Wildfires are destructive forces that can result from natural causes (like lightning), human-caused accidents (like improperly discarding cigarettes and leaving campfires unattended), or deliberate acts of arson. Climate change has increased periods of drought and extreme heat, which make wildfires more severe and dangerous, threatening the loss of life and ecosystems. However, wildfires have ecological benefits for forests. Small, low-intensity fires help rejuvenate forests and are overall beneficial for conservation. Controlled use of wildland fires for positive environmental effects is common around the world.
Wildfires that are planned and regulated are often referred to as “prescribed” or “controlled” burns. While all fires have the potential to become dangerous to property and life, controlled burns are planned extensively and performed with tight safety parameters. Humans have been performing such burns for thousands of years and for multiple reasons. For example, Indigenous populations in North America have long used fire to clear land of larger trees to allow smaller plants to grow. These plants are used for food and medicinal purposes. In Africa, traditional farming practices include controlled burns to rid areas of insects that carry disease and to create more grazing land for animals. Aboriginal Australians set controlled blazes to preserve the landscape and biodiversity.
Scientists are researching how these Indigenous practices may be implemented on a wider scale today. For example, European settlers in the United States and Australia have suppressed traditional fires for many decades, and governments and scientists are now seeing the lost ecological and cultural benefits that were once cultivated by Indigenous populations. National Geographic Explorer Kira Hoffman is a fire ecologist who researches how landscapes have been shaped by Indigenous land management techniques, such as burning, fertilizing and transplanting.
Ecosystems benefit from periodic fires because they clear out dead organic material. As dead or decaying plants begin to build up on the ground, they may prevent organisms within the soil from accessing nutrients or block animals on the land from accessing the soil. This coating of dead organic matter can also choke outgrowth of newer or smaller plants. When humans perform a prescribed burn, the goal is to remove that layer of decay in a controlled manner, allowing the healthy parts of the ecosystem to thrive. Moreover, nutrients released from the burned material, which includes dead plants and animals, return more quickly into the soil than if they had to slowly decay over time. In this way, fire increases soil fertility.
Some plant and animal populations require the benefits of fire to survive and reproduce. Seeds from the Lodgepole pine tree (Pinus contorta) are enclosed in pine cones covered in resin that must be melted to release the seeds. Other trees, plants, and flowers -- like certain types of lilies -- germinate or bloom as a result of fires. Animals depend on fire as well. Fire chaser beetles (Melanophila acuminata) have organs that help them detect fires by sensing infrared radiation. They purposely lay their eggs in areas with recent burns. The endangered Karner blue butterfly caterpillar (Lycaeides melissa samuelis) gets all of its food from a plant called wild lupine (Lupine perennis), which thrives in areas where fires have occurred. Healthier, post-burn plant populations can have broad food web effects that trickle up to the foragers and other animals in the ecosystem.
Moreover, prescribed burns are well established as a way to prevent more devastating fires. The buildup of decaying organic matter on the ground is fuel for wildfires. Without the periodic fire to clear this out, a fire—from natural or human cause—may grow and move quickly, doing much more damage that a prescribed burn, and without its safety parameters. Today, this organic fuel can catch fire more readily than in past years, as climate change has created drier conditions that are ripe for wildfires in many parts of the world.
Scientists say that climate change primed conditions for recent, severe fires. In 2023, Hawaii experienced its worst natural disaster in history when a fire broke out on the island of Maui, killing 101 people. That same year, Greece had the largest wildfire ever recorded in the European Union, burning more than 810 square kilometers (310 square miles), an area larger than New York City. Australia and parts of South America also experienced greater wildfire activity in 2023 compared to past years.
Controlled burns not only lower the chances of these severe wildfires, but they also help prevent harmful emissions that contribute to climate change. Fires on the African savanna are common, and if uncontrolled fires happen late in the dry season, they cause devastating damage and release huge amounts of carbon into the air. However, authorities in Africa, particularly those from countries across the savanna, have been starting controlled burns earlier in the dry season, when the savanna is wetter and fires cannot spread as fast. This causes less damage than a fire later in the season and reduces carbon emissions.
This method of reducing emissions has also been implemented in Australia, according to National Geographic Explorer Mercy Ndalila. Ndalila has studied the implications of both controlled burns and uncontrolled wildfires in carbon emissions estimation in Australia, as well as the ecological and societal implications of such fires in Kenya. Improved wildfire management around the world is important for both reducing emissions and protecting ecosystems that evolved around fire.
