It has needle-like foliage and bears cones, like a conifer tree. But it’s deciduous, like an aspen tree. Its green leaves turn yellow each fall, dropping to create a golden carpet of soft needles.
The dawn redwood is an ancient tree, dominant during the Cretaceous Period when dinosaurs roamed the Earth. But fifty million years ago, volcanic eruptions and methane release from ocean sediments caused a huge spike in carbon dioxide, causing temperatures to rise around the planet.
As arctic habitats became much warmer, dawn redwoods migrated to become a major element of far northern forests. Although temperatures were mild, they became deciduous in response to the three months of Arctic winter darkness.
As the earth cooled, dawn redwoods migrated south. But 20 million years ago, they disappeared from the fossil record, so botanists considered the tree long extinct.
Amazingly, in 1943, botanist Wang Zhan [Wong Chan] discovered a living dawn redwood tree growing in a remote Chinese valley. Imagine his excitement in encountering the tree version of a living dinosaur!
This discovery captivated the world. Seeds were propagated, and it became a resilient urban tree. It now grows from Washington State to Florida.
This history reminds us that even in the face of extreme climate changes, some species can survive — and even thrive. And, they help us remember that in the vast stretch of planetary time, human concerns are just a blip.
