept as a landscape management support toolMost of the European prevention and suppression systems orig-inated from a time characterised by wildfires affecting largeareas in a landscape with a lower proportion of tree vegetation,fewer prevention infrastructures (accessability, firebreaks,detection and alarm systems, risk prevention etc.) and fewersuppression facilities than currently exist.

The landscape evolution mentioned above made large wildfires

evolve towards a scenario with crown fires, effects on the wild-land-urban interface (WUI) and simultaneous fires, plus a con-siderable limitation of suppression opportunities even for well-equipped and well-organised suppression services.

This development in the conception of large wildfires must beaccompanied by changes in the approach to the problem tomove:

3. The Fire Types Concept asa support tool

from prevention based on...· linear infrastructures and water points to facili-

tate anchoring

· tracks and lookouts for fast and hard-hittingintervention

... to prevention based on...· making use of the fire´s strategic opportunities· adapting land use and forestry practices to expected wildfires· orienting forest management towards reducing vulnerability

of forests to large wildfires

Radical fire exclusion policies have not been very efficient in large wildfirescenarios. Climate, vegetation and traditional fire use are good indicatorsthat in many ecosystems fire is an element that sooner or later will affectsome parts of an area. The role of forest management is to determine thedegree of intensity and severity at which fire occurrence is accepted, andto carry out extensive forest management over an entire region to createstand structures that tolerate fire occurrence. In this context the preven-tion objective moves:

from...eliminating fire

from an ecosystem

... to...reducing vulnerability ofvegetation structure andinfrastructures to wildfireand limiting the range of

large wildfires

23fire as a tool

3.1. The Fire Types Concept as a planning element.Planning levels and fields of application

The spread of a potential wildfire is stillnot entirely predictable but there is aseries of tools that helps to reduce uncer-tainty, to understand the fire whenobserving it and to anticipate the mostlikely fire behaviour. Among these toolsthe knowledge transfer of operationalexperience accumulated by the suppres-sion system using the Fire Types Conceptshould be highlighted. This is a key tool

for the field of prevention in the concep-tual design, planning and placement ofinfrastructure that are essential for tack-ling wildfires (firebreaks, fuelbreaks, aux-iliary strips, tracks, etc.).

The implementation of the Fire TypesConcept in the planning process is anattempt to take this line of work further,paying more attention to the main charac-

teristics of a large wildfire most likely toaffect a more specific area, based on themodel of anticipating its expected move-ment and its spread pattern.

For forestry policy and public administra-tion planning bodies, different fields ofapplication of the Fire Types Concept werederived for different planning and organi-sational levels see table 4:

Table 4. Planning levels of preventive actions.

24 fire as a tool

3.2. Contributions to pre-suppression; Model Fires andStrategic Management Points (SMPs)

The Model Fires ConceptThe specification of a region through theFire Types Concept with adjustments to par-ticular landscape features is translated intothe concept of model fires. A model fireserves as a reference and describes themaximal potential of a fire to become alarge wildfire in a particular landscape unit.It provides information and criteria for dis-cussing and placing measures that need tobe implemented to provide support to firemanagement and suppression opera-tions(5). The particular landscape features ofa region can be grouped into (appendix 3a):

· depending on relief· depending on the development of a

weather episode · depending on availability of fuels

Strategic Management Points (SMPs).The model fires concept allows to under-stand the main characteristics that describethe expected movement of a large wildfirein a particular area, pointing out its spreadscheme. Accumulated operational experi-ence and the working system of each sup-pression force make it possible to deter-mine the most suitable opportunity for eachfuel type and relief.

It is therefore not necessary to wait for apotential fire to occur to look for suppres-sion opportunities, when the fire front willconstrain capacity for analysis. Instead, it is

possible to plan in advance, identifying thepotential opportunities and adapting themto the requirements of the suppressionservice.

This advance in planning allows to identifythe Strategic Management Points (SMPs) -locations throughout a region where themodification of fuel and/or preparation ofinfrastructures enables the suppressionservice to carry out safe operations to attackand limit the range of a large wildfire.

For each Fire Type, distinct suppressionopportunities with common features andconsequently SMPs with similar locations,

objectives and characteristics are devel-oped, see appendix 3b.

SMPs can have different objectives:

· Specific points limiting the multiplyingeffect of frontal fire spread: points wherefire behaviour changes(i) because of theinteraction of topography and fire move-ment, extending the range of a wildfire.These can be crest line junctions, Figure11, in wind-driven fires or ravine junc-tions in topographic fires, see Figure 10.

Figure 10. Ravine junction. In yellow,the potential area and, in red, the ravinebottom. Source: Bombers de la Generalitatde Catalunya. Figure 11. Picture of a crest line junc-

tion. Source: Bombers de la Generalitatde Catalunya.

25fire as a tool

· Points where ignition can be confined:

- to facilitate anchoring of flanks andback of the fire: opening up of pathsand tracks, agricultural areas or rockyterrain, forestry roads and areas withlow fuel loads to facilitate the anchor-ing of an attack.

- to facilitate accessibility: opening oftracks for access to very long flankssee Figure 12.

Figure 12. St. Boi de Llobregat Fire,Catalonia (11/07/2005). In red, tracksused for access and for anchoring longflanks. Source: Bombers de la Generalitatde Catalunya.

3.3. Contributions to prevention.Limiting the extent of large wildfires

Implementing the Fire Types Concept atthe regional planning level allows tounderstand the basic variables of thespread pattern that helps to evaluate thecontribution to the final extension of afire within a Homogeneous Fire RegimeZone of each landscape unit by takinginto account its morphology, locationand type of fuel.

Limiting the extent of a wildfireThe suggested methods are not neces-sarily directly linked to specific suppres-sion operations but they are intended todeactivate the spread mechanisms thatfuel large wildfires. Actions must beplanned in a way to reduce vegetation

structures with vertical and horizontalfuel continuity that are considered haz-ardous in specific areas of the region,considering the spread type of the refer-ence large wildfire for the zone.

As an example may serve landscapessensitive to convection fires duringsoutherly winds, like in Central Catalonia,that produce large wildfires with a clearsouth-north movement and massivespotting activity. The spread pattern indi-cates that south-facing (sunny) slopesare the generators of the most intenseconvection nuclei, causing massive spot-ting in a northerly direction, see figures13 and 14.

Figure 13. Possible scenario of wind entering from the south in centralCatalonia, resulting in the movement of a large wildfire in south-north direc-tion. The massive spot fires can reach slope (1) or/and (2). In situation (1), the spot fireswill move up the favourable slope, but with the wind and aspect against it. A spot firestarting in situation (2) would be the most unfavourable situation since the slope is in fullsun, with the wind and the slope in favour for the fire. Source: Bombers de la Generalitatde Catalunya.

26 fire as a tool

Figure 14. Castellnou de Bages Fire,18/07/2005. Convection dominatedfire: note the spotting activity of thefire front. Source: Bombers de laGeneralitat de Catalunya.

For such a scenario, the maintenance ofstand structures with low fuel loads onsouth-facing slopes is recommended, par-ticularly in the upper parts, in order to limitspotting activity and distance. The under-lying concept is to transform an extremelyfast moving spread dynamic with almostimmediate spotting to hot slopes, intofires which may be intense but more localin extent, affecting only two slopes (hot

and cold). In short, it means to turn an out-of-control convection dominated fire intoa more controllable topographic fire, seeappendix 3b and Figure 15.

In this sense, areas where forest manage-ment guidelines give priority to the reduc-tion of fuel load and distribution can bedetermined by considering the spread pat-tern of a large wildfire.

Figure 15. Possible scenario of wind entering from the south in centralCatalonia, resulting in the movement of a large wildfire in south-north direc-tion. In this case, the treatment zones with modified stand structure (in green) wouldlimit spotting activity and distance. Source: Bombers de la Generalitat de Catalunya.

Fire cause managementThe management of fire causes aims pri-marily at modifying fuel structure inzones with regular ignitions to limit firespread and minimise the need for sup-pression forces, particularly in peri-urbanand industrial areas.

Protection of vulnerable pointsVulnerable points (rural settlements,farmhouses, campsites, residential areas,farms, etc.) must be protected throughcreating infrastructure to maximise thesuppression service's effectiveness indefending these points, see Figure 16.

Figure 16. Low-fuel-loadstrip protecting a resi-dential area. Source:Bombers de la Generalitatde Catalunya.

27fire as a tool

3.4. Contributions to forest management

The establishment of Homogeneous FireRegime Zones (HRZs) allows to determinethe fire return interval and therefore recog-nize the importance of fire disturbanceswithin them. Based on that forest man-agers can assess the importance they mustattribute to forestry activities aimed at pro-tecting forest stands against fire occur-rence or improving their resistance to firespread, along with other factors that deter-mine the management of a specific area(other disturbances, seasonal conditions,protected fauna, etc.). As such, forestryschemes aimed at creating stand struc-

tures that are less vulnerable and moreresistant to fire occurrence can be com-menced.

Consequently, it is not only a question ofworking in specific areas to confine wild-fires (such as SMPs) or defining zones withthe priority objective of controlling fuelloads to limit the extent of any large wild-fire, but also of creating stand structuresthat increase resistance to the spread ofhigh-intensity fires, which consequentlyfacilitates the task of controlling such wild-fires.

28

4. Final considerations

This handbook aims to present a suite ofmethods and tools for tackling or minimis-ing the effects of large wildfires in modernwildland, rural and urban areas. The rela-tionship between the occurrence of largewildfires and the landscape is highlightedas a basic pairing that governs the otherelements forming part of the system (firegenerations, suppression and preventionservices, regional planning policies, typesof forest management, etc.).

Advances in knowledge about fire allowto develop strategies to cope with it, but

also show that, as in other elements ofnature, there are still scenarios whichhave not yet been experienced, yet willoccur in the future. This uncertaintymakes it necessary to maintain a spirit ofconstant adaptation in which it must bepossible to review and expand any stepforward taken.

All this means that this version of thehandbook may not be final, and that itmust remain open to the contributionsand experiences of the entire communityof experts that are working on fire.

29

1 ANDREWS P.L. (1986). BEHAVE Fire behav-iour prediction and fuel modelling system.Burn subsystem. USDA, Forest Service,Gen. Techn. Rep. INT196, IntermountainForest and Range Experiment Station,Ogden, Ut.

2 BAHRO, B; BARBER. KH; SHERLOCK, JW;YASUDA, DA. (2007). Stewardship andfireshed assessment: a process for design-ing a landscape fuel treatment strategy.Restoring fire-adapted ecosystems: pro-ceedings of the 2005 national silvicultureworkshop, Gen. Tech. Rep PSW-GTR-203,p. 41-54.

3 CAMPBELL, D. (1995). The CampbellPrediction System: A Wild Land FirePrediction System & Language. D.Campbell ed. 129 p.

4 CASTELLNOU, M. (1996). Reconstrucciónde la progresión de los incendios históri-cos y su efecto modelador en la veg-etación: Ribera de Ebro. Seminar on forestwildfires, 16-18 December. Ed. JMGonzalez. Catalan Forest TechnologyCentre. Pp 207-223. Solsona.

5 CASTELLNOU, M. (2000). Nuevasmetodologías de prevención de incendios.Iberian Forest Congress. Castelo Branco.Portugal. December 2000.

6 CASTELLNOU, M; NEBOT, E; MIRALLES,

M. (2007). El papel del fuego en la gestióndel paisaje. In: IV International WildfireFire Conference 2007, Seville, Spain.Thematic session nº1.

