Emergence, early survival, and growth of seedlings of six tree species in Mediterranean forest of Western Australia

This paper reports an experimental and comparative field study of germination, early survival, and height growth of six tree species in the northern jarrah forest of Western Australia. The species are Eucalyptus marginata and Eucalyptus calophylla (comprising the overstorey)and Banksia grandis, Allocasuarina fraseriana, Persoonia longifolia and Persoonia elliptica (all understorey). Seed weight does not correlate with germination success, survival or height growth. Germination success is greatest for B. grandis (90 percent)and zero for Persoonia spp. Survival of caged germinants is highest for B. grandis and E. calophylla; that of uncaged seedlings is least for E. marginata, E. calophylla and B. grandis because of browsing. Over 40 percent of seeds of E. marginata, E. calophylla and B. grandis do not germinate because they are harvested and presumably eaten. Viability of seeds of all species exceeds 70 percent. Germination is influenced by type and depth of litter but not by artificial shading or root competition from forest trees. Browsing by herbivores (kangaroos)is an important cause of death of seedlings of E. marginata, E. calophylla and B. grandis. Litter type and depth affect survival of E. calophyUa, B. grandis and A. fraseriana but root competition and shading are unimportant. Height growth of E. marginata, E. calophylla and B. grandis is reduced by root competition and browsers further reduce height growth of B. grandis. Litter affects growth of E. marginata and B. grandis and shading influences growth of E. marginata and E. calophylla. Poor germination explains the low abundance of both Persoonia spp. in the jarrah forest but differential seedling establishment does not explain the adult representation of the other four species.