Masting, natural regeneration and effects of defoliation in Quercus robur L. and Fagus sylvatica L
The perpetuation of the reigning dominants in climax
woodland, and the maintenance of species diversity, are
discussed by reference to published work: the importance
of the regeneration gap is outlined, and seed production
and seedling mortality are investigated as being key
factors in the establishment of young trees.
Beech masting has been studied by an eight-season
record of seed production by individual trees in many
places, developing a unique series of objective records
for England. There appears to be a basic biennial masting
pattern, with a requirement for suitable climatic
conditions and the proximity of other beech trees for
The effects of defoliation upon the growth of young
oaks has been investigated by a controlled experiment on
196 saplings in a plot in Wolverhampton. This has
contributed data on a larger population for a longer
period than has previously been published. The responses
of the trees to light defoliation were not marked but, as
the level of defoliation increased, greater numbers of
growth zones, more leaves and smaller leaves became
apparent, together with impaired relative growth rates and
abnormal wood structure.
Ramets of cloned oak have been established in a unique
outdoor plot. Their synchronous phenology permitted
further analysis of defoliation responses, including field
measurements of photosynthetic rates. Tree shelter tubes
were shown to promote earlier second flushes and to lessen
fluctuations in temperature and maintain high humidity.
Observations have been made in woodlands, especially in
the West Midlands where surveys have established that
natural regeneration is taking place, at least in the gaps
created by fallen trees. The possibility of encouraging
natural regeneration of trees and ground flora on land set
aside from agriculture is considered.
A synthesis is made of the topics investigated,
discussing the origin of the intermittent nature of the
phenomena of growth spurts and masting.