Author: Zach St. George • Published by W.W. Norton
Trees cover about thirty percent of land on Earth. Their ability to enrich the soil and filter the air provides us not only food and clean water, but shelter and shade, as well as, amusement for those who dare to climb up them. We make fuel, furniture, paper, and many other products from their wood. We find rest from our everyday distractions when we walk amongst them, and through many myths and fairy tales we have come to see them as magical beings, as well as, symbols of strength and wisdom.
Trees pull at us in ways that other plants don’t. I am thinking of the giant sycamore in my backyard that shapes my childhood memories or the majestic redwoods that mesmerize countless visitors every year. We assume that trees have always been and will always be, but reading The Journeys of Trees explains to us that trees are restless and have survived by random chance. Author Zach St. George writes,
“The migration of a forest is just many trees sprouting in the same direction. Through the fossils that ancient forests left behind, scientists can track their movements over the eons. They shuffle back and forth across continents, sometimes following the same route more than once, like migrating birds or whales.”
How did trees get to be where they are, and what might their fate be as climate change continues to accelerate at unprecedented levels? What does the future of forest conservation look like in the lens of past, sometimes misguided practices? These are the types of questions the book explores through the author’s use of science writing and travel anecdotes from around the country and overseas.
Species of trees make their "journey tree by tree."
“For individuals alike and species alike, life was chaotic, competitive, and often fleeting.”
How do some tree species find themselves in areas with conditions that don’t suit them? Why do some areas with similar climates have similar species, but other areas with also similar climates have few species? Is it due to competition and the removal of one species over another, or simply a delayed arrival? St. George explores five species in the book and focuses first on the sequoia. These gentle giants used to cover North America, but are now reduced to about seventy groves in California. Perhaps the sequoia after eons of migration has finally journeyed to the last place where the climate, soil, and precipitation suits its particular needs. If we go about saving this tree, how do we do so?
“More than any other living thing, trees define their surroundings. They break up the horizon, mark the trail, soften hard edges. You can pick them out one by one, a single thread, or as a texture, the whole cloth. Entire scenes can be conjured by the presence or absence of trees: the forest; the field; the house on the corner with the maple in the yard. A tree is a rooted thing, so a tree is also a place.”
Trees are indicators of climate change.
“At present, the climate is changing far faster than it ever has in the past…it can be hard for a person living through this transformation to judge what is normal, what is abnormal, and what is wholly new.”
Scientists of the past have disagreed about how Earth has changed when looking at the fossil record. French naturalist Georges Cuvier’s theory of catastrophe proposed that now extinct species are due to worldwide flooding whereas geologist Charles Lyell’s uniformitarianism theory suggests that the arrangement of species is due to climate change occurring over a gradual period of time from the shifting arrangement of continents and oceans. Indeed, according to the fossil record, the giant sequoia and its ancestors had a wide range extending deep into the Arctic, but today one finds various species of spruce in its place. Perhaps the spruce had become better adapted to the changing climate, or perhaps they were simply delayed in their arrival.
Humans throughout history have shifted the landscape, often with dramatic consequences.
“The very goal of agriculture is to favor one thing over another.”
From the Egyptians to the Romans, many cultures and groups of people have altered their natural surroundings and set in motion outcomes they could neither predict nor control. When civilizations became more agriculturally-focused, turning from hunter-gatherers to farmer-gardeners, these societies purposefully created a monoculture by planting certain species over others. Sometimes the motives were unintentional but devastating all the same, such as when French scientist Étienne Léopold Trouvelot brought in gypsy moths as a means to build a silk industry in the U.S. The moths escaped from his home in Massachusetts damaging many trees and spread quickly throughout New England into the Mid-Atlantic region and beyond. Similarly, as international trade grew in the early 2000s, the emerald ash borer found its way to America’s shores and quickly desiccated groves of ash trees. The damage done by the exotic beetle had far-reaching effects. Gaps in the forests allowed invasive shrubs room to grow wreaking more havoc on the native ecosystem.
Saving vulnerable species gets murky.
“There are too many variables: physical conditions, competition, or delayed arrival means we cannot predict how a species will succeed.”
Trees migrate with the climate, but the present climate is going so fast that many trees are struggling to keep up. Do we help a tree species move by planting their seeds to a more suitable climate? Do we employ biological controls such as when scientists released wasps to kill the emerald ash borer’s larvae in the hopes it would eradicate the introduced species? Do we develop new species such as blight-resistant trees that can tolerate potential pests? Whether it’s assisted migration, biological controls, or assisted evolution, the outcomes for all are unknown and cannot be predicted. Introducing new species always has the risk to potentially threaten the arrangement of others. By saving one, we may endanger another. But, if we take no action, we risk losing valuable species. It is a moral dilemma that is at the heart of this book.
St. George has artfully woven together a narrative that yes, provides clear insight on the gravity of any action/inaction to saving trees, but I also come away with a deeper sense of wonder for these magnificent beings and their long, long journeys to find a home.
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