FROM THE ARCHIVES: Trees, Please! - Premature Obituary

By Tim Clancy. First published in Let’s Talk Plants! January 2012, No. 208

Dawn Redwood, Metasequoia Glyptostroboides, the unique one of the Montsouris park growing close to the footbridge over the RER suburb train, yields an exceptional burning red color, in contrast to the whiteness of the Paper Birch, Betula papyrifera, to its left and deep green of the Austrian Pine, Pinus nigra, to its right.

On June 2nd, 1898 American humorist Mark Twain was quoted as follows: “The report of my death was an exaggeration.” If trees could talk the Dawn Redwood, Metasequoia glyptostroboides, could have said the same thing in 1944. Up until that time the tree was only known in fossil records.

 When a taxa (organism) is thought to be extinct (dead) and then later discovered to be extant (living) it is called a Lazarus taxa, referring of course to the biblical account of Jesus raising Lazarus from the dead. There are many such taxa.

 Keeping in the same vein, when a species is incorrectly identified as a Lazarus taxa only later to be confirmed as a different species that looks like what it was erroneously identified as, it is referred to as an Elvis taxa.This is a tongue in cheek nod to all the Elvis impersonators. Who says paleontologists aren’t funny?

 Since its rediscovery in the Szechuan province of China, the dawn redwood has become a popular ornamental planted around the world. This became possible in large part due to an expedition sent to China from the Arnold Arboretum in 1948. Seeds were collected and then distributed to select universities and arboreta throughout the world.

 The bark and leaves look similar to our own California redwoods. It is a fast grower and is short by redwood standards topping out at about 200 feet. Perhaps its most interesting characteristic from our perspective is that the tree, while being a conifer, is not evergreen but deciduous. In the fall its leaves turn color and to the untrained eye the tree looks like it is a diseased redwood.

The fact that the tree looks diseased brings up an important point. It is critical that you are familiar with the species you are dealing with when deciding what, if anything, is wrong with the tree. I know someone who mistakenly cut down a dawn redwood because he incorrectly identified it as a coast redwood and also incorrectly declared it dead.

 Make it a point to look at trees throughout the year so you can note various growth characteristics. What color are the leaves in the spring? What shapes are they? Do these things change as the spring turns into summer? One way to track a tree’s health is to note its growth increments from year to year. I have measured growth increments to help determine if a tree is declining. All things being equal, trees of the same species will grow about the same year to year. So when I have one that is not growing at the typical rate I know something is out of sorts.This is easy to see on trees that have had changing access to water. In years when water is plentiful growth increments are normal, but in years when water is limited growth increments are diminished.

For more information on the dawn redwood check out www. metasequoia.org. For information on conifers in general check out the gymnosperm database at http://www.conifers.org.