Austria's Forest Fire Risks: What You Need To Know

Austria has experienced forest fires, with lightning and human activity being the two major causes. Lightning-induced fires are more frequent at higher altitudes and during the summer months, with nearly 40% of all fires from June to August being naturally caused. In contrast, human-caused fires are more prevalent in the spring and are influenced by factors such as touristic activities, infrastructure, agriculture, and forestry developments. Climate change is expected to increase forest fire risk in Europe, and recent years have seen forest fires coinciding with droughts and heatwaves in central and northern European regions that are not typically prone to fires.

Lightning-induced forest fires

Lightning is the major reason for forest fire ignition in Austria, apart from human-caused fires. A study from 1993 to 2010 showed that 15% of documented forest fires were lightning-caused. Nearly all lightning-caused fires took place during the summer months, whereas almost 40% of all fires occurring from June to August were naturally caused. Most lightning-caused fires took place in the south and east of Austria. Lightning fires were more frequent at higher altitudes and primarily affected conifer forests.

A more recent study from 2023 showed that lightning-induced forest fires are exacerbated by the abundant availability of fuel with a lower moisture content and high lightning efficiency. Moreover, because of changes in the climate and weather conditions, i.e., harsh weather and climate conditions due to anthropogenic activities, lightning-induced ignition wildfires have increased over the years, and they are expected to increase in the future if the climate and weather conditions continue to aggravate.

Lightning strikes are the fundamental cause or the essential natural cause of wildfire ignition worldwide. Every second, almost 46 lightning flashes occur on the Earth due to the electric fields between the cloud and the ground, which potentially trigger wildfires. Weather conditions influence lightning-induced wildfires. Lightning-induced wildfires mostly occur in regions with extreme weather conditions, especially very hot conditions. That is, in more recent years, increased atmospheric temperatures due to global warming and extreme thunderstorms have been causing lightning strikes and wildland fires. Moreover, strong dry winds due to severe weather conditions influence and advance cloud-to-ground lightning-induced wildfires. In turn, lightning-induced wildfires contribute to the weather conditions that favour lightning and dry vegetation for wildfires.

Lightning-strike ignition wildfires in North America

In North America, approximately two-thirds of the wildfires that occur are caused by lightning strikes. From 1973 to 1982, lightning caused 34% of the 10,000 wildland fires that occurred annually in Canada. In 2005, about 48% of wildfires in Canada’s remote areas were caused by lightning strikes. From 1995 to 1999, nearly 89% of lightning-induced fires occurred in the Emas National Park in Brazil. From 2001 to 2020, the highest number of lightning-induced wildfires occurred in the southwest of North America. However, a large acreage was burned by lightning-induced wildfires in Alaska.

Lightning-strike ignition wildfires in South America

In South America, lightning strikes caused 30% and 90% of wildfires and burned areas, respectively, in Australia. In Brazil, lightning strikes caused only 5% of the fires in the Pantanal wetland. In the Daxing'an Mountains in Inner Mongolia, lightning strikes accounted for 60% of wildfire accidents from 1988 to 2007. From 2012 to 2020, lightning caused nearly 77.6% of the wildfires in the Heilongjiang Province of China.

Human-caused forest fires

Human actions cause most forest fires in Austria. These can be direct, such as an out-of-control fire, or indirect, for example, a discarded cigarette. The specific causes are varied and include forestry work, bonfires, fireworks, sparks on railways, and arson.

In the summer months, lightning is also a cause of forest fires, making up 40% of the total. However, human actions are responsible for about 85% of forest fires in Austria.

The number of fires per year varies between 100 and 300 in Austria, and they usually burn areas of up to 1 hectare. Larger fires are still rare in the country.

Forest fires pose a particular threat to the protective function of forests, which play a crucial role in safeguarding humans against natural hazards like avalanches and mudflows. With the impact of climate change, the danger of extreme forest fire events is expected to increase in the Alpine region.

Forest fire ignition risk

Austria's forest fires are predominantly caused by human activity and lightning strikes. Lightning is the major natural cause of forest fires in the country, with around 15% of documented forest fires between 1993 and 2010 attributed to lightning. These fires mostly occur during the summer months, with nearly 40% of all fires from June to August being naturally caused.

The ignition of forest fires requires the presence of oxygen, heat, and fuel. In the context of forest fires, lightning and human activities are common sources of heat, while trees, shrubs, grasses, and structures can act as fuel. Windy conditions can increase the air supply, facilitating combustion.

The National Fire Danger Rating System (NFDRS) is a tool used by managers to determine fire danger in their area. It takes into account factors such as fuel, topography, and weather conditions. Based on the assessed fire danger, managers can implement appropriate measures, such as imposing restrictions or planning for fire suppression.

The fire ignition risk is influenced by various factors, including:

• Soil moisture: Low soil moisture levels increase the risk of summer fire ignition.
• Volatile litter and atmospheric dryness: These factors contribute to winter fire ignitions.
• Forest composition and fuel loading: The type of forest and the amount of fuel present impact ignition risk.
• Weather conditions: High temperatures and low humidity cause vegetation to dry out, increasing the risk of fire ignition and rapid fire spread. Windy conditions can intensify fires by supplying oxygen and spreading embers.
• Topography: Physical features like slope and aspect influence fire behaviour. Fires burn more rapidly when moving uphill, and south- and west-facing slopes tend to have drier fuels.
• Fuel characteristics: Large, dense trees burn for extended periods and generate significant heat, while dried grasses produce a flashy fire with less heat.

