Originally published Monday, November 3, 2008 at 12:00 AM
Autumn's color is a walk, a drive or a click away
There's still time to catch fall color — and identify the leaves while you're at it.
Daily Press (Newport News, Va
Where to find fall foliage
The U.S. Forest Service maintains an informative Web site (www.fs.fed.us/news/fallcolors) as well as the National Forest Fall Foliage Hotline for updated reports on leaf conditions: 800-354-4595 and follow the prompts.
The Weather Channel's Web site (www.weather.com/activities/driving/fallfoliage/) offers regional maps, conditions and photos.
Name that tree
Yellow leaves: Ash, birch, black cherry, black maple, black walnut, box elder, ginkgo, hackberry, hickory, larch, paw paw, redbud, tulip poplar
Orange: Bigleaf maple, Bradford pear, Korean mountain ash, silver maple, sugar maple, white oak
Red: Alder, black tupelo, dogwood, euonymus, fan-leafed maple, red chokeberry, red maple, sourwood (an early changer), sumac, sweet gum (changes colors at different times depending on soil and weather)
Brown: Beech (some yellow first, keeps brown leaves through winter), chestnut oak, elm, mountain maple, sycamore
Get ski and boarding conditions all winter long with webcams, snow alerts and more at seattletimes.com/snowsports
Glorious yellow, burnished orange, radiant red: The appearance of a rainbow of color in the area's foliage marks the shortening days and reduced daylight of fall. By happy coincidence, one triggers the other. Each year, as the sunlight retreats, the leaves on deciduous trees show their underlying character. Literally.
Leaves don't actually "turn" a different color in autumn; rather they shed their green cloak. The apparent color-changing process happens as chlorophyll, the chemical responsible for green growth, disappears with reduced daylight. Chlorophyll is the necessary component for photosynthesis, the process by which plants use sunlight to turn water and carbon dioxide into glucose.
The reduced hours of daylight, rather than the prevailing temperature, determine when the leaves start to reveal their fall colors. As the nights get longer, the cells at the juncture of the leaf and stem divide rapidly and start to block the nutrients and moisture from the roots reaching the leaves. Once the food supply is cut off, the leaves' underlying tones of yellow and orange are then revealed. In this process, each leaf changes color individually, which accounts for how a tree may have uneven patches of color. What the viewer is observing is actually the absence of green.
The different colors are determined by the different chemicals inherent in each species. Brown leaves, for example, are the result of tannins in the leaves, and are typical of oaks. The orange of the bigleaf maple represents carotenoids in the system, the same chemical that colors carrots. Xanthophyll, an oxidized derivative of carotene, is responsible for the yellow pigment common to box elder, hickories, ginkgo, black maple, aspen and larch.
Only some of the bright reds and deep purples, typical of red maples, sweet gum and flowering dogwoods, are actually manufactured at this time of year by anthocyanin, which also colors plums and cranberries. Scientists have not solved the riddle of what purpose this process serves in old leaves though it appears to offer some protection from both ultraviolet rays and the frost and enables trees to keep their leaves longer.
The "leaf color flow" along the east coast of the United States actually follows a wave pattern, according to Kim Coder, professor of silvics at the University of Georgia. The wave starts in mid-September in the mountains of New England, first dominated by yellow, followed by a wave of orange, and finally red, all simultaneously moving downward and southward. When the three colors overlap, the effect is the most dramatic.
The best conditions for the brightest colors are when the growing season has ample moisture, thereby creating leaf volume, followed by a late summer that's moderately dry and an autumn with bright, sunny days and cool nights at around 40 degrees. Cloudy weather — which explains Europe's lack of fall splendor — and warm nights have the opposite effect and tend to bring drab colors. Both high winds and early frosts put an early end to the display of fall color.
Copyright © 2008 The Seattle Times Company
NEW - 7:51 PM
Special interest? There is a camp for that
Community sports & recreation datebook
Coho mark rates for sport fisheries down this year
How to tell it's time to throw out your shoes
Hope diminishing in search for missing skier

- Lakewood cop accused of embezzling $150K meant for slain officers' families
- 3 big health insurers stockpile $2.4 billion as rates keep rising
- Agency set to investigate handling of 911 call about Josh Powell
- Quick decisions: How Washington hired its new football staff
- Historic day for gay marriage as another fight looms
- Justin Wilcox's versatile defensive style is the right fit for Huskies | Jerry Brewer
- Social worker recounts minutes before Powell fire
- It's Terrence Time: Enigmatic Ross leads Huskies
- $25B settlement reached over foreclosure abuses
- Club promoter convicted in brutal 2010 murder of Des Moines prostitute
- Gay-marriage bill passes House, awaits Gregoire's signature
472 - Historic day for gay marriage as another fight looming
361 - Wanted in Seattle classrooms: more teachers of color
313 - 3 big health insurers stockpile $2.4 billion as rates keep rising
243 - Source: NY, California to sign mortgage settlement
231 - Council members get briefing on arena proposal, minus details
159 - Oregon live game thread
155 - Pac-12 picks ... including the UW game
140 - AP Source: Obama to change birth control rule
134 - Worker: Josh Powell told son he had 'surprise'
106
- State Medicaid program to stop paying for unneeded ER visits
- Wanted in Seattle classrooms: more teachers of color
- 3 big health insurers stockpile $2.4 billion as rates keep rising
- Economy, blogs give survivalists new reason to look to Northwest
- One man's audacious pursuit of sailing history
- State's share of mortgage settlement: $648 million
- Darren Berg gets 18-year sentence for Ponzi scheme
- $25B settlement reached over foreclosure abuses
- Bellevue College adds a third bachelor's degree program
- 'Gauguin and Polynesia': dazzling mix-and-match | Art review



