Tuesday, November 26, 2013

Actually, This Book Can’t Save the Planet

The most prominent endorsement on the cover of Jim Robbins’s The Man Who Planted Trees reads, “This book just might save the planet.” I regret to report that this is not true, despite the book’s interesting and valuable material.

One important premise of the book is quite credible, though unproven. Vast acreages of forests, in America and around the world, have been cut down. Lumber corporations aimed for the biggest and healthiest trees, leaving the runts behind. The perhaps predictable result was that, when the forests began to grow back (which many are, as timber corporations never fail to remind us), the runts were the seed sources. The trees that had the genes that were best for survival were eliminated by this act of unconscious artificial selection. Because of this, the heroes of Robbins’s book are trying to clone “champion trees” from around the world and replant them, to reintroduce good genes into a possibly degenerate gene pool. Of course, this cannot always be true; sometimes big trees were spared because they were remote (as was the case with the dawn redwood Metasequoia glyptostroboides), and sometimes because they were saved in time by popular support (as with the giant sequoia Sequoiadendron giganteum). But I cannot deny the appeal of this hypothesis. I am also fascinated by the suggestion that cloned cuttings pass on some of the epigenetic changes that have accumulated in the adult tree, while seedlings will not. These epigenetic changes may include an improved ability to tolerate heat or pollution or herbivores.

Much of the book is also devoted to a survey of the immense and largely invisible things that trees do to keep the Earth alive. This overview is delightful to read but suffers from two problems. First, the science behind much of it is skimpy. In this way it compares poorly to my book Green Planet: How Plants Keep the Earth Alive, which is still available from Rutgers University Press and on Amazon (in a new paperback edition). Second, many of the processes the book describes are almost certain to be wrong. I do not think that trees emit volatile chemicals to heal the ecosystem and make humans healthy (they do it to stabilize their photosynthesis at high temperatures). I do not think that trees respond to cosmic radiation. I do not think that their electric potential completes a circuit that maintains the Earth’s magnetic field. You know that when an author approvingly cites The Secret Life of Plants, as Robbins does, something is scientifically amiss.

Still, it was nice to read a book about a man whose passion was altruism rather than violence or selfishness.

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