Scientists Find Amazing Array of Amazon Life: Xingu Field Notes – PART FOUR

Written by Bronson Griscom on . Posted in Learn


Today’s post is the last in a four-day series drawn from the field notebook of Bronson Griscom, Ph.D., The Nature Conservancy’s Director of Forest Carbon Science, who recently returned from a trip to the Amazon. In the northern Brazilian municipality of São Felix do Xingu, where forests are rapidly being cleared for cattle ranches, The Nature Conservancy is working with landowners, communities, businesses and governments to support sustainable economic development that protects and restores forests. In this series of posts and the video above, Griscom brings us along into the forests on the edge of ranchlands to explain the science behind forest restoration.  

March 12 Continued: Orchids, Brazil Nuts and Busy Green Bees

We continue our trek through frontier forest on this bright Brazilian morning. Truth be told, I only recognize a few trees amidst the diversity. I’m a mediocre tropical botanist, but even the best don’t know every species – there are just too many for one human brain.

Next, I notice a young Brazil Nut tree, with grooved bark like an oak. At 20 feet tall, it will need to grow larger still before it produces nuts that might find their way into your spoonful of Rainforest Crunch ice cream. This long wait until fruit production may be one reason why all the Brazil Nuts we eat still come from huge trees in mature Amazonian rainforest.

But there’s another better reason: the peculiar sex lives of a stunning iridescent green bee that pollinates the Brazil Nut. Butter-yellow flowers of the Brazil Nut tree are folded upon themselves, like little nautilus shells. The green euglossine bees are the only creatures able to unlock those flowers, and fertilize them. The females do all the real work, fertilizing flowers and building mud nests. The males are obsessed with one thing: making perfume cocktails. So, they are the metrosexuals of the bee world (something to be proud of, considering that the term has been used on me, too).

To make their perfume cocktails, these busy bees must visit a smörgåsbord of orchids, which only grow in the complex canopy of a mature rainforest. Of course, even metrosexuals do it all for just one reason: sex. Just the right perfume cocktail is the only way to win over a female euglossine bee.

No mature forest canopy, no orchids. No orchids, no euglossine bees. No euglossine bees, no brazil nuts. So, the future of this young Brazil nut tree depends on a lot more than light and water.

We are circling back down the hillside now, and there it is, the grandmother of this story: an enormous Brazil Nut tree. It would take at least three of us to join hands around it. And there on the forest floor are the grapefruit-sized Brazil Nuts that can crack your skull when they fall. Inside these cannonballs are the individual nut wedges that make it into the mixed nuts bowls at cocktail parties.

Each ball laying on the ground has a gnawed hole in it, from an agouti: imagine a squirrel on steroids, but with the delicate legs of a ballerina. Aguotis gnaw open the hard cannonball shell and stash the nuts in burrows – just like a squirrel with acorns. A few get forgotten, and presto, you’ve got a nicely planted Brazil Nut seedling.

Keeping All the Parts

So, this relatively in-tact patch of forest is a shining example of nature’s resilience: a fragment less than 50 acres seems to be maintaining an impressive diversity of trees, including Brazil Nut trees and their co-dependents – at least for the moment. (The giant “grandfather tree” in the video at the top of the post, is in the Lecythidaceae family and related to the Brazil Nut, much like the oaks of tropical forests.)

A fragment like this is highly vulnerable to shrinking (think escaped fires, whims of landowner), and to loosing species over time. Also, large predators like jaguars and harpy eagles are surely gone, along with fruit eaters like spider monkeys. The absence of the bigger mammals has cascading impacts over time on forest regeneration – but that’s another story.

For the moment this fragment is a living warehouse of biological diversity, and a golden opportunity. We should prioritize forest restoration near patches of forest like this because:

 (1) It’s cheap. There’s no need to plant trees. Seeds will be naturally dispersed to nearby pasture.

(2) Regenerating forests will be high in diversity, since they will receive a high diversity of seeds from the nearby in-tact forest, and

(3) New forests will buffer the mature patches from further disturbance. If enough restoration happens, the large predators and monkeys will return, along with consistent rains – we hope.

Toasting Hope for Restoration

The team is ready to head home, but we slow down as we approach the booby-trapped bridge. I notice one more tree I hadn’t seen before. It has a beautifully fluted trunk.

I cut a tiny piece of bark off and place it on my tongue. A sharp bitter taste confirms my suspicion: it’s a Quina tree. The Incan name means “holy bark.” This is the original source of quinine, the first cure for malaria. It’s also the “T” in a G&T. Gin is from the berries of the juniper tree, native to my own country.  So, a Gin and Tonic on the veranda after a long day of field work is a grand union of north and south.

And wouldn’t it be grand if an organization with roots in America could help Brazil save some Quina trees? And if there is success in restoring this landscape, Brazil will have a lot to teach America about Aldo Leopold’s favorite topic: a land ethic and a Forest Code.

Bronson Griscom, Ph.D., is Director of Forest Carbon Science for The Nature Conservancy. You can read the rest of Bronson’s series, and check out video of the team trekking through Brazil’s frontier forests. Bronson also blogged about his love affair with forests and recently contributed to a serious article about sustainable logging and forest conservation

Videography by: Oliverio Cortez

Photo by: Oliverio Cortez (Mark Ashton (left), a global forest restoration expert from Yale University, confers with Bronson Griscom, director of Forest Carbon Science at The Nature Conservancy, during a trek to forest patches near the Xingu River in a part of Brazil where ranching is booming.)  

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