Taiga known as boreal forest or snow forest, is a biome characterized by coniferous forests consisting of pines and larches. The taiga is the world's largest land biome. In North America, it covers most of inland Canada and parts of the northern contiguous United States. In Eurasia, it covers most of Sweden, much of Norway, some of the Scottish Highlands, some lowland/coastal areas of Iceland, much of Russia from Karelia in the west to the Pacific Ocean, areas of northern Kazakhstan, northern Mongolia, northern Japan. However, the main tree species, the length of the growing season and summer temperatures vary. For example, the taiga of North America consists of spruces. A different use of the term taiga is encountered in the English language, with "boreal forest" used in the United States and Canada to refer to only the more southerly part of the biome, while "taiga" is used to describe the more barren areas of the northernmost part of the biome approaching the tree line and the tundra biome.
Hoffman discusses the origin of this differential use in North America and why it is an inappropriate differentiation of the Russian term. Although at high elevations taiga grades into alpine tundra through Krummholz, it is not an alpine biome. Taiga is the world's second-largest land biome, after deserts and xeric shrublands, covering 17 million square kilometers or 11.5% of the Earth's land area. The largest areas are located in Canada; the taiga is the terrestrial biome with the lowest annual average temperatures after the tundra and permanent ice caps. Extreme winter minimums in the northern taiga are lower than those of the tundra; the lowest reliably recorded temperatures in the Northern Hemisphere were recorded in the taiga of northeastern Russia. The taiga or boreal forest has a subarctic climate with large temperature range between seasons, but the long and cold winter is the dominant feature; this climate is classified as Dfc, Dsc and Dwd in the Köppen climate classification scheme, meaning that the short summer lasts 1–3 months and always less than 4 months.
In Siberian taiga the average temperature of the coldest month is between −6 °C and −50 °C. There are some much smaller areas grading towards the oceanic Cfc climate with milder winters, whilst the extreme south and west of the taiga reaches into humid continental climates with longer summers; the mean annual temperature varies from −5 °C to 5 °C, but there are taiga areas in eastern Siberia and interior Alaska-Yukon where the mean annual reaches down to −10 °C. According to some sources, the boreal forest grades into a temperate mixed forest when mean annual temperature reaches about 3 °C. Discontinuous permafrost is found in areas with mean annual temperature below 0 °C, whilst in the Dfd and Dwd climate zones continuous permafrost occurs and restricts growth to shallow-rooted trees like Siberian larch; the winters, with average temperatures below freezing, last five to seven months. Temperatures vary from −54 °C to 30 °C throughout the whole year; the summers, while short, are warm and humid.
In much of the taiga, −20 °C would be a typical winter day temperature and 18 °C an average summer day. The growing season, when the vegetation in the taiga comes alive, is slightly longer than the climatic definition of summer as the plants of the boreal biome have a lower threshold to trigger growth. In Canada and Finland, the growing season is estimated by using the period of the year when the 24-hour average temperature is +5 °C or more. For the Taiga Plains in Canada, growing season varies from 80 to 150 days, in the Taiga Shield from 100 to 140 days; some sources claim 130 days growing season as typical for the taiga. Other sources mention. Data for locations in southwest Yukon gives 80–120 frost-free days; the closed canopy boreal forest in Kenozersky National Park near Plesetsk, Arkhangelsk Province, Russia, on average has 108 frost-free days. The longest growing season is found in the smaller areas with oceanic influences; the shortest growing season is found at the northern taiga–tundra ecotone, where the northern taiga forest no longer can grow and the tundra dominates the landscape when the growing season is down to 50–70 days, the 24-hr average of the warmest month of the year is 10 °C or less.
High latitudes mean that the sun does not rise far above the horizon, less solar energy is received than further south. But the high latitude ensures long summer days, as the sun stays above the horizon nearly 20 hours each day, with only around 6 hours of daylight occurring in the dark winters, depending on latitude; the areas of the taiga inside the Arctic Circle have midnight sun in mid-summer and polar night in mid-winter. The taiga experiences low precipitation throughout the year as rain during the summer months, but as fog and snow; this fog predominant in low-lying areas during and after the thawing of frozen Arctic seas
The Pinaceae are trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, hemlocks, larches and spruces. The family is included in the order Pinales known as Coniferales. Pinaceae are supported as monophyletic by their protein-type sieve cell plastids, pattern of proembryogeny, lack of bioflavonoids, they are the largest extant conifer family in species diversity, with between 220 and 250 species in 11 genera, the second-largest in geographical range, found in most of the Northern Hemisphere, with the majority of the species in temperate climates, but ranging from subarctic to tropical. The family forms the dominant component of boreal and montane forests. One species, Pinus merkusii, grows just south of the equator in Southeast Asia. Major centres of diversity are found in the mountains of southwest China, central Japan, California. Members of the family Pinaceae are trees growing from 2 to 100 m tall evergreen, monoecious, with subopposite or whorled branches, spirally arranged, linear leaves.
