Dawn redwood

Appearance

While the bark and foliage are similar to another closely related genus of redwoods, "Sequoia", "M. glyptostroboides" differs from the coast redwood in that it is deciduous, like "Taxodium distichum". Similar to Taxodium, older trees may form wide buttresses on the lower trunk. Metasequoia is a fast-growing tree, exceeding 35 m in height and 1 m in trunk diameter by the age of 50, in cultivation.
The trunk forms a distinctive "armpit" under each branch. The bark is vertically fissured and tends to exfoliate in ribbon-like strips.

The leaves are opposite, 1–3 cm long, and bright fresh green, turning a foxy reddish brown in fall. The pollen cones are 5–6 mm long, produced on long spikes in early spring; they are produced only on trees growing in regions with hot summers. The cones are globose to ovoid, 1.5–2.5 cm in diameter with 16-28 scales arranged in opposite pairs in four rows, each pair at right angles to the adjacent pair; they mature in about 8–9 months after pollination.

Naming

Together with "Sequoia sempervirens" and "Sequoiadendron giganteum" of California, "M. glyptostroboides" is classified in the subfamily Sequoioideae of the family Cupressaceae. Although it is the only living species in its genus, three fossil species are known as well. The other Sequoioideae and several other genera have been transferred from the Taxodiaceae to the Cupressaceae based on DNA analysis.

Status

In Lichuan, Hubei, there is a dawn redwood forest consisting of barely 5,000 trees, and some smaller groups. Since its discovery, the dawn redwood has become something of a national point of pride, and it is protected under Chinese law and also planted widely. However, it is still listed as endangered in the wild. Cutting of trees or branches is illegal, but the demand for seedlings drives cone collection to the point that natural reproduction is no longer occurring in the dawn redwood forest. The species will continue to live in yards, parks and on roadsides all over China, but the "M. glyptostroboides" forest ecosystem could disappear when its mature trees die.

Pizhou, Jiangsu boasts the Longest dawn redwood avenue in the world. The avenue is approximately 60 km long with over one million trees.

In 1995, the Crescent Ridge Dawn Redwoods Preserve was established in North Carolina. Here, hundreds of dawn redwoods have been planted in a natural state where they can be observed and recorded in the wild, reducing the need for those in the U.S. to travel to China. The project goal is 1,000-5,000 trees. Currently, 200+ trees thrive in three separate groves. A fourth grove was lost to beaver depredation with loss of 125 or more trees. CRDRP remains the only eastern redwood forest in the U.S., and the sole wild dawn redwood forest outside of China. The preserve is tentatively scheduled to open to the public in 2035.

Evolution

In 1941 a forester named Kan, while performing a survey in Sichuan and Hubei provinces, happened across an enormous tree — as it turned out, an individual of "Metasequoia" — and recognized it to be special. In 1943, two more discoveries further brought "Metasequoia" to light: Chan Wang, a Chinese forestry official, also happened across an individual and collected samples from it. These samples were determined to belong to a tree as yet unknown to science. However, in the same year, a second discovery was made that ended up being supremely relevant: Shigeru Miki of Kyoto University, studying fossil samples of the family Cupressaceae, isolated a divergent leaf form that led him to describe a new genus, which he named "Metasequoia", meaning "like a sequoia." Only in 1946 was the connection made between Miki's new genus and the living samples identified by Kan and Wang. Professor Hu Xiansu is credited with making this important connection, and providing the specific epithet "glyptostroboides," after its resemblance to the Chinese swamp cypress.The genus "Metasequoia" was first described as a fossil from the Mesozoic Era by Shigeru Miki in 1941, but in 1943 a small stand of an unidentified tree was discovered in China in Modaoxi by Zhan Wang; due to World War II, these were not studied further until 1946 and only finally described as a new living species, "M. glyptostroboides", in 1948 by Wan Chun Cheng and Hu Hsen Hsu. In 1948 the Arnold Arboretum of Harvard University funded an expedition to collect seeds and, soon after, distributed seeds and seedlings to various universities and arboreta worldwide for growth trials.