7 CASTELLNOU, M; PAGÉS, J; MIRALLES, Mand PIQUÉ, M. (2009). Tipificación de losincendios forestales de Cataluña.Elaboración del mapa de incendios de dis-eño como herramienta para la gestiónforestal. Paper at the 5th National ForestCongress (Ávila), SECF

8 CASTELLNOU M; LARRAÑAGA A;MIRALLES M; MOLINA D. (2010). WildlandFire Scenarios: learning with experience.In: Towards Integrated Fire Management –Outcomes of the European Project FireParadox. EFI Report 23.

9 CASTELLNOU, M; KRAUS, D; MIRALLES,M; DELOGU, G. (2010). Suppression fireuse in learning organizations. In: TowardsIntegrated Fire Management – Outcomesof the European Project Fire Paradox. EFIReport 23.

10 EXPOSITO, R; CORDERO, T. (2004) Albiolfire. Did we learn the third time?Proceedings of the IV International FireConference. Coimbra. Portugal.

11 FINNEY, M.A. (1998). FARSITE: Fire AreaSimulator-model development and evalu-ation. USDA Forest Service, Research

Paper RMRS-RP-4, Rocky MountainResearch Station, Ft. Collins, CO. 47pages.

12 FINNEY, MA.; SAPSIS, DAVID B.; BAHRO,B. (2002). Use of FARSITE for simulatingfire suppression and analyzing fuel treat-ment economics. In: Sugihara, Neil G.;Morales, Maria E.; Morales, Tony J., eds.Proceedings of the symposium: fire inCalifornia ecosystems: integrating ecolo-gy, prevention and management; 1997November 17-20; San Diego, CA. Misc.Pub. 1. Berkeley, CA: Association for FireEcology: 121-136.

13 FINNEY, M.A. (2007). A computationalmethod for optimizing fuel treatment loca-tions. Intl. J. Wildl. Fire. 16:702-711.

14 INVENTAIRE FORESTIER NATIONAL(2008). La forêt en chiffres et en cartes.France

15 IPCC (2007): Summary for Policymakers.In: Climate Change 2007: The PhysicalScience Basis. Contribution of WorkingGroup I to the Fourth Assessment Reportof the Intergovernmental Panel on ClimateChange [Solomon, S., D. Qin, M. Manning,Z. Chen, M. Marquis, K.B. Averyt,M.Tignor and H.L. Miller (eds.)].Cambridge University Press, Cambridge,United Kingdom and New York, NY, USA.

5. References

30 references

16 LLORET F (2003). Gestión del fuego y con-servación en ecosistemas mediterráneos.Revista Ecosistemas 12 (2).

17 MINNICH, RA (2001). An integrated modelof two fire regimes. Conservation Biology.15: 1549-1553

18 MOLINA, D; CASTELLNOU, M; GARCÍS-MARCO, D and SALGUEIRO A. (2010).Improving fire management successthrough fire behaviour specialists. In:Towards Integrated Fire Management –Outcomes of the European Project FireParadox. EFI Report 23.

19 MONTIEL C. (2009). The fire as a manage-ment tool in Europe. Paper presented tothe Fire Service Technical Conference."Capacitat de gestió dels incendis fore-stals" (18 and 19 November 2009, Girona).Government of Catalonia

20 MONTIEL, C; COSTA, P; GALÁN, M. (2010).Overview of suppression fires policies and

practices in Europe. In: Towards IntegratedFire Management – Outcomes of theEuropean Project Fire Paradox. EFI Report23.

21 MONTSERRAT, D. (1998). La predicció delsGrans Incendis Forestals. Catalunya Rurali Agrària, 54, pp 5-13.

22 PIÑOL J; TERRADAS J; LLORET F (1998).Climate warming, wildfire hazard, andwildfire occurrence in coastal easternSpain. Climate Change 38: 345-357

23 PIÑOL, J; CASTELLNOU, M; BEVEN, KJ.(2007). Conditioning uncertainty in eco-logical models: Assessing the impact offire management strategies. Ecologicalmodelling 207:34–44

24 SAN MIGUEL, J and CAMIA, A. (2009).Forest fires at a glance: facts, figures andtrends in the EU. In: Living with wildfires,what science can tell us. EFI DiscussionPaper 15. Ed. Yves Birot. Finland.

31

Appendices

1 Fire as a landscape management tool ................................... 32

1.a Ecology of fire.......................................................... 32

1.b Traditional fire use.................................................... 40

1.c The use of fire as a management tool....................... 44

2 Generations of large wildfires........................................... 52

3 Proposed treatments for each fire spread type..................... 58

3.a Methodology for the development and application

of the Fire Types Concept. The Catalonian example... 58

3.b Proposed treatments for each fire spread type........75

32

Fire is an integral disturbance factor inmany natural ecosystems. Traditionallynatural disturbance was perceived as acatastrophic event and as exogenousagent of vegetation change originating inthe physical environment. This had severeconsequences for the planning of long-term goals in forest ecosystems. Sincemore recently the more endogenousnature of fire as a disturbance factor with agradient from minor to major is now wide-ly accepted, fire has to be taken intoaccount for the management of forestecosystems, especially in long-term plan-ning. While fire as a disturbance factormay be required to maintain some naturalecosystems and wildlife habitat it maywreak havoc with specific managementgoals such as timber production or soilconservation. Fire effects can therefore beintegrated into land management planningthrough an understanding of how fireaffects forest stand structure and land-scape evolution(1).

The fire regime is an important term tocharacterise the different aspects of ecosys-tem functioning. Understanding the fireregime(3) allows to determine the responseof all vegetation layers (herbaceous plants,shrubs and trees) to fire occurrence foreach type of forest structure. Knowledge ofthese processes is fundamental for deter-mining the basis for integrated manage-ment, which considers disturbance as anadditional element in ecosystem dynamics.

Integrated practices to conserve theseecosystems must consider that fire in itselfis an object of management and not only ameans for obtaining other goals, such asreduction of fuel load or an improvement ofanimal and plant populations. Fire manage-ment includes a wide range of options:from avoiding any fire and suppressing itas soon as it starts, to doing nothing andallowing the fire regime to follow its owndynamic. Another alternative is activeapplication of ignition processes: carrying

out controlled burns to mimic the naturalfire regime or simply to reduce the proba-bility of large wildfires. Any of these activi-ties affects the fire regime and is thereforeinvolved in managing it. The importantthing is to be clear about the objectivesbeing pursued(1).

The integration of fire into the ecosystemallows to establish management goals thatare adapted to the fire regime, determiningobjectives and silvicultural treatments tocreate and maintain a stand structure thatis resistant to fire, to minimize the potentialfor the occurrence of Large Wildfires, and tomaximize direct and indirect benefits.

The term wildland fire, understood as anecological process as an integral part ofecosystem functioning, both being con-trolled or not, is differentiated here fromthe term wildfire, understood as anuncontrolled fire perceived by humans as athreat to life and property.

1.a. Ecology of fire

Fire as a landscapemanagement tool

Appendix 1

33

ecology

of fireA fire regime is a generalized description of the role fire plays in an ecosystem. It is typ-ically a statistical concept and can be characterized best through the following parame-ters(2): Intensity, Severity, Extent, Frequency, Fire Return Interval andSeasonality.

Forest types develop a distinct structure under the influence of a specific fire regime asa result of the interaction between the different parameters and the ecosystem.

Considering the purpose of this document, the parameters characterising fire regimescan be described as follows:

1.a.1. Characterisation of fire regimes

IntensityFire intensity measures the physical extentof fire disturbances. It specifies the power ofa fire in terms of energy release and isstrongly dependent on stand structure,defined by the available fuel load and itshorizontal and vertical distribution. Theenergy release (kW) is expressed per unit oflength (m) of a linear fire front. As this is dif-ficult to measure, observed flame lengthcan be related to fire intensity and can serveas a rough estimate of fire line intensity.Examples of different fire intensities areshown in Figures 17, 18 and 19.

SeveritySeverity is a qualitative measure of theimmediate effects of a fire on an ecosystem.It refers to the degree of loss of organic mate-rial, mortality, effect (% of crown scorch intrees) and survival of both above- and below-ground biomass. It is determined by the heatreleased both above and below ground.Examples of different fire severities areshown in Figures 20, 21 and 22.

ExtentExtent refers to the area affected byfire. A clear distinction is madebetween outbreaks (fires smaller thanone hectare), wildfires (fires between 1and 500 ha) and large wildfires (asso-ciated with fires larger than 500 ha).Fires that become large in size usuallyreach their extent because they haveexceeded suppression capacity,although this depends also on othervariables such as the suppression sys-tem, the ecology and topography ofthe area, etc.).

FrequencyFrequency refers to the number of dis-turbances which occur in a specificarea and over a certain period of time.It is defined as the number of fires pertime unit in a particular area.Examples of different disturbance fre-quencies are shown in Figures 23, 24and 25.

Fire Return IntervalThe return interval is the time neededuntil an area may again be affected bythe same disturbance. It can be calculat-ed as the inverse of the frequency inyears between the disturbance events.

SeasonalitySeasonality refers to the physiologicalstate of the vegetation at the time a dis-turbance occurs. The effects of a distur-bance and also its development aredepending on the processes of plantdevelopment, dormancy, reproductivecontrol, and stress physiology that cre-ate a structural heterogeneity in vegeta-tion.

34 ecology of fire

Figure 20. High severity. Source:Bombers de la Generalitat deCatalunya.

Figure 21. Medium severity. Source:Bombers de la Generalitat deCatalunya.

Figure 22. Low severity. Source:Bombers de la Generalitat deCatalunya.

Figure 23. High disturbance fre-quency. Source: Bombers de laGeneralitat de Catalunya.

Figure 24. Medium disturbance fre-quency. Pinus pinea in Cap de Creus.Source: Míriam Piqué.

Figure 25. Low disturbance fre-quency. Source: Bombers de laGeneralitat de Catalunya.

Figure 17. High intensity fire Sour-ce: Bombers de la Generalitat deCatalunya.

Figure 18. Medium intensity fire.Source: Bombers de la Generalitat deCatalunya.

Figure 19. Low intensity fire. Source:Bombers de la Generalitat de Catalunya.

Severity FrequencyIntensity

35ecology of fire

Fire can act as a disturbance factorresulting in a stand replacement or ina maintenance fire regime, dependingon the intensity with which it affects aforest stand.

Figures 26 and 27. Fire as a stand replacing disturbance factor in Pinushalepensis after fires of high intensity (left).The disturbance results in a structur-al change of the forest stand and in the occurrence of new light demanding species(right), Zuera (Zaragoza/ Spain). August 2008. Source: Bombers de la Generalitat deCatalunya.

Stand replacement results from high intensity fires and causes high mortality in allstructural layers, implicating a substitution of the major part of the individualsthrough regeneration or resprouting, see Figures 26 and 27. Stand structure disap-pears, forest resources are lost and the mid- and long-term management objectiveswill have to be totally reconsidered.

Figure 28. Fire acting as a maintenance factor in a Quercus suber standaffected by a rapid surface fire, destroying the herbaceous and shrub layers.The tree layer is not severely damaged, and shade conditions are preserved (left).Figure 29. Pinus nigra regeneration in canopy gaps opened up by fire distur-bance (right). Source: Bombers de la Generalitat de Catalunya.

