Can you identify a tree by its fall colors?
By ELAINE K. DELCUZE

Over the last three months a marked change has come over our mountains. Not only have there been more vehicles in the area bringing more tourists into mountain counties, but also the very colors of our mountains have changed.

This color change began many months ago. While you played in the summer sun, the trees were busy keeping you cool, their green leaves providing shade in the same moments they were using the sunlight to convert water and carbon dioxide into sugar (glucose). This process is called photosynthesis and its chemical elements produce chlorophyll. In Autumn when the light is less intense, days become shorter, nights become cooler and the photosynthesizing slows down, the chlorophyll is used up. Then, other colors appear in the leaves. Leaf color comes from pigments, natural substances produced by leaf cells and these pigments are chlorophyll (green), carotenoid ( brown, orange,and green), and anthocyanins (red).

Why do some color seasons seem more intense than others? Here in the southern Blue Ridge, our altitude (1000 to 4000 feet), temperature difference (10-16 degrees F) than other areas in Georgia, and annual rainfall ( 90 inches per year) all figure into our color equation. The best Autumn colors are produced when we experience a warm, wet spring, a mild summer with moderate rainfall, and a fall with warm sunny days and cool nights. Contrary to most thinking, an early frost is not needed to produce great color change. In fact an early frost can cause early leaf drop by triggering the connective tissue between leaf and branch, (the separation layer) to seal off the branch and the leaf to fall. In oaks, however, the separation layer never fully detaches from the branch and dead oak leaves remain all winter.

Also, an early killing frost may freeze the sap not only in the tender leaves but also the branches, causing permanent damage to the tree because the sealing process was not complete when the tree shed its dead plant tissue.

You have probably noticed the bright reds of sumac, dogwood, and sourwood occurring in mid-August andearly September this year. The sourwood (Oxydendrum arboreum), a popular honey tree has alternate, 2 to five inch leathery leaves and grows to a height rarely exceeding 40 feet. Its blooms occur in up-turnedsprays of bell-like flowers. This early changer is purported to be a thirst quencher if the leaves are chewed during a summer hike. Black gum (Nyssa sylvatica) is another early changer.

A medium-size tree, 30 to 40 feet high, it has oval leaves 2 to 6 inches long which turn a deep scarlet red. This tree is also known as the "sourgum" tree.

The scarlet oak (Quercus coccinea) is a major color producing tree of the Blue Ridge. A late turner, its bright red angular leaves with bristle tips often indicate the color peak here in the mountains. Atree of significant size, it usually grows to heights of 70 or more feet.

The chestnut oak (Quercus prinus) is a member of the white oak family. Its 5 to 9 inch leaves are irregularly waved along their margins and turn yellow before turning a deep yellow-brown in late fall. A popular construction lumber

tree its bark was significant to the early mountain tanning industry.

Acorns from the chestnut oak are produced annually and provide a major food for the gray squirrel.

A member of the magnolia family, the tulip poplar (Liriodenron tulipifera) now occupies the areas where

American chestnut (Castanea dentata) once grew. A nearly succession tree along with pines, the tulip poplar produces tulip-like blooms in mid-spring and vibrant yellow leaves in mid fall. Its 3 to 6 inch leaves are uniquely shaped and easily recognizable.

The American chestnut was once one of the largest and

tallest trees of the forest until it succumbed to an introduced blight 100 years ago. Stump growth and young sprouts of the chestnut still a brilliant yellow hue to our fall landscape.

One of the most varied and unusually shaped leaves to be found in the mountains is that belonging to the sassafrass tree (Sassafras albidum). Though a small tree and often shrub-like, the sassafrass produces

large leaves whose lobes vary in number from one to 4, but mostly resemble a 2- or 3- fingered mitten. A popular tea, sassafras was also used to flavor medicines and perfumes. Leaves were pulverized into apowder for use in thickening gumbo and soup. Look for this popular tree among the yellows and oranges in the fall landscape.

Some maples turn a vibrant red, orange, or yellow in the fall. The mountain maple (Acer montanum), red maple (A. rubrum) and sugar maple (A. saccharum) share this characteristic; whereas the silver maple (A.saccharinum) and striped maple (A.pensylvanicum) turn a bright clear yellow in the fall.

Together with the maples, the hickories, bitternut (Carya cordiformis), shagbark (C. ovata), pignut(C. glabra), and mockernut (C. tomentosa) are the most versatile trees of the

forest providing wood and tableproducts. Most hickories can be identified by their compound leaves, having 5 to 7 leaflets along the stem with the larger, broader leaflets at the leaf tip and smaller leaflets nearest the base. All hickories turn yellow during the fall season.

Perhaps one of the most unique trees of the higher elevations is the yellow birch (Betula lutea. Micheaux). Often more than 100 feet tall, its leaves are nearly oval, double toothed, and end in a sharppoint. Its exfoliating bark is a golden yellow and is a favorite food of many species of forest animals. Leaves of this northern tree turn yellow in the fall.

As the fall season moves down the mountains this year, consider the following tree facts cited by

American Forests:

In just 25 years, more than 60 percent of tree cover has

Been lost in the Atlanta region, and city temperatures

Are 6 to 10 degrees hotter in areas without trees;

The green infrastructure of trees and green space is

Critical for healthy and livable communities and a 40 per cent tree cover is recommended for most cities.

Enjoy this gift of colorchange this year both in your

immediate surroundings and in the vistas from your deck or auto. Also in planning your home landscape consider siting your home among trees, and if wild plants are in the path of your construction activities, call a member of the plant rescue team for advice or removal of the plants to a safe site or the public gardens. Plant rescue is a free service sponsored by the Preservation Committee of the Community Council, University of Georgia Mountain Research and Education Center, Blairsville. Contact Jennifer Cordier (706- 745-9317), Joyce Hall (706-781- 9816) or Glen Henderson (706- 745-1840).