I am no longer actively involved in research projects and do not supervise postgraduate students. However, I maintain the following research interests: Plant-soil relations, especially the physiology and ecology of plant-fungal (arbuscular mycorrhizal) symbioses that occur in most plants worldwide, under many soil conditions. Soil toxicity, especially arsenic Ecology and history of Borneo, especially the development of trading links with the outside world in pre-colonial times.