242
R. DAUBENMIRE
c. MOISTURE CONTENT
In several widely scattered locations the tissue moisture content of
the new shoots on burned s i t e has been determined and found to be
higher than on nearby unburned areaa: in Georgia (Halls, 1952), in
eastern Kansas (Aldous, 1934), in California (Sampson, l944), and in
southern Africa (Cook, 1939; Mes, 1958). In eastern Texas, however,
no difference could be detected (Lay, 1956).
Probably the usually higher water content of foliage on new burns
may account for the low frost-resistance of plants in autumn as reported by Campbell (1945) in southeastern North America, and for the
reduced resistance to both frost and drought aa reported by Cook
(1939) in southern Africa.
D. PHENOLOGY
Many writers have stated that the new shoots on a fresh burn appear
one to three weeks earlier as the next growing season starts, with specific reports from wide areas: Illinois (Hadley and Kieckhefer, 1963), Iowa
(Aikman, 1956; Ehrenreich, 1959; Ehrenreich and Aikman, 1963), Missouri (Koelling and Kucara, 1965; Kucera and Ehrenreich, 1962),
Kansas (Hensel, 1923b), Tanganyika (Scott, 1951) and South Africa
(Cook, 1939; Phillips, 1936; Scott, 1934). This precocity may be repeated in the second post-burn year in Iowa (Ehrenreich and Aikman,
1963), or earliness in relation to season may disappear even during the
course of the first season (Hensel, 19235). Ehrenreich (1969) noted that
precocity was closely related to warmer soils, and if this is causal then
a return to normal phenology during the first seaaon aa reported by
Hensel (192313) would seem to find an easy explanation in a reduction
of soil temperature as the grass canopy developed.
In North Dakota (Dix, 1960) and New South Wales, Australia (Norton and McGarity, 19R5), it has been noted that gramland fires did not
advance the appearance of new grass in the subsequent growing aeaaon.
Even delays in development have been observed in Bromw tecdorum
in eastern Idaho (Pechanec and Hull, 1946), in the sour veld grasses
of southern Africa (Botha, 1945), and in the flowering of Trachypogm
montufari in Venezuela (Blydenstein, 1963).
Where shoots appear earlier on burned areas, the early tendency may
disappear a8 the season advances as pointed out above, or it may persist, with flowering and fruiting also earlier than normal, as reported
in Iowa (Aikman, 1955; Ehrenreich, 1959; Ehrenreich and Aikman,
1957) in Missouri (Kucera and Ehrenreich, 1962), and southern Africa
(Cook, 1939; Mes, 1958). A t the end of the growing season the foliage
on burned areas has been observed to stay green until later than normal,
R. DAUBENMIRE
c. MOISTURE CONTENT
In several widely scattered locations the tissue moisture content of
the new shoots on burned s i t e has been determined and found to be
higher than on nearby unburned areaa: in Georgia (Halls, 1952), in
eastern Kansas (Aldous, 1934), in California (Sampson, l944), and in
southern Africa (Cook, 1939; Mes, 1958). In eastern Texas, however,
no difference could be detected (Lay, 1956).
Probably the usually higher water content of foliage on new burns
may account for the low frost-resistance of plants in autumn as reported by Campbell (1945) in southeastern North America, and for the
reduced resistance to both frost and drought aa reported by Cook
(1939) in southern Africa.
D. PHENOLOGY
Many writers have stated that the new shoots on a fresh burn appear
one to three weeks earlier as the next growing season starts, with specific reports from wide areas: Illinois (Hadley and Kieckhefer, 1963), Iowa
(Aikman, 1956; Ehrenreich, 1959; Ehrenreich and Aikman, 1963), Missouri (Koelling and Kucara, 1965; Kucera and Ehrenreich, 1962),
Kansas (Hensel, 1923b), Tanganyika (Scott, 1951) and South Africa
(Cook, 1939; Phillips, 1936; Scott, 1934). This precocity may be repeated in the second post-burn year in Iowa (Ehrenreich and Aikman,
1963), or earliness in relation to season may disappear even during the
course of the first season (Hensel, 19235). Ehrenreich (1969) noted that
precocity was closely related to warmer soils, and if this is causal then
a return to normal phenology during the first seaaon aa reported by
Hensel (192313) would seem to find an easy explanation in a reduction
of soil temperature as the grass canopy developed.
In North Dakota (Dix, 1960) and New South Wales, Australia (Norton and McGarity, 19R5), it has been noted that gramland fires did not
advance the appearance of new grass in the subsequent growing aeaaon.
Even delays in development have been observed in Bromw tecdorum
in eastern Idaho (Pechanec and Hull, 1946), in the sour veld grasses
of southern Africa (Botha, 1945), and in the flowering of Trachypogm
montufari in Venezuela (Blydenstein, 1963).
Where shoots appear earlier on burned areas, the early tendency may
disappear a8 the season advances as pointed out above, or it may persist, with flowering and fruiting also earlier than normal, as reported
in Iowa (Aikman, 1955; Ehrenreich, 1959; Ehrenreich and Aikman,
1957) in Missouri (Kucera and Ehrenreich, 1962), and southern Africa
(Cook, 1939; Mes, 1958). A t the end of the growing season the foliage
on burned areas has been observed to stay green until later than normal,