Rainforest Trees
Chapter 8:
– Introduction
– Botanical Garden in Rio de Janeiro
– Mahogany
– Brazil nut Brazilwood
– Balsam
– Cacao
– Palms
– Facts, Figures and Superlatives
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A silk-cotton tree.
From Barrington
Brown & Lidstone, 1878.
Introduction
Eco-tourists arriving in Latin America are often bewildered by the tropical trees, for there is a certain
amount of similarity between them (they are all tall) and their branches and leaves are not always
accessible for study. Also they all look alien compared with the trees back home, so it takes a long
time to identify trees in the tropics. The number of species is bewildering; for instance it is estimated
that there are as many as 6,350 species of tree in Peru.1
It’s helpful, therefore, if there is a guide with you on an expedition or if you are arriving during the
period of high water when your nautical travels up the rivers and creeks means that you will be
dodging the foliage and will be at eye-level for better inspection. And botanic gardens are great for
helping you through these arboricultural conundrums, whether you are visiting botanic gardens in
places like Roseau in Dominica, Manaus2 or the Rio de Janeiro Botanical Garden.
Botanical Garden in Rio de Janeiro
There is no better place for an introduction to the trees of Latin America than a walk through the
Botanical Garden in Rio de Janeiro. This is a highlight for anyone interested in the plants of the area.
It is not only celebrated as one of the best tropical botanic gardens in the world, but it also has
historical importance, as Charles Darwin visited it in 1832.
Set below the towering rocks of the Sugar Loaf Mountain, the Corcovada, there is always the distant
buzz of helicopters and paragliders, and the chaos of traffic that is Rio today. Such a tranquil place
to walk in is hard to find in such a bustling city.
Looking down the characteristically straight trunk of a rainforest tree with no branches.
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The most striking element of the garden is the avenue of Caribbean royal palms, Roystonea oleracea,
leading along one edge of the garden. The palms grow tall and elegant, and with well over 100 pairs
they form a most important axis of the garden. This is not the only avenue of trees here, for there is
also a less well known, but historically important, avenue of introduced mango trees, Mangifera sp.,
with their heavy aching boles and limbs labouring along one area in the middle of the garden, and
another avenue of cannonball trees, Couroupita guianensis.
There are long pergolas cascading with the bright yellow cat’s claw trumpet vine, Macfadyena
unguis-cati, a native of Yucatan, Guatemala and Argentina, or with the huge flowers of climbing
bull’s balls, Aristolochia gigantea, a native of south-east Brazil, both of which would be decorating
trees in the wild. A centre-piece in the garden is a large lake surrounded with native trees and palms
such as Phoenix species. The gardens are mature and exhibit a huge collection of trees from around
the world, not just from Brazil. It’s like a forest in a city with the tropical wildlife all around, including
toucans and marmosets.
Other native trees in the garden include the ceiba or silk cotton trees with their silk-like tassels and
huge buttresses, for these are the giants of the rainforest, perforating the canopy and making
Ochroma pyramidale
(Bombacaceae) Balsa wood
If there is a tree that all
school children will know
that is from the rainforest it
is balsa wood that is
extremely light and is used to
make models. The balsa wood
tree is a native of South
America. A typical habitat in
which it might be found would
be by the edge of the river
where it is a successful coloniser.
Here
its typical large leaves are framed
against a backdrop of the Madr
e
de Dios river that many ecotouris
ts
will know in Manu, Peru.
Looking up the straight trunk of a Dominican mahogany.
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wonderful lookout places and safe sleeping quarters for monkeys. They are also called kapok trees,
since their downy hairs are used for stuffing pillows and mattresses, and also for wrapping around
the ends of arrows.
Also present in the garden are native Pithecellobium trees, which are also rainforest giants; there are
over 200 species, and their wood is used for building. One of the most widespread is the monkey-pod,
P. saman, which is native to Central America and northern South America. It is used as a shade tree
and is now grown extensively around the world.
Another interesting tree to be seen in the garden is the ‘monkey-pot tree’, Lecythis pisonis, which
carries fruits that are rather like small pots with lids that detach when ripe, thus allowing the seeds
to fall out, or monkeys to help themselves; this is similar to the way in which Brazil nut trees have a
large pot-like fruit capsule from which the seeds (or nuts) disperse. The ‘monkey-pot trees’ (there
are over 50 species) are native to Brazil, and the seeds are sometimes called ‘paradise nuts’.
