EVAPORATION FROM VEGETATION IN LANDSCAPES DEVELOPING SECONDARY SALINITY USING THE VENTILATED-CHAMBER TECHNIQUE .1. COMPARATIVE TRANSPIRATION FROM JUVENILE EUCALYPTUS ABOVE SALINE GROUNDWATER SEEPS

Several Eucalyptus species were grown in plantations at three locations ranging in average annual rainfall from 420 to 850 mm. The main objective was to find for each site the species with the highest transpiration. At the latest sampling which was in summer about two years after germination, E. globulus showed the highest rate per tree (37 l d-1) immediately above a seepage area at the 850-mm site. At the 500-mm site E. cladocalyx var. nana had the highest rate (30 l d-1), and at the 420-mm site E. wandoo (26 l d-1) ranked first. Transpiration varied greatly between species. For those species common to all locations, transpiration declined with rainfall. Transpiration per unit leaf area also varied between species. At the 420-mm site an increase in the average transpiration per unit leaf area, over all species, from 340 mg cm-2 d-1 in early summer to 1110 mg cm-2 d-1 in late summer suggested that the roots had reached a zone of higher water content. © 1979.