A pareto multi-objective optimisation for sustainable expansion in sago plantations

Sago palm is an emerging crop for starch production which is predominately found in southeast Asia. Its expansion has potential danger to ecologically sensitive terrestrial ecosystems. This work aims to provide expansion strategies for sustainable sago plantation expansion based on the increase in sago starch demand. Mathematical optimisation model of the class linear programming is developed. The total land area available for expansion under the different land types is considered. The developed model determines the optimised area under each land type to be used for sago plantation expansion based on the trade-off between expansion cost and carbon emissions. -constraint method is used in solving the multi-objective problem. Unlike the other methods, -constraint enables to generate a range of optimal solutions. A case study with different land use types - disturbed tropical forest, disturbed peatland and swampy shrubland were considered to demonstrate the proposed model. Pareto frontier is presented between expansion cost and carbon emission using constraint method, providing a range of expansion strategies to the decision maker. The results show that the annualised expansion cost and the annual carbon emission that is inevitable to meet the expected demand is 1.15 M USD and 4.25 t CO2-eq/ha/y.