Alder is the common name of a genus of flowering plants belonging to the birch family Betulaceae. The common name alder evolved from Old English alor, which in turn is derived from Proto-Germanic root aliso, the generic name Alnus is the equivalent Latin name. With a few exceptions, alders are deciduous, and the leaves are alternate and these trees differ from the birches in that the female catkins are woody and do not disintegrate at maturity, opening to release the seeds in a similar manner to many conifer cones. The largest species are red alder on the west coast of North America, by contrast, the widespread Alnus viridis is rarely more than a 5-m-tall shrub. Alders are commonly found near streams and wetlands, Alder leaves and sometimes catkins are used as food by numerous butterflies and moths. A. glutinosa and A. viridis are classed as environmental weeds in New Zealand, Alder leaves and especially the roots are important to the ecosystem because they enrich the soil with nitrogen and other nutrients.
Alder is particularly noted for its important symbiotic relationship with Frankia alni and this bacterium is found in root nodules, which may be as large as a human fist, with many small lobes, and light brown in colour. The bacterium absorbs nitrogen from the air and makes it available to the tree, Alder, in turn, provides the bacterium with sugars, which it produces through photosynthesis. Because of its abundance, red alder delivers large amounts of nitrogen to enrich forest soils, red alder stands have been found to supply between 120 and 290 pounds of nitrogen per acre annually to the soil. From Alaska to Oregon, Sitka alder characteristically pioneer fresh, gravelly sites at the foot of retreating glaciers, alders are common among the first species to colonize disturbed areas from floods, fires, etc. Alder groves themselves often serve as natural firebreaks since these trees are much less flammable than conifers. Their foliage and leaf litter does not carry a fire well, in addition, the light weight of alder seeds allows for easy dispersal by the wind.
Although it outgrows coastal Douglas-fir for the first 25 years, it is shade intolerant. Red alder is the Pacific Northwests largest alder and the most plentiful, alders largely help create conditions favorable for giant conifers that replace them. Alder root nodules Alder roots are parasitized by northern groundcone, the catkins of some alder species have a degree of edibility, and may be rich in protein. Reported to have a bitter and unpleasant taste, they are useful for survival purposes. The wood of certain species is often used to smoke various food items such as coffee, salmon. Most of the pilings that form the foundation of Venice were made from alder trees, Alder bark contains the anti-inflammatory salicin, which is metabolized into salicylic acid in the body
Populus trichocarpa, the black cottonwood, western balsam-poplar or California poplar, is a deciduous broadleaf tree species native to western North America. It is used for timber, and is notable as an organism in plant biology. Its full genome sequence was published in 2006 and it is the first tree species to be sequenced. It is a tree, growing to a height of 30 metres to 50 metres and a trunk diameter of over 2 metres. It is normally fairly short-lived, but some trees may live for up to 400 years, a cottonwood in Willamette Mission State Park near Salem, Oregon holds the national and world records. Last measured in April,2008 this black cottonwood was found to be standing at 155 ft tall,29 ft around, the bark is grey and covered with lenticels, becoming thick and deeply fissured on old trees. The bark can become hard enough to cause sparks when cut with a chainsaw, the stem is grey in the older parts and light brown in younger parts. The crown is usually conical and quite dense. In large trees the lower branches droop downwards, the wood has a light coloring and a straight grain.
The leaves are alternate, elliptic with a crenate margin and an acute tip, the buds are conical, long and sticky, with a strong balsam scent in spring when they open. Populus trichocarpa has an extensive and aggressive root system, which can invade, sometimes the roots can even damage the foundations of buildings by drying out the soil. Flowering and fruiting Populus trichocarpa is normally dioecious and female catkins are borne on separate trees, the species reaches flowering age at about 10 years. Flowers may appear in early March to late May in Washington and Oregon, and sometimes as late as mid-June in northern and interior British Columbia, staminate catkins contain 30 to 60 stamens, elongate to 2 to 3 cm, and are deciduous. Pistillate catkins at maturity are 8 to 20 cm long with rotund-ovate, each capsule contains many minute seeds with long, white cottony hairs. Seed production and dissemination The seed ripens and is disseminated by late May to late June in Oregon and Washington, abundant seed crops are usually produced every year.
