The world is losing its giants. Nature's largest representatives are being killed, but a small group of scientists and activists are not going to let this happen without a fight, and have established a grove they hope will bring back trees larger than any surviving today.
One of the symptoms of living through the Earth's sixth mass extinction is the loss of really large trees. Sometimes the cause is as obvious as felling for timber and cardboard. In other cases, giants are dying for reasons as yet unknown.
To fight this trend, conservationists collected DNA from five of the largest trees of recent times, cloned them, and planted the saplings in a San Francisco park.
Today the tallest tree in the world is the Hyperion, 116 meters (379 feet) high. However, the largest known single-stem tree is General Sherman, which combines a height of 84 meters (275 feet) with a diameter of 7.7 meters (25 feet). Both are giant sequoias, also known as redwoods.
We can still find the stumps of even mightier trees, testimony to a century of wanton destruction. One example is the Fieldbrook stump, which New York Times environmental science writer Jim Robbins said “is all that remains of one of the largest coast redwoods that ever lived. It’s almost 33 feet [10 meters] across… without the bark, which would have added another 2 feet [0.6 meters] to the width.”
The size a tree reaches reflects in part its location and a certain amount of luck, but you don't get to an age of 3,000 and an estimated 121 meters (400 feet) tall, as the Fieldbrook did, without excellent genes. Deciding these were worth preserving, representatives of the Archangel Ancient Tree Archive (AATA) collected DNA from the Fieldbrook and four other stumps, all wider than General Sherman, and produced sapling clones from each.
Redwoods sometimes self-clone in the wild through bumps on their trunks known as burls, producing fairy rings of genetically identical products from a single parent tree. Replicating the process in the lab proved challenging, and it took 2.5 years for the clones to grow to the size where they were ready for planting.
On December 14, 75 of these tiny trees were planted in Presidio Park in the hope they will one day form a “super grove”, and a living library of outstanding redwood DNA. Tall trees often grow best in groves because they shield each other from storms. Redwoods take thousands of years to reach their full height, so no one living will know if the project achieves its goals, but the AATA notes a single mature giant sequoia can sequester 250 tonnes of carbon dioxide a year.
As the proverb says; “Wise people plant trees under whose shade they will never sit.”
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