In a land above 11,400 feet, where average monthly temperatures never reach more then 50 degrees Fahrenheit and winds can be over 100 mph, here, when it comes to flora, only the very small are capable of survival.
As you leave the trees behind while moving up in elevation, you enter the alpine zone, also referred to as the alpine tundra. The climate here is a cold one, as air rises it expands and cools, losing about 3 degrees Fahrenheit every 1,000 feet you go up. Snow could be found year-round up here, awarding this zone a “slow” for growth. In fact, certain plants can take two or more years just to produce their flower buds.
Plants in the alpine tundra typically have, at most, 60 days of frost-free freedom. With such a short growing season, woody plants aren’t able to harvest enough energy to develop and flowering plants are stunted just a few inches above the ground. With all the restrictions of the alpine tundra, the secrets to the flora’s survival lie above and below the surface.
On top, the waxy, furry, or red pigmentation of the foliage can help defend plants against the harsh environment. Being waxy helps a plant reduce its water loss by blocking sun rays and slowing transpiration. The hairs on a plant that make them look and feel fuzzy can help break and protect them from strong winds. Hairs can also trap air that has been heated by the sun and keep it from rising away. Additionally, anthocyanins (the red pigment we often see in leaves) take sun rays and convert them into heat. This photosynthetic tissue that contains anthocyanins can also protect the leaves from sun damage by absorbing blue-green and ultraviolet light, which acts as a sort of sunscreen.
Below the surface a different story is taking root, literally. If we take a look at the alpine forget-me-not (Myosotis alpestris) you would see that it grows mere inches above the surface, as opposed to the forget-me-not (Myosotis) that can be 6 to 24 inches tall at lower elevations. However, the alpine subspecies, although miniature to its relative, has a taproot (a main root which grows downward) that can extend several feet into the soil! This comes in handy in a place where water drains quickly through shallow soils and limited precipitation is part of the annual routine. In addition, the alpine forget-me-not may also grow as part of a cushion plant, which is a large (up to 10 feet in diameter), low-growing mat. The stems of flowers in cushion plants are closely spaced and grow in rosettes at the same rate so they can shield each other from exposure. There is just enough space for dead leaves to insulate the stems and growth can be as slow as 0.06 centimeters a year.
Living in the alpine tundra can be an uncomfortable home. When we visit, we bring extra layers, our own water and food, and lather on the sunscreen in order to protect ourselves from the harsh environment. But the plants and animals that call this place home need to grow their own layers, find their own water and protect themselves from the intense sun. The varied survival strategies and life forms seen in the alpine tundra remind us that this isn’t just a slightly colder forest, it’s really a land of its own, where even the air is thinner, and each creature must find its own unique little niche in which to eke out a living. These alpine plants may be small, but they are hardy and resourceful representations of the tenacity of life even in the face of adversity.
Rachel Solomon is the adult summer instructor at Walking Mountains Science Center. Join her on a Saturday hike and explore the Colorado Rockies while learning about the rugged creatures that live here.