A reservoir is, most an enlarged natural or artificial lake, pond or impoundment created using a dam or lock to store water. Reservoirs can be created in a number of ways, including controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an embayment within it, through excavation, or building any number of retaining walls or levees. Defined as a storage space for fluids, reservoirs may hold gasses, including hydrocarbons. Tank reservoirs elevated, or buried tanks. Tank reservoirs for water are called cisterns. Most underground reservoirs are used to store liquids, principally either water or petroleum, below ground. Reservoir is most an enlarged natural or artificial lake. A dam constructed in a valley relies on the natural topography to provide most of the basin of the reservoir. Dams are located at a narrow part of a valley downstream of a natural basin; the valley sides act as natural walls, with the dam located at the narrowest practical point to provide strength and the lowest cost of construction.
In many reservoir construction projects, people have to be moved and re-housed, historical artifacts moved or rare environments relocated. Examples include the temples of Abu Simbel, the relocation of the village of Capel Celyn during the construction of Llyn Celyn, the relocation of Borgo San Pietro of Petrella Salto during the construction of Lake Salto. Construction of a reservoir in a valley will need the river to be diverted during part of the build through a temporary tunnel or by-pass channel. In hilly regions, reservoirs are constructed by enlarging existing lakes. Sometimes in such reservoirs, the new top water level exceeds the watershed height on one or more of the feeder streams such as at Llyn Clywedog in Mid Wales. In such cases additional side dams are required to contain the reservoir. Where the topography is poorly suited to a single large reservoir, a number of smaller reservoirs may be constructed in a chain, as in the River Taff valley where the Llwyn-on, Cantref and Beacons Reservoirs form a chain up the valley.
Coastal reservoirs are fresh water storage reservoirs located on the sea coast near the river mouth to store the flood water of a river. As the land based reservoir construction is fraught with substantial land submergence, coastal reservoir is preferred economically and technically since it does not use scarce land area. Many coastal reservoirs were constructed in Europe. Saemanguem in South Korea, Marina Barrage in Singapore and Plover Cove in China, etc are few existing coastal reservoirs. Where water is pumped or siphoned from a river of variable quality or size, bank-side reservoirs may be built to store the water; such reservoirs are formed by excavation and by building a complete encircling bund or embankment, which may exceed 6 km in circumference. Both the floor of the reservoir and the bund must have an impermeable lining or core: these were made of puddled clay, but this has been superseded by the modern use of rolled clay; the water stored in such reservoirs may stay there for several months, during which time normal biological processes may reduce many contaminants and eliminate any turbidity.
The use of bank-side reservoirs allows water abstraction to be stopped for some time, when the river is unacceptably polluted or when flow conditions are low due to drought. The London water supply system is one example of the use of bank-side storage: the water is taken from the River Thames and River Lee. Service reservoirs store treated potable water close to the point of distribution. Many service reservoirs are constructed as water towers as elevated structures on concrete pillars where the landscape is flat. Other service reservoirs can be entirely underground in more hilly or mountainous country. In the United Kingdom, Thames Water has many underground reservoirs, sometimes called cisterns, built in the 1800s, most of which are lined with brick. A good example is the Honor Oak Reservoir in London, constructed between 1901 and 1909; when it was completed it was said to be the largest brick built underground reservoir in the world and it is still one of the largest in Europe. This reservoir now forms part of the southern extension of the Thames Water Ring Main.
The top of the reservoir is now used by the Aquarius Golf Club. Service reservoirs perform several functions, including ensuring sufficient head of water in the water distribution system and providing water capacity to out peak demand from consumers, enabling the treatment plant to run at optimum efficiency. Large service reservoirs can be managed to reduce the cost of pumping, by refilling the reservoir at times of day when energy costs are low. Circa 3 000 BC, the craters of extinct volcanoes in Arabia were used as reservoirs by farmers for their irrigation water. Dry climate and water scarcity in India led to early development of stepwells and water resource management techniques, including the building of a reservoir at Girnar in 3000 BC. Artificial lakes dating to the 5th century BC have been found in ancient Greece; the artificial Bhojsagar lake in present-day Madhya Pradesh state of India, constructed in the 11th century, covered 650 square kilometres. In Sri Lanka large reservoirs were created by ancient Sinhalese kings in order to save the water for irrigation.
