Metasequoia glyptostroboides

While studying fossil samples of the family Cupressaceae, Dr. Shigeru Miki from Kyoto University identified a divergent leaf form.

[10] In 1943, Wang Zhan (Chan Wang, 1911–2000) of the National Bureau of Forest Research, the Ministry of Agriculture and Forests, Chongqing, collected samples from an unidentified tree in the village of Moudao [zh] (formerly Motaochi, Maodaoqi or Modaoxi)[11][12] in Lichuan County, Hubei province—now believed to be the same tree Kan discovered.

[17] Metasequoia glyptostroboides leaves are opposite, 1–3 cm (0.39–1.18 in) long, and bright fresh green, turning a foxy reddish brown in autumn.

[18][19] The tree's true potential size is much larger, as logs up to 8 meters (26 feet) wide at the base have been discovered in rice paddies.

The thickest and tallest dawn redwoods listed by Monumental Trees are both at Longwood Gardens, outside Kennett Square, Pennsylvania, United States.

The large cone type is found growing on mountain slopes, develops a broad canopy, seeds more readily and is more drought tolerant.

[22] Studies carried out between 2007 and 2009 counted 5,371 trees primarily in Lichuan, Hubei,[2][23][24] with much smaller groups in Shizhu, Chongqing and Longshan, Hunan.

[2] The floodplain of Metasequoia Valley in Hubei had already been turned to rice paddies by the time of the tree's discovery, but was once probably a more extensive dawn redwood forest.

[25] 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 type tree, 2.48 m (8.1 ft) at breast height, was in poor health and therefore excluded from the study) No seedlings were found, and if they ever do appear it is legal to remove and transplant them.

[2] 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.

By 1951, the species had entered the commercial horticultural trade in the United States,[12] and following media excitement about the new discovery, including in the San Francisco Chronicle of March 25, 1948,[12] sales soon took off.

The dawn redwood is recommended for urban areas in the Midwest, Southeast, and East Coast of North America, as its fast growth rate and tolerance for air pollution make it adaptable and able to thrive where other species might suffer.

The species tends to struggle without irrigation in arid climates such as the American West unless planted directly on or adjacent to a body of water such as a pond or stream.

[26] In the 1980s, it was discovered that many of the second-generation trees in cultivation suffered from inbreeding depression (extremely low genetic variability), which could lead to increased susceptibility to disease and reproductive failure.

[citation needed] There is a large collection of dawn redwood in the Lushan Botanical Garden within Mount Lu, Jiangxi.

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.

[35][36] Dawn redwoods thrive over a large, crescent-shaped region that encompasses the eastern and southern United States, as well as on the West Coast.

[37] There is a small grove of dawn redwoods at Bailey Arboretum in Locust Valley, New York, including one tree which is claimed to be the world's largest by diameter.

[38] The New York City Department of Parks and Recreation has begun planting dawn redwoods on sidewalks throughout Manhattan and Brooklyn, this link maps them.

Washington, D.C.'s Urban Forestry Division[39] has planted hundreds throughout that city, including all of the street trees in the 1800 block of Redwood Terrace, NW.

[41] It was planted in 1950 from a seedling from the lot brought from China by Dr. Ralph Chaney,[42] and donated by an unnamed donor to H. Spencer Lewis's widow for this purpose.

Dawn redwood
Metasequoia glyptostroboides (dawn redwood) bonsai tree