Denali National Park and Preserve is a national park and preserve located in Interior Alaska, centered on Denali, the highest mountain in North America. The park and contiguous preserve encompasses more than 6 million acres (24,500 sq km), of which 4,724,735.16 acres (19,120 sq km) are federally owned national park. The national preserve is 1,334,200 acres (5,430 sq km), of which 1,304,132 acres (5,278 sq km) are federally owned. On December 2, 1980, a 2,146,580 acre (8,687 sq km) Denali Wilderness was established within the park. Denali's landscape is a mix of forest at the lowest elevations, including deciduous taiga. The preserve is also home to tundra at middle elevations, and glaciers, rock, and snow at the highest elevations. The longest glacier is the Kahiltna Glacier. Today, 400,000 people visit the park annually. Wintertime activities includes dog-sledding, cross-country skiing, and snowmachining.
Denali National Park and Preserve is located in the Central area of the Alaska Range, a mountain chain extending 600 miles (970 km) across Alaska. Its best-known geologic feature is Denali, formerly known as Mount McKinley. Its elevation of 20,310 feet (6,190.5 m) makes it the highest mountain in North America. Its vertical relief (distance from base to peak) of 18,000 feet (5,500 m) is the highest of any mountain in the World. The mountain is still gaining about 1 millimetre (0.039 in) in height each year due to the continued convergence of the North American and Pacific Plates. The mountain is primarily made of granite, a hard rock that does not erode easily; this is why it has retained such a great height rather than being eroded.
There are three major rock provinces that run in east-west bands through the park. The oldest is in the north, and the younger ones in the south. The area is characterized by collision tectonics: over the past millions of years, exotic terranes in the Pacific Ocean have been moving toward the North American landmass and accreting, or attaching, to the area that now makes up Alaska.
The oldest rocks in the park are part of the Yukon-Tanana terrane. They originated from ocean sediments deposited between 400 million and 1 billion years ago. The original rocks have been affected by the processes of regional metamorphism, folding, and faulting to form rocks such as schist, quartzite, phyllite, slate, marble, and limestone.
The next oldest group of rocks is the Farewell terrane. It is composed of rocks from the Paleozoic era (250-500 million years old). The sediments that make up these rocks were deposited in a variety of marine environments, ranging from deep ocean basins to continental shelf areas. The abundant marine fossils are evidence that around 380 million years ago, this area had a warm, tropical climate.
Long winters are followed by short growing seasons. Eighty percent of the bird population returns after cold months, raising their young. Most mammals and other wildlife in the park spend the brief summer months preparing for winter and raising their young. Summers are usually cool and damp, but temperatures in the 70s are not rare. The weather is so unpredictable that there have even been instances of snow in August.
The north and south side of the Alaskan Range have a completely different climate. The Gulf Of Alaska carries moisture to the south side, but the mountains block water to the north side. This brings a drier climate and huge temperature fluctuations to the north. The south has transitional maritime continental climates, with moister, cooler summers and warmer winters.
The Alaska Range is a mountainous expanse running through the entire park, strongly influencing the park's ecosystems. Vegetation in the park depends on the altitude. The treeline is at 2,500 feet (760 m), causing most of the park to be a vast expanse of tundra. In the lowland areas of the park, such as the western sections surrounding Wonder Lake, spruces and willows dominate the forest. Most trees and shrubs do not reach full size, due to unfavorable climate and thin soils. There are three types of forest in the park: from lowest to highest, they are low brush bog, bottomland spruce-poplar forest, upland spruce-hardwood forest. The forest grows in a mosaic, due to periodic fires.
In the tundra of the park, layers of topsoil collect on rotten fragmented rock moved by thousands of years of glacial activity. Mosses, ferns, grasses, and fungi grow on the topsoil. In areas of muskeg, tussocks form and may collect algae. The term 'muskeg' includes spongy waterlogged tussocks as well as deep pools of water covered by solid-looking moss. Wild blueberries and soap berries thrive in the tundra and provide the bears of Denali with the main part of their diet.
Over 450 species of flowering plants fill the park and can be viewed in bloom throughout summer. Images of goldenrod, fireweed, lupine, bluebell, and gentian filling the valleys of Denali are often used on postcards and in artwork.