The embryos of Pinaceae have three to 24 cotyledons. The female cones are large and woody, 2–60 cm long, with numerous spirally arranged scales, two winged seeds on each scale; the male cones are small, 0.5–6.0 cm long, fall soon after pollination. Seed dispersal is by wind, but some species have large seeds with reduced wings, are dispersed by birds. Analysis of Pinaceae cones reveals how selective pressure has shaped the evolution of variable cone size and function throughout the family. Variation in cone size in the family has resulted from the variation of seed dispersal mechanisms available in their environments over time. All Pinaceae with seeds weighing less than 90 mg are adapted for wind dispersal. Pines having seeds larger than 100 mg are more to have benefited from adaptations that promote animal dispersal by birds. Pinaceae that persist in areas where tree squirrels are abundant do not seem to have evolved adaptations for bird dispersal. Boreal conifers have many adaptions for winter.
The narrow conical shape of northern conifers, their downward-drooping limbs help them shed snow, many of them seasonally alter their biochemistry to make them more resistant to freezing, called "hardening". Classification of the subfamilies and genera of Pinaceae has been subject to debate in the past. Pinaceae ecology and history have all been used as the basis for methods of analyses of the family. An 1891 publication divided the family into two subfamilies, using the number and position of resin canals in the primary vascular region of the young taproot as the primary consideration. In a 1910 publication, the family was divided into two tribes based on the occurrence and type of long–short shoot dimorphism. A more recent classification divided the subfamilies and genera based on the consideration of features of ovulate cone anatomy among extant and fossil members of the family. Below is an example of; the 11 genera are grouped into four subfamilies, based on the microscopical anatomy and the morphology of the cones, wood and leaves: Subfamily Pinoideae: cones are biennial triennial, with each year's scale-growth distinct, forming an umbo on each scale, the cone scale base is broad, concealing the seeds from abaxial view, the seed is without resin vesicles, the seed wing holds the seed in a pair of claws, leaves have primary stomatal bands adaxial or on both surfaces.
Subfamily Piceoideae: cones are annual, without a distinct umbo, the cone scale base is broad, concealing the seeds from abaxial view, seed is without resin vesicles, the seed wing holds the seed loosely in a cup, leaves have primary stomatal bands adaxial or on both surfaces. Subfamily Laricoideae: cones are annual, without a distinct umbo, the cone scale base is broad, concealing the seeds from abaxial view, the seed is without resin vesicles, the seed wing holds the seed in a cup, leaves have primary stomatal bands abaxial only. Subfamily Abietoideae: cones are annual, without a distinct umbo, the cone scale base is narrow, with the seeds visible in abaxial view, the seed has resin vesicles, the seed wing holds the seed in a cup, leaves have primary stomatal bands abaxial only. External stresses on plants have the ability to change the structure and composition of forest ecosystems. Common external stress that Pinaceae experience are herbivore and pathogen attack which leads to tree death.
In order to combat these stresses, trees need to evolve defenses against these stresses. Pinaceae have evolved a myriad of mechanical and chemical defenses, or a combination of the two, in order to protect themselves against antagonists. Pinaceae have the ability to up-regulate a combination of constitutive mechanical and chemical strategies to further their defenses. Pinaceae defenses are prevalent in the bark of the trees; this part of the tree contributes a complex defensive boundary against external antagonists. Constitutive and induced defenses are both found in the bark. Constitutive defenses are the first line of defenses used against antagonists and can include sclerified cells, lignified periderm cells, secondary compounds such as phenolics and resins
Taxodium is a genus of one to three species of flood-tolerant conifers in the cypress family, Cupressaceae. The generic name is derived from the Latin word taxus, meaning "yew", the Greek word εἶδος, meaning "similar to." Within the family, Taxodium is most related to Chinese swamp cypress and sugi. Species of Taxodium occur in the southern part of the North American continent and are deciduous in the north and semi-evergreen to evergreen in the south, they are large trees. The needle-like leaves, 0.5–2 cm long, are borne spirally on the shoots, twisted at the base so as to appear in two flat rows on either side of the shoot. The cones are globose, 2–3.5 cm diameter, with 10-25 scales, each scale with 1-2 seeds. The male cones are produced in pendulous racemes, shed their pollen in early spring. Taxodium species grow cypress roots, when growing in or beside water; the three extant taxa of Taxodium are treated here as distinct species, though some botanists treat them in just one or two species, with the others considered as varieties of the first described.
