The Kapayan Tree is very important to the Iban community especially to their culinary arts. According to one of my relatives the fruit is a luxury item as it is seasonal and not many people grow the tree in their garden or "temuda". The fruit when processed is delicious and enhances the flavours of meat and vegetables. Furhermore the leaves are used as part of their famous meat preservation or kasam.
Thus the leaves of the kapayan are very important and valued amongst the Ibans in the longhouses.
Although the community leaders of the Ibans have often mentioned the importance of this special tree not much has been documented about the possibility of having the plant grown in at least a small scale farm. A check in the Internet bears no result.
At the moment most longhouses would have a few of these trees growing here and there near the longhouse. A relative of mine has two trees but when I was taking the photos the trees were not fruiting as it was not in season. Perhaps another time.
Although some preserved kapayan fruit can be purchased in most Indigenous markets(tamu) I must really caution the uninitiated because poorly processed kapayan fruits may be lethal as they can be full of cyanide. (re: Greenspot)
Preserved kapayan fruit when used in cooking meat or fish gives the dish an enhanced flavour. In fact the more you eat the food enhanced by kapayan the more you will like it. It can even be seen as a kind of addiction to a small degree.
My favourite way of using slices of preserved kapayan fruit is cooking it with tapioca leaves and kechalak or bunga kentang. The aroma is fantastic!