The famous Sri Lankan king Pa
The Absaroka Range is a sub-range of the Rocky Mountains in the United States. The range stretches about 150 mi across the Montana-Wyoming border, 75 miles at its widest, forming the eastern boundary of Yellowstone National Park along Paradise Valley, the western side of the Bighorn Basin; the range borders the Beartooth Mountains to the Wind River Range to the south. The northern edge of the range rests along Livingston, Montana; the highest peak in the range is Francs Peak, located in Wyoming at 13,153 ft. There are 46 other peaks over 12,000 ft; the range is drained by the Yellowstone River and various tributaries, including the Bighorn River. Most of the range lies within protected lands including Yellowstone Park, the Absaroka-Beartooth Wilderness, North Absaroka Wilderness, Teton Wilderness, Washakie Wilderness, spanning the Bridger-Teton National Forest, Custer National Forest, Gallatin National Forest, Shoshone National Forest. U. S. Highway 212 from Billings, Montana to Yellowstone climbs over Beartooth Pass 10,947 ft in the neighboring Beartooth Mountains before winding through the Absarokas to the northeast gate of Yellowstone National Park.
It is only open during the summer. U. S Route 14/16/20 follows the Shoshone River from Cody through the range to the eastern gate of the park; the range is named after the Absaroka Indians. The name is derived from the Hidatsa name for the Crow people. John Colter, who may have been the first white person to visit the area traveled along the foot of the Absarokas in 1807 during his reconnaissance of the Yellowstone region. Early explorers included Gustavus Cheyney Doane and Nathaniel P. Langford, who climbed the summit of Colter Peak in 1870. USS Absaroka was named after this mountain range. Geologically, the section of the range in Wyoming consists of volcanic breccia, whereas there is a transition to granite and gneiss bedrock further north of the state line. Igneous rocks of the Absaroka Volcanic Province cover an area of 23,000 km2 in southwestern Montana and northwestern Wyoming, including one third of Yellowstone National Park; these extrusive rocks were erupted during the Eocene Epoch of the Paleogene Period.
Radiometric dating has shown. The eroded remnants of many large stratovolcanoes are found in the area; the dissection of these long extinct volcanoes by erosion allows geologists to see volcanic structures that are impossible to see in active volcanoes. Many terms now used in volcanology originated in nineteenth century field studies of these ancient volcanoes. Mountains and mountain ranges of Yellowstone National Park List of mountain ranges in Montana List of mountain ranges in Wyoming Media related to Absaroka Range at Wikimedia Commons
Bridger-Teton National Forest
Bridger-Teton National Forest is located in western Wyoming, United States. The forest consists of 3.4 million acres, making it the third largest National Forest outside Alaska. The forest stretches from Yellowstone National Park, along the eastern boundary of Grand Teton National Park and from there rides along the western slope of the Continental Divide to the southern end of the Wind River Range; the forest extends southward encompassing the Salt River Range and Wyoming Range mountains near the Idaho border. Located within the forest are the Gros Ventre and Teton Wildernesses, totaling 1.2 million acres. Other points of interest contained in the forest include Gannett Peak, the tallest mountain in Wyoming, the Gros Ventre landslide, one of the largest visible landslides on earth. All of the forest is in turn a part of the 20-million-acre Greater Yellowstone Ecosystem. While Gannett Peak is the highest summit in the forest, another 40 named mountains rise above 12,000 feet; the high altitudes and abundant snowfall, exceeding 600 inches at some locations, provides a constant supply of water for streams and rivers.
1,500 lakes help provide water for the Yellowstone and Green rivers, which all have their headwaters in the forest. Seven of the largest glaciers outside of Alaska are located within the forest boundaries. U. S. Route 26 and U. S. Route 287 cross over the continental divide at Togwotee Pass and enter the forest from the north, U. S. Highways 89 and 191 provide access to the forest in the vicinity of Jackson and forest lands to the south; the primary tree species include lodgepole pine, Engelmann spruce, Douglas-fir, subalpine fir and whitebark pine. Willows and sagebrush are found on the lower altitudes, while above the timberline alpine meadows are common. Threatened and endangered species found within the forest boundaries include grizzly bears, black-footed ferret and peregrine falcon. Most of the mammals that existed in the region prior to European settlement can still be found here. Elk, mule deer, bighorn sheep, coyote, marmot and cougar are but a few of the 75 species of mammals known to exist in the forest.
