Appendices & Glossary - Botanical Research Institute of Texas

1304 APPENDIX TWENTY-ONE/COMMERCIALLY IMPORTANT TIMBER TREES OF EAST TEXAS
ACER RUBRUM L. RED MAPLE
(ACERACEAE, MAPLE FAMILY)
Other Common Names: DRUMMOND RED MAPLE, TRIDENT RED MAPLE, SWAMP MAPLE, WATER MAPLE, SCARLET MAPLE, SOFT
MAPLE, CAROLINA RED MAPLE
Form and Size: medium to tall tree to 28+ m; trunk straight, to 1.5 m in diameter; crown narrow to broadly rounded.
Leaves: leaves deciduous, simple, opposite, 5–15 cm long, 3.5–10 cm wide, bright green above, pale or whitish and finely
hairy beneath, but turning vivid red, orange and yellow in autumn, 3–5 lobed, the spaces (= sinuses) between the main
lobes sharply angled or V-shaped, the lobes pointed at the tip, marginally coarsely singly or doubly toothed; petioles
slender, 5–10 cm long, smooth to slightly hairy, usually red.
Buds: 3–4 mm long, broadest near the base and rounded at the tip, covered with overlapping, dark red scales.
Flowers: flowers usually unisexual, the male and female flowers usually occurring on separate trees (plants dioecious),
sometimes with some perfect flowers (plants polygamo-dioecious) or with many-flowered clusters of male and female
flowers on the same tree; flowers appearing before the leaves develop, each flower on a slender stalk, reddish, with a 5lobed
calyx and 5 short (ca. 2 mm), inconspicuous petals; male flowers with 5–8 stamens; female flowers with a single
pistil.
Fruits: paired, one-seeded, winged samaras, dry, (12–)15–26 mm long, 6–12 mm wide, hanging on a slender stalk; wing red,
reddish-brown, or yellow, the wings spreading at a 50°–60° angle.
Bark: dark gray, thin to 1.4 cm thick, smooth at first, later developing shallow furrows and flat scaly plates or broad ridges.
Wood: sapwood white, wide; heartwood light brown, sometimes with a grayish or greenish tinge or with a faint purplish
cast; wood straight-grained (sometimes curly-grained), moderately heavy and hard; growth rings not very distinct; the
wood is known in the lumber industry as “soft maple” (in contrast to the term “hard maple” used for the wood of Acer
saccharum, sugar maple).
Habitat: most common in wet or swampy sites and low woods but also found on drier uplands.
Range: Pineywoods and eastern Post Oak Savannah, west in Red River drainage to Fannin Co., and in northern Gulf Prairies
and Marshes; widespread in the eastern U.S. and southern Canada.
Principal Uses: furniture, cabinet work, flooring, interior finish material, boxes, crates, veneers, gun stocks, woodenware,
pulpwood; burned in kilns to produce wood acetate and charcoal.
Historical Uses: plates, spinning wheels, spools and other turnery, feet for chairs and beds; pioneers made ink by adding
sulfate of iron to the tannin extracted from the bark.
Other Significant Information: Acer rubrum has something red about it in all seasons. In winter the buds are red; in spring
red flowers are present; in summer the leaf stalks are reddish; and in autumn the foliage turns crimson or wine red.
This brilliant fall foliage makes red maple extremely popular as an ornamental. The spring sap is sweet and can be
used like that of sugar maple for making syrup. However, red maple buds break dormancy earlier in the spring and the
chemical content of the sap soon changes, giving the syrup an undesirable flavor; thus there is a shorter tapping season.
The leaves and bark are poisonous to livestock. Ingestion can disrupt hemoglobin’s ability to bind oxygen, and at relatively
high doses death can result in as little as 18 hours. The specific toxins are not known, although it is thought that
tannins may be involved. Varieties are often recognized in this species; in var. rubrum the lower surface of the leaf
blades are glabrous or with hairs only along the veins, while in var. trilobum Torr. & A. Gray ex K. Koch and var.
drummondii (Hook. & Arn. ex Nutt.) Sarg. the lower surface of the leaf blades are densely and usually permanently
hairy; var. trilobum is differentiated by having 3-lobed leaf blades, the smaller lateral basal lobes suppressed, while var.
rubrum and var. drummondii have leaf blades usually with 5 lobes (the lateral basal lobes small).
Recognition in the Field: leaves simple, opposite, with 3–5 obvious, pointed, coarsely toothed lobes, the central lobe not narrowed
at base, the sinuses between the main lobes sharply angled or V-shaped; fruits paired, one-seeded, winged samaras
which eventually separate and function as wind-dispersed small “helicopters.”