244
H. DAITBENMIRE
eithtar ari ~ri~t’enw 111 riurnhc~ of tillerR or by tl thickening of the organs,
for prodiir*tivlty wan higher ( I ~ l a i w c M , 1 Wd).
On tho ( ! o l ~ ~ t i ~ I
l ’ b i i i iri f ;crorgirt fire rt.cJ~ictxl tho Biz<* of the vegetative
organs of hoth f’nqnakrrc. notaturn’ and C y &
dactybn, Etithough aa80oiates were not affected this way (Burton, 1944).
In the steppes of eastern Kansas early spring burning was found to
increase both the numbers and sizes of leaves of Andropogon awpan’us
and A . gerardi, with consequent increases in leaf area per plant of 64
and 23%, respectively (Aldous, 1934). The coverage of Sorghastrmm
nutans in western Minnesota was increased during the first (only) postburn season, but there were no consistent changes in the associated
Andropogm gerardi or 8tipa tipartea (Tester and Marshall, 1961). In
Wisconsin, fire waa observed to reduce the basal diameter of Andropogon gerardi and reduce the number of tillers of Poa pratensis (Curtie
and Partsch, 1948).
A fire sweeping through Heteropogon contortus grassland in Queensland, Australia, killed parts of the bunches, but then the basal area
was observed to increase markedly and exceed the bwal area of unburned grassland (Shaw, 1957). In southern Africa, either in wetter
regions or in places where the soil is coarse and moisture relatively more
available, basal area also was observed to increase after a fire, then
decline subsequently as litter accumulated (West, 1966). Only frequent
burning can maintain maximal basal area in moist habitats, but in
drier sites repeated burning thins the plant cover and promotes sheet
erosion, and in still drier areas fire allows annuals to replace perennials.
In the small bamboo Arudinaria tecta growing in North Carolina,
the height of new shoots produced in successive post-burn years
increased progressively, but population density declined at the same
time and eventually the plants died patchwise from disease (Hughes,
1957).
As litter accumulates after a burn, the vigor of grasses commonly
declines to a low level and remains there indefinitely. This decline may
involve size, general health, or flowering activity (see next section).
F. VITALITY (FLOWERING ACTIVITY)
Many species of grasses and forbs produce scanty seed crops year
after year if the communities remain undisturbed, but flower in great
profusion the first or second season after a fire (Biswell and Lemon,
1943). Others flower less after a burn, It is noteworthy that with one
exception (8orghastrum nutans). the species in which flowering has been
rcported to increase after fire differ from those which are adversely
affected if at all (Table 111). ThuR fire infiiicncc on the flowering activity
of grasses is more predictable than its effect on the size of shoot. The
H. DAITBENMIRE
eithtar ari ~ri~t’enw 111 riurnhc~ of tillerR or by tl thickening of the organs,
for prodiir*tivlty wan higher ( I ~ l a i w c M , 1 Wd).
On tho ( ! o l ~ ~ t i ~ I
l ’ b i i i iri f ;crorgirt fire rt.cJ~ictxl tho Biz<* of the vegetative
organs of hoth f’nqnakrrc. notaturn’ and C y &
dactybn, Etithough aa80oiates were not affected this way (Burton, 1944).
In the steppes of eastern Kansas early spring burning was found to
increase both the numbers and sizes of leaves of Andropogon awpan’us
and A . gerardi, with consequent increases in leaf area per plant of 64
and 23%, respectively (Aldous, 1934). The coverage of Sorghastrmm
nutans in western Minnesota was increased during the first (only) postburn season, but there were no consistent changes in the associated
Andropogm gerardi or 8tipa tipartea (Tester and Marshall, 1961). In
Wisconsin, fire waa observed to reduce the basal diameter of Andropogon gerardi and reduce the number of tillers of Poa pratensis (Curtie
and Partsch, 1948).
A fire sweeping through Heteropogon contortus grassland in Queensland, Australia, killed parts of the bunches, but then the basal area
was observed to increase markedly and exceed the bwal area of unburned grassland (Shaw, 1957). In southern Africa, either in wetter
regions or in places where the soil is coarse and moisture relatively more
available, basal area also was observed to increase after a fire, then
decline subsequently as litter accumulated (West, 1966). Only frequent
burning can maintain maximal basal area in moist habitats, but in
drier sites repeated burning thins the plant cover and promotes sheet
erosion, and in still drier areas fire allows annuals to replace perennials.
In the small bamboo Arudinaria tecta growing in North Carolina,
the height of new shoots produced in successive post-burn years
increased progressively, but population density declined at the same
time and eventually the plants died patchwise from disease (Hughes,
1957).
As litter accumulates after a burn, the vigor of grasses commonly
declines to a low level and remains there indefinitely. This decline may
involve size, general health, or flowering activity (see next section).
F. VITALITY (FLOWERING ACTIVITY)
Many species of grasses and forbs produce scanty seed crops year
after year if the communities remain undisturbed, but flower in great
profusion the first or second season after a fire (Biswell and Lemon,
1943). Others flower less after a burn, It is noteworthy that with one
exception (8orghastrum nutans). the species in which flowering has been
rcported to increase after fire differ from those which are adversely
affected if at all (Table 111). ThuR fire infiiicncc on the flowering activity
of grasses is more predictable than its effect on the size of shoot. The