Sweden
Sweden the Kingdom of Sweden, is a Scandinavian Nordic country in Northern Europe. It borders Norway to the west and north and Finland to the east, is connected to Denmark in the southwest by a bridge-tunnel across the Öresund, a strait at the Swedish-Danish border. At 450,295 square kilometres, Sweden is the largest country in Northern Europe, the third-largest country in the European Union and the fifth largest country in Europe by area. Sweden has a total population of 10.2 million. It has a low population density of 22 inhabitants per square kilometre; the highest concentration is in the southern half of the country. Germanic peoples have inhabited Sweden since prehistoric times, emerging into history as the Geats and Swedes and constituting the sea peoples known as the Norsemen. Southern Sweden is predominantly agricultural, while the north is forested. Sweden is part of the geographical area of Fennoscandia; the climate is in general mild for its northerly latitude due to significant maritime influence, that in spite of this still retains warm continental summers.
Today, the sovereign state of Sweden is a constitutional monarchy and parliamentary democracy, with a monarch as head of state, like its neighbour Norway. The capital city is Stockholm, the most populous city in the country. Legislative power is vested in the 349-member unicameral Riksdag. Executive power is exercised by the government chaired by the prime minister. Sweden is a unitary state divided into 21 counties and 290 municipalities. An independent Swedish state emerged during the early 12th century. After the Black Death in the middle of the 14th century killed about a third of the Scandinavian population, the Hanseatic League threatened Scandinavia's culture and languages; this led to the forming of the Scandinavian Kalmar Union in 1397, which Sweden left in 1523. When Sweden became involved in the Thirty Years War on the Reformist side, an expansion of its territories began and the Swedish Empire was formed; this became one of the great powers of Europe until the early 18th century. Swedish territories outside the Scandinavian Peninsula were lost during the 18th and 19th centuries, ending with the annexation of present-day Finland by Russia in 1809.
The last war in which Sweden was directly involved was in 1814, when Norway was militarily forced into personal union. Since Sweden has been at peace, maintaining an official policy of neutrality in foreign affairs; the union with Norway was peacefully dissolved in 1905. Sweden was formally neutral through both world wars and the Cold War, albeit Sweden has since 2009 moved towards cooperation with NATO. After the end of the Cold War, Sweden joined the European Union on 1 January 1995, but declined NATO membership, as well as Eurozone membership following a referendum, it is a member of the United Nations, the Nordic Council, the Council of Europe, the World Trade Organization and the Organisation for Economic Co-operation and Development. Sweden maintains a Nordic social welfare system that provides universal health care and tertiary education for its citizens, it has the world's eleventh-highest per capita income and ranks in numerous metrics of national performance, including quality of life, education, protection of civil liberties, economic competitiveness, equality and human development.
The name Sweden was loaned from Dutch in the 17th century to refer to Sweden as an emerging great power. Before Sweden's imperial expansion, Early Modern English used Swedeland. Sweden is derived through back-formation from Old English Swēoþēod, which meant "people of the Swedes"; this word is derived from Sweon/Sweonas. The Swedish name Sverige means "realm of the Swedes", excluding the Geats in Götaland. Variations of the name Sweden are used in most languages, with the exception of Danish and Norwegian using Sverige, Faroese Svøríki, Icelandic Svíþjóð, the more notable exception of some Finnic languages where Ruotsi and Rootsi are used, names considered as referring to the people from the coastal areas of Roslagen, who were known as the Rus', through them etymologically related to the English name for Russia; the etymology of Swedes, thus Sweden, is not agreed upon but may derive from Proto-Germanic Swihoniz meaning "one's own", referring to one's own Germanic tribe. Sweden's prehistory begins in the Allerød oscillation, a warm period around 12,000 BC, with Late Palaeolithic reindeer-hunting camps of the Bromme culture at the edge of the ice in what is now the country's southernmost province, Scania.