Amongst the native herbs of South America grown at the Botanical Garden is allspice, which might
not otherwise be seen on travels around the continent. It is a small bush and there are a number of
species, all native to various parts of South America. The familiar allspice is the dried unripe fruit of
Pimenta dioica, whilst the bay rum tree, or P. racemosa, a native of the West Indies, Venezuela and
Guinea, is used to produce ‘oil of bay’, which is used in the perfume industry and for making
bay rum.
On the ‘Nature Island’ of Dominica,3 bay oil plantations represent a small industry in the east of the
island, where rolling mountains are covered with these unremarkable trees that are harshly pruned
for their leaves and regrowth. The bay oil is not for drinking, but is extremely strong and heavily
diluted for use as an aftershave.
The next part of this chapter deals separately with some important trees in tropical Latin America,
including mahogany, Brazil nut, Brazilwood, cacao and palms in general.
Mahogany
Swietenia sp. (Meliaceae)
True mahogany comes from just three species of tree native to South America. The word ‘mahogany’
has been used by the retail trade to mean the wood from many other species, even for species that
do not come from South America, but the true mahogany species all belong to the genus Swietenia.
Bertholletia excelsa Brazil nut tree.
Cherished trees in the rainforest, Brazil nut trees are looked after and the fruit collected from the wild. They are tall trees with long straight
stems and the heavy capsules are produced high up in the trees, only to fall down when ripe. The capsule lid falls off, allowing the seeds
to be taken away by small mammals.
Inset: Fresh peeled Brazil nuts are soft and creamy and offer a totally different experience from those sold in the shops.
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The three species are S. mahagoni, S. macrophylla (the Honduras mahogany or big-leaf mahogany)
and S. humilis. The Honduras mahogany has the widest distribution from Mexico south to Venezuela,
and is not particularly confined to Honduras. However, S. mahagoni – the West Indian mahogany
– is native to the Bahamas, Cuba, Jamaica and Hispaniola as well as to southern Florida.
Mahogany has a definite role in the rainforest in that it exploits gaps in the forest, either caused by
nature – trees falling down, storm or hurricane damage – or as a result of slash and burn by man. It
is a quick-growing species that does well in disturbed habitats, such as along riverbanks that get
disturbed by the rise and fall of the water, for instance in Amazonia. Old specimens are probably up
to 200 years old. The flowers of mahogany are highly scented and attract many groups of insects;
however, the actual pollinator is still unknown. 75% of the total range of mahogany is in southern
Amazonian Brazil, considering that its full range covers 4,800 miles (8,000 km) from Mexico to
Bolivia totalling an area of some 0.78 million sq. miles (2 million km2).4
Studies by ecologists suggested that the Mayans who lived in the limestone forests of the Yucatan
in Mexico possibly grew mahogany along with two other useful tree species, Manilkara zapota for its
resin and Brosimum alicastrum for its fruit. These species now grow at greater densities over these
old sites than on other sites not previously occupied by the Mayans.
Mahogany is still eagerly sought by the Europeans and North Americans. However, with so many
sawmills along the riverside of Amazonia providing house-building and ship-building materials for the
local populations, it is thought that even banning exports would not have an appreciable effect on
the trade in mahogany. There are currently some attempts to grow mahogany within Amazonia and
Ecuador, and it is sometimes looked after by settlers who move into much of the 78,000 sq. miles
(200,000 km2) of abandoned land cleared of rainforests.
Brazil nut
Bertholletia excelsa (Lecythidaceae)
The Brazil nut is one of the best-known ‘fruits for the forest’. It is also the only commercially traded
crop in the world that is harvested almost exclusively from the wild. It is an easy tree to spot, since
it is a handsome and dominating tree. It is nearly 30 years since plantations of Brazil nut were
established near Manaus in Brazil and production has been low.5
The tree grows tall without branches up to 165 ft (50 m) and has a large canopy. The nuts develop
inside a very tough and woody capsule, and when ripe the whole capsule drops to the ground and
the nuts spill out through a lid that fractures on impact. Some people have been killed by falling
Ficus sp.
The fig family (Moraceae) is very biodiverse and chiefly Old World, with just a few native species in the New World. The strangler fig starts
life by germinating in the canopy and then works its way down a support tree. It then strangles its host as it established its roots in the
ground. An old strangler fig like this one becomes a centre-piece in the rainforest as it consolidates its position, throwing down more and
more support branches and thereby offering plenty of sanctuary to both flora and fauna.
