BATS AND THE TONKA BEAN or CUMARU TREE (Dipteryx odorata, D. Micrantha)

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The tonka bean or cumaru tree is a native of northwestern South America. A member of the legume family (Fabaceae), it can grow to 50 metres (164 feet) in height, 1.3 metres (4.3 feet) in diameter and is heavily buttressed. There are perhaps one or two trees in a hectare (2.471 acres) of forest. (13) The size and long life of the tree have given it a local significance akin to the baobab tree in Africa and Madagascar.(9)

• Artibeus jamaicensis - Jamaican fruit bat
• Artibeus lituratus - Big fruit bat
• Artibeus obscurus - Dark fruit bat
• Carollia perspicillata - Seba's short-tailed fruit bat

Products:

The tonka bean tree provides income for people. The vanilla-scented and vanilla-flavoured pods are collected, mainly from wild trees. Bats are considered the major crop pest by those collectors.(3) The beans are processed and a final product, coumarin, is used by manufacturers who incorporate it into perfume, candles, soap, bath bombs, pipe tobacco and vanilla substitutes.

The organic compound, courmarin, was synthesized from a coal tar product in 1881 by William H. Perkin(16)but a market still exists for the natural compound. Tobacco leaves destined for pipe tobacco are sprayed with natural coumarin, mainly in the United States.(6) Nigel Green states in The New Perfume Handbook (1997) that an absolute of coumarin (less than 1 percent water) is used in 10 percent of modern perfumes and in 13 percent of men's quality fragrances.(5)

Tonka bean wood makes excellent charcoal. It is a local product and a source of income for local people.

World-wide there is a distressingly enthusiastic demand for tonka bean wood, especially in China.(13) It is marketed as cumaru or Brazilian teak. Sellers of the wood for parquet floors, decking and deck furniture promote it as one of the hardest woods on earth.(4)

Allen Lee observed the arrivals of logged Dipteryx for a week at the southeastern Peruvian town of Puerto Maldenado and estimated that a thousand trees a month could be transported to that one location.(9)

Brightsmith (2)was told that a tree's owner could accept as little as $30 (about £20) for a tree with a diameter of more than 1 metre (3.28 feet). Putzel characterized a Dipteryx odorata with a diameter of 1.3 metres (4.3 feet) as a "giant".(13)

Will the wild supplies of mature trees last? Probably not, but there are over 300,000 websites that appear in response to a search for "sustainable forests + South America". Dipteryx odorata is included among the trees that are protected and/or replanted in sustainable forests.

Over 10,000 websites appear in response to a search for "cumaru + sustainable forests". The sellers listed state that the wood is guaranteed to be from sustainable forests. That assurance provides some hope that the tree will survive as a species despite its apparent relentless logging in Amazonian wild forests.

Whether the local incomes generated by collection of pods from wild trees will continue is more questionable. The sweet smelling element, coumarin, lives on by synthesis for manufacturing purposes but the income for wild pod collectors may evaporate with the disappearance of wild trees.

Macaws:

If the natural forests containing wild Dipteryx odorata and its close relative, Dipteryx micrantha, disappear, there are many losers. One group is the big macaws that need long-lasting, rain-proof shelters that are high above the ground.

Brightsmith writes that the macaw's family, Psittacidae, is the most endangered of all large bird families worldwide. His four year study in the Tambopata, eastern Peru, revealed that 75 percent of the scarlet macaws observed and 88 percent of red-and-green macaws observed had their nests in large Dipteryx micrantha trees.(2)

A large, mature Dipteryx micanthra tree can be riddled with satisfactory nest cavities, nurseries for dozens of young macaws every year. This nurturing facility can exist for tens and even hundreds of years, given the trees' potential for a lifespan of more than 1000 years.(2)

Even if Dipteryx odorata and D. micrantha are replanted in a sustainable forest scheme, it will take many years for the trees to reach the height and maturity that allows them to provide the features needed by parrots and macaws for nest sites. Anyway, the trees are being replanted for a quick, profitable harvest, not to accommodate nesting birds.

So, scarlet macaws are losers as the big Dipteryx trees vanish. Red-and-green macaws are losers. There are countless other losers in the destroyed Amazon forests. Then there are the oblivious human losers who revel in polished parquet floors, durable decking (guaranteed not to rot for 25 years) and sturdy deck chairs, all potentially made from veteran Dipteryx trees that once rose above the rainforest canopy and held that position for hundreds of years.

Chemicals:

As with many plants that have chemical defenses for their protection, human beings have learned to use those defenses to treat their bodily ailments. Decoctions from various parts of the Dipteryx trees are used in folk medicine for cramps, nausea, mouth ulcers and ear aches.(3)

The unfavourable side of a plant's therapeutic benefits is the potential physical damage to humans and animals that can be caused by the same or other self-protecting chemicals. A derivative of coumarin, Warfarin, is used medically as a blood thinner in humans. A form of Warfarin is used as a lethal hemorrhage-causing poison for rats in buildings and to kill gray squirrels in the United Kingdom during the time of year when they strip bark from trees.(7)

A medication based directly on coumarin and marketed under various names, has been used in several countries to treat lymphedema, the swelling which can accompany cancer. The medication has been withdrawn in some countries because of liver function abnormalities in tested animals and among treated patients.(10)

Coumarin as an additive to foods has been banned in the United States since 1954 although it continues to be used there in pipe tobacco. Shoppers in Mexico are warned not to buy vanilla flavouring which has a tonka bean additive.(1) Nevertheless there are almost 10,000 sites on Google for "Tonka Bean Ice Cream" and Carib people are said to enjoy a thick, vanilla-fragrant, flavourful drink by combining tonka bean paste with coconut milk, apparently without suffering remarkable ill effects.(3)