This period was characterised by small bands of hunter-gatherer-fishers using flint technology. Sweden is first described in a written source in Germania by Tacitus in 98 AD. In Germania 44 and 45 he mentions the Swedes as a powerful tribe with ships that had a prow at each end. Which kings ruled these Suiones is unknown, but Norse mythology presents a long line of legendary and semi-legendary kings going back to the last centuries BC; as for literacy in Sweden itself, the runic script was in use among the south Scandinavian elite by at least the 2nd century AD, but all that has come down to the present from the Roman Period is curt inscriptions on artefacts of male names, demonstrating th
Abies concolor
Abies concolor, the white fir, is a coniferous tree in the pine family Pinaceae. This tree is native to the mountains of western North America from the southern Cascade range in Oregon, south throughout California and into the Sierra de San Pedro Mártir in northern Baja California. White fir live over 300-years and occur at an elevation between 900–3,400 m, it is popular as a Christmas tree. The specific epithet concolor means "all one color"; this large evergreen coniferous tree grows best in the central Sierra Nevada of California, where the record specimen was recorded as 74.9 m tall and measured 4.6 m in diameter at breast height in Yosemite National Park. The typical size of white fir ranges from 25–60 m tall and up to 2.7 m dbh. The largest specimens are found in the central Sierra Nevada, where the largest diameter recorded was found in Sierra National Forest at 58.5 x 8.5 m Rocky mountain white fir exceed 38 m tall or 0.9 m dbh. Large but not huge trees, in good soil, range from 40 to 60 m tall and from 99 to 165 cm dbh in California and southwestern Oregon and to 41 m tall and 124 cm dbh in Arizona and New Mexico.
The leaves are needle-like, flattened, 2.5–6 cm long and 2 mm wide by 0.5–1 mm thick, green to glaucous blue-green above, with two glaucous blue-white bands of stomatal bloom below, notched to bluntly pointed at the tip. The leaf arrangement is spiral on the shoot, but with each leaf variably twisted at the base so they all lie in either two more-or-less flat ranks on either side of the shoot, or upswept across the top of the shoot but not below the shoot; the cones are 6–12 cm long and 4–4.5 cm broad, green or purple ripening pale brown, with about 100–150 scales. The winged seeds are released when the cones disintegrate at maturity about 6 months after pollination; as treated here, there are two subspecies. Concolor — Colorado white fir or Rocky Mountains white fir. In the United States, at altitudes of 1,700–3,400 m in the Rocky Mountains from southern Idaho, south through Utah and Colorado, to New Mexico and Arizona, on the higher Great Basin mountains of Nevada and extreme southeastern California, a short distance into northern Sonora, Mexico.
A smaller tree to 25–35 m tall 45 m. Foliage upcurved to erect on all except weak shaded shoots in the lower crown. Tolerates winter temperatures down to about −40 °C. Abies concolor subsp. Lowiana — Low's white fir or Sierra Nevada white fir. In the United States, at altitudes of 900–2,300 m from the Cascades of central Oregon south through California to northern Baja California, Mexico. A larger tree to 40–60 m tall. Foliage flattened on lower crown shoots, the leaves raised above the shoot on upper crown shoots but not strongly upcurved. Tolerates winter temperatures down to about −30 °C; the United States Department of Agriculture plants database describes this subspecies as the full species Sierra white fir - Abies lowiana A. Murray bis. White fir is closely related to grand fir, with subspecies lowiana being similar to the interior variety of grand fir A. grandis var. idahoensis, intergrading with it where they meet in the Cascades of central Oregon. To the south in Mexico, it is replaced by Durango fir and Mexican fir.
White fir is a shade tolerant, climax species, which means the forest has reached complex maturity in forest succession in western coniferous forests of the United States. White fir and yellow pine have co-existed for millennia in old growth forests throughout their range. In the presence of logging of large diameter trees and exclusion of cleansing wildfires, young trees have become abundant over the past two centuries. White fir had been regarded as a pest in the past by those in the lumber industry, but this opinion has changed. White fir is now one of the most important of all commercial softwoods according to the Western Wood Products Association; the white fir trait of retaining lower limbs creates an escape route for medium to small forest birds from larger flying predators and provides a drip zone around the roots for collecting moisture. The retained limbs can become a fire ladder. Limbing-up white fir, instead of removing medium to large diameter trees, in areas where the public is more to start fires can help keep other trees and giant sequoia from experiencing canopy fire.
Recent concern for sequoia groves has caused agencies to call for removal of white fir in the Sierra Nevada. While sequoia seedlings and young saplings are susceptible to mortality or serious injury by fire.
