Клён сахарный: описание и распространение.

Species of flowering plant in the family Sapindaceae

Acer saccharum, the sugar maple, is a species of flowering plant in the soapberry and lychee family Sapindaceae. It is native to the hardwood forests of eastern Canada and the eastern United States. Sugar maple is best known for being the primary source of maple syrup and for its brightly colored fall foliage. It may also be called "rock maple," "sugar tree," "sweet maple," or, particularly in reference to the wood, "hard maple," "birds eye maple," or "curly maple," the last two being specially figured lumber.

The sugar maple is an extremely important species to the ecology of many forests in the northern United States and Canada. Pure stands are common, and it is a major component of the northern and Midwestern U. S. hardwood forests. Due to its need for cold winters, sugar maple is mostly found north of the 42nd parallel in USDA growing zones 3–5. It is less common in the southern part of its range (USDA Zone 6) where summers are hot and humid; there sugar maple is confined to ravines and moist flatlands. In the east, from Maryland southward, it is limited to the Appalachians. In the west, Tennessee represents the southern limit of its range and Missouri its southwestern limit. Collection of sap for sugar is also not possible in the southern part of sugar maple's range as winter temperatures do not become cold enough. The minimum seed bearing age of sugar maple is about 30 years. The tree is long lived, typically 200 years and occasionally as much as 300. Sugar maple is native to areas with cooler climates and requires a hard freeze each winter for proper dormancy. In northern parts of its range, January temperatures average about 18 °C ( 0 °F) and July temperatures about 16 °C (61 °F); in southern parts, January temperatures average about 10 °C (50 °F) and July temperatures average almost 27 °C (81 °F). Seed germination also requires extremely low temperatures, the optimal being just slightly above freezing, and no other known tree species has this property. Germination of sugar maple seed in temperatures above is rare to nonexistent. Acer saccharum is among the most shade tolerant of large deciduous trees. Its shade tolerance is exceeded only by the striped maple, a smaller tree. Like other maples, its shade tolerance is manifested in its ability to germinate and persist under a closed canopy as an understory plant, and respond with rapid growth to the increased light formed by a gap in the canopy. Sugar maple can tolerate virtually any soil type short of pure sand, but does not tolerate xeric or swampy conditions. Sugar maples are deeper rooted than most maples and engage in hydraulic lift, drawing water from lower soil layers and exuding that water into upper, drier soil layers. This not only benefits the tree itself, but also many other plants growing around it. The mushroom Pholiota squarrosoides is known to decay the logs of the tree. Human influences have contributed to the decline of the sugar maple in many regions. Its role as a species of mature forests has led it to be replaced by more opportunistic species in areas where forests are cut over. The sugar maple also exhibits a greater susceptibility to pollution than other species of maple. Acid rain and soil acidification are some of the primary contributing factors to maple decline. Also, the increased use of salt over the last several decades on streets and roads for deicing purposes has decimated the sugar maple's role as a street tree. In some parts of New England, particularly near urbanized areas, the sugar maple is being displaced by the Norway maple. The Norway maple is also highly shade tolerant, but is considerably more tolerant of urban conditions, resulting in the sugar maple's replacement in those areas. In addition, Norway maple produces much larger crops of seeds, allowing it to out compete native species.

The sugar maple is one of the most important Canadian trees, being, with the black maple, the major source of sap for making maple syrup. Other maple species can be used as a sap source for maple syrup, but some have lower sugar content and/or produce more cloudy syrup than these two. The samaras which are the seeds can be soaked, and—with their wings removed—boiled, seasoned, and roasted to make them edible. The young leaves and inner bark can be eaten raw or cooked.

The sapwood can be white, and smaller logs may have a higher proportion of this desirable wood. Bowling alleys and bowling pins are both commonly manufactured from sugar maple. Trees with wavy wood grain, which can occur in curly, quilted, and "birdseye maple" forms, are especially valued. Maple is also the wood used for basketball courts, including the floors used by the NBA, and it is a popular wood for baseball bats, along with white ash. In recent years, because white ash has become threatened by emerald ash borer, sugar maple wood has increasingly displaced ash for baseball bat production. It is also widely used in the manufacture of musical instruments, such as the members of the violin family (sides and back), guitars (neck), grand pianos (rim), and drum shells. It is also often used in the manufacture of sporting goods. Canadian maple, often referred to as "Canadian hardrock maple", is prized for pool cues, especially the shafts. Some production line cues will use lower quality maple wood with cosmetic issues, such as "sugar marks", which are most often light brown discolorations caused by sap in the wood. The best shaft wood has a very consistent grain, with no marks or discoloration. Sugar marks usually do not affect how the cue plays, but are not as high quality as those without it. The wood is also used in skateboards, gunstocks, and flooring for its strength. The species is also subject to defoliation when there are dense populations of larvae of Lepidoptera species like the rosy maple moth (Dryocampa rubicunda).

The Mohegan use the inner bark as a cough remedy, and the sap as a sweetening agent, and to make maple syrup following the introduction of metal cookware by Europeans.

The United States national champion for Acer saccharum is located in Charlemont, Massachusetts. In 2007, the year it was submitted, it had a circumference of at above the ground's surface, and thus a diameter at breast height of about At that time the tree was tall with an average crown spread of Using the scoring system of circumference in inches plus height in feet plus 25% of crown spread in feet resulted in a total number of 368 points at the National Register of Big Trees. A tree in Lyme, Connecticut, measured in 2012, had a circumference of 18.25 feet (6 m), or an average diameter at breast height of about 5.8 feet (2 m). This tree had been 123 feet (37 m) tall with a crown spread of 86 feet (26 m), counting for a total number of 364 points.

The sugar maple is the state tree of the US states of New York, Vermont, West Virginia, and Wisconsin. It is depicted on the state quarter of Vermont, issued in 2001.