ECOLOGY OF FIRE IN BRASSLANDS
255
and N content of eubsoquent new grass shoote (Ma, 1968), but mowed
veld here may produce 8 times as much forage as burned veld (Botha,
1946). Such results as the above led Staples (1946) to generalize that in
southern Africa mowing produces all the desirable effects of burning,
without having any of the undairable effects of the latter. Scott (1951)
however, points out that while mowing may be superior to fire in most
respects, fire is necessary in alternate years to prevent the invasion of
woody plants in South African grasslands.
Burning Trachypogon savanna in Venezuela in November increased
shoot production and plant height more than did clipping on the same
date, whereas the same treatments repeated during the wet season
produced a reversed effect (Blydenstein, 1963). The rate of leaf growth
is slowed by either burning or close clipping, but following clipping at a
height of 16 cm growth was almost twice as fast as on burned areas,
this being equally true if the clippinga were removed or left in place
(Blydenstein, 1962).
Responses to burning and to mowing were found to be the same in
ChionochIoa rigida grassland in New Zealand (O’Connor and Powell,
1963).
In E d y @ t u - H e t e r q o g o n contorttu savanna of northern Australia
burning and mowing have markedly different effects of species oomposition (Shaw, 1957). In a nearby part of this continent, studies where
the savanna grasses chry8opogon, Sorghum, and Tiremeda dominated
showed that crude protein is increaaed by either clipping or burning
(Smith, 1960).
The fact that a fire in Wisconsin had slightly more effect than clipping
regards increasing the numbers of flowering stems of Andrqogon
gerdrdi led Curtis and Partsch (1950) to suspect that direct heat from
the fire may have had a small stimulative influence. However, Ehrenreich and Aikman (1957), pointed out that fire increases the number
of flowering culms in Iowa gramlands with similar species composition
even when the burning occurs while the soil is frozen, so direct stimulation is unlikely.
Nearly all studies on the effects of burning on Andropoqm grasslands
in the eastern part of the mid-continental grasslands of North America
are in accord in showing that fire markedly increases production in the
first post-burn season, but within 2 to 3 years vigor has declined to the
pm-burn level. In this context some results obtained in Oklahoma by
close mowing in winter and removing the cuttings are surprising (Penfound, 1964). Although productivity and flowering increased conspicuously the next year, as on a burn, and likewise showed small
stimulation the second summer, production dropped below normal the
third year, and on the fourth year was scarcely half as much as in the
255
and N content of eubsoquent new grass shoote (Ma, 1968), but mowed
veld here may produce 8 times as much forage as burned veld (Botha,
1946). Such results as the above led Staples (1946) to generalize that in
southern Africa mowing produces all the desirable effects of burning,
without having any of the undairable effects of the latter. Scott (1951)
however, points out that while mowing may be superior to fire in most
respects, fire is necessary in alternate years to prevent the invasion of
woody plants in South African grasslands.
Burning Trachypogon savanna in Venezuela in November increased
shoot production and plant height more than did clipping on the same
date, whereas the same treatments repeated during the wet season
produced a reversed effect (Blydenstein, 1963). The rate of leaf growth
is slowed by either burning or close clipping, but following clipping at a
height of 16 cm growth was almost twice as fast as on burned areas,
this being equally true if the clippinga were removed or left in place
(Blydenstein, 1962).
Responses to burning and to mowing were found to be the same in
ChionochIoa rigida grassland in New Zealand (O’Connor and Powell,
1963).
In E d y @ t u - H e t e r q o g o n contorttu savanna of northern Australia
burning and mowing have markedly different effects of species oomposition (Shaw, 1957). In a nearby part of this continent, studies where
the savanna grasses chry8opogon, Sorghum, and Tiremeda dominated
showed that crude protein is increaaed by either clipping or burning
(Smith, 1960).
The fact that a fire in Wisconsin had slightly more effect than clipping
regards increasing the numbers of flowering stems of Andrqogon
gerdrdi led Curtis and Partsch (1950) to suspect that direct heat from
the fire may have had a small stimulative influence. However, Ehrenreich and Aikman (1957), pointed out that fire increases the number
of flowering culms in Iowa gramlands with similar species composition
even when the burning occurs while the soil is frozen, so direct stimulation is unlikely.
Nearly all studies on the effects of burning on Andropoqm grasslands
in the eastern part of the mid-continental grasslands of North America
are in accord in showing that fire markedly increases production in the
first post-burn season, but within 2 to 3 years vigor has declined to the
pm-burn level. In this context some results obtained in Oklahoma by
close mowing in winter and removing the cuttings are surprising (Penfound, 1964). Although productivity and flowering increased conspicuously the next year, as on a burn, and likewise showed small
stimulation the second summer, production dropped below normal the
third year, and on the fourth year was scarcely half as much as in the