People were invited to vote from a list of 21 candidates including the state trees of all 50 states and the District of Columbia. Voters were free to write in other choices, as well. From the beginning, the oak was the forerunner. The second choice was the redwood, followed by dogwood, maple, and pine.

Many reasons explain why the oak was chosen. According to the US National Arboretum, more than 90 species of oaks are native to the United States. In addition, there are many hybrids and some introduced from other countries. Nearly every state within the continental United has some type of oak that is native. Oaks are generally strong, long-lived trees that are an important part of ecosystems throughout the country. Also, many factories and industries depend on oaks for quality wood and wood products.

Two Major Groups

ImageOaks can be either red oaks or white oaks. Distinguishing between the two types is not as important for a homeowner choosing an oak for the landscape as it is for a builder selecting siding for a house. White oak is more resistant to rot, so an informed builder will choose it for outdoor applications such as boat building, exterior siding, and outdoor furniture. The wood of the red oak is lighter and has a more porous, open grain suitable for indoor applications, such as furniture. Image

A few easily observable differences will help distinguish between the two.

  • Leaves of white oak generally have rounded lobes, while those of red oak are pointed.
  • Acorns of the white oak are produced on the current season's growth and mature in six months while acorns of the red oak are produced on the previous season's growth and mature in 18 months.
  • Acorns of white oak taste sweet or slightly bitter and inside the shell is hairless.
  • Acorns of the red oak are very bitter and inside the shell is wooly.
  • The acorns of the white oak tend to be long and narrow while those of red oak are more fat and round.

Value to Wildlife

ImageOaks are a valuable resource for wildlife. More than 100 species of animals are known to depend on acorns for food. Such mammals as white-tailed deer, squirrels, mice, voles, rabbits, raccoons, opossums, gray foxes, red foxes and wild hogs consume them. Birds such as wild turkey, bobwhite quail, ducks, blue jays, crows, red-headed woodpeckers and others depend upon them. Twigs and foliage of the oak provide browse for deer and rabbits. Many insects feed on the leaves, and the oak is the larval plant of several species of moths as well as hairstreak butterflies. Predatory spiders and birds gather to feed on the bountiful diversity of insects found living upon the oak. The crown offers cover and nesting sites for birds and squirrels, and cavities in both living and dead trees provide den, nest, and roost sites for many birds and small mammals.

Fortunately for the animals, acorns are on the ground at a time when they are most needed. By fall most of the tender grasses, forbs, and plants that are eaten in spring and summer are but a memory. The high carbohydrate content of acorns supplies energy as animals prepare for the rigors of winter.

Invasive Oak TreeImage

Several years ago my brothers planted sawtooth oaks on their 1,000 acre Mississippi plot to attract whitetail deer. This Asian native (Quercus acutissima) produces heavy crops of acorns when they are as young as five years old. Little did my brothers and other land managers know that this oak would spread to crowd out native species on its march across the land. Because the sawtooth oak produces large numbers of acorns and the seedlings of the fast-growing oak are more aggressive than native oaks and other species, it is a successful competitor for resources. For this reason, it poses a threat to the native plant community. The sawtooth oak has invaded forests in many parts of the eastern United States.

Other Threats

Oak trees in the United States face other problems. Such diseases as sudden oak death (SOD) caused by the fungus Phytophthora ramorum, and oak wilt caused by the exotic fungus Ceratocystis fagacearum cause the demise of thousands of trees. Environmentalists caution that some of these diseases are spread by the ornamental horticulture industry on plants that carry the disease but do not die from them. Unfortunately, they can be the vector that spreads the disease to oak trees in all parts of the country.

Another cause of the spread of these diseases is the movement of firewood from one part of the country to another. Oak is a choice wood for burning in fireplaces and campfires. Campers often bring firewood with them into campgrounds and parks. We can help by leaving our firewood at home and purchasing new wood near to where it will be burned.

With so many different kinds of oaks and such a legacy of its use throughout the history of our country, it is not surprising that it was chosen as our national tree. Let's all vow to treasure and protect our native oaks in natural areas and on individual properties, for they are truly national treasures.

Famous Oaks

Salt River Ford Oak -used by Abraham Lincoln as a marker in crossing a river near Homer, Illinois

Sunnybrook Oaks -Where Andrew Jackson took shelter on his way to the Battle of New Orleans

Richards White Oak - a landmark on a map used by William Penn in 1681

Live Oaks: wood used in the construction of "Old Ironsides," the USS Constitution, a military ship that could repel British cannonballs

Charter Oak in Hartford, CT - reportedly a cavity within the tree was a hiding place for the Constitution charter in 1687; after being blown down in a violent storm a chair was made that is now displayed in the Hartford Capitol Building


Picture Credits:

Jeff Beck: Live Oak (Quercus virginiana) thumbnail, and southern red oak (Quercus falcata) (Dave's Garden)

Riversandbar: Quercus lyrata (Dave's Garden)

ADK Spirit: Live Oak tree (Dave's Garden)

Charter Oak, Wikipedia: U.S. Government, Public Domain

Sawtooth Oak:, Public Domain