Physiological studies in young Eucalyptus stands in southern India and derived estimates of forest transpiration

Measurements of stomatal conductance (gs), leaf water potential (Ψ1) and leaf area index (L∗) were made in plantations of Eucalyptus camaldulensis and E. tereticornis at Puradal, near Shimoga, Karnataka, southern India during 1988 and 1989. The data were collected in a range of climatic conditions immediately following the establishment of the plantations. Physiological differences between the two species were small and largely confined to L∗.gs and Ψ1 for both species showed a similar pattern of behaviour in relation to the availability of soil moisture and the onset of the monsoon. Physiological variables and above-canopy meteorological data were combined an a multi-layer formulation to calculate hourly transpiration from the two species. Transpiration rates varied from 3.5 mm·d−1 for the post-monsoon period to 5.5 mm·d−1 prior to the onset of the monsoon for trees less than 1-year-old to 5.5 mm·d−1 and 1.0 mm·d−1, respectively, for the same climatic periods when the trees were 2 years of age.