Brrrr! Above the Tree Line!

by Catherine Ripley

Up, up, and still up! You've been hiking all morning through the dark, shady forest. As you've climbed, the trees have become shorter and shorter. Finally, you're standing in a rocky sunlight. Here and there, twisted trees sprawl over the lichen-covered stone. A chill wind is blowing—brrrr! Cushions of grasses and wildflowers seem to float across a lake of rock. Welcome to the world “above the tree line,” where it is too cold and dry and windy for trees to grow!

This high mountain world is very much like the Arctic. To live in both places, animals must first beat the cold. Then there's the WIND—almost always blowing—and the shortage of food, shelter, and even oxygen. Can any animals adapt to survive here? Yes! Very special ones indeed!

• The Rocky Mountain Goat has a double layer of extra-thick fur to protect it in sub-zero storms. The rubbery undersides of its sharp hooves let it grip the cliffs to reach food in almost impossible places and to escape predators.
• The Hoary Marmot escapes the long mountain winters by hibernating. Its body slows wa-a-a-a-y down, and it lives off its fat without ever waking up to nibble a bite of food. Zzzzz!
• After cutting and drying grasses in the summer sun, the Pika stores them in its rock-pile home. When winter comes, the icy whistling winds are no problem for the pika as it munches away beneath the snow.
• The Llama has more red blood cells than other animals. This means it can circulate lots of oxygen through its blood even though there's less oxygen in the air above the tree line.
• The Snow Leopard blends right in against the snow and rock. This makes it all the easier to surprise a mountain sheep or goat and find a meal.
• Teensy Glacier Fleas prefer the ice, thank you very much. Protected by thick black hair, they swarm onto the snow in the spring and feast on the pollen, spores, and other food that has blown up from the forests and meadows below.
• Summer is too short for Alpine Salamanders to hatch, grow up in water, and then crawl out on land as air-breathing adults. So moms spend three years carrying their young—and sometimes longer! Then they give birth to two fully developed salamanders. Their black skin helps them take in all the heat they can, and even on summer nights, they usually go underground to stay warm.
• Unlike most other mountain birds that fly down to the valleys for the winter, the White-Tailed Ptarmigan stays above the tree line year round. It has feathered legs to keep it warm, and the feathers on its toes act like snowshoes. To shelter, it burrows deep into snowdrifts. Here it also finds berries and buds to eat.

Like animals, plants have special ways to survive. Hairy leaves keep some from drying out in the wind. Twining, twisting root systems securely anchor plants so they won't blow away. Many flowers start growing in bulbs underground, to get a jump-start on the very short growing season.

Vocabulary

bulb:

An underground plant part. New plants grow from bulbs.

circulate:

To move in a closed path, such as a circle.

hibernate:

To go into a deep sleep.

lichen:

A plant made up of a fungus and an algae. Lichens grow on rocks and trees.

Back to Top