Intercropping teak (Tectona grandis) and maize (Zea mays): bioeconomic trade-off analysis of agroforestry management practices in Gunungkidul, West Java']Java

Producing high quality timber meeting export standards requires intensive tree management. Using a tree-crop interactions model (WaNuLCAS) we analyzed tree management practices in intercropped teak (Tectona grandis) and maize (Zea mays) compared to teak and maize monocultures. Tradeoff analysis in intercropped teak and maize was designed in a three-treatment factorial: initial teak density (1600 trees ha(-1) (2.5 m x 2.5 m), 1111 trees ha(-1) (3 m x 3 m) and 625 trees ha(-1) (4 m x 4 m)), thinning intensity (light (25 %), moderate (50 %) and heavy (75 %) of tree density), and pruning intensity (40 % and 60 % of crown biomass). Cumulative maize yield in the first 5 years of teak growth increased 10-38 % when tree density was reduced. All simulated intercropping practices produced a higher wood volume than a monoculture, as trees benefit from crop fertilization. Maximum wood volume (m(3) ha(-1)) was obtained at initial tree density of 625 trees ha(-1), 25 % of which was thinned in year 5 and another 25 % in year 15 with 40 % of the crown pruned in years 4, 10 and 15. However, greater stem diameter as can be obtained with further thinning is rewarded with higher market price per volume of wood. Profitability analysis taking into account the cost of labour (for maize production, thinning and pruning) and its effect on additional timber revenue showed that the highest net present value and return to labour was provided by the system with 50 % thinning in year 5. Economic optimization was not sensitive to variations around the default price assumptions.