Maintenance is a process associatedwith low and medium intensity fires. Theherbaceous and shrub layers may be par-tially or fully affected, and the tree layerpartially. The stand structure does notcompletely disappear, Figure 28.

The fire resistance of the stand isincreased, Figure 29, timber capital ismaintained and the basic managementgoals will not need to be modified

36 ecology of fire

Generally, a fire regime can be directlylinked to vulnerability of vegetationstructure. However, since a wide range offire intensities, from crown fires to sur-face fires, can result in the mortality orsurvival of individuals, depending on theecology of the species and other factors,it is not easy to see the link. Differentstand structures, when affected by thesame fire, will show different degrees ofvulnerability to fire occurrence.

Silvicultural treatments may modify a fireregime that is linked to a forest standthrough altering stand structure, i.e.accelerating processes at the most vul-nerable development stages and main-taining those structures least vulnerable

to fire over time. The frequency and typeof silvicultural treatments in any standstructure may mitigate its vulnerability ormaintain its resistance, depending on thecharacteristics it shares with the fireregime that defines it.

Vulnerability depends on type of standstructure (referring to stand characteris-tics, dominant species, spatial distribu-tion of individuals and successioncycles), terrain and weather conditions.Below (Figures 30, 31 and 32) a qualita-tive approach is used to illustrate vulner-abilities on a relative scale, where thecolour code indicates that vulnerability ishigh (red), medium (orange) or low (yel-low).

1.a. 2. Vulnerability depending onstand structure

37ecologia del foc

Relation between stand structure, fire intensity and severity in a Pinus halepensis stand based on the relative importance of vulner-ability and the effects of different types of fire on a forest stand.

Dense structure with vertical continuityfrom ground to crown, Figure 30. Nostand stagnation yet, nor general self-pruning of the lower branches. The prob-ability that the stand becomes highlyvulnerable to fire disturbance is veryhigh; medium and low vulnerability tofire have a low proportion in this type ofstructure.

Dense structure but with vertical disconti-nuity between the pine needle bed and thelive branches of the crown base, Figure 31.The stand dynamics have stagnated, withstrong self-pruning of the lower branches.The proportion of high vulnerability to fireis medium-high, although low vulnerabili-ty is significant and contributes to standdevelopment by clearing out individualsthrough heat damaging the trunk base andaffecting the cambium. This is typically thephase when prescribed burning is firstintroduced.

Figures 30, 31 and 32. Pinus halepensis stands in Central Catalonia. Source: Bombers de la Generalitat.

Explanation of the colour bars: The probability that a stand will burn in a certainway (and thus display low, medium or high vulnerability to fire disturbance) is direct-ly related to its structure (owing to silvicultural treatments) and development stage.The colours indicate the vulnerability of a stand (low, medium or high vulnerability);the length of the coloured bar resembles the relative importance of the degree of vul-nerability to fire impact.

High vulnerability

Medium vulnerability

Low vulnerability

Structure cleared and pruned, Figure 32.Vertical discontinuity and crown separa-tion (FCC<60%) prevent surface fires fromrising up to the crowns; at the same timethe separation between burning fuel andthe crown base decreases stand vulnera-bility. Only during specific weatherepisodes a surface fire burning with highintensity is able to renew the stand, thetree mortality being determined mainlyby radiation (crown scorch).

38 ecology of fire

1.a. 3. Natural Fire Rotation (NFR) andHomogeneous Fire Regime Zones(HRZ)

Natural fire regimes refer to the role of firein landscapes without human intervention,however, including aboriginal fire use(2). Inecosystems fire regimes can be charac-terised through a set of parameters (seeabove). Natural fire regimes, however, aremodified by human activity, increasing fireoccurrence (e.g. in the westernMediterranean basin) or decreasing it (e.g.in boreal forests where fire suppressionhas decreased fire frequency and extent).In fact, referring to a natural fire regimemakes little sense in regions with stronganthropogenic influence, such as theMediterranean basin. One has to go farback in time where climatic and vegetationconditions were different from today tofind a hypothetical situation with only littleimpact by humans(1).

For Catalonia there are hardly any data onfire severity and intensity, whereas a lotmore information on number of fires andburnt area is available. In this context, itappears the most viable way to charac-terise a fire regime through the calculationof fire frequency over a determined timeperiod. The Natural Fire Rotation (NFR) iscalculated to obtain area frequencies.

The Natural Fire Rotation (NFR) representsthe time period necessary to affect thewhole of a homogeneous fire regime zone,see Appendix 3a, under a given synopticsituation. As an example, for Catalonia theHomogeneous Fire Regime Zones werecalculated, see Figures 33 and 34, for aperiod of 40 years, where existing datawere extrapolated and processed.

39ecology of fire

Figures 33 and 34. Based on the analysis of fires over the past 40 years in Catalonia. FireReturn Intervals are shown for each zone. Source: Castellnou, et al, 2009(3).

For further information on the characteri-sation of fire types and homogeneous riskareas, consult Appendix 3a Methodologyfor the development and application of theFire Types Concept.

1. LLORET F (2003). Gestión del fuego y con-servación en ecosistemas mediterráneos.Revista Ecosistemas 12 (2).

2 AGEE, JAMES K. 1993. Fire ecology ofPacific Northwest forests. Washington, DC:Island Press. 493 p.

3 CASTELLNOU, M; PAGÉS, J; MIRALLES, Mi PIQUÉ, M. (2009). Tipificación de losincendios forestales de Cataluña.Elaboración del mapa de incendios de dis-eño como herramienta para la gestiónforestal. Comunicació del 5è CongrésForestal Nacional (Ávila), SECF.

REFERENCES

40

traditional

fire use

1.b. Traditional fire useFire represents a force that, once deployed, may destroy everything in its path. Masteryof it provides power and the capacity to transform the earth. The domestication of fire isconsidered one of the most important achievements of mankind, the only species thathas mastered that step(1).

Throughout the history of land use in Europe, fire has been an important element ofgrazing, agriculture and forestry and an important process in forming landscape patternsin terms of ecological and cultural diversity (2).

1.b.1. Living with fires as a model forcurrent landscapes

The crisis of the rural world at the begin-ning of the 20th century led to an increas-ing rural exodus and the associated aban-donment of traditional land managementpractices, including fire use.Industrialisation began to affect bothurban and rural environments.

In central and northern Europe, the socioe-conomic changes after WW II brought achange in land use systems (increasinguse of technology) and landscape patterns,resulting in the elimination of traditionalburning practices. Meanwhile, these

recent trends, air quality standards and theprevailing general opinion that fire is detri-mental for ecosystem stability and biodi-versity led to a complete ban on fire use inmost European countries(3).

Since early humans roamed the earth, firehas provided not only resources for sub-sistence and improvement of living condi-tions but also created habitats whichhumans are part of. With time, human per-ception of and relationship to landscapeshave changed, and with this, ecosystemshave changed(4):

41traditional fire use

Fig.35. Coexistence: Throughout early human history, the relationship between manand nature was a direct and dependent one. Low population densities and low degreesof technification made mankind aware of being a part of nature, vulnerable to environ-mental changes, and discovering new ways of survival.

Fig.36. Utilisation:The mere coexistence changed with increasing populations and theassociated extraction of resources, particularly in the form of extensive agriculture andlivestock farming, and later oversea trade on a large scale. Domestic herbivores, fire andiron tools significantly altered disturbance regimes of many landscapes. Nature pro-duced a multitude of resources for mankind's use and pleasure.

Fig.37. Engineering: With the emerging industrialisation, the degree of technification inland use systems increased. The German Black Forest model was imported to aMediterranean environment, eliminating redundancy to optimise the use of resources.Suddenly, the entire ancestral forest culture (including fire) was considered bad, and astruggle went on against it to the point of almost eliminating it, replacing it with CentralEuropean forestry.

Fig.38. Religion: An urban perception of woodlands as autonomous ecosystemsemerged where humans no longer belong to, and where human intervention divergesfrom natural succession. This created the perception of forests as an ideal, static andincombustible system and agro-forestry practices were condemned as productivist sys-tems. The forest is an untouchable god and fire, as well as chainsaws, are devils to befought.

Figures 35, 36, 37 and 38. Source: Castellnou and Nebot, 2007(4).

42 traditional fire use

1.b. 2. Current situationIt seems obvious that conservation andenvironmental management have inheritedsuch traditional practices and that they areused for various reasons: removing slashafter thinning and harvesting; improvinggrazing conditions for forage and habitatfor domestic livestock, game or otherwildlife with conservation status; elimina-ting of moribund plant material that could

become fuel for uncontrolled wildfires, orimproving the regeneration of plant speciesthat need open environments(1).

The current situation of fire use in Europeas a tool for different practices is describedin the following, from traditional fire use toprescribed burning as tools to fight wild-fires(5).

Traditional fire use

Gradual abandonment of traditional fireuse practices.

Although the use of fire has been recog-nised as a general tool in rural Europe,the current state shows a diverse situa-tion:

1) Central and northern Europe

2) Mediterranean basin

Maintenance of the use of fire as a tradi-tional tool, deeply rooted in agricultureand livestock farming. Current socioeco-nomic dynamics are fundamental inensuring the maintenance or eradicationof these traditional practices.

3) Eastern Europe

Countries where agricultural activities arean important part of the local economy,and where the use of fire as a traditionalpractice, like in the countries of theMediterranean basin, continues to be apractice rooted in rural life. See Figure 39.

Figure 39. Distribution of the traditional use of fire in Europe and North African countries. Source: Lázaroand Montiel, 2009(5).

43traditional fire use

Prescribed burning

The introduction of prescribed burning inEurope was not aimed at mimicking natu-ral processes or at reconstructing naturalfire regimes. It was presented as a tool toreplace traditional burning practices ormanagement systems which have nowbeen abandoned.

1) As a replacement tool for traditional fire use in Europe

The incipient development of prescribedburning practices in Europe has taken placein different regions with different objec-tives. The results obtained to date showhow this technique has largely been intro-duced in the Mediterranean countries inorder to prevent wildfires, while in northernEurope the main objectives are aimed atforestry and nature conservation activities.

These trends are still developing, as somecountries, e.g. Portugal and some regionsof Spain, have begun to expand theirobjectives of prescribed burning to includeforest and biodiversity management.Meanwhile, some countries in northernand central Europe might develop pre-scribed burning programmes for wildfireprevention, due to potentially increasingfire risk.

2) Development of prescribed burning

This practice is concentrated in southernEurope and has seen a strong increase atthe beginning of the 21st century.

3) Wildfire prevention

Figure 40. Distribution of prescribed burning practices and objectives in Europe and North Africancountries. Source: Lázaro and Montiel, 2010(5).

1. LLORET F (2003). Gestión del fuego y conservación en ecosistemas mediterráneos. RevistaEcosistemas 12 (2).

2. GOLDAMMER, J.G.; RIGOLOT E; BIROT Y (2009). Living with Wildfires: what science can tell u.EFI Discussion Paper

3. GOLDAMMER, J.G.; and BRUCE, M. 2004. The use of prescribed fire in the land managementof Western and Baltic Europe: An Overview. Int. Forest Fire News No. 30, 2-13.

4. CASTELLNOU, M; NEBOT, E; MIRALLES, M. (2007). El papel del fuego en la gestión del paisaje.En: IV International Wildfire Fire Conference 2007, Sevilla, Spain. Thematic session nº1.

5. LÁZARO, A. y MONTIEL, C. (2010). Overview of prescribed burning policies and practices inEurope and other countries. In: Towards Integrated Fire Management – Outcomes of theEuropean Project Fire Paradox. EFI Report 23.

