Some Convincing Evidences of a Deep Root System Within an Interfluve Aquifer of Northeast Thailand

Abstract

In Northeastern Thailand, dipterocarp forest has been cut massively in recent decades to be gradually replaced by cash crops. The aerial parts of the vegetation were sold or burned while underground parts have been degraded with time on site by microbial activity that converts the plant tissues in organic matter more or less mineralized (humus). A drilling program to implant deep piezometers (> 25 m) allowed (i) to describe and characterize the superficial formations (XRD analysis); (ii) to observe and quantify the presence of root biomass at several tens of meters in depth. Additional analyses (stable carbon isotope, SEM) showed that the deep roots are mainly from tree species and aged less than 60 years. The good state of preservation suggests favourable conditions such as the presence of a renewed deep groundwater.