Aerial and Belowground Phytomass of Banksia Scrub-Heath at Eneabba, South-Western Australia

Abstract

Three Banksia spp. accounted for 80% of the aerial biomass of scrub-heath on deep sand. Reproductive structures contributed relatively more than leaves or stems to biomass of a non-sprouting Banksia, which also retained most of its dead leaves, than to the two resprouting species. Sclerophyllous hemicryptophytes accounted for only 1% of the aerial biomass. Litter contributed 19% of above-ground dead plus live phytomass and was poorly decomposed.

The overall root f shoot ratio, to a depth of 2.5 m, was a high 2.35. Rootstocks, laterals and proteoid roots made major contributions to below-ground phytomass even though they were confined to the uppermost 15 cm of soil. Despite an exponential decline in root mass with depth, the gradient was less than in related ecosystems due to the abundance of well developed tap roots and vertical laterals (sinkers) to a depth of at least 5 m.