Attached to its cotton, the seed is light and buoyant and can be transported long distances by wind, although highly viable, longevity of P. trichocarpa seed under natural conditions may be as short as two weeks to a month. This can be increased with cold storage, seedling development Moist seedbeds are essential for high germination, and seedling survival depends on continuously favorable conditions during the first month. Wet bottom lands of rivers and major streams frequently provide such conditions, P. trichocarpa seedlings do not usually become established in abundance after logging unless special measures are taken to prepare the bare, moist seedbeds required for initial establishment
Most species are known as willow, but some narrow-leaved shrub species are called osier, and some broader-leaved species are referred to as sallow. Some willows are low-growing or creeping shrubs, for example, the dwarf willow rarely exceeds 6 cm in height, though it spreads widely across the ground. Willows all have abundant watery bark sap, which is charged with salicylic acid, usually pliant, tough wood, slender branches. The roots are remarkable for their toughness and tenacity to life, the leaves are typically elongated, but may be round to oval, frequently with serrated edges. Most species are deciduous, semievergreen willows with coriaceous leaves are rare, e. g. Salix micans, all the buds are lateral, no absolutely terminal bud is ever formed. The buds are covered by a single scale, the bud scale is fused into a cap-like shape, but in some species it wraps around and the edges overlap. The leaves are simple, feather-veined, and typically linear-lanceolate, usually they are serrate, rounded at base, acute or acuminate.
The leaf petioles are short, the often very conspicuous, resembling tiny, round leaves. On some species, they are small, inconspicuous, in color, the leaves show a great variety of greens, ranging from yellowish to bluish. Willows are dioecious, with male and female flowers appearing as catkins on separate plants and this scale is square and very hairy. The anthers are rose-colored in the bud, but orange or purple after the flower opens, they are two-celled, the filaments are threadlike, usually pale brown, and often bald. The ovary is one-celled, the style two-lobed, and the ovules numerous, almost all willows take root very readily from cuttings or where broken branches lie on the ground. The few exceptions include the willow and peachleaf willow. One famous example of such growth from cuttings involves the poet Alexander Pope and this twig was planted and thrived, and legend has it that all of Englands weeping willows are descended from this first one. Willows are often planted on the borders of streams so their interlacing roots may protect the bank against the action of the water, the roots are much larger than the stem which grows from them.
Willows are very cross-compatible, and numerous hybrids occur, both naturally and in cultivation, a well-known ornamental example is the weeping willow, which is a hybrid of Peking willow from China and white willow from Europe. The hybrid cultivar Boydii has gained the Royal Horticultural Societys Award of Garden Merit, Willows are used as food plants by the larvae of some Lepidoptera species, such as the mourning cloak butterfly. Ants, such as ants, are common on willows inhabited by aphids, coming to collect aphid honeydew
The coyote is a canid native to North America. It is smaller than its relative, the gray wolf, and slightly smaller than its other close relatives, the eastern wolf. It fills much of the ecological niche as the golden jackal does in Eurasia, though it is larger. The species is versatile and able to adapt to environments modified by humans, as human activity has altered the landscape, the coyotes range has expanded. In 2013, coyotes were sighted in eastern Panama for the first time, the coyote is more closely related to the common ancestor of wolves and other canids than the gray wolf. As of 2005,19 coyote subspecies are recognized, the average male coyote weighs 8 to 20 kg and the average female 7 to 18 kg. Their fur color is light gray and red or fulvous interspersed with black and white. It is highly flexible in organization, living either in a family unit or in loosely knit packs of unrelated individuals. The coyotes characteristic vocalization is a made by solitary individuals. Humans aside and gray wolves are the only serious enemies.
