Soils and mineral nutrients: what do we know, and what do we need to know, for wise rain forest management?

It is shown how little is known of tropical forest soils including their distribution, and how the systems of soil classification have many unsatisfactory features including their variable relevance to ecologists and land managers. A current model of rain forest adaptation to low soil nutrients is described and shown to be inadequate in the light of observations made recently on Maracá Island, Brazil. Experimental studies on the role of nutrients in limiting plant growth in undisturbed forest soils are discussed and shown to yield conflicting results. It is concluded that process-level studies of rain forest nutrition are currently failing to underpin forest management options, but that rain forest nutrients are only likely to be of crucial inmediate importance where severe disturbances such as conversion to agriculture or plantation forests are practised. Light logging and even more heavy types of logging should be sustainable to the first rotation at least, but beyond that nutrient additions may be necessary.