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 cave cavern crystal deposit drip formation Mineral Stalactite water active cloud danger geothermal geothermally hot lake natural new zealand pool red Rotorua toxic vapor vapour hill landscape Mud sulfur sulphur trees spout