Sometimes nature diverges from the standard design and produces the bizarre. Like a baby that developed outside the womb, the cashew nut hangs off the bottom of the fruit. What evolutionary selective pressures produced this strange arrangement? Trees produce fruit mostly to attract birds and mammals to help them with seed dispersal. So why does the cashew hang its seed under the enticing sweet fruit? Not to mention that the nut is coated in very toxic resins that makes them inedible when eaten raw. This has been discovered by many a tourist who after biting the raw nut find their mouths erupting with blisters, accompanied by swelling and giant red lips.
The Cashew Tree – Anacardium occidentale – is native of tropical forests of the Americas. The cashew belongs to the family Anacardiaceae which includes many toxic plants like sumac, poison ivy, poison oak, mango, pistachio. It is at home in dry coastal areas and thrives in poor sand and is moderately tolerant of salt. It is very well adapted to the coastal regions of southern Thailand. It doesn’t mind extended dry periods and also survives well in periodic swampy flooded conditions common in the monsoon season.
We can be thankful to some native cultures in the Americas that discovered hundreds of years ago that you can roast the cashew nuts and burn off the toxic resin that coats the nut. The Cashew tree followed the early trade routes of the 15th and 16th century and eventually made its way to Africa and Southeast Asia.
March and April is the season when the fruit and nuts hang heavy from the trees. Here on Koh Jum island, on the Thai province of Krabi, it is an important crop and this is the season that locals gather the fruit and nuts. The apple-like fruit come in yellow and red varieties and also is edible, sweet with a pleasant tart acidic flavour. The fruit requires no preparation and can be eaten out of hand but care should be taken to avoid eating the end of the fruit where the nut is attached. Cashew fruit are also cooked in curries.
For landscaping they are a good choice for coastal planting as long as you make sure you are at least 50 meters back from the high tide with some coastal vegetation blocking the salt spray especially if your location gets the direct hit of the monsoon winds. Although the cashew is not native, sunbirds have been observed feeding on the fruit and the flowers produce bee nectar for local bees. Cashew trees are a great addition when integrated amongst native trees in your coastal landscaping plan.
Roasting the nuts is relatively easy. An old pot full of holes is the perfect receptacle to roast the cashews over a fire. The toxic resins burn off with a blue smoke and you know the nut is ready when the blue smoke clears and the blackened nut remains. Care should be taken to remove the nuts from the fire as soon as the toxic resins burn off to make sure they are not over roasted. The black outer shell can be hammered gently revealing the golden brown cashew nut within. Freshly harvested and roasted the cashew nut retains a sweet freshness that is superior to chestnuts.
There is a tribal communal bonding that happens when people come together to gather, roast and crack open the nuts, an echo that reaches back to some Amazonian forest where the cashew’s virtue was originally discovered.
Text by Jeffrey Dietrich – Jeffrey holds a B.S. degree from Antioch College in Environmental Science and is an avid birdwatcher, tropical landscape expert and naturalist, having visited many of the world’s premier natural areas and lodges.
Read about Asianitinerary visit to a cashew nuts factory in Krabi on http://asianitinerary.com/the-cashew-nuts/