Polesia is one of Europe’s largest wetland landscapes, stretching across the Pripyat River basin and supporting vast peatlands, flood-plains and forests. These ecosystems store carbon, regulate water and provide habitat for species including European bison, moose and greater spotted eagle.
But decades of drainage, combined with climate change, have left many parts of the landscape increasingly vulnerable to wildfire. One of the clearest examples is the Chornobyl Exclusion Zone (CEZ), where fires pose a unique challenge in a landscape shaped by both ecological recovery and radioactive contamination.
Since 2019, the Endangered Landscapes & Seascapes Programme has supported restoration efforts across Polesia through a project led by Frankfurt Zoological Society and its partners. The project is helping to strengthen protected areas, improve scientific understanding of the landscape and prepare large-scale wetland restoration activities. As temperatures rise and droughts become more frequent, understanding and reducing wildfire risk is becoming an increasingly important part of safeguarding the natural values of Polesia and supporting long-term restoration efforts across the region.
A unique and vulnerable landscape
The Chornobyl Exclusion Zone that emerged after the accident at the nuclear power plant in 1986 is shared between Ukraine and Belarus and forms part of the wider Polesia landscape. It is considered one of the most heavily contaminated areas in the world.
In both countries, the Exclusion Zone is protected, controlled and studied. In 1988, the Polesie State Radioecological Reserve was founded in the Belarusian part of the CEZ. In 2016, the Chornobyl Radiation and Ecological Biosphere Reserve was established in Ukraine. Scientists and conservationists carry out research and monitoring of radiation contamination, landscape dynamics and wildlife across the Exclusion Zone.
The main consequence of the Chornobyl accident is the severe radioactive contamination of a large area. It is extremely important to take measures to prevent the spread of radioactive substances that have accumulated in the environment. Since the collapse of the Soviet Union, Belarus and Ukraine have taken such measures independently and in different ways.
How drainage increased fire risk
In 1992-1993, many of the drainage channels in the Belarusian part of the exclusion zone were blocked. This measure was planned to reduce the spread of radioactive sediment from the Pripyat River basin downstream, but a significant portion of the soluble strontium had already been carried to the Pripyat River in the years after the accident. Over time, this also led to increased water retention in the canals, contributing to the rewetting of certain areas and the recovery of wetland ecosystems.
In the Ukrainian part of the CEZ, canals in the most contaminated areas were also blocked in 1986 and the following years as part of a comprehensive plan to protect water resources from radiation contamination. At the same time, a strategy was chosen to maintain minimal flooding of the catchment area to reduce the water migration of strontium-90 and other radionuclides. These almost opposite tasks required a management approach that retained water during periods of high wildfire risk while preventing prolonged flooding.
Experts note that the total length of drainage canals in the Ukrainian part of the Chornobyl Zone is four times greater than the length of the small rivers in this territory. Since the accident, the drainage infrastructure has gradually deteriorated and many canals are now overgrown with bushes and grass. Some natural restoration of wetlands is taking place. However, the scale of these positive processes is limited and the drainage systems continue to have a draining effect on the surrounding area.
Across Polesia, decades of drainage have altered natural water regimes and reduced the resilience of wetland ecosystems. As peatlands dry out, they become increasingly vulnerable to fire. Restoring natural water levels is therefore increasingly recognised as an important tool for reducing wildfire risk while supporting biodiversity recovery.
Climate change is making the problem worse
Another factor exacerbating the problem of fires in the Chornobyl Zone is climate change. Periods of hot, dry weather have become more frequent and prolonged in recent years. Instead of sustained rainfall, there are more short-term rain events that evaporate quickly, leaving little time for rivers and aquifers to recharge. Winters with little or no snow are becoming increasingly common in Polesia, meaning that soils remain less saturated with moisture until spring.
Peat soils, which are common across the region, present a particularly high fire risk. When dry, peat burns easily, is difficult to extinguish and can continue smouldering underground for long periods before reigniting under favourable conditions.
Why do fires start?
According to research conducted as part of the Polesia project, two of the ten largest landscape fires in Polesia between 2001 and 2019 occurred in the Chornobyl Exclusion Zone, one in the Belarusian part and one in the Ukrainian part. Fire statistics in the two countries can be unreliable, but overall the number of fires occurring on the Ukrainian side is several times higher than on the Belarusian side. Specialists insist that the human factor plays a key role.
