Book Review of George E. Gruell's Fire in Sierra Nevada Forests

Review of George E. Gruell's Fire in Sierra Nevada Forests: A Photographic Interpretation of Ecological Change Since 1849
By Joan Zimmerman

Current hottest books on trees and forests. Books newly read.

Redwood prescribed burn pictures by David Auerbach.

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Photographic documentation of the Sierra Nevada ecosystem over 150 years "from the varied and generally open-canopy habitats of early European-American settlement days to the dense declining forests of today".

The most striking part of the book is the set of paired photographs, often taken a century or more apart, in a swath of the Sierra Nevada that is about 200 miles long and 80 miles wide, from Susanville in the north to a little south of a line from Visalia to Lone Pine in the south.

Problems due to over-zealous fire suppression

Because of the harsh conditions of the Sierra Nevada, especially near the tree line, trees may be stunted so that they appear more like shrubs.

Gruell's chapter "Cause for Concern" lists some of these many adverse results from lack of fire, which leads to thickening forest and shrub land cover:

• Deciduous vegetation: replaced by conifers, especially in riparian areas.
• Foraging areas (including shrub-field habitat): reduction through conversion to conifer thickets.
• Forest-threatening insects and disease: Increase.
• Fuel (dead materials) on the forest floor: Huge accumulation. Such materials can fuel catastrophic fires.
• Meadows: mountain meadows decrease under conifer encroachment. [Increasingly obvious in the Yosemite Valley, for example.]
• Nutrients from the soil: transported to and locked in woody material. [Obviously, harvesting removes these nutrients permanently from the forest. Fire, however, restores the nutrients to ash and thence to soil.]
• Under-story plants: decrease of desirables.

Natural Frequency of Forest Fire.

Gruell summarizes estimates of fire frequency writing "Studying of fire scars gives a conservative estimate of fire frequency".

Pre-1900 he estimates the average interval was 10-20 years.

Then he estimates fire frequency post-1900:

• 78 years for blue oak forest.
• 185 years for mixed conifer-pine.
• 1644 years for red fir.

Book Choice.

Sierra Nevada Tree Identifier.	My First Summer in the Sierra by John Muir.
	Sierra Nevada: The Naturalist's Companion by Verna R. Johnson. Published University of California Press.
The Ecology of Fire by Robert J. Whelan.	Fire in Sierra Nevada Forests: A Photographic Interpretation of Ecological Change Since 1849 by George E. Gruell.

Related pages.

• Home and List of Articles.
• By location in California:
  • Trees of the Sierra Nevada.
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  • Yosemite: John Muir on the Trees of Yosemite.
  • Yosemite's Trees.
• By species:
  • Conifer: How You Can Tell What Kind of Conifer You Have..
  • Oak.
  • Pines: Introducing Pines, How to Names Pines.
  • Giant Sequoia (Sequoiadendron giganteum).

Forest and Tree Home, Glossary pages: A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z.

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Copyright © 2006-2007 by Joan Zimmerman.