Forest fire prevention and management

Forest fires are a serious threat to natural ecosystems, property, and human life. While they are a natural and necessary part of some landscapes, they can also be devastating. In this article, we will discuss the prevention and management of forest fires, focusing on the context of Austria.

Understanding Forest Fires

Before delving into prevention and management strategies, it is essential to understand what a forest fire is. A forest fire is unenclosed and freely spreading combustion that consumes the natural fuels of a forest, such as duff, grass, weeds, brush, and trees. They can occur in three main forms: surface fires, crown fires, and ground fires. Surface fires burn surface litter and small vegetation but may also spread to taller vegetation and tree crowns. Crown fires advance through the tops of trees, independent of the surface fire, and are the fastest-spreading type. Ground fires consume organic material beneath the forest floor and are the slowest and most challenging to control.

Causes of Forest Fires in Austria

Understanding the causes of forest fires is crucial for effective prevention and management. In Austria, lightning strikes and human activities are the primary causes of forest fires. Lightning-induced fires are more common in the south and east of the country, affecting mainly conifer forests. Human-caused fires, on the other hand, dominate in most cases and are influenced by various factors, including climate change, land-use changes, and socioeconomic factors.

Forest Fire Prevention Strategies

Preventing forest fires involves reducing both the risk and the hazard. Risk reduction focuses on minimizing the chances of a fire starting, often by addressing human activities. This can include public education, enforcing regulations, and promoting responsible recreation. Hazard reduction, on the other hand, involves creating physical barriers to slow or stop the spread of fires. This includes:

• Compartmentalizing forests with firebreaks, or alleyways, where all vegetation is removed.
• Reducing fuel buildup by controlled burning or removing litter, branches, and fallen trees.
• Implementing a National Fire-Danger Rating System, considering constant and variable factors that affect fire behaviour and control.

Detection and Suppression

Early detection is critical for effective forest fire management. Tower lookouts, aircraft surveillance, and satellite technology are used to identify fires promptly. Once a fire is detected, the goal is to suppress it by breaking the "fire triangle" of fuel, temperature, and oxygen. This can be achieved by:

• Removing or reducing combustible materials.
• Applying dirt, water, or chemicals to lower temperature and flammability.
• Smothering fuels with dirt, water, fog, or chemical substances to reduce oxygen supply.

Firefighting Strategies

When it comes to actively fighting forest fires, a range of strategies and equipment are employed:

• Professional firefighters are typically the first responders, equipped with hand tools like spades, beaters, axes, rakes, power saws, and backpack water pumps.
• Fire crews can be transported quickly to the fire site by truck, helicopter, or even parachute drop.
• Large machines, such as bulldozers or plows, are used to create firebreaks by clearing fuels and digging down to mineral soil.
• Water is the most common extinguishing agent, but other materials like wetting agents, retardants, and foaming agents can also be used.
• Aircraft are utilized to transport water and chemicals to drop or spray on the fire.

The Role of Prescribed Fires

While the idea of using fire as a management tool in forestlands may seem counterintuitive, it has its benefits. Prescribed burning can be strategically employed to prepare seedbeds for natural tree germination, control insect and disease infestations, reduce weed competition, manipulate forest cover type, and decrease fire hazard. However, this approach requires a careful balancing of potential benefits against the risks and expected damage.

Climate change and forest fires

Climate change has been a significant factor in increasing the risk and extent of forest fires globally, including in the Western United States and parts of Europe. Warmer temperatures and drier conditions caused by climate change create an ideal environment for forest fires to ignite and spread.

In the Western United States, climate change has doubled the number of large fires between 1984 and 2015. The warming and drying of organic matter in forests, also known as fuel moisture, have increased the susceptibility of forests to fires. Additionally, the length of the fire season has been extended due to increased drought conditions. The combination of these factors has led to a higher wildfire risk.

Similar trends are observed in Europe, where climate change is enhancing the drying of organic matter and prolonging drought periods. Austria, a Central European country, has experienced an increase in temperature, particularly in the Alps, which doubles the global average. This rise in temperature, along with prolonged periods of drought and heat waves, increases the likelihood of forest fires in the country.

The impact of climate change on forest fires is also evident in the Southeastern United States, where modelling predicts a 30% increase in the area burned by lightning-ignited wildfires by 2060. The interplay between rising temperatures, reduced moisture in trees and shrubs, and longer fire seasons contributes to the heightened risk of forest fires.

To build resilience against forest fires, communities, landowners, and forest managers can implement several strategies. These include smart zoning rules that discourage residential development near fire-prone forests, increasing fire-resistant design features, and allocating more resources to firefighting and fire prevention. Additionally, removing dead trees and other fuels from at-risk forests can help reduce the potential for fires to spread.

By addressing these issues, it may be possible to mitigate the impacts of climate change on forest fires and protect lives, properties, and natural ecosystems.

Frequently asked questions