Risk/opportunity:(from the Climate Change Risk Assessment for Scotland 2012):
BD12 Wildfires due to warmer and drier conditions

Narratives: Resilience of the natural environment (terrestrial)

SCCAP theme: Natural environment

SCCAP objectives:
N2: Support a healthy and diverse natural environment with capacity to adapt

Latest figures

Financial year 2012/13

Key Habitat

Area of wildfire (ha)

Number of wildfires

Forest/Woodland

267.6

479

Semi-natural Grassland

684.5

203

Mountain, Heath and Bog

383.9

153

Trend
At a glance
  • Scotland has large and, in some cases, globally significant areas of forests, moorland and peatlands; these provide a range of important ecosystem services, such as timber production and carbon storage.
  • Consequences of wildfire in key habitats include loss of carbon (particularly from peatlands and from forests), loss of biodiversity, loss of timber production, and increased rates of soil erosion and associated reductions in water quality.
  • It is anticipated that the changing climate, particularly warmer drier springs and summers, will lead to an increased wildfire risk.
  • These (proxy) indicators monitor the potential impact of wildfire on the delivery of ecosystem services from forests and key habitats

Key habitats sensitive to fire include forests, grassland, peatlands (including blanket bog) and heathlands (HR Wallingford, 2012). In Scotland there are large and in some cases globally significant areas of woodland, moorland and peatlands.  These provide a range of important ecosystem services.  Consequences of wildfire can include loss of carbon (particularly from peatlands and forests), loss of biodiversity, loss of timber production, and increased rates of soil erosion and associated reductions in water quality.  There will also be potential impacts on communities who could be affected directly or indirectly for example through closure or blockage of transport or access routes (ibid).

Moffat and Pearce (2013) state ‘Intense forest fires may pose a risk to standing trees and the timber resource, but recent fires in Britain tend to be located in the understorey where most damage is caused to wildlife habitat, recreational opportunity and if on organic-rich soils, to carbon storage. In addition, reduction in air quality can cause nuisance and pose a risk to human health, especially if fires are located close to urban communities (Finlay et al., 2012). Fire can also increase the susceptibility of surviving trees to insect attack, for example secondary bark and ambrosia beetles in conifer forests (Lowell et al., 2010).’  They go on to say ‘[wild]fires can have serious effects on a wide range of services – even if a fire remains within the understorey and does not cause tree mortality per se.’

Habitats and species have differing levels of susceptibility to fire events. Indeed, some grassland and heathland habitats can benefit from controlled burning that can help prevent woody species colonising the area (such controlled burning used as a legitimate land management practice is not included in the wildfire data presented here). When in a dry condition, peatland can be particularly vulnerable to fire and can ‘smoulder’ or burn for prolonged periods, being difficult to extinguish. Peatland habitats store a significant amount of carbon, which can be released back into the atmosphere as a result of fire damage. Furthermore, the future ability of the habitat to store carbon, and to re-establish its original vegetation, is likely to be severely impaired or destroyed (Brown et al, 2012).

Extreme weather conditions, especially spring and summer droughts, in recent years have had an impact with Fire and Rescue Services (FRS) responding to a number of large wildfire incidents. For example, between 29 April and 5 May 2011 over 1,800 firefighters were deployed by Highlands and Islands FRS to 70 significant wildfire incidents. These wildfires destroyed around 9,200 hectares of moorland and forestry, costing Highlands and Islands FRS over £125,000 with restoration costs estimated at £7.2m to £26.4m (Scottish Government, 2013).

Climate projections for Scotland indicate warmer, drier summers on average, increasing the risk of summer drought which in turn increases the risk of wildfire (Scottish Government, 2013). Most wildfires occur in spring and summer when there is a lot of ground vegetation. During spells of hot or dry weather, much of this vegetation is dry enhancing the fire risk. Wildfires occurring in periods of drought can be especially destructive as twigs and branches on trees tend to dry out and provide additional fuel for the fire (Forestry Commission, 2014).

This indicator provides a proxy measure to help monitor the impact of wildfire on forests and other key habitats. Woodland data is based on wildfires occurring within areas classified as woodland by the National Forest Inventory (NFI). Other key habitats are identified using the Centre for Ecology and Hydrology’s Land Cover Map 2007[1] (LCM2007). The data was produced by Forestry Commission England on behalf of Forestry Commission Scotland from Fire and Rescue Service Incident Reporting System (IRS) data (see Methodology for further details).