Four subspecies of cutthroat trout are found here including the Snake River cutthroat trout. 355 species of birds have been sighted including bald eagles, trumpeter swans, sandhill cranes and Clark's nutcrackers. Over 2,000 miles of hiking trails are located in the forest providing access into wilderness areas and interlinking with trails in Yellowstone National Park. There are several dozen vehicle accessible campgrounds that have picnic tables and tent sites as well as room in some circumstances for recreational vehicles. Nighttime temperatures can be below freezing any time of the year and mosquitos in the late spring and early summer are common. Summertime high temperatures average in the 70s and the wintertime lows can drop below -50 degrees. Bridger-Teton National Forest is an administrative combination of Bridger and Teton National Forests, amalgamated in 1973; the Bridger National Forest itself absorbed Wyoming National Forest in 1923. The Wyoming National Forest had been created as the Yellowstone Forest Reserve in 1904 renamed in 1908.
The Teton Forest Reserve was created at the same time, destined to become Teton National Forest. Ranger district offices are located in Pinedale, Big Piney, Moran and Jackson; the forest headquarters is located in Jackson. In descending order of land area the forest is located in parts of Sublette, Lincoln and Fremont counties. Granite Hot Springs Green River Wilderness areas: Bridger Wilderness Gros Ventre Wilderness Teton Wilderness Official website
The Mormon Trail is the 1,300-mile route that members of The Church of Jesus Christ of Latter-day Saints traveled from 1846 to 1868. Today, the Mormon Trail is a part of the United States National Trails System, known as the Mormon Pioneer National Historic Trail; the Mormon Trail extends from Nauvoo, the principal settlement of the Latter Day Saints from 1839 to 1846, to Salt Lake City, settled by Brigham Young and his followers beginning in 1847. From Council Bluffs, Iowa to Fort Bridger in Wyoming, the trail follows much the same route as the Oregon Trail and the California Trail; the Mormon pioneer run began in 1846, when his followers were driven from Nauvoo. After leaving, they aimed to establish a new home for the church in the Great Basin and crossed Iowa. Along their way, some were assigned to establish settlements and to plant and harvest crops for emigrants. During the winter of 1846–47, the emigrants wintered in Iowa, other nearby states, the unorganized territory that became Nebraska, with the largest group residing in Winter Quarters, Nebraska.
In the spring of 1847, Young led the vanguard company to the Salt Lake Valley, outside the boundaries of the United States and became Utah. During the first few years, the emigrants were former occupants of Nauvoo who were following Young to Utah; the emigrants comprised converts from the British Isles and Europe. The trail was used for more than 20 years, until the completion of the First Transcontinental Railroad in 1869. Among the emigrants were the Mormon handcart pioneers of 1856–60. Two of the handcart companies, led by James G. Willie and Edward Martin, met disaster on the trail when they departed late and were caught by heavy snowstorms in Wyoming. Under the leadership of Joseph Smith, Latter Day Saints established several communities throughout the United States between 1830 and 1844, most notably in Kirtland, Ohio. However, the Saints were driven out of each of them in turn, due to conflicts with other settlers; this included the actions of Governor Lilburn Boggs, who issued Missouri Executive Order 44, which called for the "extermination" of all Mormons in Missouri.
Latter-day Saints were forced to abandon Nauvoo in 1846. Although the movement had split into several denominations after Smith's death in 1844, most members aligned themselves with Brigham Young and The Church of Jesus Christ of Latter-day Saints. Under Young's leadership, about 14,000 Mormon citizens of Nauvoo set out to find a new home in the West; as the senior apostle of the Quorum of the Twelve Apostles after Joseph Smith's death, Brigham Young assumed responsibility of the leadership of the church. He would be sustained as President of the Church and prophet. Young now had to lead the Saints into the far west, without knowing where to go or where they would end up, he insisted the Mormons should settle in a place no one else wanted and felt the isolated Great Basin would provide the Saints with many advantages. Young reviewed information on the Great Salt Lake Valley and the Great Basin, consulted with mountain men and trappers, met with Father Pierre-Jean De Smet, a Jesuit missionary familiar with the region.
