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Notes on Robert J. Whelan's
The Ecology of Fire

Notes on by Robert J. Whelan's The Ecology of Fire
By J. Zimmerman

Overview

Examines how fire, particularly wildfire, affects animal and plant populations as individual organisms and as populations and communities. Includes:

Emphasizes general ecological principles.

Sections of Robert J. Whelan's The Ecology of Fire.

  1. Fire ecology – an introduction.
    Definitions.

  2. Fire – the phenomenon.
    p. 12, Table 2.1 shows total heat of combusion for various forest fuels, including:

    Fuel type Heat of combustion (MJ/kg)
    Acacia melanoxylon woods 18.9
    Oak woods 19.3
    Eucalyptus woods 19.2-21.3 (varies with species).
    Pine woods 21.3
    Pine sawdust 21.7
    Pine pitch 35.1
    Eucalyptus oil 37.2

    The average maximum temperature of headfires in grasslands increases with biomass, by roughly 300°C for 7000 kg/ha, or 40°C for each 1000 kg/ha. [extrapolating from Texas data in Figure 2.10 on p.31].

    The scorch height on the vegetation increases with the two-thirds power of the fireline intensity (or effective radiation temperature of the fire front). [Figure 2.14 on p.40].

    p. 53, Table 2.3 summarizes the range of fire cycles in various ecosystems. This is a subset:

    Biome/ecosystem Fire frequency (years)
    Prairie (Missouri) 1
    Dry temperate mixed conifer (California) 7-100
    Moist evergreen scrub (Florida) 20-30
    Evergreen chaparral (California) 20-50
    Deciduous chaparral (California) 30-100
    Tundra (Alaska, Canada) 500

  3. Survival of individual organisms.

    p. 60, Table 3.2 summarizes the semi-logarithmic relationship between temperature experienced and time to cause death, and the variation by a factor of 100 or more among species exposed to the same temperature.

    p. 91, Figure 3.16 shows the increase of size of tree rings in the years following a fire, presumably because of the increased availability of sunlight to a surviving tree.

    p. 123, Figure 3.25 shows the spread in timing of seed germination.

  4. Approaches to population studies.

    Shows how population change can be assessed.

  5. Plant populations.

    p. 189, Figure 5.21 shows the decrease of tree biomass with density. Thus, the less dense the trees, not only the bigger are the individual trees, but the bigger the overall biomass.

  6. Animal populations.

    This section studies mortality and rate of return after a fire.

    p. 226, Figure 6.11 shows the mass of kites feeding on insects fleeing a fire front in the east African savanna.

  7. Community responses to fire.

    p. 249, Table 7.2 shows the relative susceptibility of North American Pacific north-west conifers:

    Level of resistance Tree
    Highest Western larch.
    High Ponderosa pine; Douglas fir.
    Medium Grand fir; Lodgepole pine; Western white pine.
    Low Western red cedar; Western red hemlock; Noble fir.
    Very low Subalpine fir; Pacific silver fir.

  8. Fire and management.

  9. References.
    35 pages, showing the phenomenal scholarship behind this book.

  10. Index.
    2 pages.

Book Choice.

Sierra Nevada Tree Identifier. My First Summer in the Sierra
by John Muir.
Buy Sierra Nevada: The Naturalist's Companion 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.


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