104
J. ROGER BRAY A N D EVILLE GORHAM
sewage will not be necessary in forest areas. Aerial application of
various fertilizers may become a widespread technique for economically renewing or improving the fertility of forest soils, as the demand
for forest products rises.
Even if forest litter does not become an economic raw material in
the near future, the study of quantitative aspects of litter-fall remains
an important part of forest ecology, dealing with a major pathway for
both energy and nutrient transfer in this type of ecosystem. And since
litter production is easy to measure in comparison with the difficult and
expensive techniques for estimating total net production of forest
stands, the possibility that litter-fall might serve as a simple and convenient index to net production provided an additional stimulus for
this review. The chief aim of the study, however, is to collate available
data on the quantity of litter produced by forests in different parts of
the world, -and to assess the influence of environment upon litter-fall
under different forest communities.
11. SOURCES OF DATA
A. UNPUBLISXED STUDY B Y J . R. BRAY
Litter production was measured by Bray from 1957 to 1961 in an
Angiosperm forest with a slight admixture of Pinus strobus. This forest
occurs on the upper slope of the east bank of the Don River valley at
Glendon Hall, Toronto, Canada (43" 40' N, 79' 22' W). It is dominated
by Acer saccharurn with a density of 247 treestha. The composition is
shown in detail in Table I.
In 1957 and 1958, leaves and stem fragments were collected from the
forest floor in late autumn at the close of the period of leaf-fall. These
collections were made from 1 f t 2 quadrats (30.5 x 30-5 cm) placed at
equal intervals along a transect. Newly fallen leaves and any stem
material included were lifted intact from the decomposed duff layer in
each quadrat. Samples were taken to the laboratory, where each leaf
was inspected for signs of decay. If a mesic, calcium-rich leaf (e.g. Acer
saccharurn, Fraxinus pennsylvanica) showed only slight decay or tiny
holes it was retained as representative of the current crop. If a leaf
with a tough, leathery surface (e.g. Quercus boreaZiis, Q. alba) was even
moderately decayed, it was rejected as belonging to the previous year's
crop. On this basis it was possible to separate the leaves of the current
season from those of the previous season in all but a few cases. Samples
were then oven-dried at 105°C.
I n early winter of 1959, Hty galvanized iron litter pails (0.093m2
in area) were placed in the forest in a regular block pattern. No pail was
located beneath a shrub or low sapling which would intercept litter
J. ROGER BRAY A N D EVILLE GORHAM
sewage will not be necessary in forest areas. Aerial application of
various fertilizers may become a widespread technique for economically renewing or improving the fertility of forest soils, as the demand
for forest products rises.
Even if forest litter does not become an economic raw material in
the near future, the study of quantitative aspects of litter-fall remains
an important part of forest ecology, dealing with a major pathway for
both energy and nutrient transfer in this type of ecosystem. And since
litter production is easy to measure in comparison with the difficult and
expensive techniques for estimating total net production of forest
stands, the possibility that litter-fall might serve as a simple and convenient index to net production provided an additional stimulus for
this review. The chief aim of the study, however, is to collate available
data on the quantity of litter produced by forests in different parts of
the world, -and to assess the influence of environment upon litter-fall
under different forest communities.
11. SOURCES OF DATA
A. UNPUBLISXED STUDY B Y J . R. BRAY
Litter production was measured by Bray from 1957 to 1961 in an
Angiosperm forest with a slight admixture of Pinus strobus. This forest
occurs on the upper slope of the east bank of the Don River valley at
Glendon Hall, Toronto, Canada (43" 40' N, 79' 22' W). It is dominated
by Acer saccharurn with a density of 247 treestha. The composition is
shown in detail in Table I.
In 1957 and 1958, leaves and stem fragments were collected from the
forest floor in late autumn at the close of the period of leaf-fall. These
collections were made from 1 f t 2 quadrats (30.5 x 30-5 cm) placed at
equal intervals along a transect. Newly fallen leaves and any stem
material included were lifted intact from the decomposed duff layer in
each quadrat. Samples were taken to the laboratory, where each leaf
was inspected for signs of decay. If a mesic, calcium-rich leaf (e.g. Acer
saccharurn, Fraxinus pennsylvanica) showed only slight decay or tiny
holes it was retained as representative of the current crop. If a leaf
with a tough, leathery surface (e.g. Quercus boreaZiis, Q. alba) was even
moderately decayed, it was rejected as belonging to the previous year's
crop. On this basis it was possible to separate the leaves of the current
season from those of the previous season in all but a few cases. Samples
were then oven-dried at 105°C.
I n early winter of 1959, Hty galvanized iron litter pails (0.093m2
in area) were placed in the forest in a regular block pattern. No pail was
located beneath a shrub or low sapling which would intercept litter