Sprouting traits of Fagaceae species in a hill dipterocarp forest, Ulu Gadut, West Sumatra

The size distribution of a tree species gives important information about its regeneration strategy. For example, a tree species that regenerates primarily by sprouting will, in theory, have fewer seedlings than species that regenerate from seedlings, which generally form an L-shaped population size structure because of trade-offs in resource allocation between vegetative sprouting and sexual reproduction (Bellingham & Sparrow 2000, Loehle 2000). The results of some field studies suggest that the number of seedlings decreases with increasing dominance of multi-stemmed sprouters (Kruger et al. 1997, Zimmerman et al. 1994). In their study of four co-occurring species of Castanopsis (Fagaceae), Nanami et al. (2004) showed that species with a high frequency of sprouting adults had fewer juveniles and vice versa. This suggested that these species were able to co-exist as a result of trade-offs between investment in seedlings and sprouting. In this study, we investigated the sprouting trait of 17 co-occurring Fagaceae species in a Sumatran hill forest. The forest stand at this site shows a varied population structure across species, and hence, should have a varied life history. We tested the correlation between population skewness and proportion of sprouting trees, following the methods of Nanami et al. (2004). We hypothesized that the species that frequently form multi-stemmed sprouts will show a lower turnover of individuals because multi-stemmed architecture favours persistence (Bellingham & Sparrow 2009).