Physiological traits of Acacia concurrens and Eucalyptus crebra with respect to radical site preparation practices in a revegetation trial,south east Queensland,Australia

Purpose

To successfully establish revegetation, there is a need for weed control. Herbicide application and top soil removal (scalping) may be used to suppress weeds. However, scalping alters soil water and nitrogen availability which in turn may affect plant physiology and performance during the early phase of establishment.

Materials and methods

A field trial was established in south east Queensland, Australia, to examine weed control methods, including herbicide application and scalping. Plant survival, mean periodic height gain, specific leaf area and leaf-level physiological traits were measured for Acacia concurrens Pedley and Eucalyptus crebra F. Muell. for 17 months following tree establishment.

Results and discussion

Plant survival and growth of A. concurrens were superior in the scalped area compared to the herbicide area, whereas neither survival nor growth of E. crebra was influenced by weed control methods. In general, there were no or little effect of site preparation practices on carbon and nitrogen isotope composition, specific leaf area, photosynthesis, maximum photosynthesis and instantaneous water-use efficiency. Photosynthetic capacity was not influenced by site preparation practices as reflected through the maximum rate of carboxylation and maximum rate of electron transport.

Conclusions

Despite altering soil nutrient availability in the scalped areas and high weed coverage in the herbicide areas, there was no substantial alteration in plant physiology for both species. E. crebra was less affected by either low nutrient availability in the scalped areas or high weed coverage in the herbicide areas compared to A. concurrens. Therefore, E. crebra could be considered as a valuable species to revegetate degraded lands.