Power take-off
A power take-off or power takeoff is any of several methods for taking power from a power source, such as a running engine, transmitting it to an application such as an attached implement or separate machines. Most it is a splined drive shaft installed on a tractor or truck allowing implements with mating fittings to be powered directly by the engine. Semi-permanently mounted power take-offs can be found on industrial and marine engines; these applications use a drive shaft and bolted joint to transmit power to a secondary implement or accessory. In the case of a marine application, such shafts may be used to power fire pumps. In aircraft applications, such an accessory drive may be used in conjunction with a constant speed drive. Jet aircraft have four types of PTO units: internal gearbox, external gearbox, radial drive shaft, bleed air, which are used to power engine accessories. In some cases, aircraft power take-off systems provide for putting power into the engine during engine start. See Coffman starter Various power transmission methods were available before power takeoffs became common, but there were applications left wanting for some of the attributes that PTOs would provide.
Flat belts lent themselves only to applications where the engine was stationary, such as factory steam engines, portable stationary engines, or traction engines parked in front of the work. For moving vehicles such as a traction engine or early tractor towing a farm implement, the implement could receive rotary power by taking it from one of its own wheels and distributing it via roller chains, but such a transmission ceases if the vehicle stops traveling; the concept of a shaft drive with connected and disconnected couplings, flexibility for driving at changing angles, was a goal to pursue. Experimental power take-offs were tried as early as 1878, various homemade versions arose over the subsequent decades. International Harvester Company was first to market with a PTO on a production tractor, with its model 8-16, introduced in 1918. Edward A. Johnston, an IHC engineer, had been impressed by a homemade PTO that he saw in France about a decade before, improvised by a French farmer and mechanic surnamed Gougis.
He and his IHC colleagues incorporated the idea into the 8-16, designed a family of implements to take advantage of the feature. IHC was not alone in the market for long, as within a year PTOs were appearing on other production tractors, such as some Case models. In 1920, IHC offered the PTO option on their 15-30 tractor, it was the first PTO-equipped tractor to be submitted for a Nebraska tractor test; the PTO was a competitive advantage for IHC in the 1920s, other companies caught up with PTO implementation. Inside the transmission, the exact point along the gear train where the power is taken off determines whether the PTO can be run independently of vehicle travel. Early PTOs were taken off the main output shaft, meaning that the vehicle had to be "in gear" in order to run the PTO; this was improved by so-called live PTO designs, which allow control of the PTO rotation independently of the tractor motion. This is an advantage when the load driven by the PTO requires the tractor motion to slow or stop running to allow the PTO driven equipment to catch up.
It allows operations where the tractor remains parked, such as silo-filling or unloading a manure spreader to a pile or lagoon rather than across a field. In 1945, Cockshutt Farm Equipment Ltd of Brantford, Canada, introduced the Cockshutt Model 30 tractor with LPTO. Most PTOs built today are live. In modern tractors, LPTO is controlled by push-button or selector switch; this increases safety of operators. The PTO and its associated shafts and universal joints are a common cause of incidents and injury in farming and industry. According to the National Safety Council, 6 percent of tractor related fatalities in 1997 in the United States involved the PTO. Incidents can occur when loose clothing is pulled into the shaft resulting in bone fractures, loss of limb, or death to its wearer. On April 13, 2009 former Major League Baseball star Mark Fidrych died as a result of a PTO related accident. Despite much work to reduce the frequency and severity of agricultural injuries, these events still occur.
Power take-off entanglements are one example of agricultural events that can lead to death or permanent disability. Some implements employ light free-spinning protective plastic guards to enshroud the PTO shaft, are mandatory in some countries. In the UK, Health and Safety Executive guidance is contained in a leaflet. Agricultural PTOs are standardized in dimensions and speed; the ISO standard for PTOs is ISO 500, which as of the 2004 edition was split into three parts: ISO 500-1 General specifications, safety requirements, dimensions for master shield and clearance zone ISO 500-2 Narrow-track tractors, dimensions for master shield and clearance zone ISO 500-3 Main PTO dimensions and spline dimensions, location of PTO. The original type calls for operation at 540 revolutions per minute. A shaft that rotates at 540 rpm has 6 splines on it, a diameter of 13⁄8". Two newer types, supporting higher power applications, differ in shaft size; the larger shaft has 20 splines, while the smaller has 21
Charcoal
Charcoal is the lightweight black carbon and ash residue hydrocarbon produced by removing water and other volatile constituents from animal and vegetation substances. Charcoal is produced by slow pyrolysis — the heating of wood or other substances in the absence of oxygen; this process is called charcoal burning. The finished charcoal consists of carbon; the advantage of using charcoal instead of just burning wood is the removal of the water and other components. This allows charcoal to burn to a higher temperature, give off little smoke; the production of wood charcoal in locations where there is an abundance of wood dates back to a ancient period, consists of piling billets of wood on their ends so as to form a conical pile, openings being left at the bottom to admit air, with a central shaft to serve as a flue. The whole pile is covered with moistened clay; the firing is begun at the bottom of the flue, spreads outwards and upwards. The success of the operation depends upon the rate of the combustion.
Under average conditions, 100 parts of wood yield about 60 parts by volume, or 25 parts by weight, of charcoal. The operation is so delicate that it was left to colliers, they lived alone in small huts in order to tend their wood piles. For example, in the Harz Mountains of Germany, charcoal burners lived in conical huts called Köten which are still much in evidence today; the massive production of charcoal was a major cause of deforestation in Central Europe. In England, many woods were managed as coppices, which were cut and regrown cyclically, so that a steady supply of charcoal would be available forever; the increasing scarcity of harvested wood was a major factor behind the switch to fossil fuel equivalents coal and brown coal for industrial use. The modern process of carbonizing wood, either in small pieces or as sawdust in cast iron retorts, is extensively practiced where wood is scarce, for the recovery of valuable byproducts, which the process permits; the question of the temperature of the carbonization is important.
Charcoal made at 300 °C is brown and friable, inflames at 380 °C. In Finland and Scandinavia, the charcoal was considered the by-product of wood tar production; the best tar came from pine, thus pinewoods were cut down for tar pyrolysis. The residual charcoal was used as substitute for metallurgical coke in blast furnaces for smelting. Tar production led to rapid local deforestation; the end of tar production at the end of the 19th century resulted in rapid re-forestation of affected areas. The charcoal briquette was first invented and patented by Ellsworth B. A. Zwoyer of Pennsylvania in 1897 and was produced by the Zwoyer Fuel Company; the process was further popularized by Henry Ford, who used wood and sawdust byproducts from automobile fabrication as a feedstock. Ford Charcoal went on to become the Kingsford Company. Charcoal has been made by various methods; the traditional method in Britain used a clamp. This is a pile of wooden logs leaning against a chimney; the chimney consists of 4 wooden stakes held up by some rope.
The logs are covered with soil and straw allowing no air to enter. It must be lit by introducing some burning fuel into the chimney. If the soil covering gets torn by the fire, additional soil is placed on the cracks. Once the burn is complete, the chimney is plugged to prevent air from entering; the true art of this production method is in managing the sufficient generation of heat, its transfer to wood parts in the process of being carbonised. A strong disadvantage of this production method is the huge amount of emissions that are harmful to human health and the environment; as a result of the partial combustion of wood material, the efficiency of the traditional method is low. Modern methods employ retorting technology, in which process heat is recovered from, provided by, the combustion of gas released during carbonisation.. Yields of retorting are higher than those of kilning, may reach 35%-40%; the properties of the charcoal produced depend on the material charred. The charring temperature is important.
Charcoal contains varying amounts of hydrogen and oxygen as well as ash and other impurities that, together with the structure, determine the properties. The approximate composition of charcoal for gunpowders is sometimes empirically described as C7H4O. To obtain a coal with high purity, source material should be free of non-volatile compounds. Common charcoal is made from peat, wood, coconut shell, or petroleum. Sugar charcoal is obtained from the carbonization of sugar and is
Splitting maul
A splitting maul known as a block buster, block splitter, sledge axe, go-devil or hamaxe is a heavy, long-handled axe used for splitting a piece of wood along its grain. One side of its head is like a sledgehammer, the other side is like an axe. Wedged mauls A typical wood splitting maul has a head weight of 6 to 8 lb or 2.7 to 3.6 kg, respectively. Traditionally, mauls have a wedge-shaped head, but some modern versions have conical heads or swiveling sub-wedges; the original maul resembles an axe but with a broader head. For splitting wood, this tool is much better than a typical axe; the weight of it is more advantageous, it is less to become stuck in the wood thanks to its width. The wedge section of a maul head must be convex to avoid jamming and it cannot have the elongated "hollow ground" concave-section that a cutting axe may use. Unlike an axe, maul handles are straight and closer to round than the elongated oval axe handles tend to be. A maul's handle, unlike an axe, is intentionally used for levering as well as swinging.
The handles are made from hickory, though synthetic fibreglass handles have become common. Plastic handles are more difficult to break and their factory-attached heads are less to work free with the levering action of a maul. In the early 1970s a triangular head design with an unbreakable metal handle was introduced called the "Monster Maul." Separate wedges Splitting may be done with a separate wedge and a large hammer. As this allows several wedges to be used together, it permits larger logs to be split. To avoid mushrooming the head of the wedge, they are driven with a heavy wooden mallet rather than an iron hammer. In parts of England the word "maul" denotes this tool with a heavy wooden head, it is known as a beetle. Powered log splitters Hydraulic log splitters are used today, they can be either vertical. The maul is most struck onto a flush-cut section of log standing on end atop a splitting stump or other suitable base. Most cut sections can be split in a single downward chop of the maul, splitting the wood apart along its grain.
Mauls become stuck in the log for several reasons, such as the wood not being struck with adequate force, the wood containing hidden knots, or the length of wood being too long. Unlike an axe, mauls are effective longer after the edge dulls, as the primary mechanism is that of a wedge pushed through along the wood grain, not a cross-grain chop of an axe. In some cases, longer logs may be split while they rest length-wise on the ground. Mauls become stuck in logs mid-split requiring a "full-lift" chop to be used; this involves the chopper reswinging the maul, but this time lifting the half-split log while still attached to the embedded maul requiring one or two additional full-lift chops. Another technique for splitting upright logs of thicker diameter is to land the maul's full force off-center of the log removing 1/4 of the mass of the log; when repeated, large logs that would ordinarily cause the maul to be embedded on a center-strike can be handled easily. Additionally, as the temperature gets colder, the fibers in the log become more brittle making the logs easier to split.
The hammer side of the maul is used in wood splitting when combined with a splitting wedge, driving the wedge into the wood in the same fashion as the maul itself. This is used when attempting to split logs with a large diameter. Modern mauls are made of a strong enough steel to withstand the metal-to-metal contact without chipping. However, it is still common for the wedge itself to chip off; this can be dangerous. This is the easiest way to break a maul's handle because the wedge is a small target as opposed to the whole log, can be overshot, resulting in the handle hitting full-force onto the wedge; this weakens the handle, can cause it to break after only a few over-shots. Harder seasoned logs which have dried sufficiently split apart with enough force that each half tumbles away at some speed, a hazard for people or objects nearby. A common danger for inexperienced splitters is to miss the upright log or give it only a glancing blow. If the maul lands beyond the log, the maul handle may either bounce or break.
If the maul lands in front of the log, it may hit the feet of the splitter if they are in a closed stance. If the maul hits the side of the log without biting in, the maul will bounce to one side and to the ground. In this situation a widened stance may still leave the splitter's feet vulnerable; when performing the "full-lift" chop described above, the splitter must never raise the maul and log above his head. Speaking, a maul should never swing to the side. Rather it should be powered through the drop. In addition a suitable splitting base is one of the most important components to splitting wood with a maul. Wood can be split directly off the ground. For one the ground, if not frozen, will give on each blow, thereby weakening the overall effect of the blow; the second disadvantage is that it can present the log to be split at a low level, forcing the person splitting the wood to bend over during the swing, which causes back fatigue. The best bases are flush-cut segments of hardwood logs about one foot tall.
