Nearctic Alpine Tundra - Code: Ne10F

Alpine tundra offers a glimpse into the polar regions. After passing through the high-mountain forests and scrubby krummholz zones, one meets this treeless, windswept landscape, the last vegetated habitat on the tops of higher mountains. Above alpine tundra is the snow line, beyond which snow and ice persist year-round, preventing even the scant growing season experienced on the alpine tundra. 
Alpine tundra is above tree line, the exact elevation of which varies with latitude. Climatically, this is one of the harshest environments in which plants survive. A suite of adaptations allows for plant growth despite high winds, frequent disturbance, poor soils, and frigid temperatures. The sedges, grasses, and forbs that dominate the landscape rarely grow more than 12 in. (30cm) tall. Many of the woody cushion plants form tight, ground-hugging mats that are an inch (2.5cm) or less above surface level. Areas sheltered from intense winds can hold small willows and taller meadow grasses but are also prone to retaining snow for longer periods, which further shortens the growing season. Furthermore, alpine tundras generally do not benefit from the endless summer sunshine of the high latitude equivalents. To counteract the truncated growing season, perennial plants keep a reserve of nutrients that allows for rapid growth under favorable conditions. Some of these plants are capable of growing, blooming, and producing seeds within a few short weeks.
In addition to their short stature, many plants of the Nearctic alpine tundra have tomentose stems and leaves—covered in dense, woolly hairs that retain moisture and trap air, protecting the stems and leaves from frost. A red pigment (anthocyanin) prevalent in many tundra plants is visible at either end of the growing season. Anthocyanin helps the plant absorb ultraviolet radiation, which is converted into heat, allowing the plant to photosynthesize at very low temperatures.