Young organized a vanguard company to break trail to the Rocky Mountains, evaluate trail conditions, find sources of water, select a central gathering point in the Great Basin. A new route on the north side of the Platte and North Platte rivers was chosen to avoid potential conflicts over grazing rights, water access, campsites with travelers using the established Oregon Trail on the river's south side; the Quincy Convention of October 1845 passed resolutions demanding that the Latter-day Saints withdraw from Nauvoo by May 1846. A few days the Carthage Convention called for establishment of a militia that would force them out if they failed to meet the May deadline. To try to meet this deadline and to get an early start on the trek to the Great Basin, the Latter-day Saints began leaving Nauvoo in February 1846; the departure from Nauvoo began on February 1846, under the leadership of Brigham Young. This early departure exposed them to the elements in the worst of winter. After crossing the Mississippi River, the journey across Iowa Territory followed primitive territorial roads and Native American trails.
Young planned to lead an express company of about 300 men to the Great Basin during the summer of 1846. He believed they could reach the Missouri River in four to six weeks. However, the actual trip across Iowa was slowed by rain, swollen rivers, poor preparation, it required 16 weeks – nearly three times longer than planned. Heavy rains turned the rolling plains of southern Iowa into a quagmire of axle-deep mud. Furthermore, few people carried adequate provisions for the trip; the weather, general unpreparedness, lack of experience in moving such a large group of people all contributed to the difficulties they endured. The initial party reached the Missouri River on June 14, it was apparent that the Latter-day Saints could not make it to the Great Basin that season and would have to winter on the Missouri River. Some of the emigrants established. Others moved across the river into the area of present-day Omaha and built a camp called Winter Quarters. In April 1847, chosen members of the vanguard company gathered, final supplies were packed, the group was organized into 14 military companies.
A militia and night guard were formed. The company consisted of 143 men, including three black people and eight members of th
The Oregon Trail is a 2,170-mile historic East–West, large-wheeled wagon route and emigrant trail in the United States that connected the Missouri River to valleys in Oregon. The eastern part of the Oregon Trail spanned part of the future state of Kansas, nearly all of what are now the states of Nebraska and Wyoming; the western half of the trail spanned most of the future states of Oregon. The Oregon Trail was laid by fur traders and trappers from about 1811 to 1840, was only passable on foot or by horseback. By 1836, when the first migrant wagon train was organized in Independence, Missouri, a wagon trail had been cleared to Fort Hall, Idaho. Wagon trails were cleared farther west, reached all the way to the Willamette Valley in Oregon, at which point what came to be called the Oregon Trail was complete as annual improvements were made in the form of bridges, cutoffs and roads, which made the trip faster and safer. From various starting points in Iowa, Missouri, or Nebraska Territory, the routes converged along the lower Platte River Valley near Fort Kearny, Nebraska Territory and led to rich farmlands west of the Rocky Mountains.
From the early to mid-1830s the Oregon Trail and its many offshoots were used by about 400,000 settlers, miners and business owners and their families. The eastern half of the trail was used by travelers on the California Trail, Mormon Trail, Bozeman Trail, before turning off to their separate destinations. Use of the trail declined as the first transcontinental railroad was completed in 1869, making the trip west faster and safer. Today, modern highways, such as Interstate 80 and Interstate 84, follow parts of the same course westward and pass through towns established to serve those using the Oregon Trail. In 1803, President Thomas Jefferson issued the following instructions to Meriwether Lewis: "The object of your mission is to explore the Missouri river, & such principal stream of it, as, by its course & communication with the waters of the Pacific Ocean, whether the Columbia, Colorado and/or other river may offer the most direct & practicable water communication across this continent, for the purposes of commerce."
Although Lewis and William Clark found a path to the Pacific Ocean, it was not until 1859 that a direct and practicable route, the Mullan Road, connected the Missouri River to the Columbia River. The first land route across what is now the United States was mapped by the Lewis and Clark Expedition between 1804 and 1806. Lewis and Clark believed they had found a practical overland route to the west coast. On the return trip in 1806, they traveled from the Columbia River to the Snake River and the Clearwater River over Lolo pass again, they traveled overland up the Blackfoot River and crossed the Continental Divide at Lewis and Clark Pass and on to the head of the Missouri River. This was a shorter and faster route than the one they followed west; this route had the disadvantages of being much too rough for wagons and controlled by the Blackfoot Indians. Though Lewis and Clark had only traveled a narrow portion of the upper Missouri River drainage and part of the Columbia River drainage, these were considered the two major rivers draining most of the Rocky Mountains, the expedition confirmed that there was no "easy" route through the northern Rocky Mountains as Jefferson had hoped.