Definitions:

Forest fire is defined as ‘uncontrolled vegetation fires spreading wholly or in part on forest and/or other wooded land’ (Camia et al. 2014).

Wildfire is defined by the Food and Agriculture Organisation of the United Nations (FAO) as: ‘Any unplanned and uncontrolled wildland fire that, regardless of ignition source, may require suppression response or other action according to agency policy.’ (Scottish Government, 2013)

2012/13

In 2012/13 the area of forest affected by wildfire was 267.6 hectares and in total 479 forest wildfires were recorded.  The Fire and Rescue Service (FRS) spent 333.5 hours fighting wildfires over this period.  In the same period, other key habitats affected by forest wildfire include 383.9 hectares of mountain, heath and bog (affected by 153 wildfires lasting for 277.3 hours); and 684.5 hectares of semi-natural grassland (affected by 203 wildfires lasting for 274.7 hours).

2009/10 – 2012/13

During the four years for which data exists, there is a high degree of variability.

Table 1 Area of wildfire in forests and key habitats, 2009/10 – 2012/13

 

Area of wildfire (hectares)

Key Habitat

2009/10

2010/11

2011/12

2012/13

Woodland

60.0

127.3

7,965.7

267.6

Semi-natural Grassland

893.3

916.6

2,022.4

684.5

Mountain, Heath & Bog

1,879.2

3,122.8

6,805.2

383.9

Scotland Total

3,473.6

4,298.1

18,991.6

1,519.8

Source: Incident Reporting System/Forestry Commission Scotland

Table 1 shows that the total area of wildfires recorded varies hugely year-on-year, not just at a national level but by habitat type. The financial year 2011/12 saw an exceptionally large area impacted by wildfires, with an especially marked increase in forest fires, although semi-natural grassland and mountain heath and bog were also heavily impacted. In 2011/12 some 42% of all wildfires were in woodland while in 2009/10 woodland accounted for less than 2% of the total. The financial year 2011/12 saw the highest wildfire impact in all key habitats included.

Table 2 Number of wildfires in forests and key habitats 2009/10 – 2012/13

 

Number of wildfires

Key Habitat

2009/10

2010/11

2011/12

2012/13

Woodland

850

1,166

1,050

479

Semi-natural Grassland

354

465

368

203

Mountain, Heath & Bog

154

211

199

153

Scotland Total

8,959

10,468

6,486

4,199

Source: Incident Reporting System/Forestry Commission Scotland

The pattern of number of wildfires recorded, shown in Table 2, differs from the area impacted (in Table 1), suggesting that the size of wildfires varies markedly, with 2011/12 in particular seeing some very large wildfires. The highest number of wildfires was recorded in 2010/11, followed by 2009/10.

Table 3 Time spent by FRS fighting wildfires (hours)

 

Time spent by FRS fighting wildfires

Key Habitat

2009/10

2010/11

2011/12

2012/13

Woodland

405.6

729.3

908.1

333.5

Semi-natural Grassland

277.0

407.3

362.9

274.7

Mountain, Heath & Bog

187.2

370.1

409.2

277.3

Scotland Total

3,622.7

5,657.6

3,858.9

2,415.1

Source: Incident Reporting System/Forestry Commission Scotland

The time spent by FRS fighting wildfires, shown in Table 3, is probably a function of a number of factors such as the location of the fire, the perceived threat, e.g. to people and properties, and availability of resources at the time. The time spent fighting wildfires, shown in Table 3, appears to correlate more closely to the number of wildfires (Table 2) than to the area affected (Table 1).

Figure 1 Area of wildfires by habitat type 2009/10 – 2012/13

Adaptation

Guidance is provided on adaptation and resilience building including the Scottish Government sponsored "Wildfire Operational Guidance" (Scottish Government, 2013). This is designed to build additional understanding and awareness of wildfire for the Fire and Rescue Services and provides information on how to tackle the behaviour, prevention and management of wildfire and wildfire incidents for those planning responses to wildfire events. Similarly, the Forestry Commission published ‘Building wildfire resilience into forest management planning’ in 2014 (Forestry Commission, 2014).

