IF THERE'S a tree to which the phrase "money grows on trees" applies so well, it is the cashew tree. So many food and industrial uses have been found for parts of the cashew tree.

Basically, the cashew tree is planted primarily for its kernel or nut. Dried or roasted, the nut is one of the world's most popular nut foods. Delicious, highly nutritious and containing a fair amount of phosphorus, iron and vitamin A, it is a favorite dessert nut in some 20 countries.

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In the United States, for instance, it is used in baking and cake-making. In the Philippines, it is used in the manufacture of ice cream, confectioneries, pastries and as a hardener for chocolates.

Cashew kernel oil can be obtained from kernel residues through cold-pressure extraction. Extensive studies have shown that the oil is comparable in nutritional value with oil from olive, corn and soybean.

Commercially, the oil can be used as insect repellent to protect posts, floors and rafters from termites and as water-proofing and preservative material for fishing lines, nets, boats, bamboo screens and light woodwork; and as a water-resistant adhesive in making bamboo board.

Although acrid-tasting, the cashew apple is juicy and has considerable food value. When fully ripe, the apple can be eaten fresh or can be used in making ades, jams, jellies, pie stock, vinegar, chutney, alcohol and wine. The unripe apple is used in the preparation of curried vegetables and pickles.

Another important product of cashew is the cashew nut shell liquid (CNSL), a brown, sticky and caustic liquid found between the outer and inner skins of the shell. CNSL is used in making adhesives, inks, paints, and oils. A mixture of five percent CNSL and 95 percent kerosene or diesel oil has been found to be an effective mosquito larvicide.

Cashew gum, an exudates made from incisions in the trunk, is used to protect books and wood carvings from insects. It is also used as a substitute for gum Arabic in adhesives and other products.

Also considered a medicinal tree, the juice from the ripe fruit may be prescribed for stomach disorders to arrest vomiting, or as gargle for sore throat. The bark of cashew may be chewed to cure sore gums and toothache. A decoction of the bark is used against diarrhea, diabetes, syphilitic swellings and ulcerations in the mouth.

Infusion of leaves and bark is also given for dysentery and infusion from the root is an excellent purgative. Mature leaves are crushed and used as a poultice for burns and skin ailments.

A word of warning, though: Before using any or all parts of cashew tree, be sure to consult your doctor.

Cashew is also an excellent species for reforestation. When planted in critically denuded areas, it can greatly reduce soil erosion, slow down the flow of water and minimize flash floods. In India, for instance, this species was introduced primarily to check soil erosion along the coasts.

Although the tree thrives in areas where other agricultural crops would barely survive, there are, however, not enough cashew trees planted in the country.

Major producing areas include Palawan, Cagayan, Zambales, Guimaras Island, Occidental Mindoro, Nueva Ecija, Cavite, Bataan, Bulacan and Pangasinan.

"Despite its great economic potential, cashew is not being given the serious attention it is getting as in other countries," laments Dr. Roberto Coronel in his book, "Promising Fruits of the Philippines."

Major nut-importing countries include Hong Kong, Singapore, and Taiwan. The nut is also uses as a substitute for imported almonds, chestnuts, walnuts, hazelnuts, and other nuts from the United States, Switzerland, France, and the United Kingdom.

A hardy plant, cashew grows well on almost all soil types: dry soil, sandy beaches, and poor laterite soil. It yields best when planted in deep loam soil with adequate moisture and good drainage.

A tropical crop, cashew grows best in areas with a distinct dry and rainy season. It produces a fairly good yield even when planted in areas 1,5000 feet above sea level. It also withstands drought fairly well and is a good tree for marginal, hilly areas.

The Bureau of Plant Industry (BPI), a line agency of the Department of Agriculture, has identified the following as good commercial varieties: Guevarra, Nagbayto, and Makiling.

Cashew may be propagated from seed and asexually by stem cutting, marcotting, inarching, budding and grafting. Technicians from the Davao-based Mindanao Baptist Rural Life Center (MBRLC) say marcotting is the best method to propagate the plant. Marcotted trees bear fruits after only 20 months.├┐ In comparison, trees grown from seed usually mature about three years.

Bearing age of cashew is three to four years. Average yield is five metric tons of nuts and 821,000 apples per hectare. For commercial apple production, the fruits must be harvested during the "boko" stage (the time when the kernels attain a complete dull greenish color), or "tandongan" stage (more advanced than the "boko" stage by a week or more).