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capsules, since a capsule that can weigh a kilo or more can kill when falling from that height.
Landowners (i.e. the ordinary folk who live along the rivers) always know where their Brazil nut trees
are, since they are like key markers in the rainforest and represent a valuable source of income. The
trees propagate themselves, the nuts being taken off by various small mammals in the forest,
germinating quickly in the thin leaf litter.
The Brazil nut is also known as the Para nut, after the old name of Belem near the mouth of the
Amazon. It is from here, and now other places in Brazil, that the nut is exported around the world. It
was reported in late 2003 that more than 45,000 tonnes of Brazil nuts were exported from Brazil
each year, with a value of £19 million.6 For those familiar with the taste of the nuts by the time they
have arrived in Europe and beyond, it comes as some surprise that the taste and texture is completely
different if the nuts are eaten from fresh capsules straight from the tree. Fresh brazil nuts are smooth
and soft, with an agreeable rich creamy taste, hence its other name of ‘cream nut’. Brazil nuts in
their shells are now not permitted to be imported into Europe following an EU ruling that the shells
may carry excessively high levels of pathogenic aflatoxins.
Roystonea oleracea
The famous avenue of Royal
palms in the Rio de Janeiro
Botanical Garden makes a
shady boulevard and
axis through the
garden. Of all the palms
the Royal palm is
majestic and tall with
straight stems making
it an ideal subject for
planning grand
gardens.
The unbranched bole of a Red Ironwood tree in Manu, Peru. There are at least eight different species of ironwood trees, and many of them
are tall and emergent from the rainforest canopy.
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Brazilwood
Caesalpinia echinata (Leguminosae)
The country of Brazil is named after this species. This is another tree exploited by the early settlers,
and its other names are ‘pernambuco’, presumably after the coastal state of Pernambuco where
fine stands once grew, or ‘pau Brazil’. It is an impressive tall tree that has been mercilessly exploited.
Today the best place to find it is in the Botanical Garden in Rio since it has now been extirpated from
its natural habitat. It is registered on the IUCN World List of Threatened trees, and has had protection
under Brazilian law since 1990.
The main reason for the demise of the Brazilwood tree in the wild is that its wood was found to be
an excellent dyewood. Consequently its timbers were exported to Europe to assist the textile
industry. When aniline dyes were invented in the 1800s this spelt the end of Brazilwood exports in
such quantities. Today Brazilwood is the premier wood used to make violin bows, since the wood is
extremely dense, is hard, and has high-strength qualities.
So from a history of servicing the textile industry in Europe, the Brazilwood has gone on to a more
refined and less destructive role, of helping in the art of making violin music.
Balsam
Myroxylon balsamum (Leguminosae)
Balsam is a tropical tree that many thousands of Indians and colonists originally relied upon for a
variety of medicinal uses and some income. Like rubber, it is tapped to drain off the oil, a 20-year-old
tree yielding about 6.6 lb (3 kg) of oil annually.7 Today the main producers are Columbia and Peru,
and El Salvador exports about 50 tonnes of the oil annually.
The tree is often called the balsam of Peru, but it is not a native of that country. It is, in fact, native
to Central America. Its name association with Peru is because the early shipments of the oil to
Europe were from various ports in Peru. An old nineteenth-century book gives an interesting account
of supplies of balsam coming down the Amazon to be traded at the mouth of the Amazon:
The quantity of balsam coparia brought down is prodigious, there were lying on the beach at
Barra two hollowed logs in which balsam had been floated down from above. One had
contained twenty-five hundred, and the other sixteen hundred gallons. They had been filled
and carefully sealed over; and in this way had arrived without loss, whereas in jars the leakage
and breakage would have been considerable. At Barra the balsam is transferred to jars and
shipped to the city.8
Crescentia sp.
The calabash tree has enormous gourd-like fruits that are harvested and made into receptacles for food and water. This one is growing in
a very humid location as it is festooned with ferns. There are six species in tropical America.
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The tree grows in Barra (the old name for Manaus), where it is a tall tree, tapped for its balsam by
cutting deep incisions into the bark. The average yield of balsam per tree is said to be 5–10 gallons
(19–38 litres).
Cacao
Theobroma cacao (Byttneriaceae)
The cacao tree, from which chocolate is made, is a native tree of the lowlands of South America.
