Local names:
English (cutnut), Pidgin English (katanat)
Cutnut is a medium-size fast growing, evergreen tree up to 24 m high but often range between 8-12 m with a crown diameter of 0.8–6 m and mature tree dbh of 2-45 cm. Cutnut produces a vigorous framework of branches following the formation of the terminal inflorescences. Leaves large, simple, lanceolate and arranged in a whorl at each node. Leaf size varies, typically measuring 21.5–66 cm long and 5–20 cm wide. The upper surface of the leaf is dark green and glossy; the lower surface is slightly paler. Typically, the leaf has a truncated base and an acuminated apex, with undulated margins. Inflorescence racemose with a 30–110 cm long pendulous spike containing up to 150 densely packed flower buds, arranged in spirally alternate pattern, and varying in colors, typically from green to white or red. Flowering is terminal on the shoots. Flower buds are semisessile to sessile and are protected by a calyx closed in the bud, which ruptures into two to four pseudolobes. Fruits multiple, sessile, elongated, oblong to obovoid, tapering toward the apex and base, and borne on a pendulous rachis. At maturity they are indehiscent, but the skin can be easily peeled off when ripe. Length of a mature fruit varies between 25–95 mm. Seed or kernel is contained in a fibrous, white to purplish, cylindrical, eight-sided endocarp shell (prominent when exocarp and mesocarp are removed). Bark smooth at early stages of growth but becomes fissured as the trees grow older. Large lenticels up to 5 mm across are present. The tree has a relatively shallow taproot and a well formed network of lateral roots, concentrated in the topsoil layer.
Ecology
Common in old gardens, mature coconut plantations, and coastal villages, and in remnants of secondary lowland humid tropical rainforests. Within its natural range are other species including canarium nut (Canarium spp.), breadfruit (Artocarpus altilis), coconut (Cocos nucifera), Tahitian chestnut (Inocarpus fagifer), poumuli (Flueggea flexuosa), sago palm (Metroxylon salomonense), Malay apple (Syzygium malaccense), Mangifera minor, Ficus spp., Macaranga spp.,Terminalia spp., and tava (Pometia pinnata).
Native range
Papua New Guinea, Solomon Islands, Vanuatu
Tree management
Cutnut is naturally self-pruning of lower branches up to about one-fifth of the height of the tree. Trees coppice and pollarded trees re-sprout well. In a small-scale plantation, seedlings should be planted at 5 x 5 m spacing, or 400 trees/ha. In agroforestry systems mixed with other species, 40 trees/ha are optimal. For silvopasture, a low planting density of 10-15 trees/ha is recommended to avoid shading of the pasture grass. Seedlings may be planted on cleared land or as line-plantings in secondary forests, in which selective thinning of the forest allows more light to reach the seedlings. Weeding is crucial for the first 2-3 years of growth in the field. As the trees mature, weeding operations should be scaled down to cleaning once a year (largely by removing vines from the trees). Trees that are too tall should be pollarded to reduce height and ensure safety around villages. Note: There is no record of cutnut becoming invasive, and in situ observation on the distribution of wildings appears to rule out any potential invasiveness.
Well formed, ripe fruits should be collected from the ground, fresh fruits collected from the tree result in low germination if immature. Fruit maturity is indicated by a distinctive dieback of the persistent stigma at the base of the fruit. Seeds are recalcitrant, do not withstand drying, and remain viable only for short period in dry storage. To maximize storage, it is best to retain the mesocarp on the nut and store the seeds in a shady, cool (19-25°C), and low-humidity environment and out of reach of pests such as crabs and rodents. There is no special pre-planting treatment for cutnut. Viability can be tested by placing them in water. Fruits that float are likely to be non-viable.
Common in old gardens, mature coconut plantations, and coastal villages, and in remnants of secondary lowland humid tropical rainforests. Within its natural range are other species including canarium nut (Canarium spp.), breadfruit (Artocarpus altilis), coconut (Cocos nucifera), Tahitian chestnut (Inocarpus fagifer), poumuli (Flueggea flexuosa), sago palm (Metroxylon salomonense), Malay apple (Syzygium malaccense), Mangifera minor, Ficus spp., Macaranga spp.,Terminalia spp., and tava (Pometia pinnata).
The most common method of propagating cutnut is by direct sowing or raising the seedlings in the nursery before transplanting. Vegetative propagation through marcotting and stem cuttings is also successful. Juvenile cuttings set in a non-mist propagator can give 100% rooting in three weeks, while 100% of marcotts root in 4 weeks. Seeds should not be exposed to full sunlight and should be sown 3-5 cm (1.2-2 in) deep in a vertical position with the basal end down. Seeds from ripe fruits will start to germinate after 7 days. It takes 2-3 months to germinate a ripe fruit. Wildings (volunteer seedlings) can be easily transplanted, and can be stored in a shaded and cool location for up to 2-3 weeks if the seed (nut-in-shell) is left attached.
Erosion control: The tree is rated high (more than 60% of farmers interviewed in Kolombangara, Solomon Islands) for soil stabilization due to a good network of lateral roots.
The fruit kernel is edible, tasty, and highly nutritious and is eaten as a snack or prepared into dishes for a main meal. It can be roasted and baked into puddings together with edible hibiscus (Abelmoschus manihot) and coconut cream. It contains protein and carbohydrate at about 10% and 25%, respectively, in its raw form. The mesocarp of a ripe fruit is aromatic and has potential for flavoring.
The kernel and mesocarp are a good feed for free-range chickens. Birds (cockatoos, parrots) and flying foxes feed on the fleshy mesocarp of fruits and on the flower nectar. The fallen kernels and mesocarps are food to some freshwater fish and prawns.
Apiculture: The tree is a good bee forage for nectar.
Fallen branches and felled trees make good firewood.
Timber: Despite its poor quality, the wood is used for crafts and temporary light construction. The wood is sometimes used for making paddles in the Reef Islands, Temotu Province, Solomon Islands.
Shade or shelter: In a homegarden situation, cutnut provides good shade and shelter to cereal and other understory crops such as sugarcane (Saccharum officinarum) and edible hibiscus (Abelmoschus manihot). With appropriate spacing, the tree can provide m
Medicine: Leaves and bark are largely used medicinally. The leaves have been used to treat inflammation of the ear and headaches. Sap from the bark has been used for treating ciguatera poisoning, coughs, and urinary infections, and the red-leafed form is used as a contraceptive and for abortion.
Ornamental: Cutnut is an attractive evergreen tree with bright flowers that beautifies rural villages. Being a medium-size tree and providing good shade, it would be suitable as a park or street tree. Its pendulous flowers and fruits are attractive in an urban landscape.
Cutnut tree can be used as support for fencing. In its native areas, cutnut indicates human settlements and provides proof of land ownership, and therefore can serve as a good boundary marker. The tree is a good medium-he
Soil improver: Fallen leaves, flowers, and dead branches enrich the surrounding soil.
Intercropping: Its open canopy structure allows sufficient light penetration to the ground level for other crops to be interplanted under it. It is compatible with common field crops such as cabbage, sweet potato, banana, Xanthosoma spp., and cassava. Farmers in Temotu province of the Solomon Islands have used cutnut as a companion and interline tree crop in an improved traditional agroforestry system. It is a good trellis tree for betel nut vine (Piper betle).
Essential oils: The kernel oil has potential for cooking and body care products.