Human presence in the Ukrainian part of the CEZ remains significant. Economic activity is limited, except for the intensive work associated with maintaining the nuclear power plant, radioactive waste storage facilities and related infrastructure such as roads, power lines and forestry operations. Before Russia’s full-scale invasion of Ukraine, tourism was also highly developed. Some people enter the zone illegally, while others have returned to homes abandoned during the evacuation. The activities of local residents living near the reserve also play a role. In some cases, dry vegetation is still burned in spring or after harvest, creating conditions in which fires can spread from agricultural land into natural areas.
The 2020 wildfire crisis
In recent years, there have been several concerning wildfire events in contaminated areas. A notable example occurred in spring 2020.
In early April, a fire broke out in an area adjacent to the Chornobyl Exclusion Zone and began to spread through the protected landscape. Investigations later suggested that it was most likely caused by the careless actions of a local resident. In dry and windy conditions, the fire spread rapidly. Embers formed in dry peatlands and reignited when winds strengthened. The fire approached the nuclear power plant and radioactive waste facilities.
The flames also reached the Red Forest, the woodland area around the power plant that received the highest radiation doses following the 1986 accident and remains one of the most contaminated parts of the exclusion zone. The total area affected exceeded 67,000 hectares.
Hundreds of firefighters and a wide range of equipment, including aircraft, were deployed to extinguish the blaze, but it took more than a month to bring the situation under control.
The situation deteriorated further following Russia’s full-scale invasion of Ukraine. In addition to natural conditions and human activities, unexploded ordnance contamination and a lack of firefighting equipment have reduced firefighting capacity and complicated fire suppression efforts. Large wildfires may become increasingly likely as a consequence of the ongoing conflict.
What happens when contaminated areas burn?
In the case of fires in the Chornobyl Zone, there are understandable concerns about the possible spread of radioactive substances through smoke and air currents.
Specialists note that the burning of ground vegetation itself does not necessarily lead to a dangerous increase in background radiation. However, fires can increase radionuclide concentrations in the air and contribute to their movement over greater distances.
Scientists at the Norwegian Institute for Air Research have studied the effects of forest fires on the atmosphere in the Chornobyl Zone in Ukraine and Belarus. They point out that increasing amounts of dead trees and forest litter provide fuel for wildfires, creating a higher risk of radioactivity redistribution in the future. According to their modelling, intense fires in 2002, 2008 and 2010 caused caesium-137 to move southwards. They warn that significant quantities of long-lived radionuclides remain in the landscape and that climate-driven increases in wildfire risk could contribute to their future redistribution.
A field study conducted jointly by Ukrainian and Japanese scientists found that the rate of radionuclide leaching and weathering temporarily increases by a factor of 30 following fire.
Impacts on wildlife and ecosystems
The Chornobyl Zone is often cited as a benchmark example of unguided rewilding. With very little human influence in recent decades, wildlife has reclaimed much of the landscape. The proportion of forests and mires has increased significantly, while populations of many wild animals, including ungulates, predators such as lynx and wolf, and rare birds have grown. In areas once dominated by intensive agriculture, plant species listed in national Red Books now occur.
However, these gains can be quickly undermined by wildfire.
Large fires cause substantial damage to natural habitats. Forests can take decades to recover. Small and less mobile animals may be unable to escape advancing flames or smoke. Larger animals often survive but may return to degraded habitats that no longer provide suitable shelter or food. Spring fires are particularly damaging because they coincide with the breeding season of many bird species.
Restoring water to reduce wildfire risk
Experience in recent years has shown that during long periods of drought, strong winds and low environmental moisture, landscape fires become increasingly difficult to control. Fighting fires and dealing with their consequences requires considerable resources and financial investment, while the environmental impacts can be severe and long-lasting.
Building the capacity of firefighting services and reducing dangerous human behaviour through education and regulation remain important priorities. In the long term, however, restoring natural water regimes may be one of the most effective ways to reduce wildfire risk, particularly as climate change is expected to intensify these challenges.
One of the current priorities of the Polesia project’s cooperation with the Chornobyl Radiation and Ecological Biosphere Reserve is the rewetting of previously drained areas. Large-scale restoration of wetland ecosystems remains challenging. However, the project is working with reserve specialists from site selection through to practical implementation, helping to build the experience and knowledge needed to continue this work in the future. By restoring natural water regimes, these efforts can help reduce wildfire risk while supporting the recovery of wetland ecosystems.
This article was originally published on the Polesia: Wilderness Without Borders website.
