The Unexpected Relationship Between Sequoia Trees and Fire

sequoia tree

Estimated to be around 2,700 years old, these trees are some of the oldest in the world as well as the largest, growing up to 300 feet tall and dozens of feet wide. The oldest known giant sequoia actually lived to be 3,200 years old! Found in only around 73 groves along the western slopes of the Sierra Nevada mountains, giant sequoias evolved from redwoods to withstand the wildfires that often sweep through the California landscape.

Giant sequoia are much more resilient to fire than most trees. The bark of a giant sequoia can be up to two feet thick, working as an insulator to protect them from fire. The bark is also rich in tannins, which protect from pests, disease, and decay, keeping the trees healthy and strong.

The cones of giant sequoia are serotinous, meaning they need heat to open and release seeds.

Giant sequoia have evolved alongside wildfires, developing a delicate balance between the two. The indigenous peoples of the area knew how to care for and maintain this balance but when european american settlers arrived, they began to offset this balance. Settlers began cutting down some of these trees, not for their wood, but to showcase the magnificent size and make a profit. Eventually, around one-third of the giant sequoia groves had been cut down. Due to the low quality, most of the wood was used for grape stakes and fence posts.

While the euro-american settlers were concerned for the giant sequoia, they did not seek out indigenous knowledge, furthering the imbalance. Indigenous tribes knew that the giant sequoia relied on fires to reproduce and would practice controlled burning. On the other hand, Settlers were adamant about the cessation of fire. The suppression of fire and removal of native peoples from their territories led to the overgrowth of surface fuels and ladder fuels. This increase in underbrush leads to much more severe fires. According to the Save the Redwoods League, “if a fire burns through a forest that has over 100 years of fuels accumulation, fire behavior will be much more intense, resulting in larger pockets of high severity than observed historically when fire burned roughly every 10 to 20 years”. Modern high-severity fires are more common and lead to the death of monarch giant sequoia trees.

So, what is the solution here? Our best chance to save the giant sequoia is to finally learn from the indigenous peoples who had coexisted with the trees for generations before the arrival of settlers. While it may seem counterintuitive, we need more fires. Not severe, out-of-control wildfires, but low-severity fires managed by firefighters. This is what is referred to as a prescribed burn. These often occur in the spring or fall and help decrease the fuel on the forest floors. Apart from decreasing fuel, it also promotes the next generation of sequoia, allowing the awe-inspiring trees to live on.