A trio of living fossils.

In these days of cultivars and hybrids, it's important to appreciate nature's unadulterated artistry. Dawn redwood, ginkgo, and sweetgum are among the remarkable tree species that have outlived dinosaurs, survived the Ice Age, and remain unchanged to this day. Call them living fossils.

SWEETGUM

Today there are three existing species of Liquidambar: one in Formosa, one in Turkey, and one native to America. We know of 20 extinct species, the oldest from the Upper Eocene rocks of Greenland, in. an age when that continent had a subtropical climate, some 55 million years ago. The fossilized sap from sweetgum trees, containing ancient and extinct insects, is prized as amber.

Liquidambar styraciflua's Latin name, which translates to liquid amber, and common name both refer to the aromatic resin that comes from the tree's bruised stems. The tree is known by a variety of names--gum ball tree, red gum, star-leafed gum, alligator wood, and gum tree--most pertaining to the prickly balls it produces.

Sweetgums have hard wood, which makes them wind-resistant and popular as a source of wood for furniture making. When young, the trees add between one and four feet to their height yearly; the trees generally are considered slow to medium growers. The canopy changes from conical to pyramidal as the trees age. Mature trees are generally between 60 and 76 feet tall and 40 to 50 feet wide.

Sweetgums have glossy leaves whose lobes resemble a five-pointed star. Four to seven inches across and growing alternately on stems, the leaves turn red, purple, or bright orange before dropping in the fall. The color does not depend on the temperature, as with other trees. Sweetgum is hardly in zones 5 to 9.

Spring flowers give way to those gum balls, woody balls covered with curved spines and containing one or two winged seeds. Green turning to tan-brown, they hang on long stems and are about an inch in diameter. Trees less than 15 or 20 years old don't usually produce flowers or gum balls.

The trees, which have a wide, shallow root system, like to stay put once planted, so think carefully before putting yours in the ground. And be sure to buy a tree that came from seed grown in your planting zone. That's because sweetgums have adapted to live in both cool and warm climates; make sure yours is adapted for the area where you live.

Sweetgums tolerate heat and drought, but need water in dry spells because they're native to riverbanks and swampy bottomlands. Plant your tree in full sun and any soil that's slightly acidic, rich in organic material, and well drained.

DAWN REDWOOD

Metasequoia glyptostroboides is a deciduous tree related to the sequoia. Now native only to China, the dawn redwood was the most common sequoia in North America during prehistoric times. The dawn redwood was first discovered, described, and named from fossils found in Japan in the 1800s; the fossil plants were estimated to be 50 million years old.

In 1941, a Chinese botanist discovered living specimens in central China near the Yangtze River, where local inhabitants called the tree shui-sha (water fir). Since 1948, when seeds were obtained by the Arnold Arboretum in Massachusetts, the dawn redwood has been introduced to temperate regions on other continents, where it is grown as an ornamental and a street tree.

Also known as a water larch, dawn redwood grows in a pyramidal shape, reaching a height of 70-100 feet and a width of 20-25 feet. The tree is fast-growing. Needles are opposite one another and about a half-inch long. The upper surfaces are bright green, the lower ones a lighter green that turns copper to brown in the fall. Dawn redwood is hardy in zones 5 through 8.

The tree bears both male and female flowers on the same tree, with male flowers appearing as clusters at branch ends; these eventually become cones that hang in groups and ripen in early December.

Dawn redwood requires full sun and loves moist, deep, well-drained slightly acidic soils. The species is relatively free of disease and insect problems but can be attacked by spider mites if planted in dry soil.

GINKGO

Ginkgo biloba is considered a true "living fossil." The gingko family reached its development peak in the Triassic and Jurassic eras, then went the way of the dinosaur as the Ice Age eliminated all but the Ginkgo biloba from the western hemisphere.

The word ginkgo comes from the Japanese word "ginkyo," which means silver apricot, a reference to the tree's fruit, which is popular in Japan.

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The first ginkgo tree recorded in America was brought from England in 1784 and planted near Philadelphia. China has some ancient ginkgos, including one thought to be 3,500 years old. In 1914, a ginkgo was found growing naturally in China's Chekiang province. It is believed to have been saved from extinction by Buddhist monks who considered it sacred.

Today ginkgos are known for the medicinal qualities they are thought to provide. Ginkgo biloba pills are touted for improving memory and mental clarity. Gingko is also known for its antioxidant value; small doses of ginkgo extract can be found in many vitamin and mineral supplements.

The tree's shape can range from broad to columnar; usually 50 to 80 feet tall, the trees can grow to 100 feet and from 30 to 40 feet wide. They are prized for their fan-shaped leaves, which turn from green to bright yellow or golden in autumn, but drop quickly.

Male and female flowers are carried on separate trees. The trees do not flower until they are at least 20 years old, when they produce green flowers. Males are preferred thanks to a smelly nut produced by females in the fall. Ginkgos bloom at night and drop the blossoms rapidly, a fact not lost on ancient poets and sages.

The trees love the sun and prefer moist, well-drained soil rich in organic materials although it will tolerate soil ranging from sand to clay. The trees can grow on either coast in zones 4 to 9. Male trees make a popular urban street tree because they are slow-growing and able to tolerate urban life including drought and reflected heat. Also, their root system does not damage sidewalks and driveways.

NATIONAL CHAMP SWEETGUM

Location: near Perfection, N. Carolina

Circumference at 4.5 ft.: 278 in.

Height: 136 ft.

Crown spread: 66 ft.

Total points: 431

Nominators: H.E. Bremer, B. Tate, S. Newcombe

The National Register of Big Trees is sponsored by The Davey Tree Expert Company.

RELATED ARTICLE: PREHISTORIC BEINGS FOR YOUR YARD

The Longwood Gardens Dawn Redwood

More than 300 years ago Lenni Lenape tribes hunted, fished, and farmed the wilderness that would become Longwood Gardens in Philadelphia. A Quaker family named Peirce purchased the land from William Penn in 1700 and established a working farm, according to Longwood Gardens.

Joshua and Samuel Peirce began planting an arboretum in 1798, Longwood's website says, and by 1850, the site was known "as one of the finest collections of trees in the nation."

Pierre duPont purchased the farm in 1906 and from 1907 until the 1930s established much of what is there today. In 1946 Longwood Gardens was turned over to a foundation.

A towering dawn redwood, planted in the 1940s, graces the Garden's oak and conifer knoll. Its descendants are propagated at the Historic Tree Nursery.

The Truman's Walk Ginkgo

Harry Truman particularly admired a neighbor's ginkgo tree and in taking his daily constitutional made sure to pass beneath the tree's stunning foliage.

Independence, Missouri, has recognized the tree's relationship to the 33rd president and marked its location on a historic walking tour of the city. Annual cuttings from the Truman's Walk Ginkgo are sent to the Historic Tree Nursery, ensuring male offspring trees. That's because the female ginkgos produce fruit with a noxious odor.

Elvis Presley's Sweetgum

Elvis Aaron Presley was born on January 8, 1935, in Tupelo, Mississippi. Exposed to gospel music while attending Pentecostal churches; Elvis also listened to blues and country-western. When the family moved to Memphis, Tennessee, in 1948, Elvis discovered black blues music.

Shortly after high school he began recording for Sun Records and then RCA. Songs like "Hound Dog" and "Don't Be Cruel" launched his stardom.

In March 1957 Elvis purchased Graceland mansion in Memphis, and moved in with his parents and paternal grandmother. At the Historic Tree Nursery, Elvis Presley Sweetgum trees are grown from seeds collected at Graceland.

--Susan Corbett

The information in this story is compiled from The Tree Book by Jeff Meyer, with permission from Simon & Schuster.