Tree Story: The History of the World Written in Rings

When you hear the word dendrochronology, what comes to mind? Perhaps a varnished cross-section of some long-dead giant tree, with colored arrows pointing to the rings that mark events in human history. Probably not an adventure story that ranges from a Stradivari violin worth $20 million to sunspots and climate, the fall of ancient Rome, and Genghis Khan’s improbable conquest of central Asia to the connection between pirates and hurricanes and how the path of the jet stream affects the rain that falls on your yard.

Valerie Trouet’s compulsively readable account of her research in dendrochronology weaves together all of these topics. It’s spiced with the travels that have taken her from the shores of Lake Tanganyika in sub-Saharan Africa to the Sierra Nevada range in California, and from the mountains of Greece–where she and her colleagues discovered the oldest living tree in Europe, over 1,075 years in age–to the treeless Sonoran Desert of Arizona where the Belgian-born scientist is now based.

Trouet is a born adventurer, and she’s also honest. At the beginning of the book, she tells the story of how she got into the scientific field with the tongue-twisting name: “Few scientists in our field dreamt of growing up to be dendrochronologists. Dendrochronology careers, like mine, start randomly, with serendipitous undergraduate or graduate field- or lab-based opportunities that morph over time into full-fledged careers.” In Trouet’s case, her introduction to tree-ring research came after her classmates at Ghent University in Belgium had already spoken for the most interesting study opportunities, “especially those involving travel and research abroad.” A professor suggests studying tree rings in Tanzania, and even though Trouet confesses she had never even heard of dendrochronology, she says yes, because she badly wants to go to the developing world.

Just getting to the field site, located 750 miles west of Dar es Salaam (the airport they flew into), with her fellow student and their equipment turns out to be an epic adventure. Their plane is 20 hours late and heavy rains have wiped out a crucial railroad bridge, turning what had been 36-hour train ride to the shores of Lake Tanganyika into a three-day bus ride just to get to the train. And then, when they finally board the train and turn to take in the view, one of their backpacks–the one with their field equipment–is stolen. “This was when I learned the first rule of fieldwork: always make a plan but always be prepared to change it.” That would be the understatement of the year!

Undaunted, Trouet and her colleague figure out how to sample trees without their tools, and six months later, when the heavy bags of wood samples they shipped back to Belgium finally arrive, the two became the first researchers to demonstrate that tree-ring sampling is possible in Tanzania. They are even able to reconstruct a few decades of climate history from their samples, the first for that part of Africa.

As for the pirates and hurricanes, and what tree rings say about the course of human history and the perils of climate change, you’ll have to read the book. Trouet is the rare scientist who tells a rollicking good story, one that will enlarge readers’ view of the world and our understanding of what trees have to teach us.