For repeated season use the top open grain may be treated slightly. The diameter of the base should be at least twice that of the wood placed atop it for splitting, the base should be placed on firm ground. Another tech
Fuel
A fuel is any material that can be made to react with other substances so that it releases energy as heat energy or to be used for work. The concept was applied to those materials capable of releasing chemical energy but has since been applied to other sources of heat energy such as nuclear energy; the heat energy released by reactions of fuels is converted into mechanical energy via a heat engine. Other times the heat itself is valued for warmth, cooking, or industrial processes, as well as the illumination that comes with combustion. Fuels are used in the cells of organisms in a process known as cellular respiration, where organic molecules are oxidized to release usable energy. Hydrocarbons and related oxygen-containing molecules are by far the most common source of fuel used by humans, but other substances, including radioactive metals, are utilized. Fuels are contrasted with other substances or devices storing potential energy, such as those that directly release electrical energy or mechanical energy.
The first known use of fuel was the combustion of wood or sticks by Homo erectus nearly two million years ago. Throughout most of human history fuels derived from plants or animal fat were only used by humans. Charcoal, a wood derivative, has been used since at least 6,000 BCE for melting metals, it was only supplanted by coke, derived from coal, as European forests started to become depleted around the 18th century. Charcoal briquettes are now used as a fuel for barbecue cooking. Coal was first used as a fuel around 1000 BCE in China. With the energy in the form of chemical energy that could be released through combustion, but the concept development of the steam engine in the United Kingdom in 1769, coal came into more common use as a power source. Coal was used to drive ships and locomotives. By the 19th century, gas extracted from coal was being used for street lighting in London. In the 20th and 21st centuries, the primary use of coal is to generate electricity, providing 40% of the world's electrical power supply in 2005.
Fossil fuels were adopted during the Industrial Revolution, because they were more concentrated and flexible than traditional energy sources, such as water power. They have become a pivotal part of our contemporary society, with most countries in the world burning fossil fuels in order to produce power; the trend has been towards renewable fuels, such as biofuels like alcohols. Chemical fuels are substances that release energy by reacting with substances around them, most notably by the process of combustion. Most of the chemical energy released in combustion was not stored in the chemical bonds of the fuel, but in the weak double bond of molecular oxygen. Chemical fuels are divided in two ways. First, by their physical properties, as a solid, liquid or gas. Secondly, on the basis of their occurrence: primary and secondary. Thus, a general classification of chemical fuels is: Solid fuel refers to various types of solid material that are used as fuel to produce energy and provide heating released through combustion.
Solid fuels include wood, peat, hexamine fuel tablets, pellets made from wood, wheat and other grains. Solid-fuel rocket technology uses solid fuel. Solid fuels have been used by humanity for many years to create fire. Coal was the fuel source which enabled the industrial revolution, from firing furnaces, to running steam engines. Wood was extensively used to run steam locomotives. Both peat and coal are still used in electricity generation today; the use of some solid fuels is restricted or prohibited in some urban areas, due to unsafe levels of toxic emissions. The use of other solid fuels as wood is decreasing as heating technology and the availability of good quality fuel improves. In some areas, smokeless coal is the only solid fuel used. In Ireland, peat briquettes are used as smokeless fuel, they are used to start a coal fire. Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy producing kinetic energy, it is the fumes of liquid fuels.
Most liquid fuels in widespread use are derived from the fossilized remains of dead plants and animals by exposure to heat and pressure inside the Earth's crust. However, there are several types, such as hydrogen fuel, jet fuel and bio-diesel which are all categorized as a liquid fuel. Emulsified fuels of oil-in-water such as orimulsion have been developed a way to make heavy oil fractions usable as liquid fuels. Many liquid fuels play a primary role in the economy; some common properties of liquid fuels are that they are easy to transport, that can be handled easily. They are easy to use for all engineering applications, home use. Fuels like kerosene are rationed in some countries, for example available in government subsidized shops in India for home use. Conventional diesel is similar to gasoline in that it is a mixture of aliphatic hydrocarbons extracted from petroleum. Kerosene is used in kerosene lamps and as a fuel for cooking and small engines. Natural gas, composed chiefly of methane, can only exist as a liquid at low temperatures, which limits its direct use as a liquid fuel in most applications.
