For some decades, researchers from the Department of Geography in the University of Cambridge have been conducting basic research into the ecology of slash and burn subsistence agriculture in the context of the acid soils of the world's humid tropics; i.e. in the typical environment of the Tropical Rain Forest (TRF).  This project profile outlines the sustainable system of subsistence agriculture that has emerged from these years of research and development, and continues by outlining the work of the NGOs in Central and South America who are implementing these findings today.

The widespread failure of slash and burn agriculture.

Slash and burn agriculture and its associated pattern of shifting cultivation have been practised for centuries in all three of the world's great tropical regions.  Under low population pressures in the past, the practice has proved broadly sustainable, but there are notable exceptions to this.  In the leached, acid-soil environments which are typical of the true rainforest zones, many indigenous agricultures of the past are reported to have required fallow periods, between cropping episodes, of perhaps 12-20 years duration. 

The projects worked on by Mike Hands, after almost 20 years of research and testing of sustainable, or non-sustainable alternative systems, have some answers:   

1. Fundamental insights have been gained into why the practice of slash and burn is temporarily successful; but also into why it fails widely after one or, at most, two crops have been grown.  In other words : "What drives shifting cultivation?"
2. Exhaustive basic research has led to the development and successful testing of a sustainable alternative system which will enable the farmer and his family to remain on one cleared site and not to have to seek fresh forest to burn in order merely to stay alive.