In the rainforests of Southeast Asia, Central and South America, and New Guinea and Australia, there's not much happening on the ground. In fact, it's pretty dark down there, with only a few animals and plants, and just the tiniest smidgeon of sunlight seeping through from above. Up in the treetops -- that's where the real party is going on! Soaring 100 feet (30.5 meters) or more in the air, the rainforest canopy is a layer of treetops, other vegetation, insects and microscopic life forms that towers so high above the Earth that human beings don't often get a close look at it, except when they glance down at it from an airplane. Plant life needs sunlight to survive and the rainforest trees thrust their leaves up into the canopy where they can get as much of it as they can. And it's not just leaves: There are so many different kinds of plants and animals up there in the canopy that they may represent as much as 75 percent of all species on Earth.
But let's suppose you're a scientist studying the rainforest canopy or even just a tourist on a tropical vacation who wants to see the most spectacular part of the rainforest up close. How would you get up there? Sure, you were probably good at climbing trees when you were a kid, but could you climb a tree 100 feet (30.5 meters) or more tall? Even more importantly, would you want to? That's a pretty long way to fall if you lose your grip or stumble on a broken branch. Worse, most rainforest trees don't even have branches for climbing at levels lower than the canopy. You'd have to be Spiderman -- or maybe an actual spider -- to climb one of these trees without special equipment.
And yet the importance of the rainforest canopy to species diversity makes it pretty urgent that scientists find their way into it and study it in detail. And when scientists go someplace as spectacular as the soaring treetops of the tropics, tourists are bound to follow. On the next few pages we'll look at some of the adventurous ways scientists have braved the dangers of the treetops and at ways that you can have your own rainforest adventures when you visit the tropics. Oh -- and we'll also look at some of the dangers involved in climbing around in some of the tallest trees on Earth.