Litterfall in a secondary forest with special reference to the relationships between leaf‐fall rate, basal area and relative growth rate on a species basis

Total basal area ( BA ), mean relative growth rate of individual basal area ( RGR ba m ), annual leaf‐fall rate ( L ), and number of trees ( N ) on a species basis were measured in a secondary forest mixed with evergreen and deciduous trees in the warm‐temperate zone of Japan. Every species had a characteristic tree size and composed the tree and the shrub layers. The layer for each species, and the tree size of the species were represented by the species mean basal area per tree ( BA/N or ba m ). A power form equation was obtained for the relation between the species mean leaf‐fall rate per tree ( L/N or l m ) and ba m . RGR ba m was correlated with leaf‐fall rate per unit basal area ( L/BA ) rather than with ba m . This suggested that RGR ba m is associated less with mean tree size ( ba m ) and dominance as total basal area ( BA ), and more with annual leaf production per unit basal area, provided that L is equal to the annual leaf production per species. Rhus succedanea , the most dominant species in the forest plot, was typical in that it showed lower values of RGR ba m and L/BA than other tree species. This would suggest a decline of R. succedanea in a secondary forest.