Watch: How giant sequoias, earth’s largest and longest-living trees, need fire to survive
Fire, the destroyer, can also be a creator.
The blackened landscape seen after forest fires, whether caused by natural or man-made factors, always gives the impression of large-scale devastation.
However, in some cases, forest fires are beneficial to the ecosystem.
For instance, forest fires have helped giant sequoias – earth’s largest and longest-living trees – to survive.
Native to the western slopes of California’s Sierra Nevada mountains, giant sequoias – which are one of the three species of coniferous trees known as redwoods – can stand up to 325-feet tall and live for more than 3,000 years.
The video above by PBS follows how fire provides conditions for this tree’s seeds to germinate.
The camera takes the viewer from the floor of the forest to the tree tops from where one gets an aerial view of the forest. Even if you haven’t seen the tree in real life, the video will give you an idea of its imposing size.
Because of its height, it is difficult for sunlight to reach the ground in groves of giant sequoias. However, these trees require strong sunlight to grow. It is here that fire plays a vital role – the heat allows the tree’s cones to split open and release its seeds. At the same time, the fire loosens the soil, clears it of leaves, and allows the seeds to fall on bare soil, which it requires to germinate.
The fire-resistant bark of these trees helps them survive forest fires as compared to other tree species. As the charred parts of giant sequoias are enveloped by newer layers, the rings in the trunk slowly record the history of each fire.
Scientists have been fascinated with the stories that groves of giant sequoias have to tell. But like other flora and fauna on earth, even these species, which go back some 8,000 years, are endangered in the face of rapid climate change.
The videos below are of forest ecologists Wendy Baxter and Anthony Ambrose from University of California Berkeley’s Dawson Research Lab who study how drought is affecting the ancient species.