One of the most exciting discoveries in the plant world during the last century was undoubtedly that of the deciduous conifer, the Dawn Redwood, Metasequoia glyptostroboides.
In 1946, acting on a tip-off and sight of some fragmentary material, Professor Cheng of the National Central University, China, sent an expedition to the remote village of Mo-tao-chi in Szechuan province to collect a complete set of specimens from a stand of recently-discovered, unidentified trees. After consultation with Dr Hu, China’s leading dendrologist, it became obvious that the trees belonged to the genus Metasequoia, hitherto only known from fossil evidence dating back 100 million years, and thought to have been extinct for 5 million years.
Seed was collected during a 1947 expedition sponsored by the Arnold Arboretum of Harvard University in Boston, USA, reaching its Director, Professor Elmer D Merrill in 1948, who then distributed the seed amongst botanic gardens in the USA and Europe for cultivation.
However, the seed from which the beautiful and fast-maturing specimen growing on the south-western shore of the Lake here at the Garden was produced came, somehow, directly from China. The Botanic Garden’s Annual Report for 1949 declares:
'Seeds of Metasequoia glyptostroboides, sent by Dr Silow from China to Professor F T Brooks, germinated freely. Three of the seedlings have been planted out: one in the Yard at the back of the Range and two beside the Pond [Lake].'
This tree on the south-western edge of the Lake, then, is the first Dawn Redwood to grow on British soil since the Mesozoic era, when dinosaurs dominated the fauna. It was judged one of the 50 ‘Great British Trees’ in honour of the Queen’s Golden Jubilee in 2002 and features in Thomas Pakenham’s Meetings with Remarkable Trees (1996). It has proved fast-growing: it was 1.5m tall at the time of the accession of Queen Elizabeth II to the throne in 1952, 17 metres by the time of the Silver Jubilee in 1977, and was approaching 23 metres in the Golden Jubilee year.
The Dawn Redwood makes a fine tree now familiar in parks and gardens. The beautiful ferny foliage is a bright, light green in spring, turning russet-brown with tints of coppery pink in autumn. The strong pyramidal winter silhouette is also very pleasing, making the Dawn Redwood a strong contender for year-round interest. The Garden’s specimen tree by the Lake has a superb, rugged, ridged trunk unusual in cultivation.
It prefers a damp habitat, and the Cambridge tree is grown next to the Lake to compensate for the low rainfall in the Eastern Region. In addition, however, it is near to its closest living relative, the Swamp Cypress (Taxodium distichum) from the United States and Mexico. This grows in the Lake and has distinctive knobbly pneumoatophores the 'knees') rising out of the water.
In nature, the Dawn Redwood is now restricted to just a few small and scattered stands in Hubei and Szechuan. The species is classified by the World Conservation Union as ‘critically endangered’ due to intensive rice cultivation and the poor prospect for regeneration in the wild.