The three hybridise where they meet. †Taxodium dubium Heer Glyptostrobus pensilis K. Koch Sequoia sempervirens Endl; the trees are prized for their wood, of which the heartwood is rot- and termite-resistant. The heartwood contains, it takes decades for cypressene to accumulate in the wood, so lumber taken from old-growth trees is more rot resistant than that from second-growth trees. However, age increases susceptibility to Pecky Rot fungus, which attacks the heartwood and causes some damaged trees to become hollow and thus useless for timber. Bald Cypress wood was much used in former days in the southeastern United States for roof shingles; the shredded bark of these trees is used as a mulch. In earth's history Taxodium was much more widespread in the Northern Hemisphere than today; the oldest fossils were found in Late Cretaceous deposits from North America. The trees persisted in Europe during the Pliocene. Bükkábrány mummified forest Gymnosperm Database - Taxodium Corkscrew Swamp Sanctuary website National Audubon Society, undated.
Corkscrew Swamp Sanctuary. A Companion Field Guide. Artype Inc. Ft. Myers. 25 p
Glyptostrobus pensilis known as Chinese swamp cypress, is the sole living species in the genus Glyptostrobus. It is native to subtropical southeastern China, from Fujian west to southeast Yunnan, very locally in northern Vietnam, it is a medium-sized to large tree, reaching 30 m tall and with a trunk diameter of up to 1 m more. The leaves are deciduous, spirally arranged but twisted at the base to lie in two horizontal ranks, 5–20 mm long and 1–2 mm broad, but 2–3 mm long and scale-like on shoots in the upper crown; the cones are green maturing yellow-brown, pear-shaped, 2–3 cm long and 1–1.5 cm diameter, broadest near the apex. They open when mature to release the small, 5–20 mm long, winged seeds, it grows in river banks and swamps, growing in water up to 60 cm deep. Like the related genus Taxodium, it produces'cypress knees', or pneumatophores, when growing in water, thought to help transport oxygen to the roots; the species is nearly extinct in the wild due to overcutting for its valuable decay-resistant, scented wood, but it is fairly planted along the banks of rice paddies where its roots help to stabilise the banks by reducing soil erosion.
There appear to be no remaining wild plants in China and few of those in Viet Nam are seed-bearing. It was reported that there were four specimens of this tree growing in Bank Hall Gardens, United Kingdom, but it has now been confirmed that they are in fact the Swamp or Bald Cypress from south-eastern USA, Taxodium distichum. A population of Chinese swamp cypress was discovered in central Laos. Gymnosperm Database: Glyptostrobus Arboretum de Villardebelle: photo of cone
Russia the Russian Federation, is a transcontinental country in Eastern Europe and North Asia. At 17,125,200 square kilometres, Russia is by far or by a considerable margin the largest country in the world by area, covering more than one-eighth of the Earth's inhabited land area, the ninth most populous, with about 146.77 million people as of 2019, including Crimea. About 77 % of the population live in the European part of the country. Russia's capital, Moscow, is one of the largest cities in the world and the second largest city in Europe. Extending across the entirety of Northern Asia and much of Eastern Europe, Russia spans eleven time zones and incorporates a wide range of environments and landforms. From northwest to southeast, Russia shares land borders with Norway, Estonia, Latvia and Poland, Ukraine, Azerbaijan, China and North Korea, it shares maritime borders with Japan by the Sea of Okhotsk and the U. S. state of Alaska across the Bering Strait. However, Russia recognises two more countries that border it, Abkhazia and South Ossetia, both of which are internationally recognized as parts of Georgia.
