Home A - Z FAQ Online Library Discussion Forum Muir Weather Maps About Search
Online Library: Title Author California Geology History Indians Muir Mountaineering Nature Management

Next: California LaurelContentsPrevious: Quaking Aspen

Trees of Yosemite (1932, 1948) by Mary Curry Tresidder


Big-Leaf Maple

Acer macrophyllum Pursh.

Big-Leaf Maple Branch. About 1/2 Natural Size
Big-Leaf Maple Branch
About 1/2 Natural Size

This maple is known as the Broad-Leaf or Big-Leaf Maple, Oregon Maple, or Water Maple—this last from its preference for moisture-filled ground.

It is a beautiful tree. The trunk of the sapling is smooth, pale, gray-green; as it grows older, the bark becomes scaly and somewhat ridged and turns to a darker gray, sometimes tinged with reddish-brown, but it is always a comparatively thin layer. The shaft is from one to two and a half feet in diameter at the base, tapering off quite rapidly, often with several shoots forming one broad, rounded crown, when the tree grows in a fairly open place, but with a narrower top when in the thick forest.

The leaves, as the name implies, are large—six to fourteen inches wide. They are cut into five lobes by deep indentation, with a rather wavy margin. In color they are yellowish-green, shiny above, pale and dull beneath, with stems six to ten inches in length. In autumn the leaves turn a clear yellow, sometimes tinged faintly with russet, before they fall.

In late spring the pale yellow flowers hang in great drooping clusters, before the leaves unfold. They become tawny as they ripen. They depend on insects for their fertilization, and for the distribution of their fruit on wind, flood waters, or animals. The flowers are not often perfectly bi-sexual. Sometimes they occur on separate trees, sometimes on the same. The fruit is a pair of one-winged seeds, or samaras.

Fine specimens of this maple are scattered throughout the floor of the Yosemite Valley, and are easily distinguished by their leaves and flower-clusters. The talus slope below Glacier Point, particularly in the neighborhood of the old spring west of Happy Isles, along the banks of the Merced at frequent intervals, and along Tenaya Creek are a few of their local habitations.

The Dwarf Maple (Acer glabrum Torr.) occurs on trails above the Valley, such as near Clark’s Point and on the Four-Mile Trail, but it is a shrub rather than a tree.



Next: California LaurelContentsPrevious: Quaking Aspen

Home A - Z FAQ Online Library Discussion Forum Muir Weather Maps About Search
Online Library: Title Author California Geology History Indians Muir Mountaineering Nature Management

http://www.yosemite.ca.us/library/trees_of_yosemite/big-leaf_maple.html