Resprouters vs reseeders in South African forest trees; a model based on forest canopy height

Abstract

1. We expect tree species that regenerate primarily by sprouting to produce fewer seedlings than co‐occurring species that regenerate mainly from seedlings, because of the trade‐off between allocating resources either to ensuring vegetative reproduction (e.g. protective bark/latent buds) or to sexual reproduction (e.g. seeds). 2. Furthermore, resprouting species, because of their multi‐stemmed nature, should be at a relative disadvantage, and therefore relatively infrequent, in tall forests. This is because a resprouting individual allocates resources to a number of basal branches/stems and buds rather than maximizing vertical extension of a single leader, as is the case in a seeder. Also, many tall stems arising from the same multi‐stemmed base, as is the case in resprouters, will be relatively poorly supported in comparison to the single stem of a reseeder. 3. To test these two ideas we surveyed a number of plots in a range of South African forests and thicket communities. We noted the numbers of seedlings and resprouts for each species and determined a mean for each site. 4. Short forests and thickets were dominated by multi‐stemmed species and there was an almost total absence of seedlings. In contrast, tall forests were dominated by single‐stemmed reseeding species and were accompanied by seedlings.