The Journeys of Trees by Zach St. George

I. Brief Summary

Zach St. George explores the slow migration of trees, as forests creep inch by inch to more hospitable places. A fascinating look at forest migration over time and with the effects of climate change, invasive species encroachment, and the conservation efforts to assist migration. Well-researched, and one of the better things I have read on how the natural world actually moves. In many ways it makes one feel better about the chances of the planet surviving climate change but then it also makes it seem very unlikely because of human experiments and interferences.

II. Big Ideas

• The central premise is that forests move. Every time a tree dies or a seedling takes root, the forest shifts. When seedlings keep landing in the same direction, the whole forest migrates over generations.
• Forests move. Every time a tree dies or a seedling takes root, the forest shifts. When seedlings keep landing in the same direction, the whole forest migrates over generations.
• The book is built around five tree species below in very different circumstances. St. George travels to each, reporting alongside the ecologists, foresters, and activists working on conservation's front lines.
  • Giant Sequoia in California – drought conditions will impact these giant groves
  • Ash – dying due to invasive emerald ash borer
  • Black Spruce – whose ancient migrations are read from Alaskan fossil records
  • Florida Torreya – rare dying conifer
  • Monterey Pine – domesticated and thriving as a plantation tree in New Zealand
• Modern obstacles are overwhelming these natural movements. Humans fell trees by the billions, global trade ferries invasive pests and diseases across oceans, and we've deforested and fragmented the land into “island” habitats too small and disconnected for forests to migrate through. Worst of all, the climate is now changing faster than forests can naturally keep pace with.
• He recaps other disasters accidentally caused by humans: the gypsy moth infestation, the chestnut blight, and the Dutch elm disease. Each has had long-lasting impacts on forests in the Northeast and beyond.
• He describes invasive pests as “biological pollution” and notes that globalization has increased their frequency and that climate change has made it easier for some harmful insects and diseases to thrive.
• The book's most provocative thread is assisted migration – humans deliberately relocating trees to help them survive.
• He profiles projects like Connie Barlow's Torreya Guardians, who plant Florida torreya across North America, and Sierra Pacific Industries' living seed bank of giant sequoias.
• The book investigates on genuine controversy and risk of assisted migration. Assisted migration is experimental and divides scientists: proponents say intervention is now necessary to prevent extinctions, while critics warn of unintended consequences — disrupting existing ecosystems, outcompeting natives, or introducing new pests.

III. Quotes

• Every species has the capacity to move from one place to another. The individuals of many species move around during their lifetime, migrating with the seasons, as birds do.
• More than any other living thing, trees define their surroundings. They break up the horizon, mark the trail, soften hard edges…. A tree is a rooted thing, so a tree is also a place.
• This is not gardening. I think assisted colonization should be strictly supervised by ecologists and conservationists. – Thomas Abeli
• The migration of a forest is communal, it's constant. It is accomplished over many generations ... It's a question of the species succeeding more in one part of its range, becoming more abundant in one part of its range, and less abundant in another part of its range.
• God has cared for these trees, saved them from drought, disease, avalanches, and a thousand storms,” Muir wrote. “But he cannot save them from sawmills and fools; this is left to the American people.
• If I can wax philosophical for a moment,” he said, “I’ve been coming by this particular sequoia for thirty-eight years . . . and it hasn’t changed. I think that’s a reason a lot of people come to see the sequoias. It seems like something permanent in this crazy world.
• The very goal of agriculture is to favor one thing over another.
• Rarity precedes extinction.
• The future is unwritten. You try to save as much of the natural world as you can. You don’t know which one will be crucial.
• The tap might be shut, but the faucet still drips.
• The equation of animal and vegetable life is too complicated a problem for human intelligence to solve.
• The only reason all our trees and plants are alive is because we have small parasitoid wasps and other natural enemies that are highly coevolved with their hosts.
• Things have gone wrong, badly and often... The worst disasters of biological control have come from creatures like carnivorous snails and mongooses.
• Life will continue, and new specialists will appear.
• When I see the old pictures of people standing beside big chestnut trees, my chest aches and I miss something I never experienced.
• The future is often stubbornly nonlinear.
• A man does not plant a tree for himself, he plants it for posterity.
• Trees are the best monuments that a man can erect to his own memory. They speak his praises without flattery, and they are blessings to children yet unborn.