Nevertheless, coyotes do sometimes mate with gray, eastern, or red wolves, Most recent studies show that most wolves contain some level of coyote DNA. As with other figures, the coyote uses deception and humor to rebel against social conventions. The animal was especially respected in Mesoamerican cosmology as a symbol of military might, after the European colonization of the Americas, it was reviled in Anglo-American culture as a cowardly and untrustworthy animal. Unlike wolves, which have undergone an improvement of their public image, Coyote males average 8 to 20 kg in weight, while females average 7 to 18 kg, though size varies geographically. Northern subspecies, which average 18 kg, tend to larger than the southern subspecies of Mexico. Body length ranges on average from 1.0 to 1.35 m, the largest coyote on record was a male killed near Afton, Wyoming, on November 19,1937, which measured 1.5 m from nose to tail, and weighed 34 kg. Scent glands are located at the side of the base of the tail and are a bluish-black color.
The color and texture of the fur varies somewhat geographically
Potentilla /ˌpoʊtənˈtɪlə/ is a genus containing over 300 species of annual and perennial herbaceous flowering plants in the rose family, Rosaceae. They are usually called cinquefoils in English, Potentilla are generally only found throughout the northern continents of the world, though some may even be found in montane biomes of the New Guinea Highlands. Several other cinquefoils formerly included here are now separated in distinct genera, some species are called tormentils, though this is often used specifically for common tormentil. Others are referred to as barren strawberries, which may refer to P. sterilis in particular, or to the closely related. Typical cinquefoils look most similar to strawberries, but differ in usually having dry, many cinquefoil species have palmate leaves. Some species have just three leaflets, while others have 15 or more leaflets arranged pinnately, the flowers are usually yellow, but may be white, pinkish or red. The accessory fruits are usually dry but may be fleshy and strawberry-like, among the Rosaceae, cinquefoils are close relatives of avens and roses, and even closer relatives of agrimonies.
Yet more closely related to Potentilla are ladys mantles and strawberries, dryas is not as closely related as long believed. The genera Horkelia and Ivesia are sometimes included in Potentilla today, the mock-strawberries of Duchesnea have been included. The marsh cinquefoil is now in the genus Comarum, and the three-toothed cinquefoil makes up the monotypic genus Sibbaldiopsis. As already proposed by John Hill in the 18th century, the silverweeds of genus Argentina may be distinct, estimates of the number of valid species in this large genus depend on the circumscription used, and they recently vary from over 300 to 400 to 500 to several hundred. See the list of Potentilla species, Argentina Comarum Dasiphora Drymocallis Sibbaldiopsis Cinquefoil in the Middle English Dictionary is described as Pentafilon – from Greek Pentaphyllon – influenced by foil, a leaf. The European cinquefoil, often used medicinally, the word is derived from Old French cinc, Middle English cink and ultimately Latin quinque – all meaning five –, and feuille and foil/foille which mean leaf.
Formerly this term referred to five-leaved plants in general, in medieval times, the word cinquefoil was used almost exclusively in England. In France, the genus was called quintefeuille, first attested in Normandy, the scientific name seems to have been influenced by a fusion of ancient names for these plants. In another medieval dictionary the French word potentille is defined as a wild Tansie, a silver weed, the related adjective potentiel/potentiells means strong, forcible, or powerful in operation. Its origin is the French potence, the origin of these words is the Latin potens, with the same meaning. Cinquefoils grow wild in most cool and cold regions of the world, most species are herbaceous perennials but a few are erect or creeping shrubs
The dark-eyed junco is a species of the juncos, a genus of small grayish American sparrows. This bird is common across much of temperate North America and in summer ranges far into the Arctic and it is a very variable species, much like the related fox sparrow, and its systematics are still not completely untangled. Adults generally have heads and breasts, gray or brown backs and wings, and a white belly. The white outer tail feathers flash distinctively in flight and while hopping on the ground, the bill is usually pale pinkish. Males tend to have darker, more conspicuous markings than the females, the dark-eyed junco is 13 to 17.5 cm long and has a wingspan of 18 to 25 cm. Body mass can vary from 18 to 30 g. Among standard measurements, the cord is 6.6 to 9.3 cm, the tail is 6.1 to 7.3 cm, the bill is 0.9 to 1.3 cm. Juveniles often have pale streaks and may even be mistaken for vesper sparrows until they acquire adult plumage at 2 to 3 months. The song is a similar to the chipping sparrows, except that the red-backed juncos song is more complex.
The call resembles that of the black-throated blue warblers, which is a member of the New World warbler family, calls include tick sounds and very high-pitched tinkling chips. It is known among bird language practitioners as an excellent bird to study for learning bird language, a sample of the song can be heard at the USGS web site here or at the Cornell Lab of Ornithology web site here. The dark-eyed junco was described by Linnaeus in his 1758 Systema naturae as Fringilla hyemalis, the description consisted merely of the laconic remark F nigra, ventre albo. A reference to a source, and a statement that it came from America, all the rest of the Body black, but in some places dusky, inclining to Lead-color. In Virginia and Carolina they appear only in Winter, and in Snow they appear most, whether they retire and breed in the North or where they go, when they leave these Countries in Spring, is to me unknown. The slate-colored junco is unmistakable enough to make it readily recognizable even from Linnaeus minimal description, Junco is the Spanish for rush, from Latin juncus.
Its modern scientific name means winter junco, from Latin hyemalis of the winter, the several subspecies make up two large groups and three to five small or monotypic ones. The five basic groups were considered separate species, but they interbreed extensively in areas of contact. Birders trying to identify subspecies are advised to consult detailed identification references, J. h. hyemalis J. h. carolinensis J. h. cismontanus This group has dark slate-gray head and upperparts
His letters and books describing his adventures in nature, especially in the Sierra Nevada, have been read by millions. His activism has helped to preserve the Yosemite Valley, Sequoia National Park, the Sierra Club, which he founded, is a prominent American conservation organization. The 211-mile John Muir Trail, a trail in the Sierra Nevada, was named in his honor. Other such places include Muir Woods National Monument, Muir Beach, John Muir College, Mount Muir, in Scotland, the John Muir Way, a 130-mile-long route, was named in honor of him. In his life, Muir devoted most of his time to the preservation of the Western forests and he petitioned the U. S. Congress for the National Park bill that was passed in 1890, establishing Yosemite National Park. The spiritual quality and enthusiasm toward nature expressed in his writings has inspired readers, including presidents and congressmen, today Muir is referred to as the Father of the National Parks and the National Park Service has produced a short documentary about his life.
John Muir has been considered an inspiration to both Scots and Americans, Muirs biographer, Steven J. Holmes, believes that Muir has become one of the patron saints of twentieth-century American environmental activity, both political and recreational. As a result, his writings are discussed in books and journals. Muir has profoundly shaped the very categories through which Americans understand and envision their relationships with the natural world, on April 21,2013, the first ever John Muir Day was celebrated in Scotland, which marked the 175th anniversary of his birth, paying homage to the conservationist. John Muirs Birthplace is a stone house in Dunbar, East Lothian. His parents were Daniel Muir and Ann Gilrye and he was the third of eight children, Sarah, Daniel and Mary, and the American-born Joanna. His earliest recollections were of taking short walks with his grandfather when he was three, author Amy Marquis notes that he began his love affair with nature while young, and implies that it may have been in reaction to his strict religious upbringing.
His father believed that anything that distracted from Bible studies was frivolous, but the young Muir was a restless spirit and especially prone to lashings. As a young boy, Muir became fascinated with the East Lothian landscape and it was during this time that he became interested in natural history and the works of Scottish naturalist Alexander Wilson. Although he spent the majority of his life in America, Muir never forgot his roots in Scotland and he held a strong connection with his birthplace and Scottish identity throughout his life and was frequently heard talking about his childhood spent amid the East Lothian countryside. He greatly admired the works of Thomas Carlyle and poetry of Robert Burns and he returned to Scotland on a trip in 1893, where he met one of his Dunbar schoolmates and visited the places of his youth that were etched in his memory. He never lost his strong Scottish accent after many years living in America, in 1849, Muirs family immigrated to the United States, starting a farm near Portage, called Fountain Lake Farm.
It has been designated a National Historic Landmark, by age 11, young Muir had learned to recite by heart and by sore flesh all of the New Testament and most of the Old Testament
International Union for Conservation of Nature
The International Union for Conservation of Nature is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in gathering and analysis, field projects, lobbying. IUCNs mission is to influence and assist societies throughout the world to conserve nature and to ensure that any use of resources is equitable. Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to equality, poverty alleviation. Unlike other international NGOs, IUCN does not itself aim to mobilize the public in support of nature conservation and it tries to influence the actions of governments and other stakeholders by providing information and advice, and through lobbying and partnerships. The organization is best known to the public for compiling and publishing the IUCN Red List. IUCN has a membership of over 1200 governmental and non-governmental organizations, some 11,000 scientists and experts participate in the work of IUCN commissions on a voluntary basis.
It employs approximately 1000 full-time staff in more than 60 countries and its headquarters are in Gland, Switzerland. IUCN has observer and consultative status at the United Nations, and plays a role in the implementation of several conventions on nature conservation. It was involved in establishing the World Wide Fund for Nature, in the past, IUCN has been criticized for placing the interests of nature over those of indigenous peoples. In recent years, its relations with the business sector have caused controversy. It was previously called the International Union for Protection of Nature, establishment In 1947, the Swiss League for the Protection of Nature organised an international conference on the protection of nature in Brunnen. It is considered to be the first government-organized non-governmental organization, the initiative to set up the new organisation came from UNESCO and especially from its first Director General, the British biologist Julian Huxley. At the time of its founding IUPN was the international organisation focusing on the entire spectrum of nature conservation Early years.
Its secretariat was located in Brussels and its first work program focused on saving species and habitats and applying knowledge, advancing education, promoting international agreements and promoting conservation. Providing a solid base for conservation action was the heart of all activities. IUPN and UNESCO were closely associated and they jointly organized the 1949 Conference on Protection of Nature. In preparation for this conference a list of endangered species was drawn up for the first time
Yosemite National Park
Yosemite National Park is a national park spanning portions of Tuolumne and Madera counties in Northern California. The park, which is managed by the National Park Service, on average, about 4 million people visit Yosemite each year, and most spend the majority of their time in the seven square miles of Yosemite Valley. The park set a record in 2016, surpassing 5 million visitors for the first time in its history. Almost 95% of the park is designated wilderness, Yosemite was central to the development of the national park idea. First, Galen Clark and others lobbied to protect Yosemite Valley from development, Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and the park supports a diversity of plants and animals. The park has a range from 2,127 to 13,114 feet and contains five major vegetation zones, chaparral/oak woodland, lower montane forest, upper montane forest, subalpine zone. Of Californias 7,000 plant species, about 50% occur in the Sierra Nevada, there is suitable habitat for more than 160 rare plants in the park, with rare local geologic formations and unique soils characterizing the restricted ranges many of these plants occupy.
The geology of the Yosemite area is characterized by granitic rocks, about 10 million years ago, the Sierra Nevada was uplifted and tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, about one million years ago and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet during the early glacial episode, the downslope movement of the ice masses cut and sculpted the U-shaped valley that attracts so many visitors to its scenic vistas today. The name Yosemite originally referred to the name of a tribe which was driven out of the area by the Mariposa Battalion. Before the area was called Ahwahnee by indigenous people, as revealed by archeological finds, the Yosemite Valley has been inhabited for nearly 3,000 years, though humans may have first visited the area as long as 8,000 to 10,000 years ago.
