152
J. D. O V I N Q T O N
Lounanian (1956) has reviewed the existing records for boron. chromium, manganese, cobalt, nickel, copper, zinc, gallium, yttrium, zirconium, molybdenum, silver, cadmium, tin and lead in various conifer
and angiosperm trees as well as in the woodland understorey plants.
He found little difference between evergreen softwoods and deciduous
hardwoods with respect to their trace element content. I n contrast,
marked differences occur in the concentrations of the major elements
and sufficient data are available t o demonstrate the main features of the
pasgage of sodium, potassium, calcium, magnesium, phosphorus and
nitrogen through different types of woodland ecosystems.
A. WEIGHTS O F C H E M I C A L ELEMENTS I N
W O O D L A N D E C O S Y S T E M S
In Tables X to XV the amounts and distribution of sodium, potassium, calcium, magnesium, phosphorus and nitrogen are given for
some of the woodland ecosystems of Table I during the summer period,
when the trees are in full leaf. At other times of the year the distribution
would be very diff'erent. Many supplementary data are available showing the range of weights of various elements in individual components
of woodland ecosystems, particularly of the litter layers (Lutz and
Chandler, 1946) and of the ground flora (Scott, 1955). Few results have
been published of the amounts of chemical elements contained in the
trees and in the woodland fauna and microflora. Grimshaw et al. (1958)
report the chemical content of the canopy invertebrates in pine woodlands t o be, as g per ha, 2.2 for Na, 7.5 for K and 8-1 for P, whilst the
birds of the three most common species contain 0.04 of Na, 0.06 of K,
0.32 of Ca, 0.01 of Mg and 0.2 of P g per ha. Consequently the omission
of the fauna from Tables X to XV probably does not modify greatly
the total figures. Part of the soil fauna and the soil microflora would be
included in the litter layers.
The accumulation of mineral elements within the organic matter of
the woodland ecosystems is greatest on the more fertile, nutrient rich
soils. Nevertheless, woodland plants are able t o regulate the conceiitration of elements within their bodies t o some extent, so that differences
in the nutrient contents of the plant organic mass of woodlands of the
same tree species and of equal age but growing on very different soils
are not so great as might be expected from differences in the availability
of soil nutrients. I n general, there is a fairly close relationship between
the amount of organic matter present and the total amount of chemical
elements it contains, although this relationship is affected by the
nature of the organic matter; thus tree leaves, the ground flora and
small twigs have much greater concentrations of chemicals than tree
trunks. The tropical forest of Ghana with its huge weight of organic
J. D. O V I N Q T O N
Lounanian (1956) has reviewed the existing records for boron. chromium, manganese, cobalt, nickel, copper, zinc, gallium, yttrium, zirconium, molybdenum, silver, cadmium, tin and lead in various conifer
and angiosperm trees as well as in the woodland understorey plants.
He found little difference between evergreen softwoods and deciduous
hardwoods with respect to their trace element content. I n contrast,
marked differences occur in the concentrations of the major elements
and sufficient data are available t o demonstrate the main features of the
pasgage of sodium, potassium, calcium, magnesium, phosphorus and
nitrogen through different types of woodland ecosystems.
A. WEIGHTS O F C H E M I C A L ELEMENTS I N
W O O D L A N D E C O S Y S T E M S
In Tables X to XV the amounts and distribution of sodium, potassium, calcium, magnesium, phosphorus and nitrogen are given for
some of the woodland ecosystems of Table I during the summer period,
when the trees are in full leaf. At other times of the year the distribution
would be very diff'erent. Many supplementary data are available showing the range of weights of various elements in individual components
of woodland ecosystems, particularly of the litter layers (Lutz and
Chandler, 1946) and of the ground flora (Scott, 1955). Few results have
been published of the amounts of chemical elements contained in the
trees and in the woodland fauna and microflora. Grimshaw et al. (1958)
report the chemical content of the canopy invertebrates in pine woodlands t o be, as g per ha, 2.2 for Na, 7.5 for K and 8-1 for P, whilst the
birds of the three most common species contain 0.04 of Na, 0.06 of K,
0.32 of Ca, 0.01 of Mg and 0.2 of P g per ha. Consequently the omission
of the fauna from Tables X to XV probably does not modify greatly
the total figures. Part of the soil fauna and the soil microflora would be
included in the litter layers.
The accumulation of mineral elements within the organic matter of
the woodland ecosystems is greatest on the more fertile, nutrient rich
soils. Nevertheless, woodland plants are able t o regulate the conceiitration of elements within their bodies t o some extent, so that differences
in the nutrient contents of the plant organic mass of woodlands of the
same tree species and of equal age but growing on very different soils
are not so great as might be expected from differences in the availability
of soil nutrients. I n general, there is a fairly close relationship between
the amount of organic matter present and the total amount of chemical
elements it contains, although this relationship is affected by the
nature of the organic matter; thus tree leaves, the ground flora and
small twigs have much greater concentrations of chemicals than tree
trunks. The tropical forest of Ghana with its huge weight of organic