Zombie fire
However, not all wildfires are the result of human activity. Lightning strikes are also a common cause. In countries such as Canada and Siberia, this leads to forest fires the size of the province of Utrecht. ‘My colleague Sander Veraverbeke from the VU recently published a paper on so-called zombie fires that can occur in peat bogs there. A fire can sometimes continue to smoulder throughout the winter inside a fallen tree, even if it is covered in snow. When the snow melts and the temperature rises, the fire flares up again.’
In doing so, Robroek highlights a key factor in both the ignition and spread of forest fires: drought. ‘In addition, combustible material must be present. Dry grass burns well, but also goes out quickly. Combined with wood and peat, however, you do get a substantial amount of combustible biomass. The third crucial factor is wind. Just as you fan a small fire or barbecue by waving your hands, the wind keeps fanning the flames of a forest fire, allowing it to spread from treetop to treetop and making it difficult to bring the fire under control.’
It is evident that wildfires cause damage. However, the extent of that damage varies enormously. ‘The loss to plant communities is considerable, but there are also trees, such as cypresses, that can protect themselves well against a surface fire and even benefit from it, recovering after a wildfire. During a wildfire, many nutrients are released, and this helps ecosystems to remain diverse.’
Disastrous consequences of wildfires
Nevertheless, the consequences of a forest fire, particularly if it persists for a long time, are disastrous. It can take decades for the trees to grow back. The consequences of a peat fire are even worse. ‘Peat grows by an average of one millimetre per year, and a fire can destroy as much as thirty centimetres; it would then take 300 years for the peat to fully recover. Furthermore, fire can cause a peatland to become hydrophobic. This means that the peat repels water. When peatlands dry out, this is accompanied by a huge increase in greenhouse gas emissions, and those emissions naturally do not decrease when a peatland becomes prone to fire.’
Robroek emphasises that wildfires will always occur, but that there is plenty that can be done to reduce their frequency and intensity. ‘In the Netherlands, over the past few decades, we have tried to channel water into the sea as quickly as possible, but we would do better to retain water in our landscape for longer, for example by allowing rivers to return to their natural beds, creating wetland ecosystems and restoring raised and lowland peatlands.’
A good living
These changes not only improve fire safety, they also offer opportunities for a different type of agriculture and provide economic benefits. ‘Through so-called paludiculture, or wetland farming, farmers can make use of the fact that some plants thrive in wet conditions. For example, it is possible to grow cattails and reeds, both of which work well as insulation materials in the construction sector. Or sphagnum moss, which serves as a base for potting compost. This can provide farmers with a sustainable source of income.’ Moreover, these wetland areas contribute to nature restoration and lower greenhouse gas emissions.
But to achieve this, political will is needed. Indeed, in recent years, much of the peatland has actually been converted into land where cows graze. Nevertheless, Robroek remains positive. ‘We have the momentum on our side. The Netherlands ranks at the bottom of the European league table for water quality. Greater attention to wetlands can help improve that quality. What’s more, without attention to nature reserves, current forms of agriculture are not sustainable either. That realisation will surely become more widely recognised in the near future. Furthermore, if we make our landscape wetter, we will face less of a threat from fires, despite drier summers.’
Photo: Fachy Marín via Unsplash