Prior to 2009 recording of wildfires in Scotland (and the rest of the UK) was limited in nature and lacked standardisation.  Since 2009, wildfire reporting in the UK has used the Incident Reporting System (IRS).

It is not possible to draw any significant trends in relation to wildfire in forests and associated land uses during the period 2009/10 – 2012/13. Four years is too short a period of time. The figures for the area affected, number and duration of fires vary considerably from year to year; however they are particularly high for the period 2011/12 – see Table 1 and Table 2.

At a UK level, in recent years 2003 and 2011 stand out, each experiencing a ‘marked upsurge’ in wildfires (Scottish Government, 2013).  Most of these fires affected grassland and heathland. During January 2003 there were an average of 40 grass and heath fires per day, rising to 762 per day in March and 1,010 in April.

In Scotland, there was a particularly high incidence of wildfire in 2011/2012. Between 29th April and 5thMay 2011, 70 significant wildfires required the deployment of more than 1,800 firefighters by Highlands and Islands Fire and Rescue Service. The fires ‘destroyed approximately 9,200 hectares of moorland and forestry, and resulted in direct costs of over £125,000 to Highland and Islands Fire and Rescue Service and wider restoration costs estimated at between £7.2m and £26.4m’ (Scottish Government, 2013).

It is estimated that by the 2080s the risk of wildfires in Scotland could increase by 30-40% due to projected climate change, compared to a 1980s baseline (HR Wallingford, 2012).  Impacts will reflect this changing level of risk and the management responses to that risk.  The CCRA 2012 (Brown et al., 2012) notes ‘Increased frequency of wildfires could result in large changes in habitat extent and species populations in vulnerable locations.  These impacts have occurred in extreme dry conditions during recent years.’

Typically, wildfires are not spread evenly in geographic terms. Together with the high degree of variability in their incidence year-on-year (seen in Figure 1), with a large number of outbreaks tending to occur over a relatively short timescale (a few weeks), they can severely impact the ability of the Fire and Rescue Service to respond while maintaining operational capacity to deal with other incidents and to manage their budgets (Scottish Government, 2013). Given the increased risk due to projected climate change, this pressure on the resilience of the Fire and Rescue Service is likely to increase.

Generally, over the period 2009 to 2012 broadleaved forests were affected by wildfire to a greater extent than coniferous forests, as shown in Table 4 and Figure 2.  The area of broadleaved forest affected by wildfire, the number of wildfires and their duration all tended to be higher than corresponding figures for coniferous forests. (A full breakdown of wildfire figures for each National Forest Inventory category is available in Appendix Two).

The figures do not correspond to the perceived inherent wildfire risk associated with different habitat types; coniferous woodland, particularly young pine, spruce and fir, is considered a high risk habitat, while broadleaved, mixed and yew woodlands are considered low risk (Forestry Commission, 2014).

There are a number of possible explanations for this result:

  • Broadleaved forest is considered to be more susceptible to wildfire when young, and broadleaved planting has increased rapidly in recent years driven by biodiversity strategy and other social drivers (increased planting of broadleaved trees was recorded between 1995 and 2014, see indicator NF5 ‘Planted forest tree species diversity index’).
  • Much new planting is closer to humans, for example that supported through Woods in and around Towns (WIAT)[1]. Location may be a factor, as the vast majority of wildfires are caused by arson (although there is no Scottish evidence to support this).
  • For the first time, we are now gathering good quality evidence, which may in turn challenge the traditional thinking regarding relative inherent wildfire risk in broadleaved and coniferous forest (A.J. Moffat, personal communication, 2015).

Table 4 Area and number of wildfires in broadleaved and conifer forests 2009/10 – 2012/13

Year

Area of wildfire (hectares)

Number of wildfires

Time spent fighting wildfires (hours)

Broadleaved

Conifer

Broadleaved

Conifer

Broadleaved

Conifer

2009/10

26.2

15.1

485

182

199

114.6

2010/11

25

81.5

605

283

296.7

244.1

2011/12

5877.6

26

536

218

276.4

168.9

2012/13

237

1.9

259

110

149.9

81

Source: Incident Reporting System/Forestry Commission Scotland.

