Oaks are a great landscape investment and a heritage planting. They represent things we revere in people: quiet strength, tenacious survival, patience, perseverance, long life and prodigious production.

These great trees can be fast- or slow-growing, massive or petite and colorful or evergreen. They're the tree treasures of Earth's northern hemisphere.

There are about 500 oak species worldwide. They grow in North Africa, Europe, Western Asia and North America. Even in places that don't have true oaks, like Australia, people have named many of their local trees oaks.

Oak (Quercus) is the largest genus of native trees in the United States, with 58 species. Of these, one is an exotic brought into the United States that is now reproducing in the wild.

The genus includes nine varieties, many hybrids and 10 shrubs. These oaks can be found almost anywhere in the United States. Georgia is blessed with 26 native species.

Most of the Georgia oaks share common names, but each has its own scientific name. For example, six Georgia oaks are called "water oak," three are known as "black oak" and four go by "swamp oak." Whether you call little oaks "scrub" and big oaks "red," the diversity of Georgia's native oaks is wonderful.

Unfortunately for landscapes, oaks aren't commercially propagated from vegetative cuttings. Almost all oaks on the market have been grown from seeds. And with seeds, you never know what you will get -- a hybrid, the requested species or something altogether different.

In a recent examination of the tree sections in some retail outlets, about 5 percent of the oaks were misidentified or were hybrids that looked greatly different from the labeled species. You can find unexpected treasures hidden among oaks for sale.

Here's a top-10 list of oaks for shade and street-tree plantings: white oak (Quercus alba), scarlet oak (Q. coccinea), Southern red oak (Q. falcata), Georgia oak (Q. georgiana), overcup oak (Q. lyrata), swamp chestnut oak (Q. michauxii), water oak (Q. nigra), willow oak (Q. phellos), Shumard oak (Q. shumardii) and live oak (Q. virginiana).

These trees will yield at least two human generations of good service, providing many values to the yard, landscape and street.

Everyone knows of an old, beat-up eyesore that's a menace. These old trees may be filled with mistletoe and have many large pruning and storm wounds.

But when you look at these trees, many of them oaks, remember that you're seeing the final days of an old tree's serviceable life. Many have survived despite neglect and abuse over almost a century. Other trees of less quality had to be taken down decades ago.

To get up close and touch any of these oaks, plus many more, visit the State Arboretum of Georgia near Braselton, Ga. Call (706) 654-2666 to arrange a visit.