The Secret World of the Redwood Canopy

By ILONA BRAY

Mushrooms cover a coast redwood branch, high above the forest floor in Jedediah Smith Redwoods State Park, CA. PHOTO: Stephen C. Sillett courtesy of Save the Redwoods League

A TREE GROWS IN A TREE: A dogwood tree (left of the researcher) grows in the giant sequoia canopy in California’s Calaveras Big Trees State Park. PHOTO: Stephen C. Sillett courtesy of Save the Redwoods League

This canopy of green resembles the underside of an umbrella. PHOTO: Peter Kaminski

Who knew that, high in old-growth redwood trees along the coasts of California and Oregon, a hidden world exists? Until recently, no one—not even scientists. You’ll see why if you visit these forests. Looking up, you’ll notice long brown trunks (with almost no low branches) and a canopy of green, like the underside of an umbrella. It’s beautiful, but you’d probably think, “Not much going on up there.”

These trees had everyone fooled. “Up in the redwood canopy, you discover an amazing ecosystem,” says Dr. Emily Limm, Director of Science at Save the Redwoods League in California. “Birds land nearby, and everywhere you look is something alive; salamanders, moss, ferns, even huckleberry bushes. The weather is different, too. I’ve been in hailstorms up top while it’s dry below.”

What’s going on up there? In a truly old-growth redwood forest, a rich layer of organic stuff builds up in the treetops, like a very high second floor. As the original treetops fall off, new trunks grow up like big fingers, and old leaves and twigs pile up amidst the giant trunks and branches. The mass is continuously trapping water and decomposing.

The resulting spongy mats of canopy soil can be the size of a small school bus. People can walk on them (carefully) and munch huckleberries. Earthworms dig through the soil, and other trees take root. A spruce tree was once spotted growing out of a redwood!

The more scientists explore this treetop world, the more they find. And the more they want to protect it, because most redwoods have already been chopped down, with the rest threatened by global warming.

DEFINITIONS:

Canopy: a covering

Old-growth forest: A forest with trees at least hundreds, perhaps thousands, of years old. Old-growth forests of trees like redwood, spruce, fir and pine still exist in areas across the United States. The biggest ones are on the West Coast.

PHOTO: RNHA/RPA National Park Service

Animals That Live in the Canopy

These creatures are known to live, or at least hang out, in the redwood canopy:

Spotted owl PHOTO: Redwood National and State Parks	Woodpecker; this is a pileated woodpecker PHOTO: Redwood National and State Parks	Marbeled murrelet (when it’s nesting) PHOTO: Redwood National and State Parks	Chipmunk PHOTO: Flickr/Dawn Huczek
Squirrel PHOTO: Flickr/Reijii	Copepod (a shrimp-like crustacean) IMAGE: courtesy of Michael Camann/Humboldt State University	Wandering salamander PHOTO: Gary Nafis and CaliforniaHerps.com

How global warming threatens the redwoods

Redwood trees take in much of their water not through their roots, but by absorbing moisture from fog. That creates potential problems as climate change causes drier weather along the California coast. Less fog = thirsty, less healthy redwoods.

How Does Anyone Climb a Redwood?

Redwoods can grow to more than 370 feet. That’s taller than any other tree in the world. It’s even taller than the Statue of Liberty, whose torch touches the sky at 305 feet above the ground.

Without equipment, your first step in climbing would have to be a skyscraper-high jump, around 25 stories into the air, just to reach the lowest branch.

Scientists who study old-growth trees have to be trained rope climbers. They learn special techniques to avoid damaging the trees, including securing ropes over branches, suspending their weight in harnesses, and wearing soft-soled shoes. It’s dangerous work. At such heights, and with all the moss and dead wood, one mistake can send a climber into a fatal tumble.

Recreational climbers tend to stay away from the redwoods. Good thing, because their presence can damage the trees. In some parks, tourists can take special canopy tours where they ride on zip-lines.

A man rides a zip-line through a forest canopy. PHOTO: bradleyolin

What’s so special about old-growth forests?

To justify logging old-growth forests, some people argue that new trees can be planted in their place. But new growth isn’t the same. Here’s why:

• Energy storage. Big trees store energy that they capture from the sun, as well as organic matter and nutrients (in the canopy, for example). All of this eventually gets recycled back into the ecosystem. Even the moss on old trees help “fix” nitrogen, fertilizing new growth.
• Standing dead trees. Called snags, these are the favorite home of owls, woodpeckers and other birds, as well as squirrels, chipmunks, bats and other mammals. The dead wood is easier to dig a hole into, and some animals live in the space between the wood and the bark.
• Fallen dead trees. These nourish the soil as they decay, and provide homes for creatures like carpenter ants, centipedes, salamanders, and shrews. Some become “nurse logs”, meaning that new trees sprout on top of them.
• The canopy. In an old -growth forest, the canopy is so thick that the trees are practically holding hands. Some animals, such as the wandering salamander, need never come down to earth. It takes a long time to create such a canopy.
• Complexity. An old forest is home to a huge variety of plants and animals. Many of these won’t survive or return after the area is logged.

What you can do to help old-growth forests

• Use less paper. Old-growth forests are still being chopped down for paper products—even toilet paper. Don’t grab handfuls of napkins if you don’t need them all, and reuse the back side of printed sheets.
• Ask your parents to buy paper products made from recycled wood. They cost a little more, but make a big difference.
• Eat less beef. Some of it comes from areas where rainforests were cut down to make room for cattle.
• Write protest letters to companies whose business practices destroy forests. You can find examples on the website of the Rainforest Action Network, at www.ran.org.

DID YOU KNOW…

• A redwood made theGuinness Book of World Records! Named Hyperion, it’s the tallest living tree at 379 feet and is located in Redwood National Park, California.
• How old is the redwood species? It’s ancient, dating back 20 million years.