The tasty Pecan. (In Profile).

Whether you pronounce it "pih KAHN" or prefer "PEE kan" the pecan tree (Carya illinoensis) is about as American as a tree can get. Archeological evidence shows native Americans in the area of Texas used pecans more than 8,000 years ago. The name comes from the Algonquin word "pacane" meaning "nut so hard as to require a stone to crack."

Pecans are native only in the United States, and crows may have contributed to their selection and distribution by carrying the thin-shelled nuts over several miles. George Washington had pecans at Mount Vernon and, not to he outdone, gardener and connoisseur Thomas Jefferson had several trees imported from Louisiana for his orchards at Monticello.

The pecan is a member of the Juglandaceae family, as is the walnut, but it is more closely related to hickories than to walnuts. Leaves and fruits contain the allelopathic juglone, which means they contain substances that are toxic to some other plants. Many plants will not grow in soil with juglone in it; especially tomatoes and other members of the nightshade family. Be sure not to use pecan leaves or shells as mulch in the vegetable garden.

The pecan is found naturally in alluvial soils and bottomlands of the lower Mississippi River and its tributaries, as well as other riverbottoms throughout its range, especially in Texas. Pecans and other hardwoods occur naturally in those bottomlands, but if they comprise more than 50 percent of the native forest biomass, the area is classified as a climax pecan forest. Established climax pecan forests became the first commercial pecan production groves in the mid-1800s.

SPACE TO GROW

When given sufficient space to grow, the pecan can soar to 100 to 120 feet, a large deciduous tree with an upright, vase-shaped crown. The trunk diameter can reach 3 to 4 feet. It tends to have a relatively short, bare trunk before its many forked branches appear. The national champion pecan resides in Weatherford, Texas, boasting a height of 91 feet, a crown spread of 120 feet, and a circumference of 257 inches.

There's no guarantee, of course, that your pecan tree will grow that big, but give it the best chance possible by trying to imitate the soil conditions found in river bottomlands. Pecans needs deep, well-drained soil with a good steady source of water. A mature pecan can require more than 2,000 gallons of water a week, That does not mean, however, that it likes wet, boggy soil--it does not. The soil must drain well for the tree to thrive.

Pecans have dark yellow-green leaves that are smooth to slightly hairy on top. The color pales slightly on the underside. The alternate, compound leaves are in clusters 12 to 20 inches long with nine to 17 leaflets that are 3 to 8 inches long and 1 to 2 inches wide.

The tree's flower goes unnoticed by most people. That's because the female flower is a small terminal spike on the end of the current season's growth. The pollen needed to turn these flowers into pecan nuts comes from the male flowers or "catkins," 5- to 6-inch pendulous spikes growing laterally on year-old wood.

Pollination is made more difficult by the fact that a tree's male and female flowers are usually not in bloom at the same time. Some varieties shed pollen from the male catkins before the female flowers are receptive, and so require pollen from another variety with a later pollen maturation date.

Pecan nuts grow in clusters of 3 to 11 with thin husks that split into four sections, often staying on the tree after the nut has fallen, The nut is light reddish-brown with irregular black or darker-brown blotches. Pecans in the shell are 1 to 2 inches long, with a large embryo composed mostly of two very tasty kernels separated by a thin, papery central plate.

For the record, it takes 1 to 1 1/2 cups of pecans to make a 9-inch pecan pie. There is clearly no agreement nationwide as to which is best in a pecan pie: whole pecans or chopped ones.

IN YOUR BACK YARD

The pecan makes a magnificent standalone shade tree in any home landscape that's situated in zones 6 through 9 and is large enough to accommodate the tree. Throughout the South, Carya illinoensis can be found in most nurseries and garden centers that sell trees. The newer varieties produce what are called "papershell" pecans--a thin shell you can break with your fingers and that contains nut meat much larger than that from native trees.

Most varieties grown for home use begin to produce some nuts in about three years--enough, at least, for that first pecan pie. Once established, a tree will average about 20 pounds of pecans in shell per year, but with good management and growing conditions that can increase to 70 or even 100 pounds per tree.

Plant and care for your pecan in the same manner that you would any large shade tree. The biggest mistake homeowners make is not giving the tree enough room. In a yard, pecans should be planted at least 60 to 80 feet from any other tree or structure. Its massive root system reaches out a good distance past its drip line.

