Maples (Acer ssp.) are some of the most beautiful and familiar trees in the world. In most places, they are an inescapable component of the natural world.
Maples grow in parks and backyards across the globe, provide delicious sap to coat waffles and yield the wood used to make furniture, floors, guitars and baseball bats.
But more than that, maples play important roles in almost every forest which they help to comprise; providing shelter, food and a yearly tithe to the leaf litter below.
Description
Maples are small to large trees, averaging less than 10 feet in height in some species to well over 100 feet for some others. Although the leaves, growth form, size and environmental preferences vary from one species to the next, most maples have a set of common characteristics. For example, all maples bear alternately arranged leaves, most of which feature palmate leaf veins.
Most maples are monoecious trees, meaning that most individuals bear both male and female flowers. The flowers typically appear early, often before the leaves have erupted. Maple flowers are small, but because the trees tend to produce so many flowers, the overall look of a blooming maple is often quite striking. A short time after flowering, maples produce double-seeds called samaras. These are the familiar “helicopters” seen falling slowly from the trees and littering the sidewalks below.
Diversity
Botanists recognize between 120 and 130 extant maple species. Some are widespread and common, while others are rare or even endangered. Most species live in the Northern Hemisphere; they are best represented in Asia, but they are also native to North America, Europe and North Africa.
A few of the noteworthy species include:
Native to much of Eastern Europe and Western Asia, Norway maples (Acer platanoides) are one of the most widely planted maple species in the world, although they are now regarded as invasive species in some locations. Norway maples rapidly colonize open areas, and once established they tend to inhibit the growth of nearby plants.
Box elders (Acer negundo) are weedy, short-lived maples, who are noteworthy for their ash-like leaves. In fact, because of their pinnately compound leaves, box elders are occasionally called ash-leaf maples. Although primarily confined to the eastern United States, box elders also grow in portions of northern California. Box elders are one of the few maple species to be dioecious and bear either male or female flowers, not both.
Japanese maples (Acer palmatum) are an important horticultural species, widely planted around the world. Japanese maples are widely prized for their elegant form, attractive foliage and small size, but they also require patience, as they are relatively slow growers. Horticulturists have produced more than 1,000 cultivars, with varying foliage and growth characteristics.
Sugar maples (Acer saccharum) are large maples, native to the northeastern United States (scattered individuals are found as far south as Georgia). Most commonly known for their contribution to the maple syrup industry, sugar maples are also attractive trees, planted as ornamentals. Sugar maples often form pure stands, and they represent an incredibly important resource for their resident wildlife.
Bigleaf maples (Acer macrophyllum) are one of the few maple species native to California. Like many California natives, bigleaf maples are rather drought tolerant after becoming established. Bigleaf maples are rather small trees, although large individuals may reach about 50 feet in height (a few records of 100-foot trees also exist, but such giants are rare). The species’ namesake leaves may reach up to 1 foot in diameter.
Native to Asia, paperbark maples (Acer griseum) bear a very attractive peeling bark. The bark is usually orange or orange-red in color, and provides a striking contrast in the winter, after the trees have shed their leaves. Paperbark maples are rather small trees, averaging about 20 to 30 feet in height.