6. CERDAN, R. Planificació territorial i dimensió socioambiental dels incensis forestals al Bages.2004. In: Incendis forestals, dimensió socioambiental, gestió del risc i ecologia del foc. XarxaALINFO XCT2001-00061. Solsona.

REFERENCES

44

management

tool

1.c. The use of fire as a management tool

The use of low-intensity fires is a very effec-tive silvicultural tool in fire prone areas toimprove the structural resistance of foreststands to fire. This treatment can be appliedwhere species are naturally adapted to fireregimes of low intensity, maximizing thebenefits of prescribed burning(1).

The most important effects of low-intensity fires are: - Reduction of dead fine fuels in the herba-

ceous and shrub layers, reducing thetotal fuel load and the vertical and hori-

zontal continuity of fuels.

- Creation of breaks in the vertical struc-ture through burning the lower treebranches and thinning out the crownsthrough radiation and convection, whichaccelerates the elimination of old leavesof evergreen species(2).

The benefits of low intensity fires forstand structure can be applied in twoways:- Through planned prescribed burning(c)

in terms of passive(d) and active(e) sup-pression.

- Through the follow-up and monitoring ofwildfires and their behaviour, allowing tointegrate the experiences with low-inten-sity fires into prescribed burning (firemanagement).

This may significantly reduce the vulnera-bility of a stand structure to wildfires as canbe seen in some fires ignited by lightningstrikes. See Figures 41, 42 and 43.

1.c.1. The role of fire for stand structure

Figures 41, 42 and 43. Lightning-ignited fires burning with low intensity. The effects produced are similar to the onesthat can be achieved through prescribed burning: surface fuel elimination, thermal pruning of low branches and thinning of crownfoliage. Depending on the return interval, these fires can create stand structures resistant to fire. Source: Bombers de laGeneralitat de Catalunya.

45management tool

1.c.2. Integration of fire intoforest management -prescribed burning

The controlled application offire as a management tool isbased on the idea of benefittingfrom fire effects on stand struc-ture under well planned anddefined conditions. This alsoknown as technical fire use inprescribed burning.

Fire as a dynamic disturbancefactor in ecosystems causes achange in stand structuredepending on its intensity andreturn interval(1). Understan-ding these changes allows themanager to control and regu-late the development of astand.

These precepts are determinedby silvicultural objectives laidout in management plans thatare mostly based on empiricalexperience (cause and effect).

The regulation of competitionbetween individuals of a foreststand is achieved through treat-ments that eliminate someindividuals to improve standstructure, mimicking succes-sion stages that can beobserved in natural processes

following disturbances such aswind throw, avalanches, orlow-intensity fires. In thatsense, silvicultural treatmentslike thinnings can be under-stood as controlled and direct-ed applications of a distur-bance that affects individualtrees of a stand. However, thisrequires knowledge and expe-rience to evaluate the intensity,frequency, as well as the formof the application of a treat-ment.

In summary, the use of techni-cal fire only intends to replicatenatural processes aiming toimprove a stand in an ecologi-cally, technically, socially andeconomically acceptable fra-me.

Prescribed burningPrescribed burning is the care-ful application of fire underspecified fuel and weather con-ditions to meet specificresource management objec-tives and long-term manage-ment goals. It is used as a toolin active and passive fire sup-pression where prescribed

burning operations are basedon the use of low-intensity firesthat aim at reducing fuel loadsand therefore reducing therisks of high-intensity fires.

These treatments use fire toachieve a predefined manage-ment objective for a foreststand through the interactionof fire with a specific ecosys-tem, according to a technicalplan.

At European level, prescribedburning practices can be classi-

fied according to the manage-ment objectives pursued, seeFigure 44.The introduction ofprescribed burning to southernEurope was primarily aimed atrisk reduction. The experiencegained in these practices lateron allowed to expand the aimstowards other managementobjectives (nature conserva-tion, forest management orhabitat management). This isthe case in France, Portugal andsome regions of Spain, such asCatalonia, Galicia and theCanary Islands(3).

Figure 44: Objectives of the use of prescribed fire. Source: Lázaro, A. &Montiel, C. (2009)(2).

46 management tool

Depending on the main goals that pres-cribed burning is applied for, it can be clas-sified into four major groups: Wildfire riskreduction, and prescribed burning in silvi-culture, rangeland management and wet-land management.

Types of prescribed burning

1) Wildfire risk reduction

This practice is concentrated mainly insouthern Europe, with a strong increase inthe beginning of the 21st century.

Objectives:a) Improvement of pre-fire stand structure

and increase of resistance to firethrough semi-regular and irregularstand structure, see Figure 45.

Figure 45. Irregular stand structure withtree individuals of different ages.Location: Font de la Pólvora (Girona). Source:Bombers de la Generalitat de Catalunya.

· Elimination of undergrowth vegeta-tion thus reducing fuel loads. In caseof a fire this stand will burn with lessintensity.

· Breaking up vertical and horizontalcontinuity, thermal pruning (see Fig.46 and 47) and reduction of the treecover. In case of a fire, there will onlybe surface fire spread and a min-imised risk of crown fires.

· Decrease of density (number oftrees/ha), clearing of undergrowthand elimination of advanced regener-ation through radiation affecting thecambium at the base of the trunk, seeFigures 48 and 49.

Figures 46 and 47. Prescribed underburning eliminating undergrowth and the lower branches through thermal pruning. Thedistance between the first live branches and the ground surface is increased, thus creating breaks in the vertical continuity. Location: PortsTortosa-Beceit; Horta Sant Joan, Catalonia. Date: January 2004. Source: Bombers de la Generalitat de Catalunya.

47management tool

b) Maintaining pre-suppression in-frastructures.

· Maintenance burning in areas oflow fuel loads, see Figures 50and 51.

Figures 48 and 49. Elimi-nation of advanced regen-eration as potential lad-der fuels. Location: PortsTortosa-Beceit; Horta SantJoan, Catalonia. Date:January 2004. Source:Bombers de la Generalitat deCatalunya.

Figures 50 and 51. Creation of an area of low fuel load. Location: Road between Balsareny– Avinyó, Catalonia. Date: February 2004. Source: Bombers de la Generalitat de Catalunya.

2) Silvicultural treatments

Objectives:a) Competition control in regular stand structure, see

Figure 52.

Figure 52. Regular standshowing a homogeneous anddense layer of trees of thesame age. Source: Bombers dela Generalitat de Catalunya.

· Clearing of undergrowth (elimination of dying,dominated and suppressed trees).

· Opening up the canopy in regular structuredyoung stands in order to control competition andwater stress, see Figures 53, 54, 55 and 56.

48 management tool

Figures 55 and 56. Competitioncontrol in a Pinus halepensisstand. Location: Sant Quirze,Catalonia. Date: Figure 55, February2006. Figure 56, May 2006. Source:Bombers de la Generalitat deCatalunya.

b) Removal of forest slash resultingfrom silvicultural treatments.

· Extensive in situ burning of forestresidues / slash resulting from thin-ning, pruning, timber harvesting orthe creation of firebreaks to elimi-nate dead fuels and to favor a rapidand efficient recycling of nutrients,see Figures 57, 58 and 59.

Figures 57, 58 and 59. Slash bur-ning after thinning. Location Figures57 and 58: Rasquera; Catalonia. Date:February 2004. Location Fig. 59:Meranges, Catalonia. Date: October2006. Source: Bombers de laGeneralitat de Catalunya.

Figures 53 and 54.Reintroduction of fire as anatural disturbance torestore fire prone standstructure in a boreal for-est. The low intensity surfacefire is selecting for fire resist-ant Pinus sylvestris individu-als and eliminating Piceaabies in the undergrowth.Location: Fagerasen,Västernorrland, Sweden.Date: June 2007.

49management tool

c) Treatments to restore vege-tation structure

· Species selection, favour-ing and/ or eliminating tar-get species of the ecosys-tem according to manage-ment objectives, takinginto account ecologicalaspects, see Figures 60-65.

· Habitat diversification,creating a mosaic of openand closed patchesdepending on the faunaone wishes to promote,see Figures 66-68.

Figures 60, 61 and 62. Management of critical points and species selection. The use of pre-scribed fire as a tool for species management: elimination of Ulex parviflorus through repeated burn-ing (aiming at the elimination of the seed bank), creating large flame lengths; restoration ofBrachypodium sp. grassland as pasture land. Location: Tivissa, Catalonia. Date: Fig. 60 and 61 May 2002,Fig. 62 June 2002. Source: Bombers de la Generalitat de Catalunya.

Figures 63, 64 and 65. The use of prescribed burning to control succession of woody vegetation in former military train-ing sites: elimination of Betula pendula through high intensity burning with large flame lengths has relatively little impact on the soilfauna and the seed bank of Calluna vulgaris due to short residence times of the fire front. Location: Drover Heide, Düren, Germany. Date:April 2007 (Figures 63 and 64), June 2007 (Figure 65). Source: Daniel Kraus, Fire Ecology Research Group, MPI Chemistry, Germany.

Figures 66 and 67. Prescribed burning to maintain open anddiverse stand structure of Pinus sylvestris in a landscape mosaicfor habitat management of Capercaillie (Tetrao urogallus).Location: Abernethy Forest Reserve, Scotland. Source: Mark Hancock,Abernethy Forest Reserve, Royal Society for the Protection of Birds(RSPB), Scotland.

50 management tool

3) Prescribed burning for rangelandmanagement

Objectives:a) Pasture renovation in areas of exten-

sive grazing.

· Brush elimination to create grazingareas, see Figures 69 and 70.

Figures 69 and 70. Burning of pastures in high mountain areas. Elimination of Juniperuscommunis and Genista balansae. Location: Dòrria, Catalonia. Date: March 2007. Source:Bombers de la Generalitat de Catalunya.

b) Maintenance and improvement of pas-tures.

· Renovation of the seed bank to increasethe quality and quantity of seeds.

· Brush control to maintain grazing areas,see Figures 71, 72 and 73.

Figures 71, 72 and 73. Traditional patch mosaic burning of coastal heathland to maintain optimal grazing conditions through-out the year. Location: Lygra, Western Norway. Date: April 2005. Source: Mons Kvamme, Heathland Centre, Lygra, Norway.

Figure 68. Heathland burning (Callunavulgaris). Created mosaic improves thehabitat of Black Grouse (Tetrao tetrix) andRed Grouse (Lagopus lagopus scoticus).Location: Scotland. Date: April 2004.Source: Bombers de la Generalitat deCatalunya.

51management tool

4) Prescribed burning in wetlands

Objectives:a) Reed bed renovation.

· Reed bed burning to create open areas favouring specific avifauna species, seeFigures 74 and 75.

Figures 74 and 75. Reed bed burning.Location: Ebro Delta, Catalonia. Date:February 2002. Source: Bombers de laGeneralitat de Catalunya.

1. AGEE, JAMES K. (1993). Fire ecology ofPacific Northwest forests. Washington, DC:Island Press. 493 p.

2 FERNANDES P.M., VEGA J.A., JIMÉNEZ E,RIGOLOT E (2008). Fire resistance ofEuropean pines. Forest Ecology andManagement 256 (2008) 246–255.

3 LÁZARO, A. AND MONTIEL, C. (2010).Overview of prescribed burning policiesand practices in Europe and other coun-tries. In: Towards Integrated FireManagement – Outcomes of the EuropeanProject Fire Paradox. EFI Report 23.

