Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic material, a natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves, it conveys water and nutrients between the leaves, other growing tissues, the roots. Wood may refer to other plant materials with comparable properties, to material engineered from wood, or wood chips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons and paper. More it emerged as a feedstock for the production of purified cellulose and its derivatives, such as cellophane and cellulose acetate.
As of 2005, the growing stock of forests worldwide was about 434 billion cubic meters, 47% of, commercial. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy. In 1991 3.5 billion cubic meters of wood were harvested. Dominant uses were for building construction. A 2011 discovery in the Canadian province of New Brunswick yielded the earliest known plants to have grown wood 395 to 400 million years ago. Wood can be dated by carbon dating and in some species by dendrochronology to determine when a wooden object was created. People have used wood for thousands of years for many purposes, including as a fuel or as a construction material for making houses, weapons, packaging and paper. Known constructions using wood date back ten thousand years. Buildings like the European Neolithic long house were made of wood. Recent use of wood has been enhanced by the addition of bronze into construction; the year-to-year variation in tree-ring widths and isotopic abundances gives clues to the prevailing climate at the time a tree was cut.
Wood, in the strict sense, is yielded by trees, which increase in diameter by the formation, between the existing wood and the inner bark, of new woody layers which envelop the entire stem, living branches, roots. This process is known as secondary growth; these cells go on to form thickened secondary cell walls, composed of cellulose and lignin. Where the differences between the four seasons are distinct, e.g. New Zealand, growth can occur in a discrete annual or seasonal pattern, leading to growth rings. If the distinctiveness between seasons is annual, these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are to be indistinct or absent. If the bark of the tree has been removed in a particular area, the rings will be deformed as the plant overgrows the scar. If there are differences within a growth ring the part of a growth ring nearest the center of the tree, formed early in the growing season when growth is rapid, is composed of wider elements.
It is lighter in color than that near the outer portion of the ring, is known as earlywood or springwood. The outer portion formed in the season is known as the latewood or summerwood. However, there are major differences, depending on the kind of wood; as a tree grows, lower branches die, their bases may become overgrown and enclosed by subsequent layers of trunk wood, forming a type of imperfection known as a knot. The dead branch may not be attached to the trunk wood except at its base, can drop out after the tree has been sawn into boards. Knots affect the technical properties of the wood reducing the local strength and increasing the tendency for splitting along the wood grain, but may be exploited for visual effect. In a longitudinally sawn plank, a knot will appear as a circular "solid" piece of wood around which the grain of the rest of the wood "flows". Within a knot, the direction of the wood is up to 90 degrees different from the grain direction of the regular wood. In the tree a knot is either the base of a dormant bud.
A knot is conical in shape with the inner tip at the point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud. In grading lumber and structural timber, knots are classified according to their form, size and the firmness with which they are held in place; this firmness is affected by, among other factors, the length of time for which the branch was dead while the attaching stem continued to grow. Knots materially affect cracking and warping, ease in working, cleavability of timber, they are defects which weaken timber and lower its value for structural purposes where strength is an important consideration. The weakening effect is much more serious when timber is subjected to forces perpendicular to the grain and/or tension than when under load along the grain and/or compression; the extent to which knots affect the strength of a beam depends upon their position, size and condition. A knot on the upper side is compressed. If there is a season check
Spring is one of the four temperate seasons, following winter and preceding summer. There are various technical definitions of spring, but local usage of the term varies according to local climate and customs; when it is spring in the Northern Hemisphere, it is autumn in the Southern Hemisphere and vice versa. At the spring equinox and nights are twelve hours long, with day length increasing and night length decreasing as the season progresses. Spring and "springtime" refer to the season, to ideas of rebirth, renewal and regrowth. Subtropical and tropical areas have climates better described in terms of other seasons, e.g. dry or wet, monsoonal or cyclonic. Cultures may have local names for seasons which have little equivalence to the terms originating in Europe. Meteorologists define four seasons in many climatic areas: spring, summer and winter; these are demarcated by the values of their average temperatures on a monthly basis, with each season lasting three months. The three warmest months are by definition summer, the three coldest months are winter and the intervening gaps are spring and autumn.
