CAUSES and EFFECTS of GLOBAL FOREST FIRES

Recommendations for preventing forest fires?

Prevent fires - Fire prevention should receive highest priority in order to reduce forest fire risk and resulting damage. First of all, the determination of root causes and an evaluation of immediate and follow-up costs of forest fires are necessary for each region and requires an appropriate statistical data basis. Only on this basis is it possible to develop regionally Due to forest cover loss, the regional climate of the Amazon basin is becoming increasingly drier. 8 Forests ablaze Causes and effects of global forest fires. 9 adapted and cause-specific, effective and efficient strategies for forest fire management. Many countries lack this prerequisite. At the same time, public awareness of fire risk and appropriate behaviour should be strengthened by sensitisation and education activities, to prevent fires provoked by carelessness.

Do not establish eucalyptus plantations or other fire-prone monocultures – Forestry in the respective countries should always take the role of fire into consideration. In forest fire regions, there should be no planting of easily flammable tree species such as eucalyptus and pine. The fire-prone eucalyptus plantations of northern Portugal which have replaced fire-resistant cork oaks are a prominent example. Reducing fire vulnerability and increasing the resilience of forests by developing natural forests should be an objective of forestry. In fire-dependent ecosystems, the accumulation of fuel can be reduced by controlled natural and prescribed burning, thus maintaining natural ecological cycles. Burn areas should only be reforested when natural regeneration is out of the question and ecological damage such as soil erosion is to be expected.

Prohibit fire clearance by law – All relevant laws should integrate the aspect of fire risk. In some countries, conversion from forest to agricultural land is subsidised, while fire clearance can cause uncontrollable conflagrations. In these cases, law reforms are crucial. The conversion of burned areas to construction land should not be permitted, as this provides incentives for arson. In some countries, the provision for severe punishment and additionally improved law enforcement are required to prevent arson (for example in the course of land use conflicts or associated with illegal logging).?

Reduce forest fire risk by adapted land use planning – Forest fire hazard should be more strongly integrated into spatial planning. New settlements should not be permitted in high-risk zones, and infrastructures like railway and power lines should be adapted accordingly to reduce risk. The decision to fragment a pristine forest should always be subject to an environmental impact assessment, as new forest roads draw in people and thereby inevitably increase the risk of human-induced fire. Clearly assign and strengthen responsibilities – When a fire breaks out, clearly assigned responsibilities should be in place. Especially in forest fire regions, it should be clear who coordinates the relevant actors (authorities, fire services, population). Sufficient financial and human resources should be made available for forest fire monitoring, so that fires can be detected in time and suppressed at an early stage. Along with training programs, different forest fire scenarios should be developed for preparing emergency forces for timely and appropriate action. In case of a fire, a quick, tactically well thought out reaction is crucial to avoid a small fire from developing into a conflagration. In most affected regions, additional trained firefighting forces are required.

The ecological role of fire??

Forest fires are a natural element of many, but not of all forest ecosystems. In cold or dry climates with limited decomposition of litter and accumulation of humus through soil microorganisms, forest fires ensure that future generations of trees are supplied with nutrients. Tree species like the North American lodgepole pine or the sequoias in California need the heat from a forest fire as an impulse for their cones to open and release seeds for new tree generations. These trees are protected by a thick bark. Heat from the fire rises up to the cones sometimes over 100m above ground and causes them to open. Their seeds fall onto the ground fertilized by the ashes rich in minerals and germinate. Through this adaptation, seedlings and saplings find optimal conditions for growth, as competition from other plants is still low and there is sufficient nutrient supply.?

Fire-dependent ecosystems

Globally, around 46 % of all ecoregions are dependent on or influenced by fire. In these regions, forest fires are as integral to sustaining the natural flora and fauna as sunshine and rain. Typical fire landscapes are the taiga, the African savannahs, the monsoon and dry forests of South Asia, the eucalyptus forests of Australia, the coniferous forests of California, the Mediterranean region, as well as all pine forests from the taiga to the subtropics. All of these ecosystems developed with fire. The frequency and intensity of fires depend on natural factors like climate, vegetation type, lightning strike, accumulated biomass or terrain conditions. Burns maintain the characteristic structure and composition of ecosystems that have evolved with fire. However, all of these ecosystems don’t burn in the same way. In many forests, grasslands, savannahs and wetlands for example, low intensity ground fires are typical and necessary to maintain an open landscape with a multitude of grasses and shrubs. Other forest and bushland ecosystems rely on infrequent but severe fires that rejuvenate the population. However, what distinguishes all fire dependent ecosystems is the plant and animal populations’ resilience and capacity to recover, as long as the fire remains within the limits posed by natural factors. Fire prevention can bring far-reaching, ecologically and socially undesirable changes to ecosystems. For example, complete fire prevention has caused the typical grass landscapes of some parts of the southwest USA, which provided food for wildlife as well as for cattle, to turn into dense pine forests with little grass growth, which provides fuel for extremely severe and destructive fires.?