REFERENCES

52

Interaction of landscape, land use, prevention/suppressionsystems and types of wildfires. The Catalonian example

The main landscape changes of the last centuriesinclude(1) :

· Industrialization and urban sprawl.

· Migration (from rural to urban areas).

· Land abandonment.

· Changing agricultural and forestry practices.

· Transition from the use of biomass to fossil fuels.

· Effective suppression of all wildfires with low andmoderate intensity.

· High intensity wildfires which exceed suppressioncapacity, being responsible of the major part of theburnt area.

The socio-economic changes of the 20th centurycan be characterized by factors that have affected allEuropean countries on a large scale but only in ashort-term period.

Graph 4. Development of the number of wildfires and burnt area inCatalonia during the period 1970 – 2006. Source: Bombers de laGeneralitat de Catalunya.

Generations of largewildfires

Appendix 2

The evolution of wildland fires in Catalonia is shown in graph 4:

53Generations of wildfires

European landscapes have evolved at the pace of the socio-economic changes followingthe patterns of re-colonization of the cultivated land by wildland vegetation and respond-ing to land use changes with their vegetation structure. Naturally, the behaviour of wild-fires has adapted to every evolutionary phase of the landscape, resulting in differentgenerations of wildfires.

Fire generations can be defined by a scenario where a specific factor limits suppressioncapacity and thus leads to the development of a large wildfire. This factor is typicallyextrinsic to the suppression systems and intrinsic to the landscape and its different phas-es of evolution which may coincide in time and space.

1st Generation Large Wildfires caused by Fuel Continuity

Determined by the availability of a continuous fuellayer, especially scrubs and grasses. The cultivatedland is abandoned and vegetation cover reachescontinuity. The lack of opportunities for anchorpoints allows large perimeters.

Fire spread

From 2 to 15 years.Fuel accumulation

period

Began in Catalonia during the late 1950s to 1960s.Period

Surface fires of medium intensities with very largeperimeters, burning between 1,000 and 5,000 ha,predominantly by wind-driven fires.

Fire behaviour

Creation of linear preventive infrastructure andwater points to facilitate anchor points and to grantbetter access to the area.

Preventive measures

The local response is reinforced with seasonal fire-fighters.

Suppression mea-

sures

High intensity fires can overcome the linear preven-tive infrastructures.

DevelopmentFigure 76. Large fire front without disconti-nuity, characteristic of first generation fires.Source: Bombers de la Generalitat de Catalunya.

54 Generations of wildfires

2nd Generation Large Wildfires caused by a high Rate of Spread

Fuel accumulation caused by abandonment of landand traditional land management allows fires thatspread with high intensities and a fast rate ofspread, advancing with spot fires.

Fire spread

From 10 to 30 years.Fuel accumulation

period

Started to occur in Catalonia in the 1970s – 1980s.Period

Fires of high intensity and rate of spread, consum-ing 5.000 to 10.000 hectares in wind and topogra-phy driven fires. The rate of spread overruns thecontrol lines.

Fire behaviour

Reduction of the time needed for the suppressionforces to arrive on scene (detection, distribution offire stations).

Preventive measures

Increase of water-based resources and aerial meansfor a more forceful attack.

Suppression mea-

sures

Spot fires can overcome linear infrastructure andrapid interventions. Crown fires overcome the sup-pression efforts of aerial means.

Development

Figure 77. High intensity fire exceeding thecapability of conventional water-basedresources. Source: Bombers de la Generalitat deCatalunya.

55Generations of wildfires

3rd Generation Large Wildfires caused by intensive crown fires

Through high intensity crown fires because of verti-cal continuity of forest fuels and forest homogeneitydue to neglected forest management and the sup-pression of all fires of low and moderate intensity.

Fire spread

From 30 to 50 years.Fuel accumulation

period

Began in the years 1990 to 2000.Period

Occurring during heat waves and generating firesfrom 10,000 to 20,000 ha, with crown fires, convec-tive columns, and massive spot fires at large dis-tances. This results in very little suppression oppor-tunities and an easily changing fire behaviour, sur-passing the capacity of the chain of command toreact to information.

Fire behaviour

Risk modelling to adapt the availability of resourcesto the probability of a large wildfire. Switching froma preventive strategy for fire elimination to a pre-ventive strategy to have tolerable fire regimes.

Preventive measures

Analysis of similar fires to anticipate fire behaviourinstead of only reacting to it. Confinement strate-gies. Amplifying fire suppression techniques: rein-troducing fire as a tool, power and hand tools,heavy machinery, reinforcing aerial attacks andimproving the efficiency combining these meas-ures. Logistics units are installed and the level ofdecision making is lowered for a quicker responseto changes in fire behaviour.

Suppression mea-

sures

Large wildfires with massive spotting potentialaffecting the Wildland-Urban Interface (WUI).Simultaneity of large wildfires

Development

Figure 78. Crown fire which overcomes thesuppression capacity. Source: Bombers de laGeneralitat de Catalunya.

56 Generations of wildfires

4th Generation Large Wildfires crossing the wildland-urban interface (WUI)

Large fires which spread through forests, residen-tial areas and houses without any differencesbecause of the density of backyard and garden ve-getation and the resulting fuel load continuitybetween forests and urbanized areas. Episodes withsimultaneity of Large Wildfires in one zone

Fire spread

--Fuel accumulation

period

Began approximately in the year 2000.Period

Fires that can start and end in the WUI, and burnmore than 1,000 ha. Independent crown fires duringheat waves.

Fire behaviour

Pyro-gardening, promoting fuel treatments withininhabited zones, fire resistant buildings.

Preventive measures

Attacking the fire while defending houses and peo-ple in a new defensive situation. GPS and GIS tech-nologies to trace resources in real time. High impor-tance of fire analysis as a tool. Strike forces to pri-oritise defensive measures.

Suppression mea-

sures

Simultaneous large wildfires crossing the wildland-urban interface (WUI).

Development

Figure 79. High intensity fire movingthrough a residential area. Source: Bombers dela Generalitat de Catalunya.

57Generations of wildfires

5th Generation Simultaneous Large Wildfires crossing the wildland-urban interface (WUI). Megafires

Simultaneous large wildfires in high risk areas withextremely rapid, virulent fire behaviour, crossingurban and peri-urban areas.

Fire spread

--Fuel accumulation

period

--Period

Simultaneous crown fires affecting also the wild-land-urban interface (WUI).

Fire behaviour

Necessity to incorporate fire into forest manage-ment directives and guidelines.

Preventive measures

Necessity of cooperation and exchange ofresources, information and experiences.Coordination between regions. Continuous learningand exchange platforms.

Suppression mea-

sures

--Development

Figure 80. High intensity fire front overcom-ing conventional water-based resources fromSan Diego (USA). Source: Dave Christenson.

Starting from this experience, some conclu-sions can be drawn for the best tools andmeasures available to face Large Wildfires:

- Integrate fire into the basic directives offorest management, adapted to the fireregimes of a zone, helping to reduce theintensity of expected fires.

- Incorporate analysis tools to anticipate thebehaviour of Large Wildfires, and to bemore efficient in their prevention and sup-pression.

- Assure access, safety and opportunitiesfor anchor points (LACES) in zones wherea change in fire behaviour can be expec-

ted allowing an efficient suppression (pre-suppression infrastructures).

- Incorporate all existing suppression tools(water, heavy machinery, hand tools, fire).This implies the integration of prescribedburning into fire management as well asthe creation of pre-suppression infrastruc-tures and the recognition of fire as a forestmanagement tool.

- Ensure an appropriate distribution of sup-pression resources to an expected fire ona daily basis. This includes resources forsurveillance (routes, lookouts, individualswith mobile phones) and for suppression(fire stations, water points).

In order to implement these measures onehas to understand the fire regime (fireecology) and the expected fire (model fireconcept), and needs a profound knowl-edge of the tools to be incorporated (pre-scribed burning, strategic managementzones).

1. CASTELLNOU, M; NEBOT, E; MIRALLES,M. (2007). El papel del fuego en la gestióndel paisaje. En: IV International WildfireFire Conference 2007, Sevilla, Spain.Thematic session nº1.

REFERENCES

58

Proposed treatments foreach fire spread type

Appendix 3

3.a Methodology for the development and applicationof the Fire Types Concept. The Catalonian example

The main phases of the methodology are(1):

- Creation of a Geodatabase of historical fire perimeters.o Reconstruction of perimeters.o Back dating and characterisation.o Breaking down and synthesis of initial information.

- Identification of meteorological situations at synoptic level for the back dated fires.

- Reconstruction of fire spread.o Examination of spread schemes and meteorological situations:

· Cataloguing of perimeters according to spread pattern.· Determining the Fire Type.· Classifying the fires in terms of the Fire Types concept.

o Characterisation of fire spread for each landscape unit.

- Location and characterisation of zones with homogeneous fire regimes.

3.a.1 Methodology

59methodology

Reconstruction of perimeters, back dating and characterisation

The basic information sources used in Catalonia for analysing historical fire perimeters are described inTable 5 and Figure 81.

Table 5. Information sources for compiling historical fire perimeters, weather conditions and spreadpatterns in Catalonia. Source: Bombers de la Generalitat de Catalunya.

60 methodology

Figure 81. Fire perimeters in Cata-lonia by years (1800-2007). Source:Bombers de la Generalitat de Catalunya.

61methodology

Characterisation of the Fire Types

Knowledge of the variables fromTable 6 allows to relate each historical fire to a Fire Type and compare its fire behaviour (Table 2).

Table 6. Spread patterns with description of the dominant factor to identify Fire Type and spread scheme andSource: Castellnou et al., 2009(1).

Wildfires with storm-dominated spread patterns are not included in this table as well as in the whole document because at presentthere is no knowledge about their management.

62 methodology

Characterisation of homogeneous risk areas. The Catalonian example

The analysis of historical fires, together withthe topographical information and thedelimitation of priority protection perimetershave allowed to identify Homogeneous FireRegime Zones (HRZ), following the metho-dology in Agee (1993) (2).

Homogeneous Fire Regime Zones (HRZ) re-present regions where fire rotation and typeof a potential large wildfire are homoge-neous, i.e. where Fire Type, model fire (refe-rence fire for planning) and synoptic situa-tion that are predicted to cause the mostproblematic wildfire for a zone can be speci-

fied(1).For the adaptation of the methodology inAgee(2) to the localisation and characterisa-tion of Homogeneous Fire Regime Zones ina territory that is widely affected by humaninfluence, the whole territory was dividedinto relative small and homogeneous zonesfor the basic calculations, and then adjacentzones were grouped:- for the establishment of homogeneous fire

regime zones a DTM (Digital Terrain Model)is used to calculate basins of approximate-ly 450 ha in size.

- the different hydrological basins are

grouped according to:

· existing landscape units identified by theDepartment of Environment (Depar-tament de Medi Ambient).

· different fires occurring that are classifiedwithin the same group of Fire Types.

· different fires occurring with the sameaxis of main fire spread (SE-NW, N-S). Thespread direction depends on the interac-tion between wind and topography, andthe same spread axis indicates zoneswhere this interaction appears homoge-neous (1).

Figure 82. Map of Fire Types per region.Source: Bombers de la Generalitat de Catalunya.

63methodology

3.a.2 Basic factors for fire spread

The entire methodology for the characterisation of the spread of each Fire Type is basedon the Campbell Prediction System (CPS) (3) and on observed fire behaviour.