That means principally the Amazon. There are, in fact, five species of Theobroma, but the species
T. cacao is the one that is cultivated throughout the continent. It is a familiar sight in villages and is
usually planted close to the houses, being fairly leafy and not too tall, i.e. just about tall enough to
walk under its branches and to notice its pink, brown and sometimes red fruits attached to the trunk
as well as the undersides of the larger branches. These ripe pods are then collected, struck open
The Walking Stick Tree,
Socratea sp. which is a native
of the rainforests of south-east
Peru is actually a palm that
raises itself off the
rainforest floor with stilts.
During the continued battle
for sunlight, it can move
by a few centimetres over a
few weeks by putting down
a stilt to get itself over
into the better light
conditions. This is a nifty
trick for a plant that
is not supposed to move.
Cecropia sp. Cecropia
One of the best pioneer species of the rainforests, cecropia is a sure indicator that man has been there before. This is a very young
specimen showing its palmate leaf structure.
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with a machete to reveal pink seeds set in a matrix of downy white fibres that, incidentally, do not
bear any resemblance to chocolate in taste, colour or smell at this stage.
To make these wet and soggy seeds ready for consumption they have to go through a process of
fermentation. The pink seeds are gathered together into a large pile and slowly roasted under a
blanket of banana leaves for a few days. The exact details of the process that goes on during this
period of ‘fermentation’ is not completely known scientifically, but the pink tasteless seeds are
turned into roasted nuts, fit to make a cup of chocolate.
Cocoa beans have been used for a long time in South America, and were even used as currency by
the Aztecs. There is not the remotest chance that the cacao tree will die out in South America in the
wild, but its future does not look secure in commercial plantations. The problem comes from two
fungal diseases that are now rife on the continent, and could get much worse. The first is Witches’
The ariquara
tree, a native of Amazonas
state in the Amazon, Brazil.
They are sometimes used
as suitable telegraph
poles in communities.
Broom Disease (WBD) – escoba de bruxa in Spanish – and the other is Frosty Pod Disease (FPD),
with both these names describing the appearance of the symptoms of the disease.9
Ecuador used to be the major producer of cocoa in the world, with up to 50% of world production
coming from the large plantations on Ecuador’s Pacific coast. It was the first to be hit by WBD in
1921, and by 1931 half of its production had halved. The movement of people was probably
responsible for the spread of the fungus, for WBD turned up in Trinidad in 1928 and, crossing the
Andes, it was soon seen in Rondonia and Acre in the west of Brazil and then in Bahia on the Atlantic
Coast. The absence of a dry season allowed the fungus to prosper. The first reported case of the
Couroupita guianensis The cannonball tree
A highly productive tree with cannonball fruits, all borne on the tree trunk, which is not untypical of some rainforest trees. The species is
native to the Guianas. It is frequently planted in botanic gardens as a curiosity. The fruits would normally tumble to the rainforest floor and
its seeds are presumably dispersed by mammals and birds.
Inset: Flowers of the cannonball tree.
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A house made
principally out of
palm leaves. Nova
Arao (Novoairao),
Amazonas state, B
razil.
disease in Bahia was in 1989, which, according to G. Griffith, caused 200,000 people to be laid off,
and a further 2 million people indirectly involved with cocoa production were affected. Whilst South
American cocoa production struggles with the vagaries of the disease, production in the rest of the
world, including West Africa, Malaysia, Papua-New Guinea and Vietnam, has prospered.
The future does not look too gloomy for South American cocoa producers, since there are attempts
to find resistant species and varieties within the rainforest and villages, there are attempts to find
biological control agents, and there are attempts to sequence the genome of the fungi causing the
trouble. This will alert scientists to any weakness in the fungus that can be exploited so that it does
not continue to wreak havoc on one of the world’s most important economic trees.
It is not just man that is dependent upon this native South American tree. Birds have become
accustomed to it, for it is now said that the loss of cacao plantations can have an impact on migratory
birds. Researchers at the Smithsonian studied the birds in and out of cocoa plantations of Ecuador
during 2003/04, and their results suggested that birds in cocoa plantations play an important role in
controlling insect pests. They recorded some 603 species of birds in the plantations, compared with
646 species of birds in the rainforest.10
Pimenta racemosa
Bay or Bay-Rum tree is a member of the Myrtaceae family. It is grown commercially in the Commonwealth of Dominica, where the hillsides
are covered with rows of the trees. These are pollarded regularly and stripped of their leaves to make oil of bay.
