Bats plant Cashew Nut Trees. In West Africa, India and the Seychelle Islands, at least seven kinds of flying foxes and fruit bats eat the cashew fruit and discard the seed or nut which drops on the ground. One of those cashew seed-planting bats is the Straw Coloured Fruit Bat.(1)

In the New World Tropics the Jamaican Fruit Bat and the Big Fruit Bat plant Cashew Trees. The Jamaican Fruit Bat, the Long-tongued Nectar Bat and the Brown Long-nosed Bat are believed by scientists to pollinate the Cashew Tree flower.(2)

WHERE DO CASHEW NUT TREES GROW?

Cashew Nut Trees first grew in northern South America. The early explorers from Portugal took Cashew Trees to other parts of the world beginning in the mid-1500’s.(3) Now Cashew Trees grow in many parts of the world including India, Africa, Sri Lanka, China, Malaysia, Philippines, Thailand, West Indies, Pacific Islands, Australia and the United States.

DO CASHEWS HAVE ANY IMPORTANCE IN ANCIENT HISTORY?

Yes, they do. If you were a Tupi Indian living in northern Brazil in the 1500’s and you owned Cashew Trees, you were an important and powerful person. The Indians depended on the Cashew Trees for food and they also used them as a calendar. They marked the passage of time by the ripening of the cashew fruit. The trees conferred on their owners a high position within a tribe. Intertribally contention over ownership of Cashew Trees could result in war.(3)

TELL ME SOMETHING ABOUT THE NATURAL HISTORY OF THE CASHEW TREE.

The evergreen tree can be about 35 feet (3 metres)tall but it looks more like a bush because the branches sweep down to the ground.(4) Cashew Trees can live for 30 or 40 years. They produce nuts for 15 to 20 years.

Here's a surprise! The nut or seed of the Cashew Tree is on the outside of the fruit, hanging from the bottom, not on the inside buried in the flesh of the fruit.(5) It is entirely different in that respect from peaches and nectarines, apples, mangoes, oranges . . . most of the fruits we are familiar with.

IS THE CASHEW TREE USEFUL FOR ANYTHING BESIDES PRODUCING NUTS TO EAT?

Very much so. Here are just some of its uses for human beings.(5)

• Tree timber is water resistant so it is used to build boats.
• Shipping crates
• Charcoal
• Furniture
• Sap or resin from the bark of the tree is used for indelible ink and insect repellents.
• Gum from the trunk of the tree is used for binding books.
  

Inside the hard cashew nut shell there is a brown oil that is toxic and powerful and valuable. It is called “cardol”. It is used for:(5)

• Foundry resins
• Waterproof paints
• Corrosion resistant varnishes
• Insulating enamels
• Special quality lacquers
• Oil and acid proof cement and tiles
• Lubricant in magneto armatures in airplanes
• Termite proofing timber
• Manufacture of plastics, varnishes, paints, printing ink, insulating material
• Reinforcement for cars, airplanes and other vehicles
  
  

WHAT ABOUT MEDICINES?

Medicines, too. People over the centuries have found relief from hundreds of undesirable health conditions using every part of the cashew tree including:(5)

• Fruit juice
• Bark
• Leaves
• Seed oil
• Green fruit
• Tender shoots

WHY ARE CASHEW NUTS SO EXPENSIVE?

Because so much of the work of processing the nuts has to be done by hand. The process goes like this:(6)

• The fruit falls off the tree.
  
• People pick up the fruit and twist off the nut.
  
• People put the nut in water for soaking.
  
• People lay out the nuts to be sun dried.
  
• People crack open every single nut individually. They use a machine that is powered by their hands and feet.
  
• People pick out the nut from the shell by hand.
  
• People remove the red skin from the nut with a knife.
  
• People grade the nuts into one of 22 grades.

THAT’S A LOT OF WORK, BUT IT GIVES PEOPLE JOBS!

You’re right. And that’s one of the things that seed-planting bats help to do is is give people work so they can earn money to raise their families and pay their bills.

People who don’t have a job in the cashew processing industries can sometimes harvest the nuts from wild trees and sell them to the processors.(6)

References:

(1)Fujita, M.S. 1991. Flying Fox (Chiroptera:Pteropodidae) Pollination, Seed Dispersal, and Economic Importance: A Tabular Summary of Current Knowledge, Resource Publication No. 2, Bat Conservation International

(2)New York Botanical Gardens Bat/Plant Databases http://www.nybg.org/botany/tlobova/mori/batsplants/database/dbase_main.htm

(3)Olaya, Clara Ines, Caju/Maranon/Merey/Acaiu/Cashew Nut; Americas, p.52

(4)Royal Botanic Gardens, Kew (1999). Survey of Economic Plants for Arid and SemiArid Lands (SEPASAL)database. Published on the Internet;http://www.kew.org/ceb/sepasal/
[accessed 9 March 2006 1430 hours]

(5)Purdue University, Center for New Crops & Plants, Duke, James A., Anacardium occidentale, Handbook of Energy Crops, unpublished, 1983; http://www.hort.purdue.edu/newcrop/duke_energy/Anacardium_occidentale.html

(6)Cashew Nut Processing, Technibrief, Practical Answers to Poverty; http://itdg.org/docs/technical_information_service/cashew_nut_processing.pdf

(7) Practical action, technology challenging poverty; http://practicalaction.org/?id=cashew_nuts