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Trees of Iowa: An Interactive Key

Maples

The Maples are among our most important timber trees.  Five species are found growing native in Iowa: boxelder, mountain maple, black maple, sugar maple, and silver maple.  The silver maple is the most common, and was used widely by the early settlers for planting in groves about their farmsteads.   Red maple  is widely planted as an ornamental and may be native in Allamakee County.

Hardiness: Maples vary in hardiness. Most fall into zones 4 through 8, but some are less tolerant of cold or heat than others. When selecting a maple tree, be sure to select a species suited for Iowa’s weather.

Growth Rate: Maples vary in growth rate. Maples that are fast growing tend to have weak wood and may suffer from wind and ice damage. Slower growing maples have heavier, harder wood, making them less susceptible to branch and limb drop.

Mature Shape: Maples typically have a large, rounded crown. Tree canopies may be very dense or wide spreading.

Height: Mature height varies with species.

Width: Width varies with species.

Site Requirements: Maple trees perform best in moist, well-drained soils. Site requirements vary with the species of maple.


Hard Maples

Hard maple is one of Iowa's important commercial species as well as one of the most spectacular trees for beauty and fall color. Hard maple is characterized by having opposite, simple leaves, 3-6" long with 3-5 lobes. The leaf margin is mostly entire with only 1-2 pairs of teeth per lobe. The leaves are dull, dark green on the upper surface and lighter, yellow green below.

Winter twigs are moderate in diameter, light brown to orange brown in color, often with a pale waxy coating. The leaf scars are V-shaped, with 3 visible bundle scars. The buds are long and sharp pointed, cone-shaped, 3/16-1/4 inch long and gray-brown in color. The secondary buds are only about 1/2 as long as the terminal buds. The flowers of hard maple are 1/4 inch long, greenish yellow, born on clusters 1-3" in length, occurring before the leaves appear in the early spring. The fruit is a samara, 1-1 3/4" long, horseshoe shaped with nearly parallel or slightly divergent wings, maturing in September and October.

Hard maple consist of two species; sugar maple (var. saccharum) has deeply lobed 5-lobed leaves with several pairs of sharp teeth and pale lower surfaces. It occurs in eastern Iowa. Black maple (var. nigrum) is characterized by having shallowly 3-lobed leaves with drooping sides, nearly entire margins. It is the only hard maple found in western Iowa. They intergrade so freely that individuals, often cannot be distinguished even with the leaves.

Hard maples are very tolerant, slow growing, long lived with a wide-spreading lateral root system. They occur naturally on a wide variety of sites, but prefer well drained, cool moist locations such as sheltered slopes facing to the north and east. Their common associates include basswood and red oak. Because of their tolerance to shade, they are often a primary understory component of Iowa's upland woodlands. 

Hard maples are a major contributor to Iowa's outstanding fall color. Colors vary from deep shades of orange, red and golden yellow. Hard maples also have great utility for urban and community planting. Because of its slower growth rates, soft and Norway maples are planted more often, but they are less desirable than the hard maples as a long lasting, desirable shade or street tree. 

The wood of hard maple is hard, heavy and shock resistant, used for a variety of products including fine furniture, flooring, veneer, musical instruments, bowling pins, billiard cues, handles, bobbins, pallets and crates. In addition, hard maple is the preferred species for maple syrup production.