Stalking the Elusive Tanoak

tanoak acorns

Two weekends ago, I went on an urban hike through the Washington Park Arboretum in Seattle across highway 520 from the University of Washington. We went in search of a tanoak, a tree I’d been reading about in Frederica Bowcutt’s new book, The Tanoak. We found a barred owl on a low branch and a Douglas-fir that had been spectacularly struck by lightening in March, but the tanoak proved elusive. Our friends had to go on to other engagements but we stuck it out and, following directions from the visitor’s center, wound our way to the south end of the park to the “Pacific Connections” area where we eventually found a scrubby tree loaded with acorns – once a major food source for native Americans in California and southwestern Oregon.

In her book, The Tanoak Tree: An Environmental History of A Pacific Coast Hardwood recently published by University of Washington Press, botanist Frederica Bowcutt draws on two decades of research to demonstrate the importance of this underappreciated hardwood tree. She not only offers the kinds of details that make history fascinating (the tannins in acorns are effective as a cough suppressant, for example, who knew?!), but also addresses larger questions such as how western science and native ecological knowledge might work together to save promote human health and landscapes that are sustainable, beautiful, and productive.

The book is generously illustrated with photos and figures, from Bowcutt’s own 1995 shot of tanoak chips hauled away on a truck to be sold for $125/ton to an image showcasing the clean lines of a handsome rocker made from tanoak to a mid-twentieth century ad grimly urging factory owners to mechanize so they “don’t have to pay the man who isn’t there.” On page 25, the nutritional content of acorns is compared to wheat and barley. Forest managers, loggers, European peasants, Native American protesters, and cooks all make an appearance as the author takes the reader through chapters covering different parts of the tanoak and perspectives on how it has been used/viewed by humans: aesthetics, acorns, bark, weed, hardwood, plague, landscapes, and conservation.

In The Tanoak, one learns of the complicated effects on workers when a local renewable resource (bark from tanoak) becomes obsolete as it is replaced by a non-renewable resource (chromium salts). One also finds that different purposes for leather informed the tanning processes and the quality of leather produced. Native Americans used animal brains and other animal parts to process skins to make soft leather chamois; Spanish cattlemen made a heavy-duty grade of leather for their saddles, first using tanoak bark and then chemicals.

Bowcutt explores in depth the complicated history of how tanoaks have been used. Scattered stands of trees, such as the pattern favored by Tanoaks, are more difficult and costly to harvest for timber. Furthermore, Tanoak was not as suitable for railroad ties – the leading use of wood in the late nineteenth century – as eastern hardwoods and redwood. By the mid-twentieth century, Tanoaks were treated with herbicides to favor the cultivation of quicker growing trees such as Douglas-fir or Redwood which were used for timber in the post-war building boom (with less expensive lumber, by 2013 house sizes more than doubled from the average of 983 square feet in 1950).

Over the course of two hundred years, the Tanoak went from being an important source of food for native populations to becoming an important commodity in the early twentieth century leather trade to being considered a “trash tree” that competed with the more commercially lucrative Redwood and Douglas Fir. The author demonstrates the caloric and nutritive value of acorns as tested in recent scientific research against the continued bias against supposedly “wild” indigenous foods. In fact, native peoples did not simply gather acorns at random but cultivated the best varieties and stands through selective thinning of trees and low intensity burns. Tanoak acorns fed native populations in California and southern Oregon for thousands of years before the settlement of western North America by Europeans.

By the end of this book, the reader is convinced of the significance of this little-known tree. In this densely packed history of Notholithocarpus densiflorus, Bowcutt restores the Tanoak to a central place in the history of human/nature interactions. She offers realistic interventions to address the Tanoak’s decline in the face of wasteful forestry practices, and now, as it faces danger from an imported pathogen, Phytophthora ramorum, the cause of sudden oak death. Western scientific research, Native American management practices, better government regulation of nursey trade (the origin of the current sudden oak death epidemic), and a deeper understanding of the Tanoak’s varied history will go far in holding out hope for preserving this useful and beautiful tree. Of special interest to environmental historians and forestry managers, this book is also rich in insights for the general reader.