A live oak (Quercus virginiana) is the sumo wrestler of the oak world. Its short massive trunk branches widely into mighty branches that seem to rest their elbows on the ground. Picturesque and impressive, live oaks grow up to 80 feet tall, with a branch spread equal to or greater that the height. Many people mistake live oak for evergreens, since they hold their dark, waxy leaves all winter and lose them only as new leaves emerge in the spring. The tree is native to the coastal plains of the East Coast.
Mark a spot on the tree about 4 to 5 feet from the ground by leaning a stick up against it. If the tree burls in that area -- if it becomes bulbous -- find a spot above or below the swell where the tree trunk returns to its normal lines.
Measure the circumference of the tree trunk at that spot. Be sure the tape measure runs evenly around the tree and does not lift up on one side or the other, which would give a false reading.
Calculate the diameter of the tree. Use your calculator to divide the circumference measurement, expressed in inches, by pi: 3.1416.
Use the following formula to figure out the age. The first 10 inches in diameter indicate an age of 76 years. Each inch after that adds six-and-a-half years up to age 154. After that, each inch adds six years.