The best known of the fabulous four is the Fraser Fir. Its leaves are flat, soft to the touch, and produce a pleasant smelling resin. Because the leaves are soft, the trees are also known as “she-balsam.” This tree grows naturally at high elevations and, along with the Red Spruce, forms the dominant forest ecosystem on our mountaintops, the spruce-fir forest. A different species of fir, the Balsam Fir or Canada Balsam, grows farther to the north, but Fraser Fir is a specialist of the southern Appalachians. These trees have been severely affected by a combination of acid precipitation and the balsam woolly aphid. Most commercially grown trees must be heavily sprayed with chemicals to protect them from the aphids, and the most successful farms are in areas with only minor acid problems. Fir trees can be identified by cones that project upward from the limbs as well as by the soft foliage.

Red Spruce, on the other hand, has stiff, sharp-pointed needles with four sides. They’ll prick you if you run your hand along the limbs. As a result, my neighbors call them “he-balsams,” as contrasted to the soft “she-balsams,” or firs. The prickly trees are less popular for Christmas trees even though they are just as shapely. Red Spruce is the other native tree of the high-elevation spruce-fir forest. It, too, is susceptible to acid precipitation, but not to the aphid. The long spruce cones hang down from the limbs.

Eastern Hemlock is much more common in low elevation mountain coves and is more widespread. It occurs from the southern Appalachians all the way up into Canada. The low, spreading limbs are adapted to shed snow, and the trees are rarely damaged by it. The small, flattened leaves are soft and silvery, with two white stripes on their underside, and tiny cones hang pendulously from the branches. Hemlocks are rarely grown commercially for Christmas trees except for sale as live trees. Although they naturally attain a sweeping conical shape, with elegant, lacey foliage, they don’t retain their leaves for long after being cut. Another introduced aphid threatens these graceful and ecologically important native trees.

White pine is the most common pine tree in the southern Appalachians, although several species occur here. It is the only pine whose leaves occur in bundles of 5 (count W-H-I-T-E) instead of 2 or 3. Like the hemlock, it is widespread in the eastern USA and Canada. It produces a whorl of branches each year, and counting the whorls will give a good estimate of the tree’s age. On trees grown for Christmas trees, however, those whorls are usually so close together as to be obscured. Under natural conditions, white pines get to be very large trees, reaching 200 feet in height. They were the primary source of ship masts during colonial times, and trees marked with the King’s Cross were restricted to just that function. Today those giant trees are gone, and the soft wood is less valuable.

If you have a cut Christmas tree in your house this season, and wonder what to do with it in January, recycling your tree as wildlife habitat or mulch are options. For those with live trees, replanting is also a way to enjoy them for years to come.