Introduction to basic fire analysis

There are various factors affecting anddetermining fire behaviour and spread.The basic fire triangle (heat, air and fuel)can be amended to the fire behaviour tri-angle: weather, topography and fuel. Inthis context, fuel is understood as wild-land vegetation.

The factors in this triangle can be brokendown into different components, asshown in Figure 83:

Figure. 83. Breakdown of the mainfactors affecting the development of awildfire. Source: Bombers de laGeneralitat de Catalunya

Defining the basic spread factor and CPS field logic

The basic factors affecting fire behaviourare too complex to be considered whenmaking real time and on site fire behaviourpredictions. The most important factors inFigure 83 have to be reduced to three basicones to come to a practical analysisapproach:

Aspect: determines fuel surface tempera-ture and flammability through solar radia-tion. The higher the fuel temperature, the

shorter is the preheating process, and thusthe intensity and speed of the combustionprocess is increased. The impact of solarradiation on fuel flammability changesduring the course of the day and can beclassified sequentially: east, south andwest, or, by order of intensity, south, westand east (in the case of the northern hemi-sphere). Temperature differences of 40ºC indead fine fuels can easily occur on sunnydays, see Figure 84.

Figure 84. Fuel flammability throughsolar radiation by time of day andaspect. Source: Campbell, 1995.(3).

64 methodology

Slope: upslope fire spread is faster and moreintense due to the fact that distance and anglebetween the inclined flame and the fuel isshorter, which facilitates the preheating of thecombustible material ahead of the fire front.Downslope fire spread produces less preheat-ing and is slower, due to greater distancebetween flame and fuel.

Wind: just like slope, wind accelerates firespread due to its effects on predrying and rein-forcing radiative heat transfer on fuels, andimpelling and oxygenating the combustion:

- Flames are inclined in a narrow angle to theground due to wind effect, see Figure 85 and86.This implies:

o larger flame lengths and therefore a largerquantity of fuel that is readily burning andinteracting.

o pyrolysis rates are increased when morefuel is exposed to flames.

Figures 85 and 86. Left: Neutral flame development without windeffect. Heat transfer through convection and radiation affects the fuel near theflame less intensely, convection is dissipated vertically and radiation is emittedabove fuel height. Right: the effect of the wind inclines the flames in a lowerangle, so there is less distance between flames and the fuel, and the fuels aheadof the flames receive more heat through convection (purple arrow) and radia-tion (yellow arrow). Source: Bombers de la Generalitat de Catalunya.

CPS field logic: TheCampbell Prediction System(CPS) can be defined as a sim-ple operational tool using thebasic fire spread factors -aspect, wind and slope – asinput variables to provide alogic and brief analysis for sug-gesting tactics based on pre-dicted fire behaviour that arelimited in space and time (timetags). The logic of the system isbased on the alignment offorces, a concept thatdescribes how the threebasic fire spread factorscoincide in favour for oragainst the fire and howthey affect the fire front.

Example: A fire occurring at thebottom of a south-facing slopeat 12:00 hrs with a southerlywind is burning in full align-ment: the fire can run upslope,with the wind and in hot fuel.

The same situation at 08:00 hrsa.m. is burning only in 2/3alignment (wind and slope),since at this time of day the hotslopes are the east-facing ones. When in this situation the windchanges from the north, the fireburns in 1/3 alignment (slope).

When the fire starts at the topof the slope, the fire is burningout of alignment as it has to

spread downslope againstthe wind on a slope with coldfuel.

Figure 87. Example of CPSlanguage. Source: Campbell,1995(3).

65methodology

3.a.3 Spread schemes for each Fire Type

Figures 88, 89 and 90. Sea breezeblows onshore along the day fromthe sea to inland (left). Land breezeblows offshore at night from land to sea(centre). Valley and slope winds blowduring the day from the lower to upperelevations and at night the other way(right). Source: Fire Weather. A Guide forapplication of meteorological informa-tion to forest fire control operations.Mark J. Schroeder.

Figures 91 and 92. Horta Fire of 2005(above) and Roda de Barà Fire of 2004(below). Examples of fires with topogra-phic spread pattern. Source: Bombers de laGeneralitat de Catalunya.

TOPOGRAPHY FIRES

66 methodology

Types of Topography Fires

Standard topography fires (diurnal)These are the most common fires becausethey coincide with the time period of high-est risk and therefore, with the highestnumber of ignitions. The local winds are inthis case upward winds (both valley andslope winds). Fires starting at lower partsof a basin have the biggest spread poten-tial since they have wind and slope infavour, see Figures 93 and 94. On the con-trary, when a fire is burning in the upperparts of a basin its spread potential islower because of downslope and counterwinds. If a fire spreads in the bottom of aravine it develops a head on each slopewith the respective flanks. The fire spreadin this case is determined by the progres-sion of the flanks upstream which giveeach slope the opportunity for new runs.

Standard topography fires (noctur-nal)By night the wind flow is downvalley anddownslope and solar radiation is not a fac-tor. The balance between the downwardwind and the topography determines thedirection of the fire spread. This is thebiggest difference to the diurnal topogra-phy fires where fires spread along theupper parts of the crest lines and are dis-sociated in two heads every time theyarrive at the junction of two crest lines.

Coastal Topography Fires (Diurnal)In the course of a day wind direction asso-ciated with the sea breeze changes. A sea

Figure 94. The spread pattern ofthis diagram is designated as aspread through ravine bottom(g) andis repeated until the fire reachesthe head of the valley or hydrologi-cal basin. In case of a complex valleywith lateral ramifications, this pattern ismultiplied in each junction of ravinesand in secondary valley confluences,extending the surface affected by thefire. Source: Bombers de la Generalitatde Catalunya.

Figure 93. Montmell Fire,06/06/2006, Catalonia. Source:Bombers de la Generalitat de Catalunya.

breeze is a wind caused by thermal com-pensation between sea and land surface.Its direction changes during the day withthe influence of solar radiation when thesun moves along the slopes. This phenom-enon occurs whenever there is direct influ-ence from the sea, i.e. when the land reliefis not a significant barrier, see Figures 95and 96.

In Catalonia, for example, the direction ofthe sea breeze changes from an easterlydirection at the beginning of the daytowards the west at the end of the after-noon, breezing from the south during

noon. It is important to understand thedefined and previsible rotation of the seabreeze in connection to the total local windflow and its effects on the area burning.

Coastal Topography Fires (Nocturnal)The spread pattern of these fires at night issimilar to the one of the nocturnal stan-dard topography fires: the flow of valleyand slope winds is descending and solarradiation is not a factor.

The balance of forces between thedescending wind and the topographydetermines the direction of fire spread.

67methodology

Figure 96. Spread scheme of a topography fire on slopes in coastalareas. Source: Bombers de la Generalitat de Catalunya.

Figure 95. Banyoles Fire 2003. The fire wasdriven by the rotation of the seabreeze that pro-duced different runs. Source: Bombers de laGeneralitat de Catalunya.

Topographic fires in main valleys andcanyons (Diurnal)The main valleys of important hydro-graphical basins have a more intenselocal wind regime and a greater air vol-ume flow than in secondary valleys. Thephenomenon of the movement of largeair volumes with greater intensity thanthe surrounding air where valleys are nar-rowing, generates underpressure and thesuction of surrounding air towards thisarea (venturi effect). Therefore, fires burn-ing in secondary valleys close to a main

valley tend to converge towards the airflow of the main valley. Fires occurringon slopes in narrow valleys typically havea spread scheme similar to the one ofmain valleys. The wind speed in canyonsincreases and can suck the fire into itsinterior, thereby creating fire runs in thecanyon and an extention of the front atthe opposed exit of the canyon. The zonesnot influenced by the canyon winds areaffected by general and topographicwind, thereby increasing the perimeter ofthe fire, see Figures 97-100.

Topographic fires in main valleys andcanyons (Nocturnal)The flow of valley and slope winds isdecreasing and insolation is not a factor bynight. The balance between the downwardwind and the topography will determinethe direction of the fire spread. Thedescending valley winds dominate thedescending slope winds.

Consequently, the perimeters of nocturnaltopography fires tend to spread their flanksfollowing the direction of the main valley.

68 methodology

In extreme cases (e.g. near canyons closeto main valleys), the descending valleywind is the only factor dominating the firespread and head fires are running in thedirection of the canyon or in parallel direc-tion to the main valley without respectingthe topography.

Figure 97. Fire perimeters affected by air suction through the main valley ofthe Segre River, Catalonia. Source: Bombers de la Generalitat de Catalunya.

Figure 98. Spread scheme of atopography fire with air suctionthrough the main valley. Source:Bombers de la Generalitat de Catalunya.

Figure 99. Alcover Fire 2003. Theimage of the perimeter shows the tenden-cy of the fire to be sucked towards the inte-rior of the canyon. Source: Bombers de laGeneralitat de Catalunya.

Figure 100. Spread scheme of atopography fire typical forcanyons. Source: Bombers de laGeneralitat de Catalunya.

69methodology

Figure 101. Escala Fire 2001. The zonewhere the smoke column comes down isaffected by spot fires. Source: Bombersde la Generalitat de Catalunya.

Figure 102. Bonas-tre Fire 2009. Firewith wind speed of140 Km/h. Flames areinclined to the sur-face. Source:Bombers de laGeneralitat de Cata-lunya.

Figure 103. Wind-driven fire in Es-pluga de Francolí24/06/2006. The redstar indicates thestarting point of themain fire run and theyellow points the spotfires. Source: Cosd’Agents Rurals.

Figures 104 and105. Example oftwo wind-drivenfires. Typical forthese fires are smokecolumns inclinedtowards the surfaceand long and out-stretched perimeters.Ventalló Fire,04/08/2006 (left) andCapmany Fire,06/08/2006 (right).Source: Bombers dela Generalitat deCatalunya.

WIND-DRIVEN FIRES

Mountain ranges perpendicular to winddirectionA mountain range perpendicular to themain wind direction produces turbulentwinds. Since the wind takes the shortestway to overcome the mountain range,these zones can produce sudden changesof the wind flux, remaining almost with-out wind (leeward) or even generatinglocal fluxes against the dominant direc-

tion (backwinds). The occurrence of lee-ward or counter winds depends on theheight of the mountain range which isperpendicular to the wind, the wind speedand the main wind channels on macroscale. In high relief the wind escapesalong the lower elevations while in invert-ed and complex relief the wind escapesover the upper elevations, see Figures109-112.

70 methodology

Types of wind-driven fires

Wind-driven fires in level terrain In level terrain and plains wind-driven firesfollow the wind direction and are openingwith an angle between 30º and 60°depending on the strength of the wind,see Figures 106 and 107. In the initialphase of a fire the flanks are opening andgenerate new runs while at the same timethe wind prevents the back of the fire fromspreading.

Figure 106. Ossó i Selvanera Fire2003. The red arrow indicates thespread direction of the fire. Source:Bombers de la Generalitat de Catalunya.

Figure 107. Ossó i Selvanera Fire.Perimeter opening at 30º and main runsfollowing the direction of the wind.Source: Bombers de la Generalitat deCatalunya.Wind driven fires in mountainous terrain

Mountain ranges parallel to wind direction The head fire is spreading along the ridgesof the mountain ranges in alignment withthe wind direction, usually affecting bothslopes, see Figure 108.

Opportunities are at the end of the waterdivide, or where the mountain rangeshave a change in aspect, at a bifurcation orwhen backwinds occur.