The indigenous natives called themselves the Ahwahneechee, meaning dwellers in Ahwahnee and they are related to the Northern Paiute and Mono tribes. Many tribes visited the area to trade, including nearby Central Sierra Miwoks, a major trading route went over Mono Pass and through Bloody Canyon to Mono Lake, just to the east of the Yosemite area. Vegetation and game in the region were similar to that present today, acorns were a staple to their diet, as well as seeds and plants, salmon. In 1851 as part of the Mariposa Wars intended to suppress Native American resistance and he was pursuing forces of around 200 Ahwahneechee led by Chief Tenaya. Accounts from this battalion were the first well-documented reports of ethnic Europeans entering Yosemite Valley, attached to Savages unit was Dr. Lafayette Bunnell, the company physician, who wrote about his awestruck impressions of the valley in The Discovery of the Yosemite. Bunnell is credited with naming Yosemite Valley, based on his interviews with Chief Tenaya, Bunnell wrote that Chief Tenaya was the founder of the Pai-Ute Colony of Ah-wah-nee
Hydroelectricity is electricity produced from hydropower. In 2015 hydropower generated 16. 6% of the total electricity and 70% of all renewable electricity. Hydropower is produced in 150 countries, with the Asia-Pacific region generating 33 percent of global hydropower in 2013, China is the largest hydroelectricity producer, with 920 TWh of production in 2013, representing 16.9 percent of domestic electricity use. The cost of hydroelectricity is relatively low, making it a source of renewable electricity. The hydro station consumes no water, unlike coal or gas plants, the average cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U. S. cents per kilowatt-hour. With a dam and reservoir it is a source of electricity since the amount produced by the station can be changed up or down very quickly to adapt to changing energy demands. Once a hydroelectric complex is constructed, the project produces no direct waste, Hydropower has been used since ancient times to grind flour and perform other tasks.
In the mid-1770s, French engineer Bernard Forest de Bélidor published Architecture Hydraulique which described vertical-, by the late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand for the Industrial Revolution would drive development as well, in 1878 the worlds first hydroelectric power scheme was developed at Cragside in Northumberland, England by William George Armstrong. It was used to power an arc lamp in his art gallery. The old Schoelkopf Power Station No.1 near Niagara Falls in the U. S. side began to produce electricity in 1881. The first Edison hydroelectric power station, the Vulcan Street Plant, began operating September 30,1882, in Appleton, Wisconsin, by 1886 there were 45 hydroelectric power stations in the U. S. and Canada. By 1889 there were 200 in the U. S. alone, at the beginning of the 20th century, many small hydroelectric power stations were being constructed by commercial companies in mountains near metropolitan areas.
Grenoble, France held the International Exhibition of Hydropower and Tourism with over one million visitors, by 1920 as 40% of the power produced in the United States was hydroelectric, the Federal Power Act was enacted into law. The Act created the Federal Power Commission to regulate hydroelectric power stations on federal land, as the power stations became larger, their associated dams developed additional purposes to include flood control and navigation. Federal funding became necessary for development and federally owned corporations, such as the Tennessee Valley Authority. Hydroelectric power stations continued to become larger throughout the 20th century, Hydropower was referred to as white coal for its power and plenty. Hoover Dams initial 1,345 MW power station was the worlds largest hydroelectric station in 1936
Glacial striations are scratches or gouges cut into bedrock by glacial abrasion. These scratches and gouges were first recognized as the result of a glacier in the late 18th century when Swiss alpinists first associated them with moving glaciers. They noted that if they were visible today that the glaciers must be receding. Glacial striations are usually multiple and parallel, representing the movement of the glacier using rock fragments and sand grains, embedded in the base of the glacier, as cutting tools. Large amounts of gravel and boulders carried along underneath the glacier provide the abrasive power to cut trough-like glacial grooves. Finer sediments in the base of the glacier further scour and polish the bedrock surface. Ice itself is not a hard material to change the shape of rock. Most glacial striations were exposed by the retreat of glaciers since the Last Glacial Maximum or the more recent Little Ice Age. As well as indicating the direction of flow of the glacial ice, the depth and extent of weathering of the striations may be used to estimate the duration of post-glacier exposure of the rock.
