Book Review

In Fire in Sierra Nevada Forests, George E. Gruell uses rephotography to demonstrate how more than a century of fire suppression has led to the deterioration of forests throughout the Sierra Nevada. He presents eighty-four sets of paired photographs, one of each set taken before 1920 (but ranging as far back as 1849), the other taken from the same location during the early 1990s. Gruell mixes photographic evidence of forest composition and density with modern field observations to document drastic transformations in mountain landscapes. Gruell concludes that Sierra Nevada forests have grown more dense and the canopy more complete and less healthy. This increase in density can be misleading. "It is hard to shake the intuitive sense that when it comes to forest, denser is better," Gruell explains. "Our purpose here is to educate our instincts, discovering what is healthier for the ecosystem as a whole" (p.1). Today's forests are more prone to disease, insect infestation, and fires of catastrophic intensity than those photographed by Gruell's predecessors.	1
The book has four sections, each devoted to one of the Sierra Nevada's major forest ecosystems: oak/pine woodlands and mixed-conifers on the western slopes, eastern-slope pine forests, and the red fir/lodgepole pines of the highest elevations. Captions describing the scene and forest composition, and highlighting changes, accompany each rephotographic set. In the conclusion, Gruell briefly considers agents of change like mining and logging, ultimately determining that fire suppression by Euroamerican settlers and forest managers has altered mountain forests most significantly. Throughout his commentary, Gruell focuses on the physical changes in the landscape, not social or scientific explanations for these transformations or motivations for fire suppression. Gruell bases his summary discussions more on current silvicultural research than on the photographic evidence that he has collected. The images therefore serve to illustrate forest transformation rather than to explain it.	2
Some of the photographs are strangely chosen. As Gruell himself points out, necessity dictated his selection, depending on the quality of early images and his ability to determine precise locations for modern re-takes. The photographs therefore do not represent either a random or systematic sample of forest ecosystems. And it is hard to see why Gruell included some of the photographs at all. For example, plate 53a shows an 1876 view of Spooner Summit, site of a heavy logging operation and a depiction of far more cut and processed timber than standing forest. The accompanying 1992 image certainly shows an increase in tree density, but it is hard to see how this image helps explain the role of fire in forest change. Also, Gruell's application of rephotographic evidence relies entirely on description, not quantification. And while the increase in density or canopy cover is usually clear, at times comments like "This repeat photograph shows a marked increase in tree cover" seem unsubstantiated (p.191).	3
Gruell accomplishes his modest goals in this rephotographic collection. He provides historians and foresters alike with a powerful tool for visualizing and comprehending the changing forests of the Sierra Nevada.	4
James Feldman, University of Wisconsin-Madison.

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