Fall leaf color, from last year, along the Richard B. Russell Scenic Highway (Ga. 348), which begins just outside Helen in White County. The highway, one of Georgia’s prime fall leaf-watching routes, runs through the Chattahoochee National Forest and is part of the Russell-Brasstown Scenic Byway. PHOTO CREDIT: Charles Seabrook

Fall leaf color process begins in early summer

Peak time for North Georgia’s greatest natural spectacle, the annual fall leaf color bonanza, is nearly here.

Some species — sassafras, sourwood, sumac, yellow birch, dogwood, serviceberry — began sporting their vibrant hues a few weeks ago, a great warm-up for the main event. The premier show, featuring big hardwoods decked out in stunning shades of red, orange, yellow and magenta, is expected next week and into early November.

To help you get set for the show, here’s a brief primer gleaned from various sources:

• Fall leaf colors begin emerging when shorter days and longer nights signal trees to start shutting down chlorophyll production and prepare for winter. The process begins as early as June 21, the first day of summer and the longest day of the year. After that, the amount of daylight steadily declines until Dec. 21, the shortest day of the year and the first day of winter.

• Leaves use green chlorophyll with the help of sunlight to make food for tree growth. Chlorophyll, however, fades over time and must be constantly replenished by leaves. During the growing season, chlorophyll is the dominant pigment, masking the leaf’s other pigments. When chlorophyll production stops and a leaf’s remaining supplies are used up, the suppressed pigments are able to emerge and create fall‘s riot of colors.

• Unlike colorful wildflower blooms that lure insect pollinators, fall leaf colors have no known biological purpose.

• Some trees stick with one color during fall. Always yellow are the leaves of tulip poplars, hickories, birches and redbud. Others may change colors. Sugar maples, dogwoods, sweet gums and sourwoods are usually red but may turn yellow.

• North Georgia’s mountains get all the glory, but brilliant hues also adorn many South Georgia natural areas in fall; some can rival any mountain color, such as the steep slopes along the Flint River in Meriwether and Talbot counties.

IN THE SKY: From David Dundee, Tellus Science Museum astronomer: The moon will be first quarter on Friday night. Venus and Mars are low in the east just before dawn. Saturn is low in the southwest at dusk and sets a few hours later and will appear near the moon on Monday night. Mercury and Jupiter are not visible.