Figure 2  Number of wildfires on broadleaved and conifer forests 2009/10 to 2012/13

Table 5 shows the area of designated sites (including RAMSAR, SAC, SPA, SSSI sites and National Parks) affected by forest wildfires over the period 2009/10 to 2012/13. This is significant because of the damage wildfires may inflict on the asset for which the site was designated, such as biodiversity or cultural value.

Table 5: Designated sites affected by forest wildfire 2009/10 – 2012/13

Year

Area of designated sites affected (hectares)

2009/10

133.2

2010/11

588.2

2011/12

1876.4

2012/13

1075.6

Source: Incident Reporting System/Forestry Commission Scotland.

A general upward increase in wildfires is expected, however with only four years of data it is not possible to detect trends at present. The high figures for wildfire in 2011/12 coincide with a warm, sunny spring with below average rainfall in 2011. Most wildfires are started as a result of human activity (accidental and deliberate) although some are started naturally, for example by lightning (Cabinet Office, 2013). Wildfires tend to result from a combination of multiple factors: a near random arson event; availability of adequate and contiguous fuel, itself the product of seasonal weather; and the particular weather (hot, dry, windy) immediately preceding the event.  Also the extent of wildfires is affected by the ability to detect and extinguish them. (A.J. Moffat, personal communication, 2015). This combination of attributing factors makes it difficult to determine causality and to identify trends due to an individual factor such as changing climate.

The IRS figures only represent wildfires responded to by the Scottish Fire and Rescue Service. They do not include wildfires extinguished by landowners alone. Due to the reasons discussed in the previous section, it is unlikely that this indicator will reveal interpretable trend data for many years.

Woodland data is based on the NFI classification of woodland and may therefore exclude some woodland areas that do not meet these criteria. See Methodology for further information.

Brown, I., Ridder, B., Alumbaugh, P., Barnett, C., Brooks, A., Duffy, L., Webbon, C., Nash, E., Townend, I., Black, H. and Hough, R. (2012) Climate Change Risk Assessment for the biodiversity and ecosystem services sector. UK CCRA. https://www.gov.uk/government/policies/adapting-to-climate-change

Cabinet Office (2013) National Risk Register of Civil Emergencies 2013 Edition.  Cabinet Office, London and www.gov.uk/government/publications/national-risk-register-for-civil-emergencies-2013-edition (Accessed 29 April 2015).

Camia, A., Houston-Durrant, T. and San-Miquel-Ayanz, J. (2014) The European Fire Database.  Technical specifications and data submission.  EUR 26546 EN, Joint Research Centre, Institute for Environment and Sustainability, Luxembourg.

Cross, D. (David.F.Cross@forestry.gsi.gov.uk), 02 October 2015. ClimateXChange Indicator – wildfire risk. E-mail to R. Monfries (r.monfries@rbge.ac.uk)

DCLG (2006) Effects of Climate Change on Fire and Rescue Services in the UK - wildfire research technical report 1/2006.  December 2006, Department for Communities and Local Government, London.

Finlay, S., Moffat, A.J., Gazzard, R. and Murray, V.  (2012) Wildfires and Health Impacts.  PLoS Currents: Disasters doi: 10.1371/4f959951cce2c.

Forestry Commission (2014) Building wildfire resilience into forest management planning. Available at: http://www.forestry.gov.uk/PDF/FCPG022.pdf/$FILE/FCPG022.pdf (Accessed May 2015).

HR Wallingford (2012) A Climate Change Risk Assessment For Scotland, report compiled for DEFRA. Available at http://randd.defra.gov.uk/Document.aspx?Document=10069_CCRAforScotland16July2012.pdf (Accessed May 2015)

Lowell, E.C., Rapp, V.A., Haynes, R.W. and Cray, C.  (2010)  Effects of fire, insect, and pathogen damage on wood quality of dead and dying western conifers. Gen. Tech. Rep. PNW-GTR-816. USDA Forest Service, Portland, Oregon.

Moffat, A. (andy@ajmoffat.co.uk), 03 May 2015; 11 August 2015. Review of wildfire indicators. E-mails to R. Monfries (r.monfries@rbge.ac.uk)

Scottish Government (2013) Fire and Rescue Service Wildfire Operational Guidance www.scotland.gov.uk/Publications/2013/10/6118/0 (Accessed 29 April 2015).

Knowledge for Wildfire www.kfwf.org.uk

Forestry Commission Scotland

Andy Moffat, Forest Research