Figure 108. Cap de Creus Fire 2000.The perimeter follows the mountainranges parallel to the prevailing winds.Source: Bombers de la Generalitat deCatalunya.

Figures 109 and 110. Coll de Nargó Fire, 29/12/2004. Left: Point of origin (red star),direction of the general wind (blue arrow), ridge axes perpendicular to main wind direc-tion (black arrow), backwinds (blue circles). Right: Fire affected by backwinds at night.Source: Bombers de la Generalitat de Catalunya.

71methodology

Figures 111 and 112. La Riba Fire 2002. Left:Spread pattern and perimeter of the fire. Right: smokecolumn pushed upward by the general wind and thenbroken by backwind effects. Source: Bombers de laGeneralitat de Catalunya.

Figures 113 and 114. Montgrí Fire 26/09/2008. Left: Point of origin (red star), mainwind direction (blue arrow), fire perimeter (red line), mountain range diagonal to thewind direction (purple line). Right: The general wind restrains the left flank and preventsit from descending downslope (green line). Source: Bombers de la Generalitat deCatalunya.

Mountain ranges diagonal to wind direc-tion The interaction of mountain ranges diago-nal to the main wind direction produces adistinct spread scheme, burning eitherwith the main wind in favour (direct) oragainst it (indirect). Diagonal mountainranges and turbulent wind zones producefire runs that spread differently from themain wind direction and create difficult sit-uations for specific direct attack opera-tions, see Figures 113, 114 and 115.

Figure 115. Fire spread through backwinds.Fire runs are generated through backwinds andarrive on top of the mountain range where thegeneral wind launches spot fires downwards, gen-erating new runs upwards by the backwinds.Source: Bombers de la Generalitat de Catalunya.

72 methodology

Figure 117. Spread scheme with subsi-dence winds. Extention of the back fire (a).Extention of the head fire (b). Source: Bombersde la Generalitat de Catalunya.

Figure 116. Cardó Fire, 1995. When the fire star-ted (green) it followed a topographic spread patternduring the day. After that the fire burned the wholenight (blue) until the afternoon of the following daywith its spread totally dominated by the subsidencewinds, when it arrived at an area that had burnedbefore in 1993. The following days, the fire burned outof alignment, spreading topographically (orange) intoa zone with difficult access where the use of handtools was restricted. Source: Bombers Generalitat.

Wind-driven fires with sub-sidenceThis phenomenon occurs incoastal mountain ranges inthe extreme south ofCatalonia when diurnal topo-graphic winds have the capac-ity to compensate high alti-tude northerly wind. At nightthe northerly winds aredescending on the surfacebeing reinforced by the alsodescending topographicwinds. During daytime the firebehaves like a standard topo-graphic fire and like a wind-driven fire at night time. Thisdynamic fire behaviourimplies that the back of thefire during the day can trans-form into the head of the fireat night and vice versa. SeeFigures 116, 117 and 118.

Figure 118.Xert Fire,2001. Wind-driven fire withs u b s i d e n c e .Source: Bom-bers de laGeneralitat deCatalunya.

CONVECTION DOMINATED FIRES

Standard Convection Dominated FiresFires with an extreme fire behaviour andheadfires overcoming the suppressioncapacity because of:

- high rates of spread (rate of linear firespread up to 6 km/ hr).

- high fire intensity (flame lengths morethan 60 mtrs).

- the surface affected (fires can consume500 ha/ hr).

The spotting distance can range from 500 to2000 meters, even though larger distancesmay have been unregistered. In this contexttopography does not directly producechanges in the fire behaviour (like in thecase of topographic fires) because the fire isable to jump from one valley to another

without having to cross valleys and slopesto keep spreading. General meteorologicalconditions have little impact once the fireenvironment is established.

The smoke column often shows the tenden-cy to go in north direction and can only beinfluenced by air masses following the mainriver valleys. See Topography Fires in MainValleys and Canyons, p. 67.

73methodology

Figures 119 and 120. Cardona Fire, 08/07/2005.Source: Bombers de la Generalitat de Catalunya.

Figure 121. Margalef Fire 2005. Interaction between spot fires and theirsuction by the main fire front. Source: Bombers de la Generalitat de Catalunya.

Figure 122. Castellnou de BagesFire 18/07/2005. High intensityfire creating its own fire environ-ment. Source: Bombers de laGeneralitat de Catalunya.

TYPES OF CONVECTION DOMINATED FIRES

74 methodology

Convection dominated fires with windThis Fire Type displays a convection domi-nated fire behaviour, but with the windaffecting its spread velocity. The windincreases the spotting distance, creating newignition points out of the influence zone ofthe convective column and accelerating thegeneral spread of the fire. The tendency ofthe smoke column follows the main winddirection while the fire is burning big topo-graphic basins and spotting is determiningthe main direction of the fire spread. SeeFigures 123 and 124.

Figure 123. Gualba Fire 1994. Theperimeter shows the general tendencyof the fire, dominated by the generalwest winds. Source: Bombers de laGeneralitat de Catalunya.

Figure 124. Castellnou de BagesFire 2005. The inclination of the con-vective column indicates the winddirection. Source: Bombers de laGeneralitat de Catalunya.

Figure 125. Cardona Fire 2005.Convective column. Source: Bombers dela Generalitat de Catalunya.

Figure 126. Cardona Fire 2005.Pyrocumulus plume in high altitudes dur-ing its formation process. Source:Bombers de la Generalitat de Catalunya.

Convection dominated fires producingpyrocumulus cloudsSome convection dominated fires allow theformation of pyrocumulus clouds in the upperparts of the convective column. This phenom-enon is only possible when stable and cold airmasses dominate the high altitudes. These actlike a tap for the vertical development of thecolumn, which condensates once it reachesthese air masses forming the typical mush-room form of a pyrocumulus cloud, Figures125 and 126. Once the pyrocumulus conden-sates it starts gaining weight until it collapses.This happens when the fuels are almostentirely consumed and the temperatures ofthe convective column start sinking, or whenthe air masses acquired by the pyrocumulusexceed their sustaining capacity. The collapseof the pyrocumulus as a cold and condensedcloud leads to the descent of cold air alongthe exterior of the column, thereby generat-ing massive spotting and an extention of thefire in all directions. This is a dangerous phe-nomenon because of the possibility of trap-pings during the collapse due to the suddenextention of the fire. By knowing and identify-ing the evolution of a pyrocumulus cloudthose situations can be avoided.

1. CASTELLNOU, M; PAGÉS, J; MIRALLES, M y PIQUÉ, M. (2009). Tipificación de los incendiosforestales de Cataluña. Elaboración del mapa de incendios de diseño como herramientapara la gestión forestal. Comunicación del 5è Congrés Forestal Nacional (Ávila), SECF.

2 AGEE, J. K. 1993. Fire ecology of Pacific Northwest forests. Washington, DC: Island Press.493 p.

3 CAMPBELL, D. 1995. The Campbell Prediction System: A Wild Land Fire Prediction System& Language. D. Campbell ed. 129 pp.

REFERENCES

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proposed

treatments

3.b Proposed treatments for eachfire spread type

Characterising the Fire Types of a region allows to identify the operational opportunitiesfor the suppression systems during a large wildfire in a specific mountain range throughidentifying the key points where infrastructures need to be created or maintained to limitthe extent of large wildfires.

These points may resemble suppression opportunities, and are called StrategicManagement Points (SMPs).

Identifying where fire behaviour willchange in favour of or against the suppres-sion service is the basis for determiningthe priority areas for fuel treatments andfor preparing preventive infrastructures.

The priority SMPs to be identified andtreated are those where fire behaviour notonly overcomes suppression capacity butalso pushes the organisation of suppres-sion systems to the limit.

Fire simulators and GIS tools as sup-portThe identification of SMPs can be backed

up in some cases by the use of GeographicInformation Systems (GIS) tools and firesimulators, particularly those based onminimum travel time to locate opportuni-ties(1).

There are mainly 3 objectives for whichsimulators can be used as a tool to supportthis methodology:

· modelling fire behaviour in backwindzones.

· modelling fire behaviour with spottingactivity.

· modelling changes in fire spreaddynamics.

3.b.1 Identification of Strategic Management Points (SMPs)

3.b.2 Creating Strategic Management Points

Objectives of StrategicManagement Points:

A series of management activities isassociated with each SMP: fuel treat-ments to influence fire behaviour or toensure safe operations, as well as cre-ation of infrastructures, such as controlor defence lines, and passing points on

forest roads.

The proposed forest management and pre-vention measures can be used to achievethe objectives set for a SMP in terms ofmanaging and suppresing large wildfires.

The planning of strategic zones for fueltreatments is based on different objec-tives:- Limit wildfire activity.

· Limit the multiplying effect of frontalfire spread.

· Limit the intensity of fire spreadthrough spotting.

· Prevent crown fires in stratifiedmature tree stands.

· Reduce continuity of shrub layers toreduce flame lengths.

- Confine ignition.· Facilitate anchor points at back and

flanks.· Facilitate the anchoring of technical

firing operations.· Management of fire causes.· Protection of vulnerable points.

- Facilitate access.· Ensure vehicle access and placement

in safe areas.· Ensure access to very long flanks.

To meet these objectives it is necessary toknow the type of fire behaviour that canmaintain the forest structure of an SMP,e.g. Figure 128, depending on the respec-tive Fire Type for planning. It is thereforenecessary to categorise fire behaviour,Figure 127, and relate it to stand structure.

76 proposed treatments

Figure 127. Example of a qualitativeclassification of fire behaviour accord-ing to the Catalan Fire Service in aseries of five images: low-, medium- andhigh-intensity surface fires, passive crownfire with torching, and active crown fire.Source: Bombers de la Generalitat deCatalunya.

Active forest management allows to increase or reduce fuel loads, and to control spatialarrangement and fuel availability through changes in stand structure. Forest managementtherefore significantly contributes to change fire behaviour to the desired level (below thelimit of suppression capacity) according to the established model fire and the determinedfuel availability scenario.

Figure 128. Example of a SMP in the northeastern foothills of the Pradesmountains. Location: Municipality of Montblanc, Catalonia. Arrangement and re-ope-ning of the road to improve access to the mountain range (1). Zones with reduced fuelload at ravine intersections to avoid the opening and bifurcation of fires towards sur-rounding valleys (2 and 4).Creation of a supporting control line along the road to con-fine possible ignitions and as anchoring zone for operations of suppression resources(3). Source: Bombers de la Generalitat de Catalunya.

3.b.3 Proposed treatments foreach fire spread type

The Fire Types concept is broadly basedon the main types of fire spread patterns(wind-driven, topographic and convec-tion dominated fires). For every spreadtype there are common recommenda-tions as well as specific ones for therespective Fire Types such as wind-driv-en fires with subsidence or coastal topo-graphic fires.

In the following, the most usual generalguidelines are described that are essen-tial for an optimal forest managementand the prevention and suppression offires.

77proposed treatments

78 proposed treatments

Figure 129. Prescribed burn at Coll de Valleta,17/03/2005, to create zones of reduced fuelloads in the upper parts of the slopes, suscep-tible to sending or receiving spot fires. Source:Bombers de la Generalitat de Catalunya.

Figure 130. Positive diagonal approach towards slope and wind. Smokeand flames do not pass the advancing fire line. Source: Bombers de la Generalitatde Catalunya.

General wind.

Positive diagonal approach

towards slope and wind.