Nonetheless, this famous expedition had mapped both the eastern and western river valleys that bookend the route of the Oregon Trail across the continental divide—they just had not located the South Pass or some of the interconnecting valleys used in the high country. They did show the way for the mountain men, who within a decade would find a better way across if it was not to be an easy way. Founded by John Jacob Astor as a subsidiary of his American Fur Company in 1810, the Pacific Fur Company operated in the Pacific Northwest in the ongoing North American fur trade. Two movements of PFC employees were planned by Astor, one detachment to be sent to the Columbia River by the Tonquin and the other overland under an expedition led by Wilson Price Hunt. Hunt and his party were to find possible supply routes and trapping territories for further fur trading posts. Upon arriving at the river in March 1811, the Tonquin crew began construction of what became Fort Astoria; the ship left supplies and men to continue work on the station and ventured north up the coast to Clayoquot Sound for a trading expedition.
While anchored there, Jonathan Thorn insulted an elder Tla-o-qui-aht, elected by the natives to negotiate a mutually satisfactory price for animal pelts. Soon after, the vessel was attacked and overwhelmed by the indigenous Clayoquot killing most of the crew except its Quinault interpreter, who told the PFC management at Fort Astoria of the destruction; the next day, the ship was blown up by surviving crew members. Under Hunt, fearing attack by the Niitsitapi, the overland expedition veered south of Lewis and Clark's route into what is now Wyoming and in the process passed across Union Pass and into Jackson Hole, Wyoming. From there they went over the Teton Range via Teton Pass and down to the Snake River into modern Idaho, they abandoned their horses at the Snake River, made dugout canoes, attempted to use the river for transport. After a few days' travel they soon discovered that steep canyon
Yellowstone National Park
Yellowstone National Park is an American national park located in Wyoming and Idaho. It was established by the U. S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872. Yellowstone was the first national park in the U. S. and is widely held to be the first national park in the world. The park is known for its wildlife and its many geothermal features Old Faithful geyser, one of its most popular features, it has many types of ecosystems. It is part of the South Central Rockies forests ecoregion. Native Americans have lived in the Yellowstone region for at least 11,000 years. Aside from visits by mountain men during the early-to-mid-19th century, organized exploration did not begin until the late 1860s. Management and control of the park fell under the jurisdiction of the Secretary of the Interior, the first being Columbus Delano. However, the U. S. Army was subsequently commissioned to oversee management of Yellowstone for a 30-year period between 1886 and 1916. In 1917, administration of the park was transferred to the National Park Service, created the previous year.
Hundreds of structures have been built and are protected for their architectural and historical significance, researchers have examined more than a thousand archaeological sites. Yellowstone National Park spans an area of 3,468.4 square miles, comprising lakes, canyons and mountain ranges. Yellowstone Lake is one of the largest high-elevation lakes in North America and is centered over the Yellowstone Caldera, the largest supervolcano on the continent; the caldera is considered an active volcano. It has erupted with tremendous force several times in the last two million years. Half of the world's geysers and hydrothermal features are in Yellowstone, fueled by this ongoing volcanism. Lava flows and rocks from volcanic eruptions cover most of the land area of Yellowstone; the park is the centerpiece of the Greater Yellowstone Ecosystem, the largest remaining nearly-intact ecosystem in the Earth's northern temperate zone. In 1978, Yellowstone was named a UNESCO World Heritage Site. Hundreds of species of mammals, birds and reptiles have been documented, including several that are either endangered or threatened.
The vast forests and grasslands include unique species of plants. Yellowstone Park is the largest and most famous megafauna location in the contiguous United States. Grizzly bears and free-ranging herds of bison and elk live in this park; the Yellowstone Park bison herd is the largest public bison herd in the United States. Forest fires occur in the park each year. Yellowstone has numerous recreational opportunities, including hiking, boating and sightseeing. Paved roads provide close access to the major geothermal areas as well as some of the lakes and waterfalls. During the winter, visitors access the park by way of guided tours that use either snow coaches or snowmobiles; the park contains the headwaters of the Yellowstone River. Near the end of the 18th century, French trappers named the river Roche Jaune, a translation of the Hidatsa name Mi tsi a-da-zi. American trappers rendered the French name in English as "Yellow Stone". Although it is believed that the river was named for the yellow rocks seen in the Grand Canyon of the Yellowstone, the Native American name source is unclear.
