OPCABSIM : A Modelling Package for Estimating Carbon Sequestration, Greenhouse Gas Emissions and Carbon Balance Associated with Oil Palm Cultivation in Malaysia : Technical Manual and Users' Guide
The OPCABSIM (Oil Palm Carbon Budget Simulator) computer model assesses carbon sequestration, greenhouse gas (GHG) emissions and resultant carbon balance, associated with oil palm cultivation and related land use change (LUC) in Malaysia. The software package consists of three sub-models or modules which operate on different scales: (i) a Regional module covering Peninsular Malaysia, Sabah, Sarawak and Malaysia as a whole, (ii) an Estate module, dealing with an individual oil palm estate comprised of different units or fields plus a mill, and (iii) a Field module, covering an individual oil palm crop. The Regional module uses real data for oil palm areas and production, whereas the other sub-models can operate either with real or hypothetical inputs. Each module facilitates the rapid evaluation of the effects of various alternative assumptions on the overall carbon balance and on GHG emission, permitting sensitivity analyses to be performed and major uncertainties to be identified. In addition, the Estate and Field modules allow effects of LUC, mill by-product use in the field, and several other factors to be examined. The boundaries of the modules extend from land clearance for planting of oil palm to FFB harvest and milling, and include the subsequent fate of mill products and by-products after milling. Refining of palm oil and production of oleochemicals and biodiesel are not presently catered for. In the Regional module, the period covered is determined by the available data, which for most aspects runs from 1980 up until 2005. However, for oil palm biomass and production data, results can be generated beginning from 1975. The Estate module can cater for a longer period, while the Field module covers a single oil palm crop with a maximum life of 30 years. As well as giving total figures for each region, estate or field, specific balances, i.e. per tonne of crude palm oil, can also be determined. The Manual describes the features, nature and workings of the three modules, provides a guide to their operation and gives some examples of output. It is complemented by a formal report2 in which further details of modelling procedures and results can be found. Where the Manual draws for illustrative purposes on material from previous reports, this is indicated.