Fire-sensitive ecosystems

In fire-sensitive ecosystems, frequent, large and severe fires were rare until recently. Most plants and animals in these ecosystems lack the ability to benefit from the positive effects of a fire or to recover quickly after a burn. 36 % of all ecosystems worldwide are classified as fire-sensitive. Their vegetation and structure usually prevent the outbreak and the spread of fires. In the long term, human-induced fires in a fire-sensitive ecosystem can affect its species composition or reduce its area. Typical examples of fire-sensitive ecosystems are the tropical wet rainforests in the Amazon and Congo basins and in Southeast Asia. In these ecosystems, even small fires have far-reaching consequences, as they trigger a cycle of increasingly frequent and severe fires which eventually generate ecological conditions that promote the establishment of vegetation vulnerable to fire, such as grasses.?

Altered fire regimes

A fire regime is a pattern in which fires occur in a certain area or ecosystem. A natural fire regime describes the entire characteristic pattern of fires over time for an ecosystem. Different fire regimes are distinguishable according to fire frequency, seasonal pattern and intensity. Frequent but mild ground fires are characteristic for African savannahs, for example. In the boreal coniferous forests of Canada and Alaska, burning is less frequent but tends to rage as severe crown fires. In tropical wet rain forests, forest fires under natural conditions are so rare that available data on natural regimes are scarce. In the case of an altered fire regime, the current fire pattern regarding key factors such as frequency and severity of fires, deviates from the natural, historical and ecologically acceptable variation range characteristic for the respective ecosystem. Ecologically acceptable fire regimes may be influenced by humans, in order to preserve plant and animal populations and the natural processes that characterise the ecosystem. Understanding fire regimes is critical to assessing whether human intervention is beneficial, uncritical, or harmful from an ecological point of view. As key attributes of a fire regime are altered beyond an ecologically acceptable variation range, this creates living conditions that threaten the survival of native animals and plants typical to the respective fire regime. Changes to one or more key attributes of a fire regime can cause the degradation of an entire ecosystem, as they critically change its composition,?structure and processes. This may in turn trigger development towards a completely different ecosystem and fire regime. In the Mediterranean region for example, forest fires are assumed to be one of the causes of increasing desertification. Evidence from a number of different ecosystems suggests that it is difficult to impossible to halt or reverse such a development once it has been set in motion. Changes in fire regimes have been identified as one of the most significant threats to global biodiversity. 84 % of the area of priority ecoregions, which are crucial to the conservation of global species diversity, are at risk from altered fire regimes. Fire regimes are only within their ecologically acceptable limits on 16 % of the area of priority ecoregions. 93 % of the area of fire sensitive ecosystems, such as tropical wet rainforests, where plants and animals lack adaptation to natural fires, is at risk. With 77 % of their area at risk, ecosystems dependent on or influenced by fire, such as the African savannahs of boreal forests, are slightly less yet still considerably endangered by altered fire regimes. Climate change can further aggravate the threat. It is assumed that, for instance, in the southern Mediterranean region wildfire risk will persist throughout the year by the middle of this century, and that the period of highest fire risk will be considerably extended on the Iberian Peninsula and in northern Italy.

After fire disasters, it often transpires that the role of fire in the dynamic processes of the respective ecosystem has not or only insufficiently been considered in the area’s spatial development plans. One reason is that the change in a fire regime is a slow and gradual process that can sometimes stretch over decades, with a multitude of underlying causes depending on specific human interventions. Changes are often not recognized until they reach a critical point. In North America and Australia for instance, real estate boom and urbanisation have brought people to settle in areas that experience regular fires. Subsequently, even small natural fires were completely supressed, causing fuel to accumulate over years, which resulted in exceptionally large, severe and destructive conflagrations. Burns can become too frequent even in fire dependent ecosystems, like in the Siberian taiga. Here, rural population growth and increasing development through infrastructures such as railway and power lines have led to more frequent outbreaks of fire. This causes loss of forest area and releases millions of tonnes of stored carbon dioxide.

