Today’s factismal: All navel orange trees are clones of the original tree.
If you have ever bitten into a juicy navel orange, you’ve probably wondered how they get new navel orange trees – after all, the fruit has no seeds. The answer is that they clone them! Though most people think of cloning as being a relatively new technology (and it is, for animals), we’ve been cloning plants for more than a thousand years. For plants like the navel orange, cloning is a simple as grafting a branch of the original plant onto a root from another plant. For example, grapes are frequently cloned by grafting a European stem onto an American root in order to combat an aphid that nearly destroyed the world’s wine-making in the 1800s. And many decorative plants like plumeria and roses are cloned in order to spread desirable colors or flower shapes.
But cloning offers more advantages than just allowing us to make lots of copies of a profitable fruit or keeping the world’s wine vats from running dry. Cloning also allows us to do a controlled experiment in climate! That’s because climate affects a large number of natural processes, from the time of the first bud to the flight of the last butterfly to the nesting of the fluffiest squirrel. All of those are influenced by rain and temperature. But they are also influenced by genetics; if the trees in a forest all burst into bloom a month earlier than the trees in another forest, is the difference because of the climate or because the trees are different? By planting clones of trees in both areas, we can control the influence of genetics and know that it is a climate signal that we see.
And that’s what one of the longest-running experiments ever is doing. Started back in 1956 with 2,500 volunteers, the Cloned Plants Project now has more than 6,000 volunteers who have planted lilacs and dogwoods to measure the changes in climate over the entire continental United States. Participation is simple: you buy a cloned lilac or dogwood, you watch to see when it blooms, buds, or drops its leaves, you tell the Cloned Plant Project, you sit back in the glow of doing some simple and fun science (and give the flowers to your friends so you can brag about it!). If you’d like to take part in the project, head over to: