Acer saccharinum is a tree to 30 m tall, bark silver-gray, flaky on older trees; twigs red to orange, rank odor when crushed; winter flower buds reddish to brownish, knobby, wider than twig; roots shallow, fibrous; associated with arbuscular mycorrhizal fungi (AM) (endomycorrhizae, Zygomycotina, order Glomales, family Endogonaceae) (Decker and Boerner 1997; Carreiro 1999) A fast growing tree with brittle wood susceptible to ice and wind damage
Leaves opposite, deeply 5 lobed, white below, teeth large, sharp; fall color yellow.
Flowers dioecious or monoecious, petals and sepals usually red; female flowers (styles) usually red; male flowers (stamens) dull white; blooming Feb.-March. Wind pollinated.
Fruit broadly winged samaras; pale green on dangling stalks, becoming dry, the largest among native maples (Burns and Honkala 1990); ripens April-May. Seeds germinate same spring.
Wetland status: FACW.
Frequency in New York City: Frequent.
Habitat: Low open areas, flood plains. Tolerates flooding or saturated soil up to 25% of growing season, soil pH 4-7. Tolerant of drought and soil compaction. Moderately salt tolerant. Shade tolerance medium, index 5.8 (Hightshoe 1988).
Notes: Buds, flowers, seeds and twigs eaten by birds and mammals (Martin et al. 1951). Squirrels eat and bury seeds (Gargiullo personal observation). Trees are attacked by numerous fungi including: Verticillium albo-atrum, soil dwelling Verticillium wilt disease (Evans 2007); Gloeosporium spp., anthracnose; and Cristulariella depraedens, gray-mold spot (Burns and Honkala 1990). Silver maple is a preferred host of Pulvinaria innumerabilis, the cottony maple scale (Homoptera, Coccidae). These are one of the largest scale insects at about 0.6 cm diameter. Females are dark, flattened, rather bluntly 3-sided, but carry their white, cottony egg masses attached to their posterior end. Large populations can cover the undersides if twigs and branches like popcorn. In early summer juvenile scale migrate to leaves where they feed on sap. Large infestations can cause dieback of young stems. Populations are controlled by parasitic wasps and flies and by lady beetles. Cottony maple scale resembles cottony maple leaf scale Pulvinaria acericola, which produces cottony egg sacs on leaves rather than on branches (Borror and White 1970; Burns and Honkala 1990; Johnson and Lyon 1991; Wayne et al. 1987). A host tree of the Asian longhorn beetle, Anoplophora glabripennis (see Norway maple).