Effect of root configuration on the relative competitive ability of Eucalyptus maculata Hook. regrowth following clearfelling

Abstract

Summary The fine root systems of Eucalyptus maculata and other species have been examined in order to help interpret differences in the competitive ability of eucalypt and acacia species within regrowth forest on the south coast of New South Wales. E. maculata was growing vigorously on upper slopes, but occupied a sub-dominant canopy position on lower slopes 12 to 18 years after clearfelling. Seedlings of competing species were grown in the glasshouse in tubes 1 m in length, and subject to different soil moisture and soil bulk density treatments. Fine root distribution was also examined in the field. The fine root length of E. maculata (0.56 cm cm −3) within the upper section (0–15 cm) of the soil in tubes was considerably less than that of E. pilularis (1.74 cm cm −3) and Acacia mabellae (2.13 cm cm −3). A similar pattern was found in the field. Alternatively. E. maculata had a greater fine root biomass deeper in the soil profile, and where grown on soil of high bulk density. It is concluded that E. maculata may be less effective in acquiring nutrients and moisture in the upper soil horizons, but more effective at acquiring moisture at depth. This may help explain differences in the competitive ability of the species along the slope.