Questioning Cloning

I'm standing below a spectacular redwood monarch. Photo by Ruskin Hartley.
I’m standing below a spectacular redwood monarch. Photo by Ruskin Hartley.

People are cloning the world’s oldest redwoods. Archangel Ancient Tree Archive is planting their clones en mass around the world in an effort to create robust forests of the future. They say these ancient clones will reverse deforestation across the planet and combat climate change in the process. These are lofty claims and they have me worried.

I’m an advocate of reforestation, but as a conservationist and scientist I question why redwoods, why clones, and why now? Global reforestation with redwoods sounds like a great idea on the surface. After all, redwoods have the potential to capture and store a tremendous amount of carbon dioxide (1) – the primary gas causing global warming. But nothing happens in a vacuum. Instead of forests with native trees, the redwood clones will create exotic plantations. Some wildlife, like birds, need their own native tree species to thrive (2) and creating alien forests will not restore the habitat they’ve lost.

Even in the natural redwood range, redwood plantations may be risky because clones may spread their gene copies into wild populations over time and therefore lower genetic diversity. Archangel plants only clones of the oldest redwoods because they view them as superior trees that have withstood the test of time. These ancient redwood monarchs thrived in a markedly differently world than the one redwood seedlings of today will face in the next millennium. Archangel assumes that a clone of the last ancient is better suited for the future than a young seedling with a new combination of genes. How presumptuous! The truth is we don’t know which is better suited for uncertain future conditions and it’s a gamble to pretend we do. Reducing genetic diversity just as the redwood forest faces one of their greatest ever challenges is short-sighted at best, and at worst poses significant risk for the future of the forest.

I think the smartest approach is to let genetic diversity remain high in our forests and let natural selection pick the best trees of tomorrow. So yes, the time is now to halt deforestation and support reforestation. And yes the redwoods can play a role. But so too do the oaks, and sycamore, and eucalyptus, and the rich variety of trees and forests around the planet that soak up carbon dioxide in their native forests and provide a rich and varied habitat for the world’s plants and animals, and inspirational places for all people to enjoy.

On this Arbor Day, let’s celebrate trees and think carefully about how we use them. What do you say?

(1) Sillett, S. C., Van Pelt, R., Koch, G. W., Ambrose, A. R., Carroll, A. L., Antoine, M. E., & Mifsud, B. M. (2010). Increasing wood production through old age in tall trees. Forest Ecology and Management259(5), 976-994.

(2) Ikin, K., Knight, E., Lindenmayer, D. B., Fischer, J., & Manning, A. D. (2012). The influence of native versus exotic streetscape vegetation on the spatial distribution of birds in suburbs and reserves. Diversity and Distributions.


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