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Palms (Palmae)
Palm trees are widely seen across tropical Latin America, on terra firme, growing along creeks or
alongside mangrove trees in the water. They are a large group and widely distributed, traditionally
used by man both for food and for the construction of houses and boats.
Of all the palm species that exist (over 2,000 species), one particular palm is vitally important to
millions of Brazilians, and that is the babassu palm. This has a huge distribution across the Amazon
from Rondonia in the west to Ceara in the east and Minas Gerais in the south. It is also found in the
Mato Grosso, and is especially common in Goiás. It is a keen coloniser and is said to cover 78,000
sq. miles (200,000 km2) over the Amazon Basin.11 300,000 households are estimated to be the most
dependent upon this palm’s survival in the Maranhão region. This is in Tocatins state along the
coast, just south of the mouth of the Amazon.
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fruits are often
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Stifftia grazielae
This is a new species of shrub described as recently as 1996. Rio de Janeiro Botanical Garden.
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In terms of this palm’s contribution to natural stands of vegetation, it is known from one study area
(Lago Verde) that the babassu palm is the most ecologically important species in the stable primary
forest. It succeeds in primary forest since its seedlings are eaten relatively rarely, and it persists in
relative shade to close the canopy when there is a gap developing. Essentially it out-competes all
other species and becomes dominant quickly. It succeeds because it has rapid growth, and its
seedlings can withstand rainforest cutting and burning. With a density of 10,000 seedlings per
hectare, very few other plants are able to colonise.
Babassu palm is one of those species that grows up rapidly and swamps an area, particularly after
fire or deforestation. The locals love the species, for the kernels are a source of oil for cooking,
animal feed, soap production, and the husks are made into charcoal.
The babassu palm actually exists as many different species and natural hybrids of the Orbignya
genus. Although there have been at least thirty species described, only twenty are known to be true
species. Babassu palms live a long time, up to 165 years, and grow very tall over time.
Large numbers of fruits are produced by babassu palms and they generally stay around the tree
rather than being dispersed by animals, though paca and agouti do eat some seeds. Over twentyeight insect species are recorded from the seeds; some of the big, fat, white beetle grubs are food
to the women who crack the kernels out.
When man has felled the forest, the babassu palm has expanded its range, since it is such a good
coloniser. Fortunately for those that practice slash and burn, the palm is a useful plant that springs
out of the black earth. The threat to many a forest family is that many stands of these long-lived
palms will be clear-felled so that their trunks can be carted away to distant cellulose factories and
their fruits cracked mechanically in large industrial units.
If you want to learn more about the role of the babassu palm, one of the best sources of information
is ‘The Subsidy from Nature, Palm Forests, Peasantry, and Development on an Amazon Frontier’ by
Anthony Anderson and colleagues, published in 1991.
Facts, Figures and Superlatives
• There are 6,350 species of tree known in Peru.
• Brazil is named after a tree – the Brazilwood.
• Brazil nuts are harvested almost entirely from the wild.
• Palm hearts are still collected from the wild unsustainably.
• Strangler figs germinate in the canopy.
Brownea grandiceps, the rose of Venezuela, family Leguminosae, native to Venezuela, Columbia and Ecuador.
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• Balsa wood is used for rafting as well as modelling.
• Tall rainforest trees are used by monkeys for sleeping.
• The ariquara tree makes perfect telegraph poles.
Endnotes
1. Pennington et al. 2004. The authors believe that this figure is
likely to rise by at least 10%, since several genera have yet to
be revised; they had already shown that 1,968 tree species
come from only forty genera.
2. Adolpho Ducke Botanic Garden covers 39 sq. miles (100
km2) east of Manaus and is set up for tourists, who can
discover the different rainforest woods, walk the trails, and
visit nurseries and exhibitions.
5. Mori, S. 1992.
6. Peres, C. et al. 2003. Science, 19 December 2003,
2112–2114.
7. Tropical Plant Database [see http://www.rain-tree.com/
balsam.htm].
8. Edwards, W.H. 1847.
9. Griffith, G. 2004.
3. The Commonwealth of Dominica, not to be confused with the
Dominican Republic.
10. See http://nationalzoo.si.edu/conservationandscience/
migratorybirds/research/cacao/default.cfm
4. Pennington, T. 2002.
11. Anderson et al. 1991.
The Holy tree, as it is known in Manu, Peru, is a member of the Triplaris genus, a very distinctive tree found in lowland secondary rainforest.
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