TRANSPIRATION IN TWO COMMON TREE SPECIES OF AUROVILLE, TAMIL NADU, INDIA, USING THE CALIBRATED HEAT PULSE METHOD TO MEASURE SAP FLUX

摘要

The community of Auroville since 1968 has been reforesting large tracts of land on the Coromandel Coast near Pondicherry. Well over three hundred species of indigenous and exotic trees have been introduced to the area, as well as shrubs, grasses, and creepers. The groundwater has, however, witnessed a steep decline, yet rainfall patterns have not varied out of the ordinary, Although one of the major reasons for this depletion is the huge increase in borewell-irrigated agriculture, it was posited that the reforestation in Auroville must have played some part in modifying the water balance of the area. The purpose of this research therefore, is to understand in more depth, the role of Auroville's forests on the replenishment of groundwater, with a possible view to managing the forests of Auroville according to the requirements of the area's water balance, The technique employed here to determine transpiration is known as 'the calibrated heat pulse method', Measurements started in Auroville in March 1994, on two common tree species, Acacia auriculiformis and Peltophorum pterocarpum, The trees examined were planted in 1982, and the data, taken for five months between March and July 1994, showed that P. pterocarpum transpired more than three times as much as A. auriculiformis. Although the results were revealing, it was clearly seen that measurements would be required over a period of at least one year, and on more species of trees, to obtain a detailed hydrological picture of the area. [References: 3]