Seed rain and soil seed banks in Chinese fir plantations and an adjacent
natural forest in southern China: implications for the regeneration of
native species
Abstract
The natural regeneration of native broadleaved species underneath forest
monoculture plantations is important to recover ecosystem functions and
to mitigate adverse environmental effects. To understand how seed rain
and soil seed banks facilitate natural regeneration, we surveyed their
density and composition in a monoculture Chinese fir plantation, a mixed
Chinese fir–broadleaf plantation, and an adjacent natural broadleaved
forest for two years in southern China. Twenty-eight species (16
families) were in seed rain, and 45 species (27 families) were in soil
seed banks. Seed rain density did not differ significantly across
stands; however, the number of taxa in seed rain was highest in the
mixed plantation and lowest in the natural forest. Seed bank density was
significantly higher in the mixed plantation than in the other stands.
The Sørensen similarity indices of species composition between seed
sources and aboveground vegetation were relatively low
(<0.50). In addition, the seeds of native tree species common
to the seed banks of the three forests indicated the adjacent natural
forest was a seed source for the natural regeneration of native species
in forest plantations. To augment regeneration and accelerate the rate
of conversion, we recommend direct seeding or planting of desired
species.