Replanting/underplanting strategy for old coconut plantations in Papua New Guinea

In most producing countries, the population of coconut palms is growing old, and ways of replacing them are rarely implemented to ensure that production is maintained and the future of the industry and its profitability are safeguarded. Rehabilitating/replanting coconut plantations and adopting appropriate intercropping systems is one of the main challenges to be taken up for the future of coconut in the Asia-Pacific region. The example of Papua New Guinea (PNG) reveals one of the lowest yields per hectare among the countries in the Asia-Pacific zone. Almost 106,000 ha were planted between 1910 and 1940, amounting to around 40% of the current coconut plantings, hence 80 to 100,000 ha can be expected to disappear in the next twenty years. Faced with this forecast, the PNG Cocoa and Coconut Research Institute (PNG CCRI) launched several operations, beginning with the creation of a coconut research centre on the PNG mainland: examination of a replanting strategy for old coconut plantings, based on hybrid planting material, distribution of improved planting material through the creation of a seed garden, and development of a system for controlling pest populations in high-risk zones. The experiments set up at the station are designed to optimize the felling date for old coconut palms, by measuring the effects of competition with the underplanted hybrids, and to determine from an economic point of view the best strategy to be applied for implementing rehabilitation and/or replanting programmes in old coconut plantings. This paper describes the results of these operations.