180
J. D. OVINOTON
increased tree growth 2 to 3 times over a 7- to 9-year period. The growth
increase was associated with a,n increase in the weight of leaves carried
by the forest and although the nitrogen content in the trees doubled
that of phosphorus showed little change. Determination of the total
nitrogen within the ecosystem suggested that little of the applied
nitrogen was lost by leaching. Mayer-Krapoll (1956) gives the results of
several German forest experiments showing improved tree growth following the application of nitrogen. Weston (1958) found that a top
dressing of phosphate increased the growth of intermediate quality
stands of Pinus radiata in New Zealand and Van Goor (1955) has
stressed the need to consider the very different phosphorus demands of
trees of different species when applying phosphate fertilizers. Positive
growth responses by red pine to potassium have been reported by
Heiberg et al. (1959) and to calcium by Hausser (1956). Liming, particularly when accompanied by nitrogen application, can have a very
dramatic effect in increasing litter breakdown (Lohwasser, 1953) but
there is a danger that over-liming may decrease tree growth (Van
Goor, 1953).
The effect of increasing the supply of one element upon the availability
and uptake of others has received scant attention and little is known of
the long-term effects of fertilizer application particularly in relation to
the dynamics of the ecosystem as a whole. It is evident that the effects
of fertilizers are not confined to the trees, since different treatments
stimulate or depress the production of fruit bodies by agarics (Hora,
1959) and change the ground flora (Malmstrom, 1943) and microfauna
(Franz, 1957). More intensive and comprehensive research utilizing the
ecosystem approach is needed to place the technique of fertilizer
application on a more scientific basis, and to elucidate the interactions
of different chemical elements.
F. O U T P U T
Previously, data have been given of the loss of nutrients by the
cropping of tree boles but harvesting of foliage, game and litter may
cause some drain on the nutrient capital. Another important, factor on
the debit side of the nutrient budget of woodlands is the removal of
nutrients in the drainage water but unfortunately virtually no quantitative data are available. Since a forest cover reduces the outflow of
water from catchment areas the total loss of nutrients in this way may
be less under woodlands than under other types of plant cover but many
diverse factors are concerned. On infertile soils there would apparently
be greater competition between woodland plants for the limited
amounts of nutrients available so that fortunately soil leaching may be
at a minimum in these areas. Viro (1953) has calculated the loss of
J. D. OVINOTON
increased tree growth 2 to 3 times over a 7- to 9-year period. The growth
increase was associated with a,n increase in the weight of leaves carried
by the forest and although the nitrogen content in the trees doubled
that of phosphorus showed little change. Determination of the total
nitrogen within the ecosystem suggested that little of the applied
nitrogen was lost by leaching. Mayer-Krapoll (1956) gives the results of
several German forest experiments showing improved tree growth following the application of nitrogen. Weston (1958) found that a top
dressing of phosphate increased the growth of intermediate quality
stands of Pinus radiata in New Zealand and Van Goor (1955) has
stressed the need to consider the very different phosphorus demands of
trees of different species when applying phosphate fertilizers. Positive
growth responses by red pine to potassium have been reported by
Heiberg et al. (1959) and to calcium by Hausser (1956). Liming, particularly when accompanied by nitrogen application, can have a very
dramatic effect in increasing litter breakdown (Lohwasser, 1953) but
there is a danger that over-liming may decrease tree growth (Van
Goor, 1953).
The effect of increasing the supply of one element upon the availability
and uptake of others has received scant attention and little is known of
the long-term effects of fertilizer application particularly in relation to
the dynamics of the ecosystem as a whole. It is evident that the effects
of fertilizers are not confined to the trees, since different treatments
stimulate or depress the production of fruit bodies by agarics (Hora,
1959) and change the ground flora (Malmstrom, 1943) and microfauna
(Franz, 1957). More intensive and comprehensive research utilizing the
ecosystem approach is needed to place the technique of fertilizer
application on a more scientific basis, and to elucidate the interactions
of different chemical elements.
F. O U T P U T
Previously, data have been given of the loss of nutrients by the
cropping of tree boles but harvesting of foliage, game and litter may
cause some drain on the nutrient capital. Another important, factor on
the debit side of the nutrient budget of woodlands is the removal of
nutrients in the drainage water but unfortunately virtually no quantitative data are available. Since a forest cover reduces the outflow of
water from catchment areas the total loss of nutrients in this way may
be less under woodlands than under other types of plant cover but many
diverse factors are concerned. On infertile soils there would apparently
be greater competition between woodland plants for the limited
amounts of nutrients available so that fortunately soil leaching may be
at a minimum in these areas. Viro (1953) has calculated the loss of