Common name: Pili nut

Pili is a nut-producing tree native to the Philippines, its natural range limited to southern parts of Luzon island. Nowadays, it has a much wider distribution and can be found cultivated in other parts of the Philippines and faraway places such as Hawaii and Honduras.

It is a medium-sized tree reaching 20 m (65 ft) tall with a straight trunk 40 cm (1.3 ft) in diameter. The trunk is straight, buttressed at the base of large trees, and supports a densely branched rounded crown. The bark is brown and flakes in large pieces.

The leaves are large, up to 30 cm (12 in) long and feathery, being made up of dark green, pointed oval leaflets arranged in pairs along the length and with an extra leaflet at the tip. They remain on the tree in all seasons and in a dense arrangement that casts a deep shade.

The flowers are small and inconspicuous, creamy-white and borne either female or male on separate trees, though some male trees carry a few perfect flowers. They bloom mainly in summer, held in branched clusters arising at the ends of the branches. 

The fertilised flowers are followed by oval fruit 4 to 7.5 cm (1.5 to 3 in) long, green when young becoming dark purple to near black when ripe, usually in the tropical winter season. The ripe fruit have thin yellow pulp surrounding a thick-shelled triangular nut with a single oily kernel inside.

Use

The kernels are edible and are roasted and eaten like a nut. They are highly esteemed and by many are considered superior to almonds (from Prunus dulcis). Extracting them can be a challenge as the nutshell is thick and hard.

Pili kernels are eaten out-of-hand, mostly roasted, unsalted, salted or sugar-coated, or are incorporated in baked goods or confectionery, including chocolates. The kernels are up to 70% oil and can be ground into nut butter or the oil can be extracted by mechanical pressing. It is a pale yellow, sweet-tasting oil that is suitable as a salad or cooking oil and has good keeping qualities.

It is listed as a vulnerable tree species by the International Union for Conservation of Nature and Natural Resources (IUCN), which brings attention to the need for conservation its in its native range.

A resin tapped from the trunk of Pili trees, but principally from the Elemi tree (Canarium luzonicum), is a soft, granular, clear to pale yellow elemi resin resembling crystallised honey. Known as 'Manila elemi', it is readily soluble in alcohol and was at one time exported in quantity from the Philippines to Europe for use in wood varnishes. It is also used in nail polishes for gloss and adhesion. Possessing a pleasingly fresh, lemon-like fragrance, it is also used in pomander pastes in deodorizers and as  fixative in sachets and pot pourri.

Health use

Elmi resin has been used as an ingredient in ointments and as a natural plaster for wound healing, due to its antiseptic properties, pasty consistency and ability to dry quickly.

Climate

Grows naturally in moderately humid to very humid tropical climates, generally frost-free areas with annual lows of 19 to 25°C, annual high of 27 to 35°C, annual rainfall of 1500 to 5000 mm and a dry season of 3 months or less, extending to 5 months with irrigation or groundwater.

Growing

New plants can be grown from seed or by grafting or air-layering (circumposing). However, seedling trees tend to be highly variable with respect to both tree and nut characteristics, and it is difficult to determine their sex before the tree reaches maturity. For these reasons, it is best to produced new plants vegetatively, using propagation material from known male and female trees. Also, female trees should be productive and producing nuts with desirable characteristics. A ratio of one male to every twenty to twenty-five female trees is suggested as adequate for good pollination.

Annual average nut yields per tree of 35 kgs (77 lbs) have been recorded for Pili plantations in Honduras, but there are reports of exceptional trees in the Philippines yielding up to 100 kgs (220 lbs) of nuts.

Performs best on deep, rich free-draining clay and loam soils of a moderately acid to neutral nature, generally with a pH of 4.5 to 7.0, and on sites with full to partial sun exposure.

Problem features

It is recorded as naturalised on the Pacific island of Pohnpei but there is otherwise no record of it as a weed or invasive species.

Books

• Axtell, B. L & Fairman, R. M 1992, Minor oil crops, Food and Agriculture Organization of the United Nations (FAO), Rome

• Barwick, M., et al. 2004, Tropical & subtropical trees : a worldwide encyclopaedic guide, Thames and Hudson, London

• Coppen, J. J. W. 1995, Gums, resins and latexes of plant origin, Food and Agriculture Organization of the United Nations (FAO), Rome

• Groom, N. 1997, The new perfume handbook, 2nd ed., Blackie Academic & Professional, London

• Jamieson, G. S. 1943, Vegetable fats and oils : their chemistry, production, and utilization for edible, medicinal and technical purposes, 2d ed, Reinhold, New York

• Janick, J., & Paull, R. E. 2008, The encyclopedia of fruit & nuts, CABI Publishing, Wallingford, Oxfordshire

• Macmillan, H. F. 1943, Tropical planting and gardening : with special reference to Ceylon, 5th ed, Macmillan Publishing, London

• Menninger, E. A. 1977, Edible nuts of the world, Horticultural Books, Stuart, Florida

• Page, P. E. 1984, Tropical tree fruits for Australia, Queensland Department of Primary Industries (QLD DPI), Brisbane

• Rosengarten, F. 1984, The book of edible nuts, Walker and Company Publishing, New York

• Wickens, G. E 1995, Edible nuts, Food and Agriculture Organization of the United Nations (FAO), Rome

• Winter, R. 2009, A consumer's dictionary of cosmetic ingredients : complete information about the harmful and desirable ingredients found in cosmetics and cosmeceuticals, 7th ed, Three Rivers Press, New York

Articles, Journals, Reports and Working Papers

• Lantican C.B. 2015. Philippine Native Trees – What to Plant in Different Provinces. Unpublished Terminal Report to DOST-PCARRD.