Wednesday, June 6, 2012

Dawn Redwood: Critically Endangered?





Species name: Metasequoia glyptostroboides

Common name: Dawn redwood

Location: Ontario

This species of redwood is unique in many ways, only one of which being that it was only recently (well, in the grand scheme of things it's recent) rediscovered in 1949 after thoughts it had gone extinct in the late 1800s. It is native to a very small region in China, and within its native range there are only a few individuals of this species left so it is critically endangered. That being said, it's also an incredibly popular ornamental tree (gaining popularity in North America) so cultivated species of this plant will likely always exist even after the wild members of the population are long gone. Another unique aspect of this tree is that unlike it's close relatives, the Giant Redwood (Sequoiadendron) and the Coastal Redwood (Sequoia), this is a deciduous tree and a conifer at the same time. It produces cones like you would picture from a redwood or even a cedar, but loses its leaves during the fall like an oak or maple tree would. As you can see from the pictures, the leaves are like feathers, and it seems like they all appear overnight after the buds have persisted on the branches for many days or weeks. While you might imagine the debris from this tree would be quite impressive since it can be a huge tree (up to 200 feet in the wild) with many leaves, the leaf-like needles actually decay very quickly. It's certainly not the padded ground cover that you find in pine plantations!

The Dawn redwood is what we refer to as being a "monotypic" species, meaning that it is the only species that is currently alive in the genus. There are an estimated three other species that have once existed in the genus based on evidence from the fossil record. These trees seemed to be abundant in the early Paleocene, between 55-60 million years ago. The changing climate likely led to their demise, which seems to be repeating itself with the last remaining species. The Dawn redwood is also very sensitive to urban pollutants, so living in the city and trying to grow one of these outside is probably a losing proposition (and a good reason why urban encroachment is one of the contributing factors to the status of the last remaining wild population of this species). That being said, this is a popular plant species to turn into a bonsai, so growing it indoors can work well if you have time and patience!

These trees are a source of national pride in China, so much so that it's actually illegal to take branch cuttings from any one of the remaining 5,000 trees left in the wild. Unfortunately, cone collection is not protected in the same way so natural regeneration of these trees has essentially stopped. Once the mature trees in the stand die, the species will be extinct in the wild. The state of North Carolina has attempted to do its part by planting an enormous stand of Dawn redwood trees over three different sites. Their goal is to have 5,000 trees planted in various stages of growth by the year 2035, which is when the nature preserve is slated to open to the public. Hopefully this enormous undertaking will continue to thrive with changing national budget priorities! I would love to go see it someday.