Ralph E. Taggart, Professor
Department of Plant Biology
Department of Geological Sciences
Michigan State University
As you will have noticed from earlier descriptions, redwood fossils are widely distributed in the fossil record of western North America. Based on the work of European paleobotanists such as Oswald Heer, the American fossils were generally placed in the genus Sequoia. Given the narrow range of tolerance for modern coast redwoods, American workers such as Ralph W. Chaney of Berkeley, used the presence of Sequoia as the primary datum in the reconstruction of the paleoecology of these Oligocene and Miocene assemblages from the Pacific Northwest.
In 1941, Shigeru Miki, a Japanese paleobotanist, was studying what he initialy assumed to be Sequoia fossils from Pliocene deposits in Japan. However, as he examined his fossils more closely, he realized that his fossils differed from living Sequoia sempervirens in a number of significant ways:
The "discovery" tree at Modaogi, photographed by the 1980 Sino-American Expedition.
This would have been interesting enough, but about the same time that Miki was naming his new genus, a Chinese botanical expedition was visiting isolated sites in Sichuan and Hupei provinces in central China. A forester, Gan, observed three individuals of an unusual Glyptostrobus-like tree in the village of Modaogi, but the deciduous conifer was lacking leaves at that time.
Later (1944), another forester, Z. Wang, was dispatched to collect specimens of foliage and cones, which found their way to W.C. Cheng in the Department of Forestry of the National Central University. Cheng noted that the plant did resemble Glyptostrobus, but that it also had features similar to Sequoia and Sequoiadendron. Suspecting that the tree might represent a new genus, Cheng sent a graduate student (Xue) on two trips to the remote area in 1946, finally gathering enough material for a definite determination of the proper nomenclature and classification of the tree. Some of the collection material reached H.H. Hu of the Fan Memorial Institute of Biology in Beijing. Hu was familiar with Miki's paper and wrote a short note on the discovery of living Metasequoia.
Meanwhile (1947), Cheng, who was the first Chinese national to earn a PhD in Botany from Harvard, sent seeds to E. Merril of the Arnold Arboretum in Massachussetts. Merril became caught up in the significance of the discovery and provided funds for additional seed collections in 1947. In 1948, Hu and Cheng published a joint paper naming the new plant Metasequoia glyptostroboides. This was the first case in which a living plant was assigned to a genus recognized on the basis of fossil material! That same year Merril began distributing seed and seedlings to academic institutions world-wide, including MSU.
Meanwhile, Ralph W. Chaney in Berkeley, who had spent decades studying fossil redwoods from Pacific Northwest Tertiary floras, was also caught up in the Dawn Redwood frenzy. Chaney and science journalist Milton Silverman, with the San Francisco Chronicle, embarked on an expedition to China that was financed by the Chronicle and the Save-the-Redwoods League.
A few more small scientific teams were able to visit the type area for the Dawn Redwoods within the next year and, at least on paper, the area was set aside as the first National Park in China. Unfortunately for the Nationalist government at the time, they were soon driven from the mainland with the success of the communist revolutionary forces. For the next 30 years, there was essentially no news in the west regarding the fate of the approximately 1000 trees known at the time from Sichuan and neighboring areas of Hubei province. Since that area of China was experiencing growing population pressure, it was generally assumed (incorrectly, as we shall see) that the trees might have disappeared from the wild. However, Merrill's efforts to distribute seed and cuttings had virtually assured the survival of the species in cultivation and it was soon growing in temperate areas around the world.
The legacy of the Miki's recognition of a new genus of fossil redwoods and the discovery of living trees in China was Chaney's realization that most of the fossil Sequoias he had recognized in Pacific Northwestern Tertiary floras were really Metasequoia! In the best traditions of science, Chaney got to work and, in 1957, published a major monograph that reclassified the major North American fossil redwoods in light of the discovery of Metasequoia. The largest and oldest Metasequoia tree on campus is located in the Beal Garden behind the library. This tree dates from Merrill's original 1948 seed distribution and is now about 30 meters (100 ft) tall. In 1968, the graduate students of the Department of Botany and Plant Pathology invited Professor Ralph W. Chaney to the MSU campus for a series of seminars. This photo, taken in the Beal Botanical Garden, shows Chaney (left) and Professor Aureal T. Cross (right), MSU paleobotanist, taken at the base of the large Beal Metasequoia.
The Status of Metasequoia Today
Dawn Redwood populations did suffer inroads, particularly in Sichuan, during the early days of the formation of the revolutionary People's Republic of China. However, the tree is now protected and many more individuals (perhaps 6000 or more) have been located in Hubei and Hunnan provinces.
The photo at left shows a mature Metasequoia in Hubei Province. The trees may reach a height of 45 meters (146 feet). While not as large as the two California redwoods, the trees are impressive. To put this photo into scale, note the people sitting at the base of this tree!
While Dawn Redwoods are widely cultivated and doing just fine in that context, one problem has emerged. Although all the original trees are now well into functional reproductive age, little viable seed is produced, even under mild climatic conditions. The problem appears to be a phenomenon known as inbreeding depression. All the trees now in cultivation were derived from a single isolated population (and perhaps even a single tree) in the village of Modaogi. In effect, the trees in cultivation are not breeding effectively because they are clones of a single population with very limited genetic diversity. To combat this problem, John Kuser of Rutgers University and Donald Hendricks of the Dawes Arboretum initiated a program of seed collection from across the range of living trees in China. Several hundred trees from this mixed population are now being cultivated at the Dawes Arboretum. The goal is to allow these trees to eventually interbreed, producing viable seeds that would incorporate much of the total genetic diversity of the species as it exists in China today.
Ralph E. Taggart (firstname.lastname@example.org)