21 2
R. DAUBENMIRE
its writing. Nor could the opinions weembled by Rosevear be backed
with quantitative data.
This negative attitude toward grass burning prevailed during the
first third of our century, but then as quantitative data began to
accumulate, it slowly became clear that fire is not always detrimental,
and that under the right circumstances desirable effects can be maximized with undesirable influences prevented or at least kept to m
innocuous level.
Not only does grassland burning have a different and somewhat leaser
significance than forest burning, and so was ignored for a longer period,
but the problems here have some distinctive facets so that the results
of forest fire research are not directly applicable to grasslands. Whereas
most trees are killed by fire, most herbs are adapted to survive, for less
fuel is available and so less heat is generated when herb cover is consumed by fire; and too, the perennating buds or seeds lie just at or
below the ground surface where the temperature remains relatively low.
Since the material consumed is mostly already dead and in any event
contains but little supporting tiesue, there is much less wastage of
energy to the plant when the evanescent shoot of an herb burns in comparison with a tree, whose messive perennial stem system is killed,
even should its root remain alive. Not only does fbe put herbaceous
plants at less of a direct disadvantage in this way, but with a lower
intensity of heat the soil is leas modified. And finally, the relatively
short time required for herbaceous plants to redevelop normal shoots
minimizes the period when lack of ground cover allows special microclimatic conditions to prevail.
A collation of the literature is not only desirable because graas burning differs generically from forest burning, but because the effede of
grass fires are so very different from o m climatio region to another.
11. THE MEASUREMENT G B TEMPERATURES DUBINU
VEUETATION FIRES
Temperatures during grass fires have usually been measured by either
of two claaaes of apparatus. One of these involves setting out a comparative series of heat -sensitive materials with different reaction pointe,
these being &the form of paints applied as stripes on mica plrttes or
aluminum strips (Fenner and Bentley, 1960; Hopkins, 1965; Whittaker,
1961), heat-sensitive crayons (Miller et al., 1966), metal ribbons (Nelson
and Sims, 1934), slender glass tubes containing organic compounds
(Beadle, 1940), or especially manufactured pellets (Silen, 1966). Some
limitations of this technique are that a wide variety of units with different temperature sensitivities must be used simultaneously a t each
R. DAUBENMIRE
its writing. Nor could the opinions weembled by Rosevear be backed
with quantitative data.
This negative attitude toward grass burning prevailed during the
first third of our century, but then as quantitative data began to
accumulate, it slowly became clear that fire is not always detrimental,
and that under the right circumstances desirable effects can be maximized with undesirable influences prevented or at least kept to m
innocuous level.
Not only does grassland burning have a different and somewhat leaser
significance than forest burning, and so was ignored for a longer period,
but the problems here have some distinctive facets so that the results
of forest fire research are not directly applicable to grasslands. Whereas
most trees are killed by fire, most herbs are adapted to survive, for less
fuel is available and so less heat is generated when herb cover is consumed by fire; and too, the perennating buds or seeds lie just at or
below the ground surface where the temperature remains relatively low.
Since the material consumed is mostly already dead and in any event
contains but little supporting tiesue, there is much less wastage of
energy to the plant when the evanescent shoot of an herb burns in comparison with a tree, whose messive perennial stem system is killed,
even should its root remain alive. Not only does fbe put herbaceous
plants at less of a direct disadvantage in this way, but with a lower
intensity of heat the soil is leas modified. And finally, the relatively
short time required for herbaceous plants to redevelop normal shoots
minimizes the period when lack of ground cover allows special microclimatic conditions to prevail.
A collation of the literature is not only desirable because graas burning differs generically from forest burning, but because the effede of
grass fires are so very different from o m climatio region to another.
11. THE MEASUREMENT G B TEMPERATURES DUBINU
VEUETATION FIRES
Temperatures during grass fires have usually been measured by either
of two claaaes of apparatus. One of these involves setting out a comparative series of heat -sensitive materials with different reaction pointe,
these being &the form of paints applied as stripes on mica plrttes or
aluminum strips (Fenner and Bentley, 1960; Hopkins, 1965; Whittaker,
1961), heat-sensitive crayons (Miller et al., 1966), metal ribbons (Nelson
and Sims, 1934), slender glass tubes containing organic compounds
(Beadle, 1940), or especially manufactured pellets (Silen, 1966). Some
limitations of this technique are that a wide variety of units with different temperature sensitivities must be used simultaneously a t each