Black Maple
Acer nigrum
Maple family (Aceraceae)

Description: This tree is 60-80' tall at maturity and its trunk is 2-3' across. In relatively open areas, the densely branched crown is globoid to ovoid in shape. Saplings that are growing in dense shade, however, have a narrow open crown with only a few ascending branches. Trunk bark is grayish brown or grayish black, becoming more rough and irregularly furrowed with age. Branch bark is gray and more smooth, while twigs are various shades of gray or brown, glabrous, and covered with scattered white lenticels (air pores). Non-woody young shoots are light green and either short-pubescent or glabrous. Pairs of opposite leaves occur along the twigs and young shoots. Individual leaves are 4-5" long and similarly across; each leaf has 3-5 palmate lobes and an orbicular outline. The leaf lobes have a tendency to droop downward. The tips of these lobes are pointed, while their sinuses are rounded; the sides of the terminal lobe usually contract gradually into a terminal point without intermediate teeth. The margin of each leaf is slightly to moderately undulate; it has either no teeth or very few teeth. When such teeth exist, they are large and dentate. The upper leaf surface is dark green and glabrous, while the lower surface is pale to medium green and sparsely to densely canescent or short-pubescent. The slender petioles are 3-5" long, light green to yellowish green, and either glabrous or short-pubescent.



Black Maple is either dioecious or monoecious, producing separate male and female flowers on the same or different trees. Male flowers are produced in drooping umbels or sparingly branched corymbs about 2-4" long. Individual male flowers are about 1/8" long, consisting of a yellowish green calyx with 5 teeth and a variable number of exerted stamens (usually about 6-8). Female flowers are also produced in drooping umbels or sparingly branched corymbs, but they are shorter (about -2" long). Individual female flowers are about 1/8" long, consisting of a yellowish green calyx with 5 teeth and a 2-celled ovary with a divided style. Both male and female flowers can occur in the same inflorescence. The long slender pedicels of both male and female flowers are hairy. The flowers bloom during mid- to late spring as the leaves emerge (which are yellowish green at this time of year). Cross-pollination is achieved by the wind during a 1-2 week period. Fertile female flowers are replaced by paired samaras that become mature during the fall. The paired samaras form a 45 to 90 angle with each other. Individual samaras are about 1" long, consisting of a plump one-seeded head with a membranous wing; they are distributed by the wind. The woody root system consists of much-branched lateral roots that are relatively shallow. During the autumn, the deciduous leaves usually become bright yellow; less often, they turn orange or red.


Cultivation: The preference is full sun to light shade, moist to mesic conditions that are well-drained, and soil containing loam, silt-loam, or some mineral-rich glacial till. Similar to Sugar Maple, the saplings of Black Maple are able to survive in moderately dense shade, although higher levels of light are preferred. Poor drainage with standing water isn't tolerated for any substantial length of time. Because Black Maple casts a heavy shade underneath its leaves, it can kill turf-grass and other kinds of vegetation. This tree can live up to 200 years.

Range & Habitat: The native Black Maple is occasional to locally common in central and northern Illinois (see Distribution Map), while in the southern section of the state it is uncommon or absent. Black Maple is more abundant in the lower Midwest than elsewhere; it becomes relatively more common than Sugar Maple toward the western limit of its range (e.g., in Iowa), otherwise it is less common. Habitats of Black Maple include rich mesic woodlands, moist bottomland woodlands, and shaded riverbanks (above the flood zone). Black Maple is more vulnerable than most trees to wildfires.

Faunal Associations: The foliage, plant juices, and wood of Black Maple and other maples (Acer spp.) are sources of food to many insects. Chief among these feeders are the caterpillars of Dryocampa rubicunda (Rosy Maple Moth), Heterocampa biundata (Maple Prominent), and many other moths (see Moth Table). Another group of insect feeders include the larvae of Glycobius speciosus (Sugar Maple Borer), Xylotrechus aceris (Gall-Making Maple Borer), and other wood-boring beetles (see Wood-Boring Beetle Table). Other insect feeders include leafhoppers (mainly Eratoneura spp.), aphids (Drepanaphis spp. & others), plant bugs (Coccobaphes frontifer, Lygocoris hirticulus, Lygocoris vitticollis, & Plagiognathus flavipes), Neopulvinaria innumerabilis (Cottony Maple Scale), Phenacoccus acericola (Maple Mealybug), larvae of the sawfly Caulocampus acericaulis (Maple Petiole Borer), the larvae of Dasineura communis (Maple Gouty Vein Midge), and the wood-boring larvae of some horntails (Xiphydria abdominalis & Xiphydria maculata). After the protective bark has been damaged during the spring, some insects feed on the copious sap flow of Black Maple. These sap feeders include honeybees, some adult butterflies, and many kinds of adult flies: Syrphid flies, Tachinid flies, flesh flies, blow flies, Muscid flies, skipper flies (Piophilidae), and the sap-feeding fly Aulacigaster leucopeza. Another small invertebrate species, Oligonychus aceris (Maple Spider Mite), feeds on the foliage.



Vertebrate animals also use Black Maple and other maples as a source of food and protective cover. Some upland gamebirds and songbirds eat the buds or seeds (see Bird Table), while the Yellow-Bellied Sapsucker drills holes into the bark to feed on the sap. The Eastern Chipmunk, Fox Squirrel, Gray Squirrel, Red Squirrel, Southern Flying Squirrel, Meadow Vole, and White-Footed Mouse also eat the seeds of the samaras. White-Tailed Deer and Elk (now extinct in the Midwest, except where it has been reintroduced) browse on the leaves and twigs, while the Beaver feeds on the wood. Because of heart rot, old maple trees provide dens for tree squirrels and such cavity-nesting birds as the Black-Capped Chickadee, Northern Flicker, Pileated Woodpecker, and Screech Owl. Other birds construct nests on branches of maples that vary in size from small saplings to mature trees.


Photographic Location:
The Arboretum of the University of Illinois in Urbana, Illinois.




Comments:
 For commercial purposes, Black Maple is not distinguished from Sugar Maple: its sap is just as useful in making maple syrup, and its wood has very similar properties that make it useful in the construction of furniture and other wooden objects. Black Maple can be distinguished from Sugar Maple as follows: 1) Its leaves have drooping lobes, rather than the more even lobes of Sugar Maple, 2) the margins of its leaves have fewer to no teeth, 3) its leaves typically have 3 tapering lobes, rather than 5 parallel-sided angular lobes, 4) its leaf undersides are canescent or short-pubescent, rather than glabrous or nearly glabrous, and 5) on older trees, its trunk bark tends to be more black and furrowed. In Illinois, individual trees that display evidence of hybridization between these two species are fairly common. For this reason, Black Maple has been classified as a variety or subspecies of Sugar Maple by some taxonomists, or Acer saccharum nigrum. It is also possible to confuse Black Maple with the introduced Acer platanoides (Norway Maple), which is often cultivated as a street tree. Norway Maple can be identified by the milky sap that exudes from the base of a petiole after it has been broken off from a branch; in contrast, the sap of Black Maple is clear. Norway Maple also has paired samaras that are more divergent (forming an angle that exceeds 120) and it has larger flowers in more erect clusters that are insect-pollinated.


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