The East Slavs emerged as a recognizable group in Europe between the 3rd and 8th centuries AD. Founded and ruled by a Varangian warrior elite and their descendants, the medieval state of Rus arose in the 9th century. In 988 it adopted Orthodox Christianity from the Byzantine Empire, beginning the synthesis of Byzantine and Slavic cultures that defined Russian culture for the next millennium. Rus' disintegrated into a number of smaller states; the Grand Duchy of Moscow reunified the surrounding Russian principalities and achieved independence from the Golden Horde. By the 18th century, the nation had expanded through conquest and exploration to become the Russian Empire, the third largest empire in history, stretching from Poland on the west to Alaska on the east. Following the Russian Revolution, the Russian Soviet Federative Socialist Republic became the largest and leading constituent of the Union of Soviet Socialist Republics, the world's first constitutionally socialist state; the Soviet Union played a decisive role in the Allied victory in World War II, emerged as a recognized superpower and rival to the United States during the Cold War.
The Soviet era saw some of the most significant technological achievements of the 20th century, including the world's first human-made satellite and the launching of the first humans in space. By the end of 1990, the Soviet Union had the world's second largest economy, largest standing military in the world and the largest stockpile of weapons of mass destruction. Following the dissolution of the Soviet Union in 1991, twelve independent republics emerged from the USSR: Russia, Belarus, Uzbekistan, Azerbaijan, Kyrgyzstan, Tajikistan and the Baltic states regained independence: Estonia, Lithuania, it is governed as a federal semi-presidential republic. Russia's economy ranks as the twelfth largest by nominal GDP and sixth largest by purchasing power parity in 2018. Russia's extensive mineral and energy resources are the largest such reserves in the world, making it one of the leading producers of oil and natural gas globally; the country is one of the five recognized nuclear weapons states and possesses the largest stockpile of weapons of mass destruction.
Russia is a great power as well as a regional power and has been characterised as a potential superpower. It is a permanent member of the United Nations Security Council and an active global partner of ASEAN, as well as a member of the Shanghai Cooperation Organisation, the G20, the Council of Europe, the Asia-Pacific Economic Cooperation, the Organization for Security and Co-operation in Europe, the World Trade Organization, as well as being the leading member of the Commonwealth of Independent States, the Collective Security Treaty Organization and one of the five members of the Eurasian Economic Union, along with Armenia, Belarus and Kyrgyzstan; the name Russia is derived from Rus', a medieval state populated by the East Slavs. However, this proper name became more prominent in the history, the country was called by its inhabitants "Русская Земля", which can be translated as "Russian Land" or "Land of Rus'". In order to distinguish this state from other states derived from it, it is denoted as Kievan Rus' by modern historiography.
The name Rus itself comes from the early medieval Rus' people, Swedish merchants and warriors who relocated from across the Baltic Sea and founded a state centered on Novgorod that became Kievan Rus. An old Latin version of the name Rus' was Ruthenia applied to the western and southern regions of Rus' that were adjacent to Catholic Europe; the current name of the country, Россия, comes from the Byzantine Greek designation of the Rus', Ρωσσία Rossía—spelled Ρωσία in Modern Greek. The standard way to refer to citizens of Russia is rossiyane in Russian. There are two Russian words which are commonly
Larix kaempferi, the Japanese larch or karamatsu in Japanese, is a species of larch native to Japan, in the mountains of Chūbu and Kantō regions in central Honshū. It is a medium-sized to large deciduous coniferous tree reaching 20–40 m tall, with a trunk up to 1 m diameter; the crown is broad conic. The shoots are dimorphic, with growth divided into long shoots and bearing several buds, short shoots only 1–2 mm long with only a single bud; the leaves are needle-like, light glaucous green, 2–5 cm long. The cones are ovoid-conic and 2 -- 3.5 cm long, with 30 -- 50 reflexed seed scales. The old cones remain on the tree for many years, turning dull grey-black, it grows at altitudes up to 2,900 m on well-drained soils, avoiding waterlogged ground. The scientific name honours Engelbert Kaempfer, it is sometimes known by the synonym Larix leptolepis. Japanese larch is an important tree in forestry plantations, being grown throughout central and northern Japan, widely in northern Europe Ireland and Britain.
