agroforestry bactris-gasipaes center-core centre-core cluster cultivated cylinders cylindrical delicacy dietary-fiber dietary-fibre edible exotic food growing-buds heart-of-palm hollow inner-core labor-intensive-harvesting labour-intensive-harvesting long-lived-plant mineral-rich multiple-stems palm palm-cabbage palmetto palmito peach-palms perennial plate salad-vegetable self-suckering taste tropical tropics ubod vegetable vitamin-rich white yellow