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Up a Tree

Host Nalini Nadkarni on a research location in Costa Rica.
Christian Sinibaldi
Host Nalini Nadkarni on a research location in Costa Rica.

Even though I’m in the tropics, it’s dark, damp and still here on the ground.

The sun’s intense rays are absorbed by the layers of leaves over my head. Looking upward, I feel a familiar jig of excitement. What will I find today?

It wasn’t all that long ago that scientists called the tree canopy "the last biotic frontier." Until about 30 years ago, there was no safe way to get up there — it was a world waiting for exploration.

I step into my seat harness and leg loops. Clamping my ascenders onto the rope, I’m ready to climb. As I inchworm my way up the rope, my view begins to shift. Now, I look down see how the leaves are arranged to capture every bit of light.

10 more minutes and I’m at the top. Everywhere I look, there are huge branches covered with carpets of orchids and ferns.

I’m not the first scientist to notice the diversity up here. Canopy researchers have documented over 24,000 species of flowering plants in the tree tops — far more than you’d find rooted on the forest floor.

One reason for this high diversity is that the canopy environment is very different. Up here, there's more sunlight, greater extremes of humidity and temperature and more wind, too, which let’s canopy plants send their seeds to populate other suitable homes in forests far away.

And the canopy provides a different surfaces for the plants to rest on — from skinny young twiglets to limbs as broad as picnic tables — giving them more choices about where they can flourish.

By documenting the canopy’s plants, scientists are able to have a more complete inventory of the forest community. Without this knowledge, the complex jigsaw puzzle of the rainforest would be incomplete.

Exchanging my ascenders for my rappelling gear, I start my decent. As I move through the thousand, thousand leaves, a purple-throated mountain gem flashes by, attracted to my red shirt, a wonderful bonus for this trip aloft.

Dr. Nalini Nadkarni is an emeritus professor of both The Evergreen State College and the University of Utah, one of the world’s leading ecologists and a popular science communicator. Dr. Nadkarni’s research and public engagement work is supported by the National Geographic Society and the National Science Foundation. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation. @nalininadkarni
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