Dawn Redwood: A Living Fossil

Have you ever wondered what the earth looked like when the dinosaurs roamed?  Humans didn’t realize that we have a living fossil among us that offers a glimpse into the past until the 1940s when the dawn redwood tree (Metasequoia glyptostroboides) was “discovered” by scientists in China.  This discovery has been noted to be one of the greatest for botany in the 20th century and the story behind the find is certainly a noteworthy tale in world history.

In 1941, a Japanese paleobotanist described a sequoia-like species from fossils of the plant found in Pliocene fossil beds near Tokyo, naming it MetasequoiaMetasequoia fossils had long been a part of many Northern Hemisphere collections under a variety of incorrect names, but it was Miki that was first able to describe the genus correctly.  The genus consisted of 3 species that were all thought to be long extinct, but were found extensively in fossil beds throughout the Northern Hemisphere.  A short time later, in July 1943, Chan Wang, a scientist with China’s National Bureau of Forest Research, discovered a tree growing in a small, remote village in West-Central China that he believed could be new to science.  The locals referred to it as shui-sa or “water fir”.

Wang’s specimen attracted attention from Chinese botanists, but without a complete specimen containing all the plant’s anatomy, botanical classification was not possible.  Collection of additional samples was quite challenging as it required a difficult trek through 220 miles of remote mountainous trail that traversed dangerous “bandit-infested regions”.  To further complicate things, World War II and the concurrent China Civil War were draining resources and further distancing the scientific community.   Despite these challenges, complete specimens were collected and eventually ended up in the desk of Chinese botanist H. H. Hu in 1946.  By chance, Hu happened to have a reprint of Miki’s paper from 1941 and made the connection.  This was a new species to science and one that spanned over 60 million years of time on the earth!

The scientific community and the general public were fascinated with this glimpse into our botanical past and the dawn redwood was named a “living fossil.”  The exciting new find captured the attention of the US plant community and in 1947, Harvard’s Arnold Arboretum funded the extensive collection of seeds by Chinese botanists.  Upon receipt in 1948, Harvard botanist E.D. Merrill distributed them around the world and the rest is history, leading to widespread propagation of the popular landscape plant. 

The dawn redwood is a member of the Cupressaceae family, which includes its American cousins the coast redwood (Sequoia sempervirens) and giant sequoia (Sequoiadendron giganteum). Although it is the shortest species of redwood, it still reaches up to 200ft in height.  One other fascinating feature of this tree is that it is deciduous.  The dawn redwood loses its leaves each fall, which is rare among confers.  Prior to leaf drop, needles turn a beautiful orange to reddish-bronze giving a spectacular fall display.  It is adapted to wide range of soil conditions, but favors full sun.  Dawn redwood makes an excellent large shade tree and has surprisingly fast growth rates, with some specimens approaching 100 feet of height in just 30 years.

At the time of discovery, native populations of dawn redwood were estimated at about 1,000 trees.  The tree was at risk of extinction due to continued local use for lumber products. Due to its timely discovery and subsequent conservation efforts, today’s population is estimated at about 5,400 trees.  The original tree that was discovered in 1943 is still alive in China today and is estimated to be 400 years old.