Forest fires and climate change

Forest fires cause 32% of global carbon monoxide and 10% of methane emissions, as well as over 86% of soot emissions.

By causing the release of greenhouse gases (GHG), forest fires contribute significantly to climate change. Warmer climate leads to forests becoming dryer and degraded, which increases their vulnerability to fire. The number and scale of fires increase, thereby creating a positive feedback loop. Savannah and forest fires annually release 1.7 to 4.1 billion t of carbon dioxide into the atmosphere; additionally around 39 million t of methane (CH4; 1 t CH4 = 21 t carbon dioxide, CO2) as well as 20.7 million t of nitrogen oxides (NOx) und 3.5 million tonnes of sulphur dioxide (SO2) are released annually. 15 % of the global GHG emissions are attributed to forest fires – most of them caused by fire clearance in tropical rainforests and resulting land conversion. Forest fires cause 32 % of global carbon monoxide and 10 % of methane emissions, as well as over 86 % of soot emissions.?

Different studies assume that climate change will increase the number of hot and dry days with high fire risk, extend the fire season and increase the frequency of electrical storms. This will increase the frequency of forest fires as well as the affected forest area.

Development and suppression of forest fires

Only about 4 % of globally occurring forest fires have natural causes like extreme weather events (high temperatures, drought and storms), lightning or volcanic eruptions.7 Humans cause fires deliberately by fire clearing or arson, or by carelessness, for example by bonfires or discarded cigarette butts or matches. Glass bottles and shards can bundle sunbeams like a burning glass and cause dry leaves or grass to ignite. Hot catalytic converters, car exhaust pipes and motorcycles parked on forest floors are common but underestimated causes. Sparks flying from power or railway lines can also ignite adjacent forests. The development of a forest fire can be divided into three phases: Usually, grass and dry undergrowth ignite first. This generates a ground fire, which is easy to control. If it grows into a wildfire, it can leap into the treetops, especially in the case of conifers, leading to a crown or canopy fire where the flames spread rapidly. Crown fires are considerably more difficult to control and can easily grow into a conflagration, which is practically impossible to extinguish.

Wildfire suppression

Appropriate firefighting measures depend on the type of fire. Creating firebreaks helps in the case of a ground fire. In this case several metre wide strips are cleared of fuel by controlled burning so that the fire cannot spread, however flying sparks may be able to pass the firebreak. A crown fire requires the use of firefighting planes and helicopters, which is dangerous as the pilots have to fly closely above the fire and sometimes crash. In 2012 in Turkey five people died in a helicopter crash during a firefighting mission. In Italy in 2007, all three pilots died when a helicopter and a plane crashed while fighting a forest fire. Despite the risks and high costs, countries primarily invest their resources in technical upgrading.

The problem of water supply

One issue for fighting forest fires is its water demand. Water supply is problematic for most forest fires, as water sources are often far away and water pumping and transport have to be set up over long distances. Additionally, forest fires mostly occur in areas with seasonal or year-long drought. Fighting forest fires requires tremendous amounts of water which then causes shortages for other important uses like agricultural irrigation. Large-scale fires can also affect a region’s water household. With the loss of a forest, its water-retaining function and balancing effect on the water household also get lost. Instead, water quickly runs off the burned surfaces and can erode the soil down to the bedrock.?

Forest fires in Turkey

In Turkey, there are over 2,000 forest fires every year on average. The coastal area from the Syrian border in the south to Istanbul is particularly affected. This area includes around 60 % of Turkey’s forested area, around 12 million ha. Annual forest cover losses have been under 15,000ha since the 1990s, with the exception of extreme fire events in 1994, 2000 and 2008. However even these values lie within a size range that its neighbour Greece reaches in an average fire year, even though Turkey’s forest surface is almost three times as large as Greece’s. For instance, in 2008 29,749ha burned in Turkey, almost the same area as in Greece, where 29,152ha burned. For Turkey this represented the second largest forest cover loss since the beginning of statistics. For Greece, in contrast, this value was below the 1991 to 2003 average.

With a similar fire incidence, Turkey has been losing far less forest cover than its neighbour Greece. 5.5ha are burned in an average forest fire in Turkey, compared with 26ha in Greece; almost five times as much. One of the reasons may lie in the fact that forest fires are quickly controlled in the heavily populated Turkish coastal areas. In addition, Turkey has taken a number of preventive measures, like planting fire resistant tree species or establishing an early warning system for forest fires.