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.