Spread direction.

Wind and slope.

Initial strategy: KEEP FLANKSCLOSED to prevent them from opening.Opportunity 1: BACKWIND: the head ofthe fire reaches the narrowing main

ridge lines, with a local backwind effecton the slope. This opportunity allows toconstrict the fire front, but spot firesescape the influence zone of the back-wind onto the other slope, burning nowwith the general wind in favour.Opportunity 2: BACKWIND: similar to 1but with a less pronounced backwindeffect; the width of the valley allows towork on the descending flank, but thelack of access and visibility hamper theaction.Opportunity 3: CHANGE OF ALIGNMENTOF RIDGE LINE: a ridge line junctionopens the front when arriving on theleast aligned ridge line. From there thefire begins to slow down, but spottingactivity and the opening head along sev-eral ridge lines widen the front.Opportunity 4: END OF RIDGE LINE: abreak in fuel continuity in the forest-farmland mosaic allows to attack the var-ious spot fires and limit their spread.

79proposed treatments

Figure 131. Alcover Fire 5/08/2003. Useof the road (red) as anchoring line for parallelattack (yellow) to confine and define the flank.Safety zones in blue. Source: Bombers de laGeneralitat de Catalunya.

Figure 132. Prades mountains. Secondarytrack parallel to the ridge line and strip of lowfuel load along the ridge line. Source: Bombersde la Generalitat de Catalunya.

3.b.4 Validation of pre-defined opportunities

In the following remarkable operationalaspects, fire behaviour observations andprincipal suppression opportunities aredescribed, both success stories as well asfailures, as a necessary process to validateopportunities during large wildfires.

Ventalló Fire, 1011 ha, 04/08/2006

VALIDATION OF PREDEFINED OPPORTUNITIES IN WIND-DRIVENFIRES IN LEVEL TERRAIN

80 proposed treatments

Sallent Fire, 134 ha, 12/07/2007

Initial strategy: CLOSE FLANKS particularly the RIGHT FLANK before itreaches the torrent to the east.Opportunity 1: PLOUGHED FIELDS. A torrent to the east with ploughedfields in the valley bottom. This opportunity is taken to close 2/3 of theright flank in these fields, preventing it from opening up on the fullyaligned slopes.Opportunity 2: LOSS OF ALIGNMENT AND PLOUGHED FIELDS TO STA-BILISE THE HEAD. Spotting occurs to the north from runs from the upperpart of the first basin. An increasing proportion of fields allows to narrowthe head between ploughed fields and a burning out operation that isanchored at a forest road.Opportunity 3: PLOUGHED FIELDS AND LOSS OF ALIGNMENT TO CLOSETHE LEFT FLANK. The water-based resources progress rapidly with thesupport of aerial means to zones with small alignment and anchor pointsin ploughed fields.

VALIDATION OFPREDEFINEDOPPORTUNITIES INTOPOGRAPHICFIRES

VALIDATION OF PREDEFINED OPPORTUNITIES IN WIND-DRIVEN FIRES IN MOUNTAINOUS TERRAIN

Montgrí Fire, 671 ha, 26/09/2004 Initial strategy: KEEP FLANKS CLOSED to prevent them from openingand CONFINE the fire to the two mountain ridges.Opportunity 1: CLOSE OFF THE HEAD BEFORE IT REACHES THE SECONDRIDGE LINE: there is an opportunity - although a very slight one because offuel continuity - to stop the head before it enters the wind dynamic of theridge. The flanks can be closed, but the head escapes and affects the ascend-ing slope with the wind in favour. The other flank also opens rapidly.Opportunity 2: CLOSE THE LEFT FLANK BEFORE IT REACHES THE OPPO-SITE SLOPE: operation to prevent the left flank from reforming and makingnew runs in alignment with the secondary ridge line.Opportunity 3: BACKWIND:The left flank opens because of the effect of thevalley diagonal to wind direction, which channels part of the wind. Smallbackwinds are generated, pushing the flank inside.Opportunity 4: BACKWIND: a pass between two aligned ridge lines; theslowing down of the fire spread and the backwinds have the effect that theprogress of the suppression teams is equal to fire spread, but terrain, fuelcontinuity and smoke hamper the operation.Opportunity 5: RIDGE LINE JUNCTION: Ridge line junction: bifurcation ofthe secondary ridge line; the fire arrives there with the backwind from themain ridge and its further spread is limited at the point where its rate ofspread is lowest.

81proposed treatments

VALIDATION OF PREDEFINED OPPORTUNITIES IN CONVECTION DOMINATED FIRES WITHOUT WIND

Initial strategy: ANCHOR BACK AND CLOSE LEFT FLANK to preventit from opening.Opportunity 1: LEFT FLANK MOVES OUT OF ALIGNMENT and beginsdescent towards the ravine to the north. A change in general wind direc-tion affects fire behaviour, although wind speed remains low, with spotfires crossing a ravine and runs in full alignment.Opportunity 2: THE NEW LEFT FLANK LOSES ALIGNMENT and can beanchored in discontinuities in the main ravine bottom, preventing it fromopening up on the next slope. A quarry and small fields reaching from theback to the most northerly part can be used to anchor the flank.Opportunity 3: A PATCH-MOSAIC OF FIELDS allows to confine the spotfires with burning out operations, stabilising the head. Up to there the firewas capable of crossing all ravine bottoms with spot fires, offering noopportunities for burn outs or backfires. On the previous ridge a backfireis used to slow down fire spread for 1 hour and limit the fire's spottingpotential.

Rocafort Fire, 869 ha, 19/07/2005

1. FINNEY, MA.; SAPSIS, DAVID B.; BAHRO, B. (2002). Use of FARSITE for sim-ulating fire suppression and analyzing fuel treatment economics. In:Sugihara, Neil G.; Morales, Maria E.; Morales, Tony J., eds. Proceedings ofthe symposium: fire in California ecosystems: integrating ecology, preven-tion and management; 1997 November 17-20; San Diego, CA. Misc. Pub. 1.Berkeley, CA: Association for Fire Ecology: 121-136.

REFERENCES

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83

Glossary

a Fire environment

b Time Lag

c Prescribed Burning

d Passive suppression

e Active suppression

f Preheating process

g Spread through ravine bottom

h Backwinds or leewinds

i Trigger points

j Direct attack

k Parallel attack

l Indirect attack

m Classification of forest roads and tracks

n Alignment of forces

84

Environmental conditions generated through the fire itself and directly influencedby it. When a fire has built up sufficiently in extension and intensity, it creates itsown fire environment, thereby modifying the meteorological components (rise oftemperature, decrease of relative humidity and, above all, the formation of a con-vective column through fire suction). The fire environment and its behaviour areclosely related parameters. However, not every fire is able to create its own fireenvironment, only those with high intensities.

a) Fire environment

There exist fuels of:- 1 hr (diameter < 6 mm), e.g. herbs, needles and leaves; - 10 hr (6 mm – 2.5 cm), like small branches; - 100 hr (2.5 – 7.5 cm), thicker branches; - 1000 hr (7.5 –20 cm) like logs and tree trunks.

Glossary

Time lag is the time dead fuels need to reach equilibrium of their moisture con-tent with the surrounding relative humidity. This parameter is measured in hoursand depends mostly on the form and size of the fuel.

b) Time Lag1 HR

10 HR

100 HR

1000 HR

85

glossary

Careful and planned application of fire under specified fuel andweather conditions to meet specific resource management objectivesand long-term management goals.

c) Prescribed Burning

d) Passive suppression

e) Active suppressionOperations carried out in the instant of a fire, with the objective ofsuppressing the fire or modifying fire behaviour. These include direct,parallel and indirect attack.

Treatment of defined points/zones in the landscape, be it with pre-scribed fire, silvicultural treatments or other methods with theobjective of preparing the suppression of fires based on the capac-ities of the suppression system.

Phase in the combustion process. The temperature rise, close to thewater boiling point, leads to predrying of the fuel, releasing gases oflow flammability like water steam. With continuous increase of thetemperature the drying process advances to the interior of the fuelparticle.

f ) Preheating process

Fires that spread topographically following thehottest slopes. The most important spread vari-able is the time of day which determines theheating of the slopes and therefore where thefire can reach the highest intensity. The dynamicof local and sea/ terrestrial winds will affect thefire behaviour being able to convert the back ofa fire into its head.

9:00 14:00 17:009:00 14:00 17:00

g) Spread throughravine bottom

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h) Backwindsi) Trigger points

Backwinds or leewinds are wind currents con-trary to the direction of the general wind, orig-inating in the turbulences developing in lee-ward slopes through friction of the generalwind at abrupt mountain ranges perpendicularto it.

Points in the landscape where fire behaviour and fire potential willchange. From this point fire behavior can become better or worsefrom a suppression point of view.

j) Direct attackStrategy in the frame of active suppression. Direct attack on theflames and surrounding fuel with water, hand tools, heavy machin-ery or retardants.

k) Parallel attackStrategy in the frame of active suppression. Fire attack from the dis-tance, advancing parallel to the fire, basing the actions on a fire lineand eliminating the fuel among the line.

l) Indirect attackStrategy in the frame of active suppression, creating another firefront with equal or superior intensity and with the capacity to suck inthe original fire. The starting point for such operations is a criticalpoint to the front of the fire with the objective of stopping its advanceor decreasing its spread.

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m) Classification of forestroads and tracks

Roads or tracks where two type I fire engines(dimensions: 2.45 m wide, 3.05 m high and 6.7m long) can pass each other on the whole oralmost whole route.

PRIMARY ROADS

Roads or tracks where two type I fire enginescan pass each other at passing points. The dis-tance between the passing points must notexceed 200 m.

SECONDARY ROADS

Roads or tracks that only allow the traffic of typeI fire engines in one direction.

TERTIARY ROADS

Road or track where no vehicles can pass.

NOT ACCESSIBLE

Road or track where fire engines temporarily can-not pass, but current state can be easily mendedto allow traffic.

CLOSED

n) Alignment offorces

Degree of coincidence of the three basic factorsdetermining fire spread (slope, aspect andwind), indicating favourable or unfavourablebehaviour of the fire front. In can be expressedas in full, medium or small alignment, or out ofalignment.

In the last few decades several European regions, particularly inMediterranean countries, have been characterised by dramaticland use changes. The abandonment of farmland and reducedgrazing have led to an increase in wildland areas. These changesin the landscape have contributed to a more aggressive spread oflarge wildfires all over Europe. Over the last few years, the occur-rence of large wildfire episodes with extreme fire behaviour hasaffected different regions of Europe: Portugal (2003 and 2005),south-eastern France (2003), Spain (2006 and 2009), and Greece(2000, 2007 and 2009).

In this context, the aim of this handbook is to introduce themethodology of the Fire Types Concept as a prevention and pre-suppression tool. This handbook includes the integration of fireuse into forest planning in order to prevent large wildfires. It canbe used as a tool to complement and support forest policies.

The handbook consists of two parts. The first part of the docu-ment gives an overview on the current state and the develop-ment of European forests over the last 50 years. The causes ofthe increase of large wildfire events are discussed, with a focuson land use changes and policies that aimed to increase fire sup-pression capacity. The fire type concept, and the analysis ofspread patterns are presented and described for forest and land-scape planning to identify strategic management points.

The second part of the handbook consists of three annexes: (1)the use of fire as a forest and landscape management tool, (2)prevention strategies depending on fire generation and (3) ma-nagement activities for each type of fire spread.