Vine maple autumn.
The first hint comes on a crisp morning in midSeptember when I stand on my deck and look toward Mount jefferson, 50 miles distant. I can smell the change in the air and hear it overhead, and I know that soon the vine maple will come into its own.
The cool weather is causing the buildup of a hormone that stops the flow of sap in the vine maples and cuts off their production of chlorophyll. The pigments previously masked will soon begin to dominate. The leaves start out as a medium green and then turn, stage by stage, from pastel green to pastel yellow, bright yellow, orange, magenta, red, and purple. Not all go through every stage, but often a single tree sports three or four distinctly different colors. It may have red, orange, gold, and green leaves, all at the same time.
Just why the vine maple produces such brilliant hues is a mystery. Big differences in fall colors exist within the same species, according to Stanley Krugman, director of timber management research for the U.S. Forest Service. A case in point is the silver maple. Unlike its western cousin, the silver maple produces virtually no fall colors. "With the silver maple, the rate of decay is so rapid that the other pigments don't have a chance to come out, " says Krugman. "But some trees just have a greater abundance of secondary pigments. Evidence exists for each of these theories. "
Every year my wife and I set aside the first two weekends of October so that we can head up into the Cascades and feed our souls with this marvelous display. The vine maple, Acer circinatum, is found mixed with conifers on the western side of the Cascade Range from British Columbia south to northern California. The tree is hardly noticeable until it blazes forth gold and red against that blue October sky. Most of the brightly colored foliage you see along the mountain roads is courtesy of the vine maple.
Vilified with the name bois du diable by the early French for its devilish habit of tripping unwary river travelers during portages, the vine maple earned no love from loggers either. Despite its splendid fall show, the lumbermen cursed it for the way its slender, weak stems often sprawl along the ground, winding over and under logs like a vine-hence its name-or a running lasso, as one naturalist described it. Sometimes, said another, the prone tree is so covered with forest litter "that its existence is not suspected until its narrow crown is stumbled over in the tangle." More reason for its name.
Classified as a tree, the vine maple in many cases more closely resembles a shrub because it often has several principal trunks, sometimes only a half-inch in diameter and seldom more than five inches. The height averages six to 12 feet and rarely exceeds 20 feet.
A hardy tree, the vine maple is not particular about its habitat. It grows profusely along highways and the shady banks of streams, on sunny hillsides, and even amid volcanic lava flows. But even where it grows in what appears to be an impossibly dry place, some source of water is always present.
I usually notice the first show of color near the mountain passes, at an elevation of 3,500 to 4,500 feet, in midSeptember. As the season progresses, the color moves down Mount jefferson until the change peaks the first two weeks of October. All told, the vine maple puts on its show for a month to six weeks.
Several things affect the timing and brilliance. Drier soil produces earlier color, as does soil with low fertility-within the tree's tolerances. A cold fall speeds up the change, and direct sunlight generates leaves with brighter hues than achieved by those in shade.
Loggers consider the vine maple a weed tree. The wood is tough and close-grained but checks badly. The Indians used the young spring shoots for weaving and called it the "basket tree." They employed its slender branches to construct scoop nets for taking salmon.
Because it has never been a commercial species, the vine maple has not been studied extensively. We have no evidence whether it is sensitive to air pollution, for example. The Forest Service's director for pest management in Oregon, William Ciesla, points out that we also know little about other stresses. "There are an array of insects that feed on the vine maple and diseases that work on it," says Ciesla, "but there are no serious problems to our knowledge. It is not listed as a host species in the USDA's Western Forest Insects. "
The vine maple may hold no allure for the lumberman or the scientist. But when it comes to autumn, for me the vine maple says it all.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||tree profile|
|Date:||Sep 1, 1989|
|Previous Article:||Tailgate troubleshooting.|
|Next Article:||Trees and your health.|