Living fossil returns home

I first saw dawn redwoods (Metasequoia glyptostroboides) in 1995 when I was taking a course in identifying trees at the Arnold Arboretum. Entering the arboretum’s main gate, visitors come upon a grove of these magical trees growing beside a stream. When I had a chance to plant new trees two years later, there was no question but this would be one of them.

Dawn redwood in May, Willow Pond, Mt. Auburn Cemetery

    This species has an intriguing history. It was found in fossils dating back 165 million years to the Mesozoic era but was thought to have gone extinct at least 5 million years ago. In the early 1940s, Chinese scientists found living specimens in a remote area in Sichuan and Hubei provinces in southwest China. They communicated with colleagues in the U.S. and sent seeds to the Arnold Arboretum, whose director at the time, E.D. Merrill, distributed them to botanical gardens and arboreta around the world. These seeds grew readily in a wide range of conditions, and dawn redwoods became popular ornamental trees.

Dawn redwoods in fall at Wisley Gardens, Surrey-ukgardenphotos

    The stand of trees discovered in the 1940s, revered locally under the name of “water fir,” is now down to about 5,000 trees, having lost ground to conversion of the area to rice paddies. Fully grown trees can live to 265 years, reach trunk diameters of 7 feet, and grow as tall as 165 feet. The trees are legally protected, but all the cones are scooped up by people who want to try growing their own dawn redwoods. There’s no sign that the mature trees are reproducing anymore, so the international diaspora may be the only hope for survival of the species.

    Our dawn redwood came to us at about five feet tall. It’s since grown to at least forty feet high with a trunk 16 inches wide. The trunk is already showing the distinctive buttressing that gives the species some of its fairytale quality. 

Our dawn redwood has grown fast

The ferny leaves are soft, not like most waxy conifer needles. They begin the year a bright lime green and turn a rusty orange in fall before falling.

Soft, ferny leaves

    Dawn redwood is one of the few deciduous conifers, a group that includes bald cypress (Taxodium distichum), larch (Larix spp), and golden larch (Pseudolarix amabilis). 

Golden larch about to shed its leaves

Why deciduous? Apparently dawn redwoods grew so far north in Canada during a warm period in the earth’s history that they experienced polar light conditions: three months of unceasing sun in summer and total darkness in winter. They adapted by evolving from evergreen to deciduous.

Dawn redwood at Arnold Arboretum in winter-photo Glasser

    I like knowing that this tree was once common in my area—back when the dinosaurs roamed the earth, literally. This points out the complexity of defining native plants. Enthusiasts usually think of natives as plants that grew in North America before European settlement. But the moment Europeans set foot on our soil with foreign seeds stuck to their shoes is only a brief snapshot in the botanical history of the continent. I can rightly say that by planting a dawn redwood, I reintroduced a New England native.