You Are There! Hike the Highline Trail
As we venture higher, we pass through the tree line into a rugged topography ranging from 9,000 to 13,000 feet. Here the alpine flora offers another world unto itself with most flowering species not exceeding a few inches in height. Local endemism is high, but boreal disjuncts find their way down from the extreme northern latitudes of Canada. Because of the harsh, cold, dry, open environment, plants have evolved adaptations that allow them to complete their life cycle within the short growing season. More than 99 percent of alpine plants are perennial and form compact, cushion-like mats. The perennial habit ensures survival of these plants that need to flower, set seed, and produce fruit all within about six weeks. Many alpine plants have various coatings of long, felty, or wooly hairs that protect the delicate photosynthetic cells from ultra-violet light and at the same time reduce water loss in this windy environment. Where there is protection from blasting winds and the piercing sun, plants find a niche and grow a few inches taller. Alpine plants are adapted to many distinctive environments, including krummholz stands, alpine meadows, fellfields, and boulder fields, talus and scree slopes.
The alpine environment is very sensitive to effects from global climate change including but not limited to, increases or changes in temperature, carbon dioxide, and ultraviolet radiation. Tree line (timberline) at alpine (unlike other ecosystems we passed through earlier where edges and boundaries intermix blurring the line between adjoining ecosystems), is a distinct sharp demarcation between two climatic zones. One can literally stand with a foot in each zone: Temperate (subalpine) and Arctic (alpine). A leading influence in creating such a sharp demarcation is the point at which there is no replacement water from frozen soils. Past this point, there are no tree branches and no filtering haze. Even subtle changes in topography, moisture, and geological substrates have influenced the development of unique individual plant communities. To prevent severe dehydration, ultraviolet poisoning, wind damage, and extreme cold temperatures; most alpine plants (including woody plants) have a waxy coating, hairy surfaces, short height, and diminutive growth form.
Krummholz translates to "elfin timber" or "crooked wood." Above the tree-line, the tall trees from the conifer forest below become a stand of stunted shrub-like trees. Many alpine creatures shelter here. Do not be fooled by the short height of these trees, some are older than 300 years. Under an occasional band of stunted trees, a small number of persistent and durable wildflowers make a last stand before the environment gives way to a treeless alpine landscape. Two gorgeous wildflowers, sulfur paintbrush (Castilleja sulphurea) and flowery phlox (Phlox multiflora) can be found in Krummholz stands.
Up ahead, we arrive at an alpine meadow that is bursting with life. Wet meadows are teeming with extensive fields of marsh marigold (Caltha leptosepala), American bistort (Polygonum bistortoides, Parry primrose (Primula parryi) and arctic gentian (Gentiana algida). Rushes, sedges and grasses are abundant and their long, fine roots go deep into the more mature and developed soils. On drier sites we see fields of alpine daisies (Erigeron simplex), several kinds of Paintbrush species (Castilleja spp.), cinquefoils (Potentilla spp.), and buttercups (Ranunculus spp.). Ground which is exposed by late melting snow supports species such as spring beauty (Claytonia lanceolata) and alpine buttercup (Ranunculus adoneus). Chances are we will also spot a treat in this gorgeous landscape, the white Snowdon alpine lily (Lloydia serotina var. serotina) or even smaller yet, the alpine willow (Salix arctica var. petraea).
Nearby we see many distinctive low-growing cushion-like plants in areas where a bit of soil is newly formed from nearby rocks and the slope is more stable. These areas are called fellfields. Because the soils are dusty, full of gravel, beaten by winds, and are subject to rapid drainage, they are nothing better than extremely impoverished locations for a very small diversity of plants. As we traverse this alpine community, the herbaceous inhabitants that survive this extreme environment are usually reduced to cushion plants. Examples of such plants are able to adhere to these soils and include alpine forget-me-not (Eritrichium nanum) and the electric-pink, moss campion (Silene acaulis var. subacaulescens). In addition, we will occasionally see alpine fescue grass (Festuca brachyphylla) interspersed between the rock and gravel. When stable, fellfields can exist for hundreds to thousands of years.
Boulder, Talus, and Scree Slopes
As we move through the alpine ecosystem we are about to traverse across talus and scree slopes. Talus slopes are usually composed of rocks no larger than a fist and the scree slopes are characterized by bedrock material even smaller yet, about the size of marbles. Scree slopes are often ankle deep and on both slopes, we will often be reduced to crawling up a steep, unforgivable terrain. Two of the most successful plants in stabilizing potential slippage are alpine dryad (Dryas octopetala var. hookeriana) and mountain sorrel (Oxyria digyna). Nestled just below the peaks of these giant mountains are large boulder fields scoured and deposited from recent glaciers.
One of my favorite experiences in this ocean of boulders and rock is finding patches of several hardy flowering plants nestled in secretive crevices, such as the Sticky Jacobs-ladder (Polemonium viscosum). Often, in the lee side of larger rocks, we will be able to find beautiful displays of Colorado columbine (Aquilegia coerulea var. coerulea). Columbines range in color, and in nearby adjacent mountains we find yellow, red, and purple. For more information about columbines, see Aquilegia Express: Columbines.
The plants and animals of the alpine ecosystem possess many astonishing adaptations for survival in the harsh landscape above the trees. They have evolved under the toughest conditions imaginable, yet they are fragile and vulnerable to the impact of countless human feet. As we wander among these alpine treasures, remember to tread lightly, stay on trails, or step on rocks if we can. Leave nature’s infinite complexity and beauty to inspire others as it has done for us.
Our Journey's End
We have reached the end of this trek. Please, take your shoes off, sit for a while, and enjoy what you have climbed so far to see, "life at the top of the world."