Deep Jungle: Monsters of the Forest
The Amazing Brazil Nut Tree

Taking a walk through the Amazon rainforest? Might want to keep an eye out for what look and sound like cannonballs, crashing down from above at more than 50 miles an hour. If you are unlucky enough to be in the way, you could end up dead — or at least severely dazed!

The balls, which can weigh up to 5 pounds, aren’t really fired from a cannon. They are actually the fruit of the Brazil nut tree, one of the most marvelous and mysterious trees in the rainforest. Each ball-shaped fruit or pod holds up to two-dozen seeds we conventionally know as Brazil nuts.

For centuries, however, Brazil nut trees presented a puzzle to biologists. For one thing, they couldn’t figure out what kind of animal was able to break open the rock-hard fruits so that the nuts could sprout into new trees. For another, it wasn’t clear why only trees in undisturbed forests bear fruit.

As NATURE’s Deep Jungle: Monsters of the Forest shows, researchers have begun to solve the Brazil nut’s mysteries. In addition to learning more about the tree’s mysterious existence, viewers get a look at one of the Brazil nut’s archrivals — the incredible strangler fig, which can choke a huge Brazil nut tree to death within a few decades.

Brazil nut trees are among the giants of South America’s Amazon. They tower up to 200 feet high, and their spreading branches and flowers provide habitat and food for numerous forest creatures. The Brazil nut is also the foundation of a global business worth $50 million a year. Collectors harvest the nuts by gathering fallen pods and chopping them open with sharp tools. A single mature tree can produce more than 250 pounds of nuts a year.

But how do the nuts get free from their rock-solid pods in the wild? No Amazon creature, it seemed, had jaws powerful enough to crack open the cannonballs.

One answer, it turns out, is the agouti — a small mammal that looks a bit like a large guinea pig. Agoutis have small, chisel-like teeth that can penetrate the Brazil nut’s seed case. They eat some of the nuts. But, just as important, they carry away and bury others for future meals. If forgotten, these seeds can stay dormant in the soil for years, waiting for the perfect conditions to germinate and grow into a new Brazil nut tree.

The agouti isn’t the only animal that Brazil nut trees need to survive. It appears that they also rely on certain bees, and even other plants, to reproduce. Orchid bees visit flowering Brazil nut trees to collect nectar; as they buzz about feeding, the bees inadvertently carry pollen from tree to tree, fertilizing the flowers and helping the trees produce nuts. For the bees to survive, however, the males must attract mates, and to do that, the male bees need fragrance from a particular orchid to attract female bees. If the forest is damaged and the orchids disappear, so will the bees — and the Brazil nuts.

Forest disturbance isn’t the only threat to Brazil nut trees. Competition also comes from a sneaky plant known as the strangler fig tree. Strangler figs start out as tiny, almost invisible seeds deposited on a branch by small mammals or birds. The seed sprouts, and a tiny root gains a foothold. It’s the beginning of the end.

Eventually, the root creeps down the trunk to the forest floor, stealing water and nutrients from the tree through its bark as it goes. More roots soon join in, wrapping tight around the Brazil nut tree, encasing its victim. Ultimately, over decades, the tree dies, leaving the fig standing like a hollow monument to this epic struggle.

  • Annette

    When and where will this episode air? I am in Ottawa, ON Canada. Since my son just completed a grade three assignment where he created a diorama with the the brazil nut tree as the feature plant, this show would be a fantastic wrap up. Let me know please and thanks. A

  • jelina

    this is a very interesting topic. thank you for sharing this. :D

  • Dallas

    I’m a student and need to find these videos for deep jungle. i can’t find them no matter where i look. There should be a link to those videos. Can someone help me?

  • Dave G

    PBS I would like to see more of capybaras. Maybe their own nature special along with cavies and other rodents of that class. I find them fascinating. Capybara’s are the world’s largest rodents and yet seem to be the world’s best kept secret. Maybe a special on all forms of rodentia.

  • Daniel

    I saw this episode air about 5 yrs. ago or so. I just started looking for the dvd and cannot find it anywhere. If there is anyone who has knowledge about how I can get this episode on dvd please let me know.

  • tomas

    i am doing a report on the Bazil nut tree and i am having truble finding info on it. i have been on here for a hour already.

  • kays

    how long it takes for this tree to matured?
    \

  • fiorella

    when was this tree created?

  • jewel

    stop the madness of deforestation!! soon we will have no brazilian nut trees!!

  • Jean-Philippe

    I just ordered the DVD set of Deep Jungle on the following website: http://www.shopthirteen.org/product/show/30812
    Some people above were seeking a way to buy the DVDs; I hope this helps.

  • Jenny

    This tree is a true gift and of we don’t stop the crap people are doing to the rain forest soon we will no longer have these gifts!!!!!!!!!

  • an online banking

    Thanks for another great idea (and I’ve added “Putting things By” to my Book List too)! :)

  • Love Being Green

    Congratulations on your informative account of the Brazil Tree, it was fascinating and educational. Why, even at 78 years of age, I did not know how these nuts grew! You can always learn something more! lol Thank you so much and I can’t wait to impress my grandchildren … husband too!

  • Sou

    couldnt agree more Jenny of june 16th 2011 puts it well . We can save all the people we need but no eco system no earth, no earth no place to live. Surely saving it is a priority not an optian.

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