The wood is durable, used for general construction work. Small larch poles are used for fencing. Larix kaempferi is used for ornamental purposes in gardens, it is widely used as material for bonsai. The dwarf cultivars ‘Blue Dwarf’, growing to 1.5 m tall and broad, ‘Nana’, growing to 1 m tall and broad, have gained the Royal Horticultural Society’s Award of Garden Merit. In late 2009 Phytophthora ramorum or sudden oak death disease was first found in Japanese larch trees, in the English counties of Devon and Somerset; the disease was found in Counties Tipperary in Ireland the following year. Gymnosperm Database: Larix kaempferi
The Atlantic Ocean is the second largest of the world's oceans, with an area of about 106,460,000 square kilometers. It covers 20 percent of the Earth's surface and about 29 percent of its water surface area, it separates the "Old World" from the "New World". The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, the Americas to the west; as one component of the interconnected global ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, the Southern Ocean in the south. The Equatorial Counter Current subdivides it into the North Atlantic Ocean and the South Atlantic Ocean at about 8°N. Scientific explorations of the Atlantic include the Challenger expedition, the German Meteor expedition, Columbia University's Lamont-Doherty Earth Observatory and the United States Navy Hydrographic Office; the oldest known mentions of an "Atlantic" sea come from Stesichorus around mid-sixth century BC: Atlantikoi pelágei and in The Histories of Herodotus around 450 BC: Atlantis thalassa where the name refers to "the sea beyond the pillars of Heracles", said to be part of the sea that surrounds all land.
Thus, on one hand, the name refers to Atlas, the Titan in Greek mythology, who supported the heavens and who appeared as a frontispiece in Medieval maps and lent his name to modern atlases. On the other hand, to early Greek sailors and in Ancient Greek mythological literature such as the Iliad and the Odyssey, this all-encompassing ocean was instead known as Oceanus, the gigantic river that encircled the world. In contrast, the term "Atlantic" referred to the Atlas Mountains in Morocco and the sea off the Strait of Gibraltar and the North African coast; the Greek word thalassa has been reused by scientists for the huge Panthalassa ocean that surrounded the supercontinent Pangaea hundreds of millions of years ago. The term "Aethiopian Ocean", derived from Ancient Ethiopia, was applied to the Southern Atlantic as late as the mid-19th century. During the Age of Discovery, the Atlantic was known to English cartographers as the Great Western Ocean; the term The Pond is used by British and American speakers in context to the Atlantic Ocean, as a form of meiosis, or sarcastic understatement.
The term dates to as early as 1640, first appearing in print in pamphlet released during the reign of Charles I, reproduced in 1869 in Nehemiah Wallington's Historical Notices of Events Occurring Chiefly in The Reign of Charles I, where "great Pond" is used in reference to the Atlantic Ocean by Francis Windebank, Charles I's Secretary of State. The International Hydrographic Organization defined the limits of the oceans and seas in 1953, but some of these definitions have been revised since and some are not used by various authorities and countries, see for example the CIA World Factbook. Correspondingly, the extent and number of oceans and seas varies; the Atlantic Ocean is bounded on the west by South America. It connects to the Arctic Ocean through the Denmark Strait, Greenland Sea, Norwegian Sea and Barents Sea. To the east, the boundaries of the ocean proper are Europe: the Strait of Africa. In the southeast, the Atlantic merges into the Indian Ocean; the 20° East meridian, running south from Cape Agulhas to Antarctica defines its border.
In the 1953 definition it extends south to Antarctica, while in maps it is bounded at the 60° parallel by the Southern Ocean. The Atlantic has irregular coasts indented by numerous bays and seas; these include the Baltic Sea, Black Sea, Caribbean Sea, Davis Strait, Denmark Strait, part of the Drake Passage, Gulf of Mexico, Labrador Sea, Mediterranean Sea, North Sea, Norwegian Sea all of the Scotia Sea, other tributary water bodies. Including these marginal seas the coast line of the Atlantic measures 111,866 km compared to 135,663 km for the Pacific. Including its marginal seas, the Atlantic covers an area of 106,460,000 km2 or 23.5% of the global ocean and has a volume of 310,410,900 km3 or 23.3% of the total volume of the earth's oceans. Excluding its marginal seas, the Atlantic covers 81,760,000 km2 and has a volume of 305,811,900 km3; the North Atlantic covers 41,490,000 km2 and the South Atlantic 40,270,000 km2. The average depth is 3,646 m and the maximum depth, the Milwaukee Deep in the Puerto Rico Trench, is 8,486 m.
The bathymetry of the Atlantic is dominated by a submarine mountain range called the Mid-Atlantic Ridge. It runs from 87°N or 300 km south of the North Pole to the subantarctic Bouvet Island at 42°S; the MAR divides the Atlantic longitudinally into two halves, in each of which a series of basins are delimited by secondary, transverse ridges. The MAR reaches above 2,000 m along most of its length, but is interrupted by larger transform faults at two places: the Romanche Trench near the Equator and the Gibbs Fracture Zone at 53°N; the MAR is a barrier for bottom water, but at these two transform faults deep water currents can pass from one side to the othe