An outstanding example of glacial grooves can be found at the Glacial Grooves at Kelleys Island, the most impressive of which is 400 feet long,35 feet wide and these grooves cut into the Columbus Limestone. Striations cover the sides and bottoms of the grooves, the following affect the rate of abrasion, The amount of rock debris in the basal surface of the ice. As the bedrock is being worn away the abrading fragments within the glacier are being worn, similarly to sandpaper being worn away with use. A continued supply of abrading fragments is required to uphold a similar level of abrasion, the fragments must be harder than the bedrock. Quartz fragments will abrade shale but shale fragments will not abrade a quartz rich bedrock, a constant flow of melt water between the basal surface and the bedrock speeds abrasion. The meltwater constantly rinses away the rock allowing the coarser fragments to abrade bedrock. The faster the glacier moves, the faster the bedrock will be eroded, thicker ice is heavier ice which causes more downward force and increased pressure between the abrading fragments and the bedrock.
There is a limit to how much ice will enhance abrasion, if the friction force between fragments and bedrock is too great the ice will flow around the fragments. If the meltwater is under high pressure it will cause the ice to effectively buoy up
Populus tremuloides is a deciduous tree native to cooler areas of North America, one of several species referred to by the common name aspen. It is commonly called quaking aspen, trembling aspen, American aspen, mountain or golden aspen, trembling poplar, white poplar, the trees have tall trunks, up to 25 meters tall, with smooth pale bark, scarred with black. The glossy green leaves, dull beneath, become golden to yellow, rarely red, the species often propagates through its roots to form large groves originating from a shared system of rhizomes. Populus tremuloides is the most widely distributed tree in North America and it is the defining species of the aspen parkland biome in the Prairie Provinces of Canada and extreme northwest Minnesota. The quaking or trembling of the leaves that is referred to in the names is due to the flexible flattened petioles. The specific epithet, evokes this trembling behavior and can be translated as like tremula. Some species of Populus have petioles flattened partially along their length, while the aspens and some other poplars have them flattened from side to side along the entire length of the petiole.
Quaking aspen is a tall, fast growing tree, usually 20–25 m at maturity, with a trunk 20 to 80 cm in diameter, the bark is relatively smooth, colored greenish-white to gray, and is marked by thick black horizontal scars and prominent black knots. Parallel vertical scars are tell-tale signs of elk, which strip off bark with their front teeth. The leaves on trees are nearly round, 4–8 centimeters in diameter with small rounded teeth. Young trees and root sprouts have much larger nearly triangular leaves, aspens are dioecious, with separate male and female clones. The quaking aspen is the State Tree of Utah, quaking aspen occurs across Canada in all provinces and territories, with the possible exception of Nunavut. It occurs at low elevations as far south as northern Nebraska, in the western United States, this tree rarely survives at elevations lower than 1,500 feet due to hot summers experienced below that elevation, and is generally found at 5, 000–12,000 feet. It grows at altitudes as far south as Guanajuato, Mexico.
Quaking aspen grows in a variety of climatic conditions. January and July average temperatures range from −30 °C and 16 °C in the Alaska Interior to −3 °C and 23 °C in Fort Wayne, average annual precipitation ranges from 1,020 mm in Gander and Labrador to as little as 180 mm in the Alaska Interior. The southern limit of the range roughly follows the 24 °C mean July isotherm. Shrub-like dwarf clones exist in environments too cold and dry to be hospitable to full-size trees