Argan (Argania spinosa (L.) Skeels) is a thorny tree from the arid and semi-arid regions of Morocco and Algeria. It is mainly cultivated for its oil and it is an important fodder tree in Morocco, particularly for goats. The fruit pulp and the oil extraction by-products are also fed to livestock.
Argan is a long-lived (150-200 years) evergreen, thorny tree (Lamnauer, 2005). It is a medium-sized tree that reaches a height of 8-10 m, sometimes up to 20 m. Its strong root system can reach a depth of 35 m, making it able to survive droughts, and suitable for arid and semi-arid areas (Orwa et al., 2009). The trunk is knotty and has a diameter of up to 1 m. The tree bears many criss-crossed stems. The leaves are small, clustered and lanceolate (Wickens, 1995). They can absorb any moisture from the air (Lamnauer, 2005). The inflorescences are axillary borne. The flowers are bisexual, greenish-yellow in colour (Wickens, 1995). The fruits are ovoid fleshy drupes that can need 1 year to ripen. They are green to bright yellow in colour and their pulp contains a milky latex unpleasant for humans (Wickens, 1995). They are quite similar to olive fruits, but larger and rounder, and they may contain up to 3 seeds (Lamnauer, 2005). The argan seed is a hard-shelled nut containing 1-3 kernels and yielding 50% of edible oil (Orwa et al., 2009; Lamnauer, 2005; Wickens, 1995).
Argan is an important economic resource for local populations in Morocco. It is primarily grown for its oil, which is edible and used in cooking, salads and couscous. Argan oil was imported into Europe during the 18th century but could not compete with olive oil due to its stronger flavour (Wickens, 1995). Argan oil has a valuable fatty acid profile, as it contains 80% polyunsaturated fatty acids, including 13% palmitic acid (C16:0), 48-59% oleic acid (C18:0) and 30-40% linoleic acid (C18:1)(Charrouf et al., 2009). It was reported to reduce harmful cholesterol and triglycerides (Charrouf et al., 2010). Argan oil contains large amounts of vitamin E (Wickens, 1995). Argan oil has cosmetic and dermatological properties, and is traditionally used to treat belly stretch marks, chicken pox pustules and acne (Orwa et al., 2009; Charrouf et al., 1998). Argan oil is used to make yellow soaps and hair and skin care products. Oil extraction residues can be mixed with sugar or honey to make a dip similar in taste to peanut butter (Orwa et al., 2009; Wickens, 1995). Argan wood is particularly resistant to insects and is much used for carpentry, construction and utensils. It provides firewood and charcoal. The nut shells are used as fuel for cooking (Orwa et al., 2009).
The argan tree is a major source of forage for sheep, goats, camels and cattle in Morocco. The leaves can be lopped or directly browsed by livestock. Fruits and leaves are readily consumed by goats who climb on the trees to eat them. Argan fruits can be eaten by livestock without hampering oil production as the seeds are not digested and can be recovered in the dung. The press cake resulting from oil extraction is sun-dried and is fed to livestock (FAO, 2015). Bees nest in argan trees that are thus a good source of honey (Orwa et al., 2009).