I Metasequoia in the Park Today.

When I was in Horticulture school way back in the dark ages we learned about 300 trees and shrubs, the hardest for me were getting the conifers correct in my mind. These are the needle trees and shrubs such as Junipers of which there are many species, hybrids and cultivars. Of the group of conifers we were introduced to and studied several lost their needles every autumn.  These species which lose their needles are not that common around here except for the curious case of  the Metasequoia glyptostroboides (Dawn Redwood) and what an interesting story it has!

Fantastic fall coloring of the Metasequioa glyptostroboides, A..K.A. Dawn Redwood.

Metasequoia glyptostroboides is a very old and yet new plant. It described in 1941 by Shigeru Miki, a Japanese Paleobotanist. The genus was already known from fossil samples which where in collections in various places. This may be why this tree was called a ‘living fossil’ when it was found. In 1943 C. Wang(Zhen Wang) from the National Bureau of Forest Research was visiting Wan Xian Agricultural School and heard about a huge unknown tree which was found in Modaoxi which was nearby. Wang then decided at that time to take his team and go and investigate this tree, they followed the directions they were given and travelled through high mountains to get to Wan Xian,Sichuan (now in Hubei province). They arrived in late July and collected branch and cone samples from the huge tree which was found there. In 1946 more specimens were collected from the same tree.

The cones of Dawn Redwood trees are small valved capsules.

The tree specimens form the herbarium collections Wang had sent  back were at first mis-identified by him as a new species Glyptostobus pensilis. More study were done at the Department of Forestry at the National Central University(Chongqing) by W. C.Cheng who was a professor of Dendrology and Dean of the Department there. Cheng decided Wang was wrong.  Cheng and Wang published “Metasequoia glyptostroboides Hu et Cheng” jointly in 1948.

Dawn Redwood Shed branchlets which are made up of needles in the fall.

Fossil samples show there were as many as 20 species and subspecies of Metasequoia at  one time which covered a wide area in the Northern Hemisphere. Samples have been collected as far north as Axel Heiberg Island(Canada) which parallels Greenland.  The ‘Bandlands’ of Western North America are full of fossilized stumps and other tree remnants. These fossils are from late Cretaceous to Miocene strata which they are well represented in.

One of several of the Dawn Redwood found at Beacon Hill Park.

Most of the older Meatasequoia glyptostroboides are from the original seed sample material that was sent to Arnold Arboretum in 1948 and then germinated for distribution. The  new seedlings were sent to universities, other arboretum and  important parks for further study of the tree’s growth habits.  Most trees we have come from this original collection and this has created problems with in-breeding depression. To solve this problem in 1991 extensive seed collecting took place from the wild forests along the Sichuan-Hubei border in China. This will increase genetic diversity in the cultivated species. Plants which have come onto the market since this time are considered much stronger.

The delicate branches of the Dawn Redwood give this tree a delicate whimsical look.

Dawn Redwoods are a fast growing tree which are normally are low limbed, making them great trees for climbing.  They need a large area, growing 75-100ft(23-30.5m) tall and 15-25ft(4.5-7.7m) wide. They like full sun and a well-drained moist site for the best growth.they do not like alkaline soils.  it is best to avoid planting these trees in frost pockets where the delicate emerging foliage can be damaged by late frosts. This tree is generally pest and disease if well taken care of.  They grow best in zones 4 through 8.

Older Dawn Redwood trees which retain their lower limbs can develope buttresses bases which are much-loved by children.

Metasequoia glyptostroboides is a true Sequoia and is related to the two other species (Sequoia sempervirens and Sequoiadendron giganteum) which are found on the west coast of North America. All tree species are listed in the subfamily Sequoioideae. The cones, and bark are similar,but the shedding of the foliage is different and highly unusual for any conifer.

More on Metasequoia:

A great source of information on all important conifer trees: http://www.conifers.org/cu/me/index.htm

Metasquoia has it’s own tree website: http://www.metasequoia.org/

A great source of information is alway found on this site: http://www.hort.uconn.edu/Plants/m/metgly/metgly1.html

Until we meet again……….

 

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