LP gas is a mixture of propane and butane, both of which are compressible gases under standard atmospheric conditions. It offers many of the advantages of compressed natural gas (CN
Larix laricina
Larix laricina known as the tamarack, eastern larch, black larch, red larch, or American larch, is a species of larch native to Canada, from eastern Yukon and Inuvik, Northwest Territories east to Newfoundland, south into the upper northeastern United States from Minnesota to Cranesville Swamp, West Virginia. The word tamarack is an Algonquian name for the species and means "wood used for snowshoes". Larix laricina is a small to medium-size boreal coniferous and deciduous tree reaching 10–20 m tall, with a trunk up to 60 cm diameter. Tamaracks and Larches are deciduous conifers; the bark is tight and flaky, but under flaking bark it can appear reddish. The leaves are needle-like, 2–3 cm short, light blue-green, turning bright yellow before they fall in the autumn, leaving the pale pinkish-brown shoots bare until the next spring; the needles are produced spirally in dense clusters on long woody spur shoots. The cones are the smallest of only 1 -- 2.3 cm long, with 12-25 seed scales. Key characteristics: The needles are borne on a short shoot in groups of 10–20 needles.
The larch is deciduous and the needles turn yellow in autumn. The seed cones are small, less than 2 cm long, with lustrous brown scales. Larch are found in swamps, fens and other low-land areas. Tamaracks are cold tolerant, able to survive temperatures down to at least −65 °C, occurs at the Arctic tree line at the edge of the tundra. Trees in these severe climatic conditions are smaller than farther south only 5 m tall, they can tolerate a wide range of soil conditions but grow most in swamps, bogs, or muskeg in wet to moist organic soils such as sphagnum peat and woody peat. They are found on mineral soils that range from heavy clay to coarse sand. Although tamarack can grow well on calcareous soils, it is not abundant on the limestone areas of eastern Ontario. Tamarack is an early invader. Tamarack is the first forest tree to invade filled-lake bogs. In the lake states, tamarack may appear first in the sedge mat, sphagnum moss, or not until the bog shrub stage. Farther north, it is the pioneer tree in the bog shrub stage.
Tamarack is well adapted to reproduce on burns, so it is one of the common pioneers on sites in the boreal forest after a fire. The central Alaskan population, separated from the eastern Yukon populations by a gap of about 700 kilometres, is treated as a distinct variety Larix laricina var. alaskensis by some botanists, though others argue that it is not sufficiently distinct to be distinguished. Tamarack forms extensive pure stands in northern Minnesota. In the rest of its United States range and in the Maritime Provinces, tamarack is found locally in both pure and mixed stands, it is a major component in the Society of American Foresters forest cover types Tamarack and black spruce–tamarack. Black spruce is tamarack's main associate in mixed stands on all sites; the other most common associates include balsam fir, white spruce, quaking aspen in the boreal region. In the better organic soil sites in the northern forest region, the most common associates are the northern white-cedar, balsam fir, black ash, red maple.
In Alaska, quaking aspen and tamarack are never found together. Additional common associates are American elm, balsam poplar, jack pine, paper birch, Kenai birch, yellow birch. Tamarack stands cast light shade and so have a dense undergrowth of shrubs and herbs; because the tree has an extensive range, a great variety of shrubs is associated with it. Dominant tall shrubs include dwarf and swamp birch, speckled alder, red-osier dogwood. Low shrubs include bog Labrador tea, bog-rosemary, leather leaf, small cranberry. Characteristically the herbaceous cover includes sedges, three-leaved false Solomonseal, marsh cinquefoil, marsh-marigold, bogbean. Ground cover is composed of sphagnum moss and other mosses. Tamarack is monoecious. Male and female cones are small, either solitary or in groups of 2 or 3, appear with the needles. Male cones are yellow and are borne on 1- or 2-year-old branchlets. Female cones resemble tiny roses, they are reddish or maroon, have needles at their base which are shorter and bluer than the other needles on the tree.
They are borne most on 2 to 4-year-old branchlets, but may appear on branchlets 5 or more years old. Cones are produced on young growth of vigorous trees. On open-grown trees, cones are borne on all parts of the crown. Mature seed cones are brown, oblong-ovoid, 13 to 19 mm long; the wood is tough and durable, but flexible in thin strips, was used by the Algonquian people for making snowshoes and other products where toughness was required. The natural crooks located in the stumps and roots are preferred for creating knees in wooden bo
