One of the main causes of tropical rainforest destruction is the need for more agricultural land, which is largely a consequence of rapid population growth and rising economic expectations. The Area Production Model simulates long-term land use changes and the prediction of primary and secondary yields from agricultural and forest lands. The model's demand and supply scenarios for agricultural products and land are generated primarily by growth rates of population and GDP, and by changes in land productivity.
The APM uses the concept of land allocation. If demand for land in a particular agricultural class increases, transfers of land from one class (e.g. forest land), to another are generated by the model. The APM requires numerical data input. Its output is in tabular and graphic form.
A spatial component was developed and combined with the model for a part of East Java. In East Java, Indonesia, strict control prevents conversion of state forest lands to non-forestry purposes. Demand for new agricultural land will lead to scrub land. A positive relationship between the amount and location of new agricultural land, as calculated by the APM over a given period of time, and the actual increase in area of scrub land in the same period.
Detailed analysis of the locations were scrub expansion took place indicates the need for further enhancement of the spatial APM. This will permit the determination of key operators that influence extent and location of future forest degradation.
Key words: deforestation, land use modelling, remote sensing.
Correspondence: Alfred de Gier, International Institute for Aerospace Survey and Earth Sciences (ITC), P.O.Box 6, 7500 AA Enschede, The Netherlands
E-mail: degier@itc.nl