NUTS, NUTS, NUTS

For 150 years growers have managed and harvested nuts from pecan groves found throughout the tree's native territory. New native groves are sometimes planted from seedlings grown from nuts. A native grove can have 30 trees per acre (trunks up to 13 inches in diameter), but as they grow that number can be thinned down to 10 trees with trunks greater than 20 inches.

Nuts from native trees are small but have excellent flavor and so retain their value in the marketplace. Yields from a well-managed native grove can average about 600 pounds per acre; in fact, yields of 1,000 pounds per acre are not that unusual.

About 100 years ago, breeding and grafting techniques designed to help growers improve quality resulted in varieties that produce more nuts and nuts with a greater percentage of meat. These are planted in pecan "orchards." There are hundreds of pecan cultivars available today, but only a few dozen make up the commercial industry. Sometimes these improved varieties are grafted onto native rootstock, but just as often the breeding process produces new, improved rootstock.

Pecan trees planted in orchards can start at about 30 trees per acre and over time be thinned down to seven. New orchards can begin harvesting pecans about four to six years after transplanting, although maximum yields may not be achieved for 10 years or more. Starting a brand new pecan orchard takes some serious patience and major financial security, but it does pay off. Orchard yields generally range from 800 to 1,200 pounds per acre but can reach as high as 2,500 pounds.

Because pecans require well over 200 frost-free days for nuts to reach maturity, pecan production in the United States is restricted pretty much to southern states and California, those that fall within growing Zones 6 to 9.

The top five pecan producers, including both native and improved stock, are Georgia, Texas, New Mexico, Arizona, and Louisiana. Homeowners can grow pecans up into Maryland, and some of the more adventurous are known to grow pecans as far north as Wisconsin in very protected settings.

HARVESTING PECANS

Pecans are usually harvested from mid-October through November when the shuck loosens from the shell or splits. The trees in commercial production are harvested with trunk or limb shakers that literally shake the nuts off the tree to be collected by various means.

Homeowners usually use a long cane pole to whap the nuts down or find some 10-year-old kids willing to spend an entire afternoon throwing baseball gloves or old sneakers up into the tree to knock nuts down. That's how my mother got hickory nuts for cakes and cookies many years ago. Wait to pick up the nuts that fall to the ground naturally, and you're competing with the wiley squirrel--and may well lose.

Squirrels can be a real barrier to successful back yard pecan growing. It has been estimated that a single squirrel can consume about 50 pounds of pecans in a single season--the total production of two trees. Nuts can be stored in their shells for about four months at room temperature before becoming rancid. They'll last up to nine months in the refrigerator and a year or two when stored in the freezer.

PECAN WOOD AS LUMBER

Pecan and other hickory woods are rated as the number three hardwood group in the United States. It falls behind only black walnut and black cherry in terms of value. Carya illinoensis has close-grained, hard wood that is pale reddish-brown with occasional dark streaks.

Pecan is difficult to dry because its high moisture content leads to heavy shrinkage during the process, but once properly seasoned the wood is stable and reliable, You'll see pecan wood used for furniture, tool handles, skis, gymnastic bars, flooring material for gymnasiums and roller skating rinks, piano construction, and ladder rungs.

As a relative in the hickory family it is sometimes used for smoking meats and cheese.

The pecan is definitely an American institution; only about 15 percent of the crop is exported, and most of that goes to Canada. Why has Europe not embraced the pecan? Theories abound, but probably it is because the walnut found its place in the European diet centuries ago.

Consider, too, that pecans are big trees that require a lot of space, and that commodity is pretty uncommon in Europe. Adding another complication, the growing conditions required by pecans are scare there. Personally, I suspect that the pecan has not caught on in Europe because those deprived folks have not yet been exposed to pecan pie.

Next time you log onto the Internet, do a search for pecan pie recipes. Your search will turn up more than 1,000 different versions from as many as 10,000 hits. Looking for the best pecan pie recipe is akin to searching Texas for the best chili recipe. There is no such thing as a bad pecan pie...some just taste better than others. In my biased view, as long as there is pecan pie, there will be a thriving pecan industry in the United States.

Jeff Ball appears on NBC's "Today Show" as a gardening expert and writes online for yardener.com.

RELATED ARTICLE: THE NATIONAL CHAMP

Pecan (Carya illinoensis)

Location: Weatherford, Texas

Circumference at 4.5 feet: 257 in.

Height: 91 ft.

Crown spread: 120 feet

Total points: 378

Nominator: Billy & Lynn Finch

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