Reference Benchmarks - The inherent fertility and depth of these soils resulted in their priority clearing and development from about 1875. No empirical data have been found earlier than the 1960s when formal soil surveys commenced. By that time, almost 100 years of change had occurred. There is a small number of relatively undisturbed sites in the local area. Such sites include the Pioneer Reserve in Kongwak. Soil sampling in this reserve may provide useful reference data for future refinement of existing Econd values.