Abstract

Shigo, A. A. 1986. Journey to the center of a tree. Am. Forests 92 (6): 18-22, 46-47

Trees are so common that we often forget how extraordinary they really are. They live on all continents except Anarctica and in an astonishing variety of environments, from tropical to subarctic, rainforest to desert fringe. How have trees been able to survive and thrive? The answers lie within that tree out your window. As we journey to the center of that tree—or any tree—we’ll find that the answers lie more specifically in the structural properties and growth processes of a tree. You’ll also see that a better understanding of these can have practical applications, such as helping you prune your trees to their advantage and prevent unnecessary wounds. But a journey to the center of a tree will require you to visualize and think about trees in a way that you probably never have before. Trees can adapt to changes in the environment, when change occurs too quickly, they may not be able to respond fast enough. Two species, American chestnut and American elm, were driven to near extinction when people imported other species of chestnut and elm infected with diseases that indigenous trees were not adapted to resist. A journey to the center of these trees would have revealed that they were not able to compartmentalize quickly enough to fight off the unexpected foreign invaders. Our journey has shown us that trees are far more complex than what appears when we look out our window. We have also found that trees rely on structures and processes that no other organisms possess. Perhaps this is how they have survived all these eons and have watched dinosaurs come and go.