<< Back 9/4/02 Dry conditions should lead to bright fall colors, expert says SMN Dry weather conditions across most of North Carolina during the spring and summer should translate into an explosion of bright fall colors in the central parts of the state and brilliant but spotty colors in the mountains of the west. That’s the word from J. Dan Pittillo, the Western Carolina University biology professor who has been tagged “the Alan Greenspan of fall foliage forecasting.” Pittillo, a specialist in Appalachian plant ecology who has become a sought-after expert for his yearly predictions of the quality and intensity of the fall color season in Western North Carolina, bases his forecast on a variety of factors, including the amount of rainfall received during vegetation’s prime growing season of the warm-weather months. It’s his theory that the best fall color is seen after summers with below-average rainfall, when plant growth is stunted by a lack of sufficient water. Although much of WNC remains under drought conditions in terms of the overall water table, the area has received adequate amounts of precipitation to facilitate plant growth, he said. “It has been my observation that when droughts occur in the early part of the growing season, brilliant fall foliage color follows in late September to mid-October,” Pittillo said. “Much of North Carolina has been affected by drought during the growing season this year and should have a brilliant fall color leaf display — especially the area between Charlotte and the Raleigh area.” Most of the mountain area has had low rainfall in recent weeks, but adequate amounts of precipitation during the growing season. “For the western part of the state, this pattern suggests that there will be spotty fall color, with some locations displaying more brilliance than others,” Pittillo said. Development of foliage color is a complicated process, he said. Environmental stresses, including precipitation amounts and temperature extremes, are primary factors that determine the intensity of the fall color show. The biological process that results in the bright hues of fall is already under way. Cooler nighttime temperatures and the change in the intensity of sunlight as summer gives way to autumn contribute to the environmental stresses that induce the decomposition of chlorophyll, the chemical that gives leaves their green color in spring and summer. As chlorophyll breaks down, other pigments — always present in the leaves, but masked by the green of chlorophyll — are revealed. Predicting the quality of the fall color season is an inexact science, Pittillo is quick to disclaim, as changing weather conditions may still impact vegetation. “If there are early freezes, with temperatures below about 28 degrees Fahrenheit, colors can be quite dull, with dry green or brown leaves,” he said. “If there is too little moisture for a given tree, as often is noted in shallow soils near rock outcroppings, the leaves often turn brown.” Mother Nature’s color show will begin first in the higher elevations of the northwestern sections of North Carolina, probably in early October, and progress southward and down slopes through mid-October and early November. Yellow birches, red sourwoods, red and yellow maples, yellow pin cherries and yellow poplars will be the first colors to show, Pittillo said. They will be followed by the yellow and red of oaks and sweet gums, yellow of hickories, yellow and brown of beeches, and a myriad of other colors in the vines, shrubs and understory trees. Wildflowers always add to the color mix, Pittillo said, with white and blue asters, yellow goldenrods and royal purple ironweeds among the most prominent blooms of fall.