Sugar Maple

Sugar maple (Acer saccharum)
DBH: 13.58 (cm) measured on 02/04/2022


From Wikipedia, the free encyclopedia

Acer saccharum, thesugar mapleorrock maple, is a species ofmaplenative to the hardwood forests of eastern Canada, from Nova Scotia west through southern Quebec,centralandsouthern Ontarioto southeastern Manitoba aroundLake of the Woods, and the northern parts of the Central and Eastern United States, fromMinnesotaeastward to the highlands of the upper eastern states and the interiorMidwest.[2]Sugar maple is best known for its bright fall foliage and for being the primary source ofmaple syrup.[3]

Acer saccharumis adeciduoustree normally reaching heights of 25–35m (80–115ft),[4][5]and exceptionally up to 45m (148ft).[6]A 10-year-old tree is typically about 5m (16ft) tall. Although heights of 120 feet are possible, few sugar maples exceed 70 feet. As with most trees, forest-grown sugar maples form a much taller trunk and narrower canopy than open-growth ones.

Theleavesare deciduous, up to 20cm (7.9in) long and equally wide,[4]with five palmate lobes. The basal lobes are relatively small, while the upper lobes are larger and deeply notched. In contrast with the angular notching of thesilver maple, however, the notches tend to be rounded at their interior. The fall color is often spectacular, ranging from bright yellow on some trees through orange to fluorescent red-orange on others. Sugar maples also have a tendency to color unevenly in fall. In some trees, all colors above can be seen at the same time. They also share a tendency withred maplesfor certain parts of a mature tree to change color weeks ahead of or behind the remainder of the tree. The leaf buds are pointy and brown-colored. The recent year's growth twigs are green, and turn dark brown.

The sugar maple can be confused with theNorway maple, which is not native to America but is commonly planted in cities and suburbs, and they are not closely related within the genus. The sugar maple is most easily identified by clear sap in the leafpetiole(the Norway maple has white sap), brown, sharp-tipped buds (the Norway maple has blunt, green or reddish-purple buds), and shaggy bark on older trees (the Norway maple bark has small grooves). Also, the leaf lobes of the sugar maple have a more triangular shape, in contrast to the squarish lobes of the Norway maple.[citation needed]1⁄4in) long. The seeds fall from the tree in autumn, where they must be exposed to 45 days of temperatures below 4°C (39°F) to break their coating down. Germination ofA. saccharumis slow, not taking place until the following spring when the soil has warmed and all frost danger is past.[7][need quotation to verify]It is closely related to theblack maple, which is sometimes included in this species, but sometimes separated asAcer nigrum. The western Americanbigtooth maple(Acer grandidentatum) is also treated as a variety or subspecies of sugar maple by some botanists.

Although many people think a red sugarmaple leafis featured on theflag of Canada, the official maple leaf does not belong to any particular maple species; although it perhaps most closely resembles a sugar maple leaf of all the maple species in Canada, the leaf on the flag was specially designed to be as identifiable as possible on a flag waving in the wind without regard to whether it resembled a particular species' foliage.[8]

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 thenorthernand Midwestern U.S. hardwood forests.

The minimum seed-bearing age of sugar maple is about 20 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).[9]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 50°F (10°C) is rare to nonexistent.

Acer saccharumis among the mostshade tolerantof large deciduous trees. Its shade tolerance is exceeded only by thestriped 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 inhydraulic 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.[10]

In some parts of New England, particularly near urbanized areas, the sugar maple is being displaced by theNorway 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.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. Climate change has contributed to the decline of the sugar maple by pushing the suitable habitat range for the trees further north, where temperatures are cooler. This has resulted in a gradual northward migration of the species.[11]The sugar maple also exhibits a greater susceptibility to pollution than other species of maple.Acid rainandsoil acidificationare some of the primary contributing factors tomaple 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.[12][13]