As climate change gets worse, more and more reports of disastrous forest fires have been hitting the news. But not all fires in the woods are bad—some of them can actually be instrumental in keeping an ecosystem healthy!
Fire ecology is the study of how wildfire interacts with the environment. The field acknowledges the idea that fire is a natural part of the ecosystem and promotes change. It can clear away leaf litter and plants to provide nutrients and space for new growth.
One of the best and most well documented examples of a fire-dependent species is the longleaf pine. Once covering over 92 million acres across the US, heavy logging had reduced it to just 3% of its natural range by 1992. The pine grows fast, thin, and tall, and has evolved to rely on fire to give it a start.
In order for its seeds to germinate, the tree relies on starting on a forest floor free of any leaf litter. After the seed germinates, it grows a into a dense cluster of pine needles, low to the forest floor. These needles help provide fire resistance to the plant, protecting its bud from any fires. Its bud grows rapidly, allowing it to quickly grow above typical flame heights.
Fire enables its growth by clearing the forest of competition from hardwoods and other pines. It maintains conditions best suited for longleaf growth and recycles nutrients into the soil. Fire also allows helps clear out insects and pests that can impede plant growth.
Longleaf pines aren’t fireproof—they can still burn in its early stages of growth. But they are incredibly fire resilient. Mature longleaf pines have thick, plated sheets of bark that protect the trunk from fire. The canopy is usually high above the forest floor, enabling it to avoid fire altogether.
Nowadays, the US Forest Service encourages and carries out controlled burns to ensure our remaining longleaf forests remain healthy. But this wasn’t always the case. When America was being colonized, early settlers and loggers didn’t know about the role of fire in longleaf ecosystems, and ignored indigenous knowledge that touted its benefits. Fire prevention became the forestry ethic to live by, because it felt paradoxic to burn the forest on purpose to keep it healthy. But as soon as they began preventing fires, they realized that naturally occurring forest fires became more disastrous.
Because there weren’t frequent, little fires clearing out the forest, the fuel load, or flammable content, of the forest floor would keep growing. When it hit critical mass and finally caught fire, the fires would be massive and even harder to control. A lack of fires also led to a lower biodiversity. The fire habits of longleaf ecosystems leads to one of the highest species-per-acre densities—it’s been known to reach 40 species in a single square meter! Red-cockaded woodpeckers, indigo snakes, Bachman’s sparrow, flatwoods salamanders, sandhill lilies, and Sherman’s fox squirrel are just a few species that rely on longleaf ecosystems, which wouldn’t be possible without fire.
To see a really cool visual of a longleaf pine stand’s growth over a year, check out this story map created by the Longleaf Alliance.
Works Cited
https://www.fireinthepines.org/learn/the-longleaf-ecosystem/
https://longleafalliance.org/what-is-longleaf/restoration-management/prescribed-fire/
https://www.nclongleaf.org/burningLongleaf.html
https://www.nps.gov/articles/learning-about-fire-ecology-basics.htm
https://longleafalliance.org/what-is-longleaf/the-ecosystem/built-by-fire/