Spring, when defined in this manner, can start on different dates in different regions. Thus, in the US and UK, spring months are March and May, while in New Zealand and Australia, spring conventionally begins on September 1 and ends November 30. Swedish meteorologists define the beginning of spring as the first occasion on which the average daytime temperature exceeds zero degrees Celsius for seven consecutive days, thus the date varies with latitude and elevation. In some cultures in the Northern Hemisphere, the astronomical vernal equinox is taken to mark the first day of spring, the summer solstice is taken as the first day of summer. In Persian culture the first day of spring is the first day of the first month which begins on 20 or 21 March. In other traditions, the equinox is taken as mid-spring. In the traditional Chinese calendar, the "spring" season consists of the days between Lichun, taking Chunfen as its midpoint ending at Lixia. According to the Celtic tradition, based on daylight and the strength of the noon sun, spring begins in early February and continues until early May.
The beginning of spring is not always determined by fixed calendar dates. The phenological or ecological definition of spring relates to biological indicators, such as the blossoming of a range of plant species, the activities of animals, the special smell of soil that has reached the temperature for micro flora to flourish; these indicators, along with the beginning of spring, vary according to the local climate and according to the specific weather of a particular year. Most ecologists divide the year into six seasons. In addition to spring, ecological reckoning identifies an earlier separate prevernal season between the hibernal and vernal seasons; this is a time when only the hardiest flowers like the crocus are in bloom, sometimes while there is still some snowcover on the ground. During early spring, the axis of the Earth is increasing its tilt relative to the Sun, the length of daylight increases for the relevant hemisphere; the hemisphere begins to warm causing new plant growth to "spring forth," giving the season its name.
Any snow begins to melt, swelling streams with runoff and any frosts become less severe. In climates that have no snow, rare frosts and ground temperatures increase more rapidly. Many flowering plants bloom at this time of year, in a long succession, sometimes beginning when snow is still on the ground and continuing into early summer. In snowless areas, "spring" may begin as early as February or August, heralded by the blooming of deciduous magnolias and quince. Many temperate areas have a dry spring, wet autumn, which brings about flowering in this season, more consistent with the need for water, as well as warmth. Subarctic areas may not experience "spring" at all until May. While spring is a result of the warmth caused by the changing orientation of the Earth's axis relative to the Sun, the weather in many parts of the world is affected by other, less predictable events; the rainfall in spring follows trends more related to longer cycles—such as the solar cycle—or events created by ocean currents and ocean temperatures—for example, the El Niño effect and the Southern Oscillation Index.
Unstable spring weather may occur more when warm air begins to invade from lower latitudes, while cold air is still pushing from the Polar regions. Flooding is most common in and near mountainous areas during this time of year, because of snow-melt, accelerated by warm rains. In North America, Tornado Alley is most active at this time of year since the Rocky Mountains prevent the surging hot and cold air masses from spreading eastward, instead force them into direct conflict. Besides tornadoes, supercell thunderstorms can produce dangerously large hail and high winds, for which a severe thunderstorm warning or tornado warning is issued. More so than in winter, the jet streams play an important role in unstable and severe Northern Hemisphere weather in springtime. In recent decades, season creep has been observed, which means that many phenological signs of spring are occurring earlier in many regions by around two days per decade. Spring in the Southern Hemisphere is different in several significant ways to that of the Northern Hemisphere
Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, reinforce, protect, or drain. Made from polypropylene or polyester, geotextile fabrics come in three basic forms: woven, needle punched, or heat bonded. Geotextile composites have been introduced and products such as geogrids and meshes have been developed. Geotextiles are able to withstand many things, are durable, are able to soften a fall if someone falls down. Overall, these materials are referred to as geosynthetics and each configuration—geonets, geosynthetic clay liners, geotextile tubes, others—can yield benefits in geotechnical and environmental engineering design. Geotextiles were intended to be an alternative to granular soil filters; the original, still sometimes used, term for geotextiles is filter fabrics. Work began in the 1950s with R. J. Barrett using geotextiles behind precast concrete seawalls, under precast concrete erosion control blocks, beneath large stone riprap, in other erosion control situations.
He used different styles of woven monofilament fabrics, all characterized by a high percentage open area. He discussed the need for both adequate permeability and soil retention, along with adequate fabric strength and proper elongation and set the tone for geotextile use in filtration situations. Geotextiles and related products have many applications and support many civil engineering applications including roads, railroads, retaining structures, canals, bank protection, coastal engineering and construction site silt fences or geotube. Geotextiles are placed at the tension surface to strengthen the soil. Geotextiles are used for sand dune armoring to protect upland coastal property from storm surge, wave action and flooding. A large sand-filled container within the dune system prevents storm erosion from proceeding beyond the SFC. Using a sloped unit rather than a single tube eliminates damaging scour. Erosion control manuals comment on the effectiveness of sloped, stepped shapes in mitigating shoreline erosion damage from storms.
Geotextile sand-filled units provide a "soft" armoring solution for upland property protection. Geotextiles are used as matting to stabilize flow in stream swales. Geotextiles can improve soil strength at a lower cost than conventional soil nailing. In addition, geotextiles allow planting on steep slopes, further securing the slope. Geotextiles have been used to protect the fossil hominid footprints of Laetoli in Tanzania from erosion and tree roots. In building demolition, geotextile fabrics in combination with steel wire fencing can contain explosive debris. Coir geotextiles are popular for erosion control, slope stabilization and bioengineering, due to the fabric's substantial mechanical strength. Coir geotextiles last 3 to 5 years depending on the fabric weight; the product degrades into humus. While many possible design methods or combinations of methods are available to the geotextile designer, the ultimate decision for a particular application takes one of three directions: design by cost and availability, design by specification, or design by function.
Extensive literature on design methods for geotextiles has been published in the peer reviewed journal Geotextiles and Geomembranes. Hard landscape materials Sediment control Geomembrane Jual Geotextile Jual Geotextile Jual Geotextile Koerner, R. M.. Designing With Geosynthetics, 6th Edition, Xlibris Publishing Co. 914 pgs. Koerner, R. M. Editor. Geotextiles: From Design to Applications, Woodhead Publishing Co. AMsterdam, 617 pgs. John, N. W. M.. Geotextiles, Blackie Publishing Ltd. Glasgow, 347 pgs
In earth science, erosion is the action of surface processes that removes soil, rock, or dissolved material from one location on the Earth's crust, transports it to another location. This natural process is caused by the dynamic activity of erosive agents, that is, ice, air, plants and humans. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind erosion, zoogenic erosion, anthropogenic erosion; the particulate breakdown of rock or soil into clastic sediment is referred to as physical or mechanical erosion. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Natural rates of erosion are controlled by the action of geological weathering geomorphic drivers, such as rainfall; the rates at which such processes act control. Physical erosion proceeds fastest on steeply sloping surfaces, rates may be sensitive to some climatically-controlled properties including amounts of water supplied, wind speed, wave fetch, or atmospheric temperature.
Feedbacks are possible between rates of erosion and the amount of eroded material, carried by, for example, a river or glacier. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, which control the arrival and emplacement of material at a new location. While erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the natural rate of erosion in the region. Excessive erosion causes both "on-site" and "off-site" problems. On-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the eventual end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of water bodies, as well as sediment-related damage to roads and houses.
Water and wind erosion are the two primary causes of land degradation. Intensive agriculture, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion. However, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, the surface runoff which may result from rainfall, produces four main types of soil erosion: splash erosion, sheet erosion, rill erosion, gully erosion. Splash erosion is seen as the first and least severe stage in the soil erosion process, followed by sheet erosion rill erosion and gully erosion. In splash erosion, the impact of a falling raindrop creates a small crater in the soil, ejecting soil particles; the distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rainfall rate is greater than the rate at which water can infiltrate into the soil, surface runoff occurs.
If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope. Sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes. Where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are of the order of a few centimetres or less and along-channel slopes may be quite steep; this means that rills exhibit hydraulic physics different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when runoff water accumulates and flows in narrow channels during or after heavy rains or melting snow, removing soil to a considerable depth. Valley or stream erosion occurs with continued water flow along a linear feature; the erosion is both downward, deepening the valley, headward, extending the valley into the hillside, creating head cuts and steep banks.
In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is steep. When some base level is reached, the erosive activity switches to lateral erosion, which widens the valley floor and creates a narrow floodplain; the stream gradient becomes nearly flat, lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion, by far the most erosion occurs during times of flood when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone
The City and Borough of Wrangell is a borough in the Alaska, United States. As of the 2010 census the population was 2,369, up from 2,308 in 2000. Incorporated as a Unified Home Rule Borough on May 30, 2008, Wrangell was a city in the Wrangell-Petersburg Census Area, its Tlingit name is Ḵaachx̱aana.áakʼw. The Tlingit people residing in the Wrangell area, who were there centuries before Europeans, call themselves the Shtaxʼhéen Ḵwáan after the nearby Stikine River. Alternately they use the autonym Shxʼát Ḵwáan; the central part of Wrangell is located at 56°28′15″N 132°22′36″W, in the northwest corner of Wrangell Island, whereas the borough now encompasses the entire eastern half of the former Wrangell-Petersburg Census Area, in addition to the area around Meyers Chuck, in the Prince of Wales-Outer Ketchikan Census Area. It includes Thoms Place, a former census-designated place on Wrangell Island. Tlingit people and their ancestors have inhabited this island for thousands of years. According to Naanyaa.aayí clan traditions, Tlingit people migrated down the Stikine River during a time when the river still flowed underneath glaciers.
The population moved down the river, settling in different locations such as Tlákw.aan "Ancient Village", Sʼiknáx̱ "Across from the Grass", Shaal.aan "Fish Trap Town", Xakw.aan "Sandbar Village", Kayáash "Platform", Hehl "Foam People", Hehl being the senior of house of the village. Settlements on the coast included Chʼuxʼáasʼaan "Waterfall Town", Ḵeishangita.aan "Red Alder Head Village", Kʼaatsʼḵu Noow "Among the Sharps Fort", An.áan "Village that Rests", many others. The numerous petroglyphs found at Petroglyph Beach just north of Wrangell, as well as those scattered on the beaches of the many islands in the vicinity, attest to the long Tlingit presence, it is known and somewhat forgotten, that first peoples coastal migration to the Stikine River happened from the south. The Nass River people had several migrations into the area; the "Git Setti" people tell of their migration story in a totem raised in Wrangell in 1894 called "Kickssetti" Totem. The salt water inlet, now Wrangell Harbor was traditionally called Ḵaachx̱ana.áakʼw "Ḵaachx̱án's little lake".
Before the harbor mouth was dredged and cleared in the late 19th century, the mouth of this inlet would go dry at low tide, which led to its being called a lake. Ḵaachx̱án was a man from the village variously known as Ḵaalchʼalʼaan or Chʼaalʼít.aan, meaning "Willow House Village". The village site today is known as "Old Town" or "Old Wrangell". Ḵaachx̱án was a hermit who preferred living away from his relatives, lived in a smokehouse located on the rear shore of the lake, named after him. Wrangell was founded by Russians as one of the oldest non-Native settlements in Alaska, they started trading for furs with area Tlingit in 1811 at the site of present-day Wrangell. In 1834, Baron Ferdinand Petrovich Wrangel head of Russian government interests in Russian America, ordered a stockade built near the Naanyaa.aayí clan house of Chief Shakes, called Shéiksh Hídi. This house was located about 13 miles north of Old Wrangell, on a small island in the middle of what is today Wrangell Harbor; the stockade, named Redoubt Saint Dionysius, was founded at the location of present-day Wrangell and stood near the end of the small peninsula that forms the northeastern side of the mouth of the harbor.
The British Hudson's Bay Company named the stockade Fort Stikine. The Tlingit had used the Stikine River as a trade route to the interior since ancient times, they protested when the Hudson's Bay Company began to use their trade routes. Two epidemics of smallpox in 1836 and 1840 reduced the Tlingit population in the area by half, as they had no acquired immunity, silenced most of the protest; the HBC abandoned the fort in 1849 after the area's stocks of sea otter and beaver were depleted, ending the fur trade. Fort Stikine remained under British rule until Alaska's purchase by the United States in 1867. In 1868, the U. S. built a military post called Fort Wrangell at the site, it remained active until 1877. The community around the post continued to grow through commerce with prospectors in the gold rushes of 1861, 1874–77, 1897; as in Skagway, businessmen looking to make money off the miners built many gambling halls, dance halls, bars. Thousands of miners traveled up the Stikine River into the Cassiar District of British Columbia during 1874, again to the Klondike in 1897.
The Wrangell Bombardment occurred on the 25th of December 1869 when a Stikine Indian named Lowan bit off Mrs. Jaboc Muller's third right finger, was killed in an ensuing fight by soldiers who mortally wounded an additional Stikine Indian; the following morning, Scutd-doo, the father of the deceased, entered the fort and shot the post trader's partner Leon Smith fourteen times. Smith died some 13 hours later; the US army made an ultimatum demanding Sccutd-doo's surrender, following bombardment of the Stikine Indian village, the villagers handed Scutd-doo over to the military in the fort, where he was court-martialed and publicly hanged before the garrison and assembled natives on 29 December, stating before he was hanged that he had acted in revenge against the
Bacteria are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. A few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, are present in most of its habitats. Bacteria inhabit soil, acidic hot springs, radioactive waste, the deep portions of Earth's crust. Bacteria live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, only about half of the bacterial phyla have species that can be grown in the laboratory; the study of bacteria is known as a branch of microbiology. There are 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants and animals. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere.
The nutrient cycle includes the decomposition of dead bodies. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Data reported by researchers in October 2012 and published in March 2013 suggested that bacteria thrive in the Mariana Trench, with a depth of up to 11 kilometres, is the deepest known part of the oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, "You can find microbes everywhere—they're adaptable to conditions, survive wherever they are."The famous notion that bacterial cells in the human body outnumber human cells by a factor of 10:1 has been debunked. There are 39 trillion bacterial cells in the human microbiota as personified by a "reference" 70 kg male 170 cm tall, whereas there are 30 trillion human cells in the body.
This means that although they do have the upper hand in actual numbers, it is only by 30%, not 900%. The largest number exist in the gut flora, a large number on the skin; the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial in the gut flora. However several species of bacteria are pathogenic and cause infectious diseases, including cholera, anthrax and bubonic plague; the most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year in sub-Saharan Africa. In developed countries, antibiotics are used to treat bacterial infections and are used in farming, making antibiotic resistance a growing problem. In industry, bacteria are important in sewage treatment and the breakdown of oil spills, the production of cheese and yogurt through fermentation, the recovery of gold, palladium and other metals in the mining sector, as well as in biotechnology, the manufacture of antibiotics and other chemicals.
Once regarded as plants constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and harbour membrane-bound organelles. Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two different groups of organisms that evolved from an ancient common ancestor; these evolutionary domains are called Archaea. The word bacteria is the plural of the New Latin bacterium, the latinisation of the Greek βακτήριον, the diminutive of βακτηρία, meaning "staff, cane", because the first ones to be discovered were rod-shaped; the ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, about 4 billion years ago. For about 3 billion years, most organisms were microscopic, bacteria and archaea were the dominant forms of life. Although bacterial fossils exist, such as stromatolites, their lack of distinctive morphology prevents them from being used to examine the history of bacterial evolution, or to date the time of origin of a particular bacterial species.
However, gene sequences can be used to reconstruct the bacterial phylogeny, these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. The most recent common ancestor of bacteria and archaea was a hyperthermophile that lived about 2.5 billion–3.2 billion years ago. Bacteria were involved in the second great evolutionary divergence, that of the archaea and eukaryotes. Here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves related to the Archaea; this involved the engulfment by proto-eukaryotic cells of alphaproteobacterial symbionts to form either mitochondria or hydrogenosomes, which are still found in all known Eukarya. Some eukaryotes that contained mitochondria engulfed cyanobacteria-like organisms, leading to the formation of chloroplasts in algae and plants; this is known as primary endosymbiosis. Bacteria display a wide diversity of sizes, called morphologies.
Bacterial cells are about one-tenth the size of eukaryotic cells
Alberta is a western province of Canada. With an estimated population of 4,067,175 as of 2016 census, it is Canada's fourth most populous province and the most populous of Canada's three prairie provinces, its area is about 660,000 square kilometres. Alberta and its neighbour Saskatchewan were districts of the Northwest Territories until they were established as provinces on September 1, 1905; the premier has been Rachel Notley since May 2015. Alberta is bounded by the provinces of British Columbia to the west and Saskatchewan to the east, the Northwest Territories to the north, the U. S. state of Montana to the south. Alberta is one of three Canadian provinces and territories to border only a single U. S. state and one of only two landlocked provinces. It has a predominantly humid continental climate, with stark contrasts over a year. Alberta's capital, Edmonton, is near the geographic centre of the province and is the primary supply and service hub for Canada's crude oil, the Athabasca oil sands and other northern resource industries.
About 290 km south of the capital is the largest city in Alberta. Calgary and Edmonton centre Alberta's two census metropolitan areas, both of which have populations exceeding one million, while the province has 16 census agglomerations. Tourist destinations in the province include Banff, Drumheller, Sylvan Lake and Lake Louise. Alberta is named after the fourth daughter of Queen Victoria. Princess Louise was the wife of Marquess of Lorne, Governor General of Canada. Lake Louise and Mount Alberta were named in her honour. Alberta, with an area of 661,848 km2, is the fourth-largest province after Quebec and British Columbia. To the south, the province borders on the 49th parallel north, separating it from the U. S. state of Montana, while to the north the 60th parallel north divides it from the Northwest Territories. To the east, the 110th meridian west separates it from the province of Saskatchewan, while on the west its boundary with British Columbia follows the 120th meridian west south from the Northwest Territories at 60°N until it reaches the Continental Divide at the Rocky Mountains, from that point follows the line of peaks marking the Continental Divide in a southeasterly direction until it reaches the Montana border at 49°N.
The province extends 660 km east to west at its maximum width. Its highest point is 3,747 m at the summit of Mount Columbia in the Rocky Mountains along the southwest border while its lowest point is 152 m on the Slave River in Wood Buffalo National Park in the northeast. With the exception of the semi-arid steppe of the south-eastern section, the province has adequate water resources. There are numerous lakes used for swimming, fishing and a range of water sports. There are three large lakes, Lake Claire in Wood Buffalo National Park, Lesser Slave Lake, Lake Athabasca which lies in both Alberta and Saskatchewan; the longest river in the province is the Athabasca River which travels 1,538 km from the Columbia Icefield in the Rocky Mountains to Lake Athabasca. The largest river is the Peace River with an average flow of 2161 m3/s; the Peace River originates in the Rocky Mountains of northern British Columbia and flows through northern Alberta and into the Slave River, a tributary of the Mackenzie River.
Alberta's capital city, Edmonton, is located at about the geographic centre of the province. It is the most northerly major city in Canada, serves as a gateway and hub for resource development in northern Canada; the region, with its proximity to Canada's largest oil fields, has most of western Canada's oil refinery capacity. Calgary is about 280 km south of Edmonton and 240 km north of Montana, surrounded by extensive ranching country. 75% of the province's population lives in the Calgary–Edmonton Corridor. The land grant policy to the railroads served as a means to populate the province in its early years. Most of the northern half of the province is boreal forest, while the Rocky Mountains along the southwestern boundary are forested; the southern quarter of the province is prairie, ranging from shortgrass prairie in the southeastern corner to mixed grass prairie in an arc to the west and north of it. The central aspen parkland region extending in a broad arc between the prairies and the forests, from Calgary, north to Edmonton, east to Lloydminster, contains the most fertile soil in the province and most of the population.
Much of the unforested part of Alberta is given over either to grain or to dairy farming, with mixed farming more common in the north and centre, while ranching and irrigated agriculture predominate in the south. The Alberta badlands are located in southeastern Alberta, where the Red Deer River crosses the flat prairie and farmland, features deep canyons and striking landforms. Dinosaur Provincial Park, near Brooks, showcases the badlands terrain, desert flora, remnants from Alberta's past when dinosaurs roamed the lush landscape. Alberta has a humid continental climate with cold winters; the province is open to cold arctic weather systems from the north, which produce cold conditions in winter. As the fronts between the air masses shift north and south across Alberta, the temperature can change rapidly. Arctic