tree's discovery. Most of the other vegetation has been cut, and most of the area is no longer suitable ground for seedlings. Between 1950 and 1980 several hundred were logged in Metasequoia Valley, some over wide. A survey in the 2000s counted and measured all wild dawn redwoods. The remaining healthy trees range from to wide at breast height, in height, and estimated 41–265 years in age. The average size was tall and wide at breast height, with an estimated age of about 95 years. (The type tree, 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. 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. Cultivation Since the tree's rediscovery, the dawn redwood has become a popular ornamental tree in parks and gardens worldwide. Dawn redwood seed arrived at the Arnold Arboretum on January 5, 1948, and was shipped to arboreta around the world soon after. By 1951, the species had entered the commercial horticultural trade in the US, and following media excitement about the new discovery, including in the San Francisco Chronicle of March 25, 1948, sales soon took off. Dawn redwood has proved an easy tree to grow in temperate regions, and is now widely planted as an ornamental tree. Planted trees have already reached at least up to in diameter at breast height and tall, despite being in cultivation for only 70 years. This rapid rate of growth has led to consideration for using the tree in forestry plantations. It has been discovered that M. glyptostroboides will thrive in standing water, much like bald cypress, and if left branched to the ground in full sun, will develop the large, contorted boles that have made it famous. Limbing or pruning at an early age will prohibit this formation later on. In cultivation, M. glyptostroboides is hardy to USDA Zone 5, making it hardy down to lows of . It is tolerant of soggy, waterlogged soils; in the wild it is adapted to growing on flood plains. Until it is established in a specific site, it is prone to drought and inadequate water availability. The dawn redwood is recommended for urban areas in the Midwest, Southeast, and