By Ankush Bharadwaj on December 17, 2018
Tree Spotlight Series: Follow along as we learn about the fascinating trees that live among us. This series is in partnership with Rhee Lab in the Plant Biology Department of the Carnegie Institution for Science.
In 1941, Professor Shigeru Miki, a paleobotanist from Kyoto University came across tree fossil samples from at least 150 million years ago from what became central China. With no newer fossils, he decided this tree was extinct and named it Metasequoia for its properties resembling the sequoia tree.
Five years later, after hearing rumors of an unidentified tree growing in the dense forests of central China, Professors Wan Chun Cheng and Hu Xiansu made the connection between these trees and the Metasequoia thought to be extinct for millennia, sparking a craze to learn about this tree.
By 1948, universities and research institutions across the world had seeds of these trees, now called Metasequoia glyptostroboides, or the dawn redwood, and the world embarked on growth trials to investigate this hitherto extinct species.
The dawn redwood is a large, fast growing tree that can surpass 115 feet by the age of 50. The largest observed specimen passes even this at 165 feet tall, over 15 stories, and more than 7 feet wide.
The dawn redwood is a conifer, but unlike most conifers, it isn’t evergreen. Rather, the species is deciduous, shedding its leaves during the fall and winter, when the normally green leaves turn reddish orange and fall down. With tolerance to soggy soils and low temperatures, the dawn redwood is easy to grow in most temperate regions.
Since its discovery in China, there has been a rallying cry for the conservation of dawn redwood trees. While still an endangered species, the tree is stringently protected in China, where the main forest of dawn redwoods has dropped to only 540 trees, with smaller groups elsewhere in the world topping at 30 trees.
In China, some conservation efforts that rely on replanting the trees have also threatened the species. Since seed collection is a crucial aspect of conservation, many people partake in cone collecting from trees in their native range. As a result, existing forests don’t grow as many new trees as they should in their native habitat, contributing to the thinning of dawn redwood forests. However, while the forest may be getting smaller, the trees are still being planted throughout the world, so conservation efforts must be succeeding, right? Wrong.
Since the trees are re-planted individually, they must rely on self-fertilization to pollinate their cones, resulting in lower genetic diversity for the species and making them more prone to pests. Although the effort to preserve the dawn redwoods has succeeded in the nearly 80 years since its discovery, much needs to be accomplished to re-establish the forests.
Due to the tree’s recent discovery, many of its potential uses are still unknown and unexplored. Expeditions to the tree’s native habitat have shown that the species has been used by local farmers for rafts and houses, as well as myths from the river valley area where the trees are used to predict that season’s harvest based on the cones’ locations on the tree.
However, much about this tree is still unknown, especially since the dawn redwood is what is known as a living fossil, which means that the tree’s closest relatives are found only in fossils, shrouding the chemical properties and physical adaptations of the tree in further mystery. In the dawn redwood, we see a species that has survived from the time of the dinosaurs until the modern era, demonstrating the stalwart nature and strength of trees.
Ankush Bharadwaj is a 2018 summer intern at the Rhee Lab in the Plant Biology Department of the Carnegie Institution for Science. He is currently an undergraduate student majoring in Microbiology, Immunology, and Molecular Genetics at the University of California, Los Angeles. His hobbies include being outdoors, where he usually spends his time kayaking, hiking, or simply skateboarding around.