The trees act as mini drills with their root structures sampling very large volumes of soil and in the case of phreatophytes the root structure searches out the water table and may extend hundreds of metres below the surface. The choice of package depends on the elements and detection limits required.
Humus (Decaying Surface Vegetation) – The material is dried below 60oC and then macerated with a cutting mill with a 1mm internal sieve. The ground material can be compressed into a briquette for INAA or ashed and analyzed by digestion and ICP or ICP-MS.
Vegetation (dried and ground in a cutting mill to homogenize it. Then can be analyzed by compressing into a briquette, by ashing and analysis of ash, or analysis on unashed material.