The human history of the park begins at least 11,000 years ago when Native Americans began to hunt and fish in the region. During the construction of the post office in Gardiner, Montana, in the 1950s, an obsidian projectile point of Clovis origin was found that dated from 11,000 years ago; these Paleo-Indians, of the Clovis culture, used the significant amounts of obsidian found in the park to make cutting tools and weapons. Arrowheads made of Yellowstone obsidian have been found as far away as the Mississippi Valley, indicating that a regular obsidian trade existed between local tribes and tribes farther east. By the time white explorers first entered the region during the Lewis and Clark Expedition in 1805, they encountered the Nez Perce and Shoshone tribes. While passing through present day Montana, the expedition members heard of the Yellowstone region to the south, but they did not investigate it. In 1806, John Colter, a member of the Lewis and Clark Expedition, left to join a group of fur trappers.
After splitting up with the other trappers in 1807, Colter passed through a portion of what became the park, during the winter of 1807–1808. He observed at least one geothermal area near Tower Fall. After surviving wounds he suffered in a battle with members of the Crow and Blackfoot tribes in 1809, Colter described a place of "fire and brimstone" that most people dismissed as delirium. Over the next 40 years, numerous reports from mountain men and trappers told of boiling mud, steaming rivers, petrified trees, yet most of these reports were believed at the time to be myth. After an 1856 exploration, mountain man Jim Bridger reported observing boiling springs, spouting water, a mountain of glass and yellow rock; these reports were ignored because Bridger was a known "spinner of yarns". In 1859, a U. S. Army Surveyor named Captain William F. Raynolds embarked on a two-year survey of the northern Rockies. After wintering in Wyoming, in May 1860, Raynolds and his party – which included naturalist Ferdinand Vandeveer Hayden and guide Jim B
United States National Forest
National Forest is a classification of protected and managed federal lands in the United States. National Forests are forest and woodland areas owned collectively by the American people through the federal government, managed by the United States Forest Service, a division of the United States Department of Agriculture; the National Forest System was created by the Land Revision Act of 1891, signed under the presidency of Benjamin Harrison. It was the result of concerted action by Los Angeles-area businessmen and property owners who were concerned by the harm being done to the watershed of the San Gabriel Mountains by ranchers and miners. Abbot Kinney and forester Theodore Lukens were key spokesmen for the effort. In the United States there are 155 National Forests containing 190 million acres of land; these lands comprise 8.5 percent of the total land area of the United States, an area about the size of Texas. Some 87 percent of National Forest land lies west of the Mississippi River in the mountain ranges of the Western United States.
Alaska has 12 percent of all National Forest lands. The U. S. Forest Service manages all of the United States National Grasslands, around half of the United States National Recreation Areas. There are two distinctly different types of forests within the National Forest system; those east of the Great Plains in the Midwestern and Eastern United States were acquired by the federal government since 1891, may be second growth forests. The land had long been in the private domain and sometimes logged since colonial times, but was purchased by the United States government in order to create new National Forests; those west of the Great Plains in the Western United States, though established since 1891, are on lands with ownership maintained by the federal government since the U. S. acquisition and settling of the American West. These are lands that were kept in the public domain, with the exception of inholdings and donated or exchanged private forest lands. Land management of these areas focuses on conservation, timber harvesting, livestock grazing, watershed protection and recreation.
Unlike national parks and other federal lands managed by the National Park Service, extraction of natural resources from national forests is permitted, in many cases encouraged. However, the first-designated wilderness areas, some of the largest, are on National Forest lands. There are management decision conflicts between conservationists and environmentalists, natural resource extraction companies and lobbies, over the protection and/or use of National Forest lands; these conflicts center on endangered species protection, logging of old-growth forests, intensive clear cut logging, undervalued stumpage fees, mining operations and mining claim laws, logging/mining access road-building within National Forests. Additional conflicts arise from concerns that the grasslands and forest understory are grazed by sheep, and, more rising numbers of elk and mule deer due to loss of predators. Many ski resorts and summer resorts operate on leased land in National Forests. List of U. S. National Forests United States National Grassland National Forests of the United States topics State forest National Forest Management Act of 1976 Protected areas of the United States USDA Forest Service USDA Forest Service - The First Century 100 Years of Federal Forestry