A broadscale land evaluation program to assess the potential for growing particular trees in Africa

A microcomputer program is presented which can indicate the broadscale suitability of any tree taxon for cultivation at sites across Africa. The program uses a climatic and edaphic database for over 10,000 locations. The Fertility Capability Classification devised by Buol and Sanchez is used to provide a relatively simple means to define the effects of different soil types on the selected taxon. The user estimates the limiting effects for a particular tree of four type (topsoil texture) and five substrate (subsoil texture) types, as well as 14 modifiers such as salinity, soil acidity and cation exchange. The program is demonstrated using the Petford provenance of Eucalyptus camaldulensis and the output is compared with results for 32 African countries derived from 292 publications. It is concluded that together the database, model and user interface provide a useful tool to assist preliminary testing of descriptions of tree species requirements and to identify